1937-1957 Rear Brake- Fit Problem

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VintageTwin
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1937-1957 Rear Brake- Fit Problem

#1

Post by VintageTwin » Mon Apr 11, 2005 5:45 am

This (VT 22-0709) Big Twin R. Backing Plate assembly won't fit into a (VT 23-0430) '37-57 (rigid) Brake Drum. I tried an OEM backing plate assembly with the V-Twin drum and the OEM backing plate fit. Since the internals of both look identical, My thinking is the shoes on the reps. are too thick, except both shoes VT (left), and (1994 era) bonded shoes (right), seem to be about the same thickness.
Strict 60 day warranty on V-Twin parts. Plan accordingly.
Don't order any rear brake parts until your ready to assemble them. It's a wilderness out there in a few (genuinely, becoming fewer all the time) areas of '37-59. [Rigid, rear brake assemblys, knuckle frame top motor mounts, and '54-up throttle spirals are all that come to mind. And those issues aren't too much to overcome]. The brake drums and shoes come and go. I got unlucky, the next person may get an assembly that fits. You'd think that with so few '37-59's on the road, there'd only be one manufacturer making drums and brake shoes. Not so. Paughco? http://www.paughco.com/ makes a rear drum. Alot of their parts fit. I have an antique Paughco chain guard that's stamped "Paughco, Los Angeles, Calif." from '69 or 70. It's going on the rigid Pan.

Disclaimer: We're (me) not trying to run any mfgr.'s parts down...only finding a path towards a '41-59 OHV Big Twin kit completion. Whatever it takes. Whoever makes the parts, we don't care, as long as we can bolt them on and go. It may take getting certain parts from different mfgrs. but we'll know by the time I'm done. Now's the time to invest and build. 8)
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Last edited by Anonymous on Tue Aug 02, 2005 1:40 pm, edited 14 times in total.



VintageTwin
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#2

Post by VintageTwin » Mon Apr 11, 2005 5:47 am

Rep. (left). OE plate (right). Shoes look the same thickness. The two different rear brakes related to '37-59 OHV BT are the '48 to '56 (one-spring) and '57 (two-spring). All the literature written about the BT rigid rear brake is OEM cast shoe related. Clymer's Pan manual talks about the '57, two-spring brake shoes, and the Kick-Start "perpetual" catalog illustrates the current '57 two-spring design. The rep. brakes of today are based on the '57 (two spring) design, and the brake drums are drawn steel, not cast iron. Cast iron, I was told, can warp and egg-shape, if left stored on it's side.
If a person had the dough to do it right, they could order all their parts from a company like Kick-Start (616) 245-8991, M-F, 10 am-5pm (EST), and at least talk to the sales rep that sold them to you. Might even-out costwise, when you consider the shipping charges for "blind purchases", disappointments, having to return parts, and lost time.
5/3/04 Here's the Kick-Start shoe. I can tell the lining's thinner, but I need to change-out the shoes off the V-Twin backing plate, to see if it all fits. You can't buy a '37-57 bare backing plate from V-Twin. If you buy the "backing plate complete" the shoe linings may be oversized (thick). Paughco sells the backing plate all pieced-out. http://www.paughco.com/2003_catalog/page189.htm
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Last edited by Anonymous on Wed May 11, 2005 7:57 pm, edited 18 times in total.

VintageTwin
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#3

Post by VintageTwin » Tue Apr 12, 2005 5:44 am

Got a tip on the brake shoe problem from JW:


"the edges of the shoes need to be fitted. I think the service manual makes mention of this . the leading edge. If you look at your old shoes and new ones you'll probably see where to file them down. both shoes near their pivot points".
--------------------- --------------------- ----------------------------------

Guess I better try that. :? I'll post the results. Nice rep. backing & anchor plate laminate though. Deserving of the name Replica, but ditch the shoes that come with it.
Last edited by Anonymous on Wed May 04, 2005 2:29 am, edited 3 times in total.

