Hydra forks not working correctly

Information on forks/springers/shocks
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51Hog
Posts: 664
Joined: Fri May 20, 2005 7:29 pm
Location: Wasilla, Alaska

Hydra forks not working correctly

#1

Post by 51Hog » Fri Jan 13, 2006 2:03 pm

Description: It doesn,t seem to have any rebound dampning. Is this typical of the Hydra Forks?

Post by 51Hog on May 20, 2005, 6:24pm

Just finished installing my new fork tubes. All internals are new and factory assembled---I did not look inside the tubes.
I installed them into the sliders with new seals and felts.
Added 7 oz of Harley fork oil per repair manual.
If I lock my front brake and push bike forward to compress forks, then let them rebound and pull back on the handle bars at the same time, when the forks reach their fully extended position, they bang or hit hard. It doesn,t seem to have any rebound dampning.
Is this typical of the Hydra Forks?
Do I have the correct amount of oil in them?
Unfortunately, I cannot road test as I am still waiting on a tranny gear that seems to be lost in the mail.

Post by fourthgear on May 21, 2005, 4:18pm

51Hog
There was a thread about that , not sure how long ago , theres a spacer thats not needed with the newer replacement parts , something along that line . I will check prior posts to see if its still around . Some one should remember .

Post by 51Hog on May 21, 2005, 5:46pm

I have been searching using different criteria but can,t find anything. I seem to remember seeing something a while back.

Post by VintageTwin on May 21, 2005, 6:00pm

Well, that might have been me. If you left the "spacer" in that may be the problem, or you have more than 0.004" between the tubes bottom circ-clip. First we're talking about stock length tubes and stock sliders on a '49-59 non-adjustable fork? Aftermarket? If so, it' shown in the '49-57 parts book. The spacer is 46045-49. It's not in the '58-68 parts book. My OEM tubes wouldn't work with this spacer. I also have a set of new AM forks, that have a ruined damper stud and a slightly galled knurled slider washer. I'm waiting for a knurled washer from http://nosparts.com/. The washer I need may be here today or Monday. I have one AM (aftermarket) leg with 7 oz. of oil in it. Doesn't leak. Ready to go. The other leg that leaks, I'll have to pull apart the tube to replace the damper. I'll investigate how they built the damper and we'll figure this out. The best way to remove the spring loaded tube cap, is to first remove the tube and slider assembly from the tree. Then, remove the tube from the slider and put the tube back in the lower tree, but install the tube with it's fork tube cap 2" below the bottom of the top tree, and tighten the pinch bolt. This way when you remove the fork tube cap it will pop-up and hit the top tree and stop. The tube cap won't travel far. The springs are only compressed about an inch and a half. Keep you fingers out of the way or you'll lose a little skin. The only way to drain the AM fork slider is to remove the damper nut and let the oil drain into a pie tin or or wide bowl. You can save the fluid this way, or dump the oil out once the tube is removed from the slider. Now that I'm thinking about it, the slider may not have that spacer in it, if it was AM made in Mexico. Careful with those sliders, the aluminum gets scratched easliy.

Post by 51Hog on May 21, 2005, 9:52pm

Thanks for the info VT
Unfortunately, I will not be able to work on the bike for about a week.
We are takeing some time off and are going to spend several days in a wonderful cove about 125 miles from anywhere. No other boats-people-cell phones...etc...
It is going to be tough--We are taking crab pots and shrimp pots and are going to look for some Halibut. Hopefully we will get a chance to check out the new onboard freezer...

Post by VintageTwin on May 22, 2005, 12:26am

Sounds good. Do a little bottom-fishing.... Stare at a campfire. I'll have my fork leg tore apart by the time you get back. Don't forget any appurtenances that make camping-life easier. My buddy found a portable espresso maker for his Coleman stove. That was nice when we were surfing down in Baja.... cliff dwelling.

Post by 51Hog on May 22, 2005, 7:16am

Great.
Thanks for the tip on the Espresso maker--Already have one! Have to try to live the good life.----Camp fire hummmm.... I think I will not feed the mosquitos and just kick back on the sofa in the boat. The skeeters don't often travel far from the shore. Man they are hungry this time of year. I probably won't set foot on shore for at least a week.

Post by VintageTwin on May 22, 2005, 7:36am

Yeah,...kinda hard to have a campfire out on the water, I reckon!
Forks banging on a factory rebuild. That's a puzzler. Well, I'll pix the insides of mine. I have two sets of forks, one set OEM I rebuilt, without fluid in them yet. So I better juice them up and bounce test them before I pull the V-Twin forks apart and see what's in their tubes damper parts-wise. They build V-Twins in Mexico using the later Gary Bang kit. No felts, and a later seal. No big washer under the retaining ring and the ring is a clip, not a circ-clip like the old OEM style. Fewer parts. Probably no spacer in there or old style shims either. My OEM forks, I rebuilt with an OEM style V-Twin kit...felts, etc., like the old style. I put the spacers back in there, but the V-Twin damper parts wouldn't fit with the spacer, so I took them out. Kept all the old orginal parts. Left out the shim(s), because I couldn't get the 0.004" clearance called-out for, between the tubes circ-clip and the bottom of the damper assemblys bushing (not the slider bushing). But once the one shim was removed from both OEM damper assemblys, the V-Twin parts kit fit perfect. I had both slider bushings (top and bottom) replaced and honed at the dealer. Stett did 'em. You really need to keep the sliders wrapped in cloth all the time...anything will gouge them externally.
Good trip.

Post by VintageTwin on May 24, 2005, 5:15am

Anybody ever removed a knurled washer from the bottom of a slider? I removed the fork tube and set the leg upright on a cloth covered 2 x 4 and used an 18" length of 1/2" rigid, Type L, copper (plumbing) tube. A perfect fit on top of the knurled washer, and gave it a few smacks with a brass hammer. The knurled washer didn't budge. No damage to anything, the copper tube end softened the blows. I'm considering leaving the damaged knurled washer in the slider and just replacing the previously damaged damper stud.
Note: The stud was damaged at the factory when they didn't have the damper stud shoulder correctly seated into the elongated hole of the knurled washer and unknowingly tightened the flexloc nut over the aluminum crush washer. The sealing surface is the paper washer that is sandwiched between the bottom machined surface of the slider bottom and the bottom of the damper bushing. Any help would be appreciated........."cause I didn't sign-on for these problems." I was told this replicating work was a piece of cake, and I was lied to man.

Post by VintageTwin on May 24, 2005, 8:57pm

I just received a call from Mr. Colony and we talked about the (46128-48 damper tube nut plain washer) which isn't so plain as it's directional (has a shoulder on the damper side) and it's knurled, and it's hardened, and it's installed as a part that's not meant to be removed, even though the excellent Clymer Panhead manual has a pix of one being held by a pair of needle nose pliers like you could remove it. Mr. Colony laughed and said, "Yeah they probably had to split the slider to get it out !". We came to the quick conclusion that Harley-Davidson engineered the assembly to have a sacrifical part (the damper stud) and a non-sacrificial part (the knurled washer). So, that if someone wasn't paying attention, and didn't get the damper stud fully registered into the slot of the knurled washer; and went ahead and tightened the damper nut, that the damper stud would be the one to get chewed-up (like mine did). I think that the "seal" is the paper washer under the (46121-4 damper tube lower bushing resting on a machined surface at the bottom of the slider. Roger thinks that your asking alot from the paper gasket considering the head pressure created by fluid compression from the fork action, and that the integrity of the slot in the knurled washer is important. We'll see. Kick-Start sent me his only damper left in stock. When I install the new damper and fill the forks with oil, we'll know. If my knurled washer (which is slightly galled, and I'm unable to remove) causes the fork slider to leak, I'm in big trouble. I'll have to buy another left side leg. Bum.....er, I'll know by Friday.

Post by caschnd1 on May 24, 2005, 10:48pm

VT,

I have '49 sliders on my panhead. When I rebuilt them about a year ago, I removed the knurled washer at the bottom. I used a piece of pipe smaller then the diameter of the washer. Didn't take a lot of force to remove the washer from either of the fork legs. Both had been installed correctly with the "shoulder" side going into the hole at the bottom of the slider first. Are you sure that the end of the copper tube was contacting the washer and not hung up on a ridge at the bottom of the slider? Just a thought.