VintageTwin
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#4

Post by VintageTwin » Wed Apr 13, 2005 6:08 am

First I installed the V-Twin backing plate and shoes into a used OEM rigid drum because they'd fit in there, but somewhat tightly. Then installed the wheel and tightened the axle sleeve, and axle nut, spun the wheel repeatedly to make burnish marks on the places where the drum made contact with the shoes, and/or dust rim, and/or/all, the back of the drum (The OE drum had a dust ring that had taken some minor hits in the past. Pic #1. I used black magic marker on suspect areas as "Dy-Kem") Everything scraped. Took the wheel off and ground a slight taper to both ends of both shoes (because all ends of the shoes became burnished with fake Dy-Kem) Then, ground-off the burnish marks made by the forced spinning; by removing the shoes and "arcing them, rocking them across 180 grit paper on a flat surface". - the Palmer book; pg. 124. Wore a 3M cannister respirator. After about 5 grind-sessions, I'd removed enough material so the backing plate now fit in the V-Twin drum. Then, with about 10 more complete nut tightening change-outs, I had the backing plate and shoes to where; axle sleeve installed, I could spin the backing plate assembly by holding the brake lever, turning it round and round while the wheel just sat on the deck. Done slowly the backing plate wouldn't rock and hit the dust ring. This left the necessary tell-tale burnish marks again. A couple of shoe removals and grind-downs of the high spots and I was able to install the wheel in the frame. Tightened all the nuts.
The wheel still makes intermittent scrapes.
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#5

Post by VintageTwin » Wed Apr 20, 2005 3:01 pm

These pix are from an OEM backing plate w/ circa 1994, re-pop bonded brake shoes. I think the OE backing plate may be warped. You can see where the shoe on the right wants to rise up about 1/8" away from the plate. I'll need to remove the shoes and figure out if it's warped, and how and where to apply pressure to bend it back to it's original position. They say bent metal wants to return to it's original state, as long it hasn't been creased.
The pix with the pencil shows how much of an exposed metal edge there is along one shoe, which may mean nothing, concerning the scraping against the back of the drum. Another pix is the burnish marks made as the shoe(s) make contact with the inside of the drum. The scrapes on the drum now happen, only after I have tightened the axle nut. The shoe(s) don't scrape with just the axle sleeve tightened. I've ask a parts supplier about this and he said, "Sometimes only re-pop will work with re-pop. People ask me for those original cast (webbed) shoes for a rigid, and I tell them, "There's no guarantee that OEM shoes are going to work, and that once bought I won't accept them back as a return".
5/9/05 Note: The old OEM backing plate wasn't warped. All the scraping problems disappeared when I changed-out the brakes shoes to a set with a standard thickness linings from Kick-Start. The V-twin backing plate and drum are good parts. In what might be called "Replica Progress", the mfgrs. got rid of the cast iron drum, standardized a compatible shoe lining material for drawn-steel. Made it better. Made it "kit-able" for the future. One Replica in every garage.
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#6

Post by VintageTwin » Wed Apr 20, 2005 3:09 pm

Here's the offending shoe. It was hard to tell if these were the scrape marks, it was the only place on the shoe where the light coating of anodizing had been removed. I ground the expose metal edge off the shoe, colored it with black marking pen and spun the wheel again. Warped backing plate is thought to be the reason at this point. The shoe(s) still scrape when the axle nut is tightened, but not in the first stage when only the axle sleeve nut is tightened.
The top pix here is of the pivot stud rebuild kit. This OE back plate still has a warp in it and that "chrome" operating shaft that's in it now, is worn. So's the bushing. I'll remove the old bushing with a stepped drift, then "use a piece of all-thread round stock, nuts and washers to squeeze the new bushing in that pre-sized with less chance of distortion", as Cotten once sugggested. And this bushing is already sized pretty good. Feels less than .002 side-play between the bushing and stud. Kit was from Kick-Start. Priority mailed. Got here from here Michigan in three days.