-Craig

Post by Mbskeam on May 25, 2005, 4:57am

hello,
get a file and file the damper shaft flats tru again.
fit this untill it drops in free to the slot. had mine smashed up when I got it.
use silicone on the gaskets top and bott. you dont need a lot, put the copper crush washer on the outside the the nylock.
no leakey.
Do you need this washer?
or send it to me and I can fix it.
mbskeam

Post by VintageTwin on May 25, 2005, 6:01am

I need the plain washer, but it's not copper, It's aluminum and it has a deep imprint of the damper's flat-side shoulder in it now. I was going to try to just flip it over, but the i.d. of the aluminum washer is kinda scored now too. I think it's going to leak. I guess I could use a dab of silicone on both sides of the paper damper washer now, since I rinsed the hydraulic fluid out of the slider with disc brake cleaner spray, and I have two new paper washers (the big ones) from Kick-Start. If I send you the scored aluminum washer as a template could you make me a new one? I think I'd try to true the shoulders before I'd replace the damper though.
Better, would be to make the washer and send it to me. The V-Twin forks use OEM sized parts. Strange though, that this aluminum crush washer is not in any of the parts books. The knurled washer 46128-48 is illustrated, but called a "plain damper nut washer". However, if you look closely (under magnification) in the parts book, you can see the elongated straight-sided hole, but there's no plain washer we're talking about, under the knurled washer or above the nut.
Charge me and I'll send you some dough. I'm anxious to get these forks on, wire the machines and get-them-on-the-road. Thank you.
Yeah..Craig, I took a piece of sand screen and removed a little material from the driven end of the Type L copper tube. When I finished smacking it a few times with a brass hammer, I could see where the copper tube had gone in about 1/4". So, I think the copper tube drift made solid contact with the knurled washer in the slider. It didn't EVEN budge. Not a bit. I didn't see where it may have hung up on a ridge inside the bottom of the slider though. They did a good job putting it in there. A gold sticker was stuck to the outside of the slider..Made in Mexico. They do a good job on these forks. I can see though, that the damper stud galled the elongated hole some and Colony Roger thinks that the fit of the flat shouldered stud into that slot in the knurled washer...is critical. I feel queasy and slightly doomed. But, I have to try and fix it with a new damper, before I go the RTV route. I just don't feel comfortable pounding on the knurled washer to remove it.
Craig, You had to match the original knurled pattern with the new washer you put in yours didn't you? If you didn't you'd still have the old knurled indents in the slider hole wouldn't you? Did your new knurled washer take much pounding to get it seated correctly again?

Post by Mbskeam on May 25, 2005, 7:28am

hello,

time to get out your manual....panhead service manual48-57(green cover)
on pg 39 with the exploded view of the forks......
put rtv under #18 into #17, then under # 17 put rtv on both sides or #16

I put in this order
#16 with sealant on both sides
#17
#18 with sealent on bott side
# 19, the damper assy and fork tube, etc....
then on the out side, I put a copper crush washer on top of nut #13, up into the counter bore of the slider.

if the damper assy #19 shoulder sticks out below, into the counter bore, then the long tube shoulder must be cut down, I had to do this on mine it took .025 to get the damper to seat correctly and seal the gaskets. Other wise the nut will bott. out on the damper shoulder, and not compress, it will then leak.
the washer on the outside is a seal that I came up with after looking at it use on a mercedes.

mbskeam

Post by VintageTwin on May 26, 2005, 9:12pm

I posted some pix of the damper over on the other forum>Projects> If you want to check them out. We're putting your method of rescuing the damper (crediting you with the repair) along with installation of a new damper in the book, to pick up where Clymers left off. Thanks.

Post by VintageTwin on May 27, 2005, 7:22pm

mbskeam, I talked to Stett. He said don't use RTV to seal the paper gasket, because over time the fork oil will work between the RTV seal. He said the only substance that will work is Hylomar®. And also, if you coat both sides of the paper washer with Hylomar, you'd better do a good job, because the paper will be glued down in the bottom of the slider forever. Can you imagine the problem you'd have ever getting all the residue of paper and Hylomar off the bottom machined surface of the slider? Yikes. Any tool you used would score the machined surface of the aluminum at the bottom. I'm doing some serious thinking about whether I want to commit to a Hylomar fix. The flat edges of the knurled washer are slightly galled, Roger thinks it might leak, but fork oil is easier to clean out than Hylomar. I have a couple sets of paper washers.....I'm going to try and put it back together without Hylomar and just use the paper gaskets. If it fails I'll go with Hylomar. Roger wants a report on what happens. Here I go.
Once my forks work, I'm trailering my rolling rigid Pan down to Stett's and we're going to load that complete STD Pan motor into the frame.
51 Hog, There was no spacer in the slider. There are no shims in the damper assembly. V-Twin has this replica Glide fork down to a minimum of parts. The ultimate modern Glide fork disguised as antique. A beautiful reproduction. I wish I could find something with the forks to complain about but there isn't anything.

Post by VintageTwin on May 29, 2005, 4:13am

I prepared the inside of the slider by spraying streams of disc brake cleaner in there. Reamed it with paper towels and a wooden stick, blew it out with an air blast, coated both sides of the paper washers with Hylomar®, carefully re-assembled the slider's (leg), lower damper bushing, tightened the new damper stud nut over the good side of the aluminum crush washer and put 2 oz. of fork oil (as a leak test) into the top of the tube with a honey-bear bottle. No drips. I turned up the music and was dancing around the shop for a few minutes... even. Then I heard a drip-drip hitting the pie tin I left under the leg just for safety. Har! F-a-a-a-ha-ha-ha-ha! Unbelievable. Pulled the nut off, jerked the slider off and the Hylomar had turned to jelly.
I remember Craig saying that he had no problem with getting the knurled washer out of a '49 leg, so I cleaned the slider out again and got the recommended tool in a Harley emergency....a bigger hammer! A 3 lb. sledge with a honking long handle. Used the same 1/2 rigid, type "L" copper tube, set the slider leg on a 2x4 and smacked it real good a few times. The copper tube drove the knurled washer out! V-Twins knurled washer is aluminum not hardened steel and has no shoulder. I pixed the process and will post side by side pix of both knurled washers. Drove the OEM hardened washer into the leg, shoulder first, and will rebuild new paper washers into the slider tomorrow. I'm calling Roger at Colony Tuesday. He can make these knurled washers, especially since they're made out of aluminum. I'll check with JW first and see if Tedd has any plans to sell the knurled washers they use in the legs. We need them. There'll be more people that will gall theirs. Especially now that I've found out their al-u-min-ni-mum. Thanks mbskeam. Thanks Craig.... for pushing me into it.

Post by VintageTwin on May 29, 2005, 11:09pm

Finally figured it out, but, it kicked my butt for about a week. One of my legs was fine. Held oil. The left leg was the one with the galled damper stud and knurled washer. The problem was that the machined floor of the leg was cut too deep at the factory.
Using only the one 46111-48 damper tube stud gasket and the one 46125-48 damper bushing gasket was not enough.
I drove the replacement OEM knurled washer into the bottom of the slider, and fitted the damper stud into it, and then before I put on the aluminum crush washer, I used a small tipped screwdriver to feel if there was any damper shoulder sticking out of the new knurled washer. One one shoulder it felt like there was about 1/64" of protrusion, but on the other
shoulder of the damper stud there felt like there was about 1/32" of protrusion. In either case, too much protrusion for the crush washer to allow to be buried.
Because the protrusion was uneven, I first thought the the shoulders of the stud weren't even, but each shoulder was 10/64" in length, on V-Twins damper and on my old rusted OEM ones too. Then I thought maybe I
hadn't driven in my new knurled washer evenly, so I set the leg upside down and tapped it again with copper plumbing tube driver and the 3 lb.sledge. It was bottomed out completely and the stud protrusion
didn't change at all. So, I removed the damper and started stacking paper washers into and below the damper bushing. I installed (4) 46111-48 and (4) 46125-48 paper washers, where only one each is called out for, until I could get both stud shoulders at least 1/64" recessed below the top surface of the knurled washer. Then, installed (the remaining good
side towards the slider) the aluminum crush washer first, and then turned-on the flexloc nut and torqued it to 15 ft. lbs.; put 2 oz. of "test" oil into the fork with a honey squeeze bottle and waited for leaks.
Then I squeezed in another 5 oz. of fork oil. No leaks.
Tell them, we need knurled washers, (4 or of each of the paper washers and the aluminum crush washers in a V-Twin kit, because it's going to happen to other builders and we can't let Pilgrims get discouraged or
we'll slow this whole kit building thing down to a crawl. - kp