5/9/05 Note: The above problem of inner drum scraping was the edge of the shoes... where you see the pencil pointed at the leading edge of the shoe..
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#7

Post by VintageTwin » Tue Apr 26, 2005 3:52 pm

From JW:
"didn't mean to put you thru too much with cutting down the shoes, that usually works. the measurement is in the service manual and? i looked the other day?,? it's only cut down on one side of each shoe . if you got to that point ( sounds like you passed there ) then maybe something else is not......."
____________________ ______________ __________________

yep.......I'm passed there! I looked in the '48-57 service manual on pg.48. Actually, on the Front brakepage, they talk about replacing shoes. It says,
"set rivets with hand tools...and bevel lining ends". And then on page 51 where they actually have a '48-56 drum.....they show an illustration of the '48-56 (one spring) shoe with (as the M/C travels) the rear shoe (bottom leading edge only) marked with 5/8", as the area where that one shoe needs to be beveled. And that's it for OEM rear brake shoe info. I found a better description in the factory '40-47 Knucklehead Manual, pgs. 20, 21, " ling must be beveled at lower end (of rear shoe) for a distance of 5/8", as shown in Illus. 12." The rear brake that the '48-57 factory manual talks about, is the '48-56 single spring assembly with a cast iron drum. The rear brake assembly being made today is the '57 style, with two springs and a pressed steel drum. I haven't measured the i.d of the VT rear drum, but it should be 8". The early re-pop pressed steel drum that the VT shoe assembly will just about fit into might be 8.010". Palmer's book makes mention of all '30-57 drums having an 8" diameter rear brake, and that the "hydraulic" pressed steel drum can be turned-out to a maximum of 8.040". So, if the VT drum needs turning to make the shoes fit, I know a brake shop that has the mandrel. I had to do that to a VT pressed steel '58-62 rear drum. Palmers book and the '48-57 book, talk about the cast (webbed) shoes. Palmer's states that, "two springs were used on the '30-38 shoes, but with a new re-disigned pivot stud, only one (lower) spring was used on the '38-57 rear brake shoes".
Clymers (pg. 440) and Kick-Start are the only manuals that say the '57 rear brake uses two springs and the '48-56 one spring. Look at the pix #11 and 12 on pg. 442 in Clymer's..
The VT rigid brake is the '57 type with stamped shoes. The AM (aftermarket) shoes and spring hook arrangements are not in any service manual except the Kick-Start catalog.
I got the operating lever kit from Kick-Start to re-do the OEM backing plate, and will measure both drums, and maybe need to have the VT drum turned to a larger i.d. and get new shoes (don't want to have the rear brake lock-up since I've ground-off alot of material).
Last edited by Anonymous on Tue Aug 02, 2005 2:00 pm, edited 8 times in total.

VintageTwin
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#8

Post by VintageTwin » Tue Apr 26, 2005 7:29 pm

To JW:
i talked to Kick-Start. They said they get the shoes in bulk
from a wholesale only distributor, and they've never had a problem
with them, or had people complain about them not fitting. I
bought two sets to check them out. I may have to have
the new VT drum turned at a shop to get the shoe
assembly to fit in the drum. will know more when the
shoes get here at the end of this week or first of
next week, if he sends them first class. I think it's
the shoe thickness. Kick-Start's are riveted shoes too. They gave me the name of Vintage Brake in the Calif. (209) area code. this guy does nothing but brakes. left a message with "the brake god". 8)
Last edited by Anonymous on Wed May 11, 2005 8:19 pm, edited 6 times in total.

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#9

Post by VintageTwin » Tue Apr 26, 2005 9:40 pm

Talked to Michael @ Vintage Brake. http://vintagebrake.com/ He said that the re-pop drums get twisted; cast iron being the worst for egg-shaping if left on their side during storage, but for the kit builders, it's the pressed steel drums we're concerned with. The repop drum is the same old story, "Taiwan will make you a better drum if you want to pay for it. They can build you a cheap one for lets say $11.99, or a better one for $2.00 more, but the mfgrs. don't want to pay 2 bucks more, so we get what we get...and go fix it yourself".