Post by Mbskeam on May 30, 2005, 12:00am

hello,
this is what I have been saying about the damper rod sticking out to far.
What is up with this alum washer? is this for v-twin kits

mbskeam

Post by VintageTwin on May 30, 2005, 1:56am

Yep, you were right about the shoulder sticking out, but for me, the fix has to be something that can be done without RTV or Hylomar (well, Hylomar didn't work at all), but it can't involve grinding or altering anything on the V-Twin forks. It can involve adding more paper washers though. Being able to remove the slider in the future and install and hone new slider bushings (top & bottom) is important to the future "kit" builders.
Now that your damper paper washers are glued to the bottom of the slider, and to the bottom of the damper bushing, and the small paper washer to the bottom of the damper stud, can you still pull your fork tube out, and is there a chance that the damper bushing will be glued to the bottom of the slider? I'm not knocking the fix, just wondering.
The aluminum knurled washer is the V-Twin version of the OEM hardened steel knurled washer. None of the service manuals or parts books have a crush washer in them. In the green rigid Pan service manual, the illust. on page 39 shows #13 as a damper valve stud lock nut. OK, but there was maybe a plain (crush) washer, and there is for sure a knurled washer, not pixed in that book. In the '49-57 Parts book and '58-68 Parts book there is the 46128-48, which is the knurled washer. However, where it's listed on pag 70, of the '58-68 parts book, they call it a "Damper tube nut plain washer". Somebody goofed, or they started calling it the 46128-48 Damper tube end washer in '58. It's actually the knurled washer with the elongated hole. They still don't pix a crush washer under the flexloc nut. They engineered the V-Twin damper assembly to include this aluminum plain washer as a crush washer, so if the factory did machine the slider leg floor a little too deep, this aluminum crush washer would indent enough to accept a little shoulder protrusion, but no more than 1/32", any more protrusion than that and the fork would leak, as you and I found out. What you did was remove 0.025" of shoulder so your protrusion was only a shoulderless threaded stud, and your copper crush washer took up the extra stem protrusion. Would that be a correct assumption?
I'm going to post some pix of what I did and a pixes of the counterbore of the slider for the knurled washer, after I removed the VT aluminum knurled washer. After I pulled all this stuff apart, I see what the engineers at V-Twin did. Those guys had it figured out, except the factory goofed more than usual and machined a deeper and apparently (slightly) un-level floor in my left slider. This was compensated for by 6 extra paper washers (total of on my part and it's a fix that V-Twin will appove. Now, what I want is a kit offered for this odd-problem, consisting of extra paper washers and an extra aluminum crush washer. The kit can be for one leg. The pix are over on the other site > Projects> Damper Problems. I couldn't have made my discovery without your imput and Craigs urging to go ahead and pound out the knurled washer. I had to expose the knurled washer for what it is (aluminum and not hardened steel) and how it was driven in, and what the floor under it looked like. I feel good for a change.....and my forks still hold 7 oz. of oil. Thank you getting me thinking!

Post by Mbskeam on May 30, 2005, 2:52am

hello,
well I took off the .025 so that shoulder did not stick out.
this made for the nut to bottom out and not compress the stack of parts that we have been posting about.
I put the copper washer on the outside, on the stud as a last stop seal, this was my idea that is not in the service book.
the sealant I use is permatex ultra blue, if you need to pull it apart it will come. I get the gasket out if it is stuck in the bottom, with a long flat blade screw driver.not a problem to clean up.
I still think that this sealer is the best way to go.
if every thing compresses right, then oil cant get between the gaskets and alum.

mbskeam

Post by VintageTwin on May 30, 2005, 5:05am

Okay. We ended up with forks that don't leak and it had me stopped for sure. Next is wiring and the next problem that pops up. Wonder how the fishing is for 51 Hog?