----In defense of V-Twin, at this point, we don't know if my new drum is perfect and only the shoe linings are too thick.----

Michael said the best thing to do, is start with oversize shoes that have enough meat on them.
You can chuck the entire backing plate in a lathe, on an axle stub, so now you're truing the entire shoe assembly while it's on the backing plate, and it won't mattter if your drum is warped or not, generally speaking.
The other way, is to take the drum into a brake shop with a mandrel (however he reports that some of the OE style mandrels won't work with the re-pop drums) and have it turned, so at least you're starting with a drum that has a concentric i.d. surface.
I'm waiting on Kick-Start supplied shoes, and see how, or if they fit, then if they don't, I'm sending the drum and shoes and backing plate to Vintage Brake. He reports that the shoe material on re-pop brakes isn't the best, and a long story short, plan on another 40-100 or so bucks to get it right. He gets several calls a year from customers that say, "Your work saved my life, because when I needed a back brake in an emergency it was there for me". His words:
DRUM BRAKE TIPS:
1. Carefully inspect drum surface for grooves (obvious), crown (not so obvious), out of round and high-low spots (dial indicator). Crown often occurs with riveted linings. High-low spots commonly result when relacing hubs. There is no substitute for a freshly turned drum for premium friction materials to bed-in against. It's like putting a new piston in an old bore...never as good as with a fresh bore and hone. And you should inspect drum surface with the same critical eye. Tolerance: .002 to .004?" any dimension. Up to.010? out-of-round may be tolerated.

2. If you are re-riveting new linings yourself, DO NOT drill out the rivets. Chisel off the peened end and drive the rivet out.

3. Materials currently available far exceed those previously available. Reline your shoes with a current premium compound.

4. Keep in mind the low unit pressures required for "mechanically" operated drum brakes. Most linings require the higher unit pressures available hydraulically.

5. Very few modern materials are compatible with pressed steel drums. ? :shock:

6. Lay-back leading edge of leading shoes in 1/2 inch increments to minimize initial "bite" if brake is too "grabby", especially when hot.

7. The expanded metal used to cover scoops is typically 15% to 23% open area. Replace them with stainless steel screens with 50% to 60% open area, tripling air flow.


8. Use sealed wheel bearings --grease vapor can contaminate linings. Once contaminated, they never recover.

9. Lubricate backing plate components SPARINGLY with a 500F. + degree grease, such as Sta-Lube Sta-Plex Extreme Pressure, available at NAPA?.? Liberally lube parts and assemble. Disassemble and carefully remove all excess grease.

10. Check to see how far the backplate extends into the drum. Too far in and the sides of the shoes drag on the hub, creating excessive heat. Epoxy a shim to the inside of the backplate. Not far enough, and a ridge forms where there is no contact. Bend backplate or remove material to correct.

11. Worn pivot shafts cause uneven actuation. Rebush if necessary.

12. If a stay is used, make sure it does not cock the backplate.

13. Always apply brake when tightening axle.

14. If you want to arc the linings yourself, and have access to a lathe, first mount the relined shoes on the backing plate. Turn on the lathe (300-350rpm) to .020" under drum I.D. in .010" cuts.
________ ______________ ________________ ___________

He said that a good investment are the 12" digital calipers from Harbor Freight for $50-60. I called though, and H. Freight has dis-continued them.
Last edited by Anonymous on Wed May 11, 2005 8:22 pm, edited 5 times in total.

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#10

Post by VintageTwin » Mon May 09, 2005 6:09 am

The oversize lining problem was fixed with a change out to Kick-Starts's brake shoes and linings, as shipped. Didn't even have to bevel the bottom leading edge of the rear brake lining 5/8" back, to get the wheel to turn with no scraping; but I will, before I grease both sides of the pivot stud on final assembly.
Removing the oversize shoes, then drenching the grease residue off the backing plate, with Disc Brake Cleaner spray, made multiple re-assemblies of the wheel, in and off the frame easier. It kept from contaminating the linings, until I was sure the wheel turned without drum noise. And it's more fun working with dry parts.
Kick-Start (616) 245-8991 M-F 10 am- 5 Pm (EST). The trusted "chuck wagon" on this trail drive.
The Parkerized springs are Taiwan and ship with the complete backing plate from V-Twin. The zinc springs are Harley-Davidson. The tension on both springs feels the same, but the import wire gauge looks lighter than Harleys. The Taiwan springs have reportedly given good service with no complaints, but I'd feel better with the thicker gauge spring wire inside the drum. Ordered them from Kick-Start, priority. Shipped in an envelope.
Needle-nose Vise-Grips work well for removing the springs. The Vise-Grip clamp pressure on the wire can be adjusted, so the spring wire doesn't get overly galled.
Remove both springs, then the cotter pin and (outside) brake shoe cup. Note the eye of the cotter pin is at the bottom. A traditional cotter key positioning, so why change it ?
The spring on the left is OEM. The spring on the right Taiwan. No problems have been reported with the Taiwan spring.
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#11