Post by 51Hog on May 31, 2005, 5:40am

Cheated death again!! Had to cut the fishing trip short due to bad weather. Wind Rain and high seas didn't make for a very enjoyable trip. Still went fishing and claming---Ended up with a 40 lb. and several 20-30 lb. Halibut. Dug a bucket of Steamer clams.
We listened to the weather forcast and didn't see a break in the weather--Decided that the Harley was sitting in the garage getting lonely, so we came home.
Went for a ride today and put on about 80 miles before I had to pull on the reserve. Looked at the plugs and they were pretty sooty--Black-- Looks to me like too much fuel. I cleaned and set the points to factory specs. Put in a new Condenser, cleaned and gapped the plugs. I leand out the carb and it still appears to run well. It doesn't starve at cruise. It doesn't back fire as much now when I let off on the throttle.
The forks are still banging when they are quickly extended-----Holding front brake and pushing bike for and aft----
On a good note, the kit that came with my new tubes, also came with the knurled washers that press into the bottom of the sliders. They are Steel. I knocked out the originals, and knocked in the new ones. No leaks.
I added 7oz. of fork oil. I do not know the manufacturer of the tubes that I have, as a local shop ordered them for me. I ASSume that the forks are supposed to damp in as well as out. Can anyone verify this?
What a great Forum!!!

Post by Billy on May 31, 2005, 5:53am

Yes they dampen in & out. Fluid assists w/the dampening.
But it wasn't until '77 IIRC that they started using short 3/4" tall aprox. rebound springs. These cushioned the forks as they fully extended. Look at the manuals, they will show the changes after '77
My 73 forks are assembled correctly & when I make it top-out, it is felt.. But works just fine & the only time, I can hear this, is in my shop, 'trying to do it'.........
But that is just the nature of the design. (assuming yours is correctly assembled) I'd think it is.?

Post by 51Hog on May 31, 2005, 7:30am

I would like to think that they are correctly assembled since they came to me ready to drop into the sliders. They definately top out hard when fully extended with little or no dampning effect
Looks like I will be talking to the shop that ordered them for me.

Post by VintageTwin on May 31, 2005, 9:58pm

Let us know what you found out.

Post by Billy on Jun 1, 2005, 12:51am

I agree w/Vintage Twin-
Yes, let us know what you find out.
Also agree /Mbskeam-
I only use a bit of sealer on the washer just before I add the nut. (No Leaks) & no headaches..

Post by panster on Jun 1, 2005, 1:47am

FWIW,
My Hydras used to top out like that, I added a little more oil to
each leg and it was cured. If you're going to pull them apart anyway,
it might be worth a try first, (2oz maybe).
J.

Post by 51Hog on Jun 3, 2005, 4:34am

Well, I talked with the guy who ordered my fork tubes.
He said he didn't remember whether he got them from Teds VT or CCW.
And that the forks ---all of the Hydra forks only damp in compression--not in extension. I think he is trying to feed me a line of.......
How about you guys that have Hydras testing yours for me.
Engine off- Sitting on bike---Front brake locked---Push bike forward to compress forks and pull back as if trying to lift front wheel up. Do you hear the forks hit solidly when they reach their fully extended position?
Thanks

Post by Ente on Jun 3, 2005, 8:32am

Hi.
Don't know if it is relevant, but I have forks from 73 cuz I need disc-stoppers... But anyway... doing that kind of procedure... I hear/feel a nearly metallic 'clonk', dont know if something missing or broken, but they do their compression-job well anyhow....