Post by VintageTwin » Mon May 09, 2005 6:23 am

The (outside) brake shoe cup is a tight fit over the top of the shoe bosses. It's amazing that a brake shoe cup and pivot stud from one manufacturer, will fit with such precise perfection, over another manufacturers brake shoe bosses. And it's tight, but still...it's a hand-press fit.
The sideplay was measured on the (new) V-Twin backing plate's operating shaft. It was 0.003" looser than the old OEM backing plate. You can really feel the 0.003" by moving the brake lever laterally.
Different than the operating shaft bushing I replaced on the old OEM plate, which turned out to be 0.003" tighter.
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#12

Post by VintageTwin » Mon May 09, 2005 6:30 am

This is the old OEM plate (with the chrome operating shaft), of which, the bushing was replaced and reamed. Used a hand reamer, making light cuts until the operating shaft would turn with only the slightest drag.
Both machines are now offically "rolling stock". 8)
-------------------------- ------------------------ ---------------------------
:twisted: Yeah...he thinks so. Har! Wait'll he gets to the front brake side cover and trys to make things fit. We'll have some yuks then! :twisted:
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Latest Pix

#13

Post by VintageTwin » Sat May 14, 2005 2:47 pm

Here's three pix to show the rear brake springs available. From left to right: The Paughco spring, the Taiwan spring that ships with the "complete" backing plate, and an OEM (mechanical) rear brake spring..... and the 5/8" margin needed to be tapered, on the bottom leading edge of the back shoe lining.
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#14

Post by VintageTwin » Sun May 15, 2005 4:18 pm

Here's the four pix process for beveling the bottom edge of the rear shoe. This is the only scuff mark made on one of the Kick-Start shoes; after I tightened the axle sleeve, the axle nut, then loosened the pivot stud nut, applied the brake and kept it applied, until after I tightened the pivot stud nut, then spun the wheel. The sand block is a piece of 180 grit emery paper (3M weatherstrip-glued to a 2x4), and a strip of 180 glued to a paint stir-stick. A 10" flat rasp. The stir-stick sandblock is used to finish the bevel after rasping.
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#15

Post by VintageTwin » Sun May 15, 2005 4:19 pm

Here's Shop Dope 157A, 4/13/37, with the '57 style two-spring brake, from the Kick-Start catalog/manual. Excpet this is when they had a different front and rear shoe, before they went to a one-spring brake. It has both shoe linings, bottom edges beveled, beginning 1-3/4" back from the leading edge. The top leading edges of each shoe lining are beveled 5/8" back. An interestng note that is not included here, but is on the original Dope Sheet, is that allowing the brakes to chatter and applying them in an emergency can break-off the backing plates torque stud (the u-shaped bracket that fits into the rectangular-hole frame boss) and will allow the breaking plate to rotate, and then break the operating shaft, taking the brake out of commision. A more recent report from a rider said that his lug broke free and caused the rear brake to lock up at 55 mph on a freeway. Don't let the brake shoes chatter.
Bevel all the lining ends 5/8" back on the linings and that should do it. The way they talk in the early service manual; it seems that with the '38 one-spring brake, they changed the pivot stud to make it self adjusting, when you loosened the stud nut and held the brake pedal down to center the linings to the drum. You were told when removing the shoes; to remove the one spring and pry the shoes off. The pivot stud today isn't cam ground and I don't see how loosening it, holding the pedal down and tightening it, can help adjust anything. The pivot stud will be returning to it's same spot right? Or maybe the rear backing plate has a slot instead of a hole? A slot would let the pivot stud move whichever way the shoe centering procedure moved it.
The last pix is the beveled end of the bottom leading edge of the rear shoe. Bevel each of the four shoe ends the same way.[/b]
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Last edited by Anonymous on Wed Dec 07, 2005 3:57 pm, edited 8 times in total.

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