Post by VintageTwin on Jun 3, 2005, 3:00pm

"Do you hear the forks hit solidly when they reach their fully extended position?
Thanks"
---------------------------------------------------
Here's how the AM '49-up Glide forks are set up parts wise. From top to bottom: Tube cap, spring, damper assembly, lower damper bushing. The only clearance spec's are the 0.004 max. free-play between the circ-clip and the bottom surface of the lower damper bushing. Before you remove the tubes's circ-lip, push on the damper stud and see if you can make it move back and forth, indicating over-clearance. If you had more free-play than 0.004", then when the spring is fully extended, you might get a thump; however, the spring is always under pressure, because it has to be pushed down into fork tube to get the top cap screwed on.
The other possibility is that your upper and lower slider bushings are not sized right and they're letting the tube rack within the slider. Doubtfull, if the forks are new AM ones.
Look at the top of your slider. Is the clip that holds the big slider seal a "circ-clip" (with two holes for circ-clip plier posts to fit into)...or is the clip a bent piece of polished wire? If bent wire then the forks are V-Twin and that's the clip to a Gary Bang '77 slider seal. If so, and you want to pull your forks apart, go over to the other site ("Projects") and print out the procedure. Do the fork spring removal thing as shown. You'll need a two-step operation to get the cap off the fork tube. First, once you have started removing the cap, and you see two or three threads exposed, loosen the pinch bolt and move the tube down another 1/2-3/4" so the the top of the cap is still 1/8" up into the top tree (for projectile guidance); so when the cap comes off, it will shoot up into the top tree and stop. Keep you fingers out of the way. On the fifth exposed thread... the caps gonna snap-up. It caught the skin on my finger and I ripped away a chunk outta fear, but you're suppose to bleed on your bike or it's not really yours.
Oh yeah, your AM fork sliders shouldn't have a drain plug on the back of the slider. If they do, then they're OEM sliders and probably have the early multi-piece (felt, washer, etc.) seal.

Post by 51Hog on Jun 3, 2005, 5:17pm

Thanks for the response.
The tubes come to a loud, hard sudden stop when they reach their upper limits of travel. I am worried about damaging the soft bolt on the bottom end of the damper---Like maybe pulling the nut off of it from all of the banging. (A lot of our roads up here are pretty rough)
My sliders are original with the drain plugs in the bottom, the felt upper seals with the metal washer and wire clip. I do know that the slider bushings are at their limits as far as being worn out. I will need to replace them, probably this winter. The sound that I am hearing cannot be the tubes racking in the sliders----The hit is too loud and solid. I would think that the racking tubes in the sliders would be more like a rattle causing a shimmy or vibration while braking.
I might try adding some oil to the 7 oz that I already put into each fork as was suggested in an earlier post.
What is the worst result of adding too much fork oil??? Leaks??
Thanks,
Dale

Post by Sonny on Jun 3, 2005, 6:00pm

My hydra is same way (as designed) look in your manual
there are no return springs to cushion, so this is correct for the design. add a couple xtra oz oil & ride it.

Post by VintageTwin on Jun 3, 2005, 6:07pm

Okay, you have OEM forks. Since the lower slider bushings are the hardest to remove, and the honing such an exact procedure, I'd say your busings are shot. You may have that spacer in there, whcih probably has nothing to do with your problem. Too much oil in the slider may be forced out of the tube caps vent hole on compression. That's about all that will happen. The worn slider bushings could be causing it. I wouldn't worry about damaging the "soft" area of the tube caps, the damper has a spring loaded stick with a series of baffle cups in there, all which will be replaced when the forks are rebuilt. V-Twin has a fork rebuild service, bushings, etc. done for about $225. retail, plus shipping, but pounding should be fixed. El Cajon Harley did my '59 forks once, but they couldn't do the bottom bushings. I asked George their motorhead what would happen if I started losing fluid and ran it anyway, and he said, "It will just wear more".

Post by Pan ster on Jun 3, 2005, 7:08pm

Hi ,
of course the Hydra forks have rebound damping!
As I said adding a little more oil cured mine.
J.

Post by 51Hog on Jun 3, 2005, 7:44pm

Since it can't hurt anything, I am going to add one oz oil to them. If that doesn't work then I'll add another.
If that doesn't work, they are going to bang till I put her away for the winter. Then I will pull the forks apart and replace the bushings in the sliders and have them honed. I already know how to build a puller for those hard to pull bushings. I plan on rebuilding the motor then also.

Post by fourthgear on Jun 3, 2005, 8:02pm

For your info , according to the catalog I just got from Bills Custom Cycles , he will do the set for $ 80 including bushings . 1949 to 1976 . http://www.billscustomcycles.com . Hes out of Bloomsburg, Pa. 570-759-9613.

Post by 10 toes on Jun 4, 2005, 7:49am

You can't beat that price..I would still prefer Bill's to do it rather than ted's monkeys, even if the prices were reversed. But I do my own stuff. So if I screw up, I can kick my-self in the ass.

Post by VintageTwin on Jun 4, 2005, 3:29pm
"Since it can't hurt anything, I am going to add one oz oil to them. If that doesn't work then I'll add another.
If that doesn't work, they are going to bang till I put her away for the winter."
Excellent solution !.....only a Harley would let you do that.

Post by 51Hog on Jul 7, 2005, 9:40pm

Well, I still haven't done anything about the banging at full extention. I did notice that there is a fine mist of fork oil on the inside of the windshield tho.
Hummmm, Wonder how much oil is left from the original 7.5 oz. that I put in when assembling the forks...
Wonder why the forks are misting the windshield.....

Post by Mbskeam on Jul 7, 2005, 10:10pm

hello,
I think that if the book calls for 7.5oz that is when fully clean,
when just dumping and adding them it will be 6.5oz,
do your top fork nuts have the baffles in them?if not then this might be why you have a oil mist, or they are way over filled.
o-ya......there also is a rubber seal ring that goes on the under side of the bolt. it will stop some of the oil mist that you are talking about (this just came back to me) I wonderd what these were for in the fork seal kit I got years ago, then I saw them in the parts book ill. : then it hit me... duhhhh
in they went and no oil around my nuts.....
mbskeam

Post by 51Hog on Jul 7, 2005, 10:37pm

The tubes were new never installed into sliders so I suspect that they are not over filled with the 7.5 oz of oil.
I assume that the baffles are in there place in the top of the tubes as the tubes were factory assembled. There is a rubber washer in place under the vented cap nut.
Thanks



VT

#2

Post by VT » Tue Apr 04, 2006 3:10 pm

Did anyone notice if the repop hydra-glide forks have the the baffle cup assemblies installed in the bottom of each frok tube plug? As I remember it now, mine did not and I have to remove the oil and disassemble the sliders and tube again. It won't be real soon, but I'll let you know. Anyone else have a set of forks apart? Give a holler :!:

51Hog
Posts: 664
Joined: Fri May 20, 2005 7:29 pm
Location: Wasilla, Alaska

Re: Hydra forks not working correctly

#3

Post by 51Hog » Sat Mar 21, 2009 12:17 am

Anyone know what the clearance should be between the fork tubes and the slider bushings? I cant seem to find any specs on it. I would suspect .001 or so??
Dale

51Hog
Posts: 664
Joined: Fri May 20, 2005 7:29 pm
Location: Wasilla, Alaska

Re:

#4

Post by 51Hog » Mon Mar 23, 2009 4:33 pm

VT wrote:Did anyone notice if the repop hydra-glide forks have the the baffle cup assemblies installed in the bottom of each frok tube plug? As I remember it now, mine did not and I have to remove the oil and disassemble the sliders and tube again. It won't be real soon, but I'll let you know. Anyone else have a set of forks apart? Give a holler :!:
VT--
Mine did not have the baffles in the top of the tubes either. Just picked up a pair of used originals and am going to install them since I have the forks apart now.
I am in the process of checking out the reason for the hard hit on rebound.
Think I have it figured out, and will start a new thread if/when I know for sure.

VT

Re: Hydra forks not working correctly

#5

Post by VT » Mon Mar 23, 2009 7:23 pm

Yeah, I was crying about the lack of baffles sticks back in 2004, however I did remove the tube plugs and install the baffle sticks.
Anyone know what the clearance should be between the fork tubes and the slider bushings?
I still have pound on re-bound, but I think Robert Luland, nailed the problem (yrs. back) when he suggested that he and his buddies thought that the smooth surface of hard chromed tubes allowed the tube to rebound on compression too fast (past the honed bushings). He said that the cross-hatching surface of OEM and Forking by Frank would cure the problem.
No I don't know the clearances between the tube and upper and lower bushings, but Robert was right in my opinion. Slick tubes won't help the top-out clunk problem and I sure wish somebody would get the cross-hatched tubes from Frank and apply Roberts theory.
Because fork slamming is driving me nertz.
But here's the continued article on FHP. The search stopped with the last post.
http://flatheadpower.com/tech/viewtopic.php?f=13&t=9750
Synopsis as of 3/23/09:
Nobody's popped for forks from Frank yet. Something as important as this, I would be on the phone asking Frank about the cross-hatch theory and cure this problem, if possible.
If you call him, tell Frank we're using his parts over at http://hydra-glide.com/

http://www.frankmain.qpg.com/

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