1937-1957 Rear Brake- Fit Problem

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VintageTwin
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#16

Post by VintageTwin » Mon May 16, 2005 6:17 am

The only place you need to grease are both sides of the shoe bosses . Put a tiny bead on the scalloped edges of the (top) shoe end and wipe a film on the (bottom) shoe ends. No grease in the pivot cup. All the grease will do is pick up grit and become a coarse rubbing compound. A heavier amount of grease will separate and eventually drop to the bottom of the drum and wind up on the shoes.
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Panacea
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mechanical drum brakes

#17

Post by Panacea » Mon Oct 17, 2005 2:21 am

HI...I've had my rear mechanical brake jackhammer itself to peices, on two different bikes! My 49 and my 51,on the 49 not only did the torque loop on the backing plate shear of like butter but the arm also rounded itself on the square cam shaft. unfortunatly I only had rear brakes at the time,so me and my bike were on foot, only a couple miles....On the 51 I thought I was re-living an earlier experience, But having just bought the bike, and failing to do a complete inspection before my first ride,found out there was no axle nut on the bike,the rest was history...repeating itself. On the last post you made reference to how loosening the pivot stud with the brake on and re-tightening could make a diference,the pivot stud is in an elongated hole so the stud can move to find it's center. Thanks for the info on shoe fitment,I'll be fixing up this 51. I'm glad I found this site for very usefull information.PANACEA

VintageTwin
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#18

Post by VintageTwin » Mon Oct 17, 2005 2:47 am

I've heard that several things can make the rear backing plate to frame anchor-cleat break off. The operating cam having too much freeplay in the bushing, and/or combined with worn down shoes will alow the brake to lock when the pedal's hit hard. The anchor cleats on the AM backing plates not being securely (flush) riveted and failing under brake chatter, and all four of the brake lining ends not being tapered and causing chatter. If I had an AM rear backing plate I wasn't sure of, I think I'd arc-weld a puddle over each of the anchor plate's flush rivets just to be safe.

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Re: 1937-1957 Rear Brake- Fit Problem

#19

Post by 58flh » Mon Oct 17, 2011 2:29 pm

VT------I to had the same issues!---You have to place in drum & I would spin /with very minor brake applied!(minor)-take it all apart & start filing,Also I got a new plate from J&P cycles-V-Twin,I have a rivet machine I bought from an old school shop going out of biz. sale. I rivet all my shoes from center-out!--Basically I did the same as you had to, after everything is finally done!--ALWAYS apply brake before tightening axle! I have no lock-up problems/& I can lock them up to a skid-with no problems after!---Very good wright-up for the men!----58flh :!:

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Re: 1937-1957 Rear Brake- Fit Problem

#20

Post by Sir_Rat » Mon Oct 17, 2011 11:03 pm

I guess I lucked out...I bought the complete rear brake assembly from V-Twin and it all fit fine. I still need to adjust and arch the shoes...I guess its just the luck of the draw.

Aloha..Mike

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Re: 1937-1957 Rear Brake- Fit Problem

#21

Post by PanScott » Sat Feb 04, 2017 10:27 pm

In regards to the VT cast brake drum, mine had issues. I checked it for run out and it was at about .010". I turned it (actually bored)just to get a clean up that took about .020 on the diameter. When I put it on my 1956 FL The shoes rubbed the face of the drum where it was machined during manufacturing. This is afer I beveled the edges AND ground the brake linings flush with the VT replica cast shoe. Worst of all.... the end of the pivot stud rubs on the inner face of the drum as well.
The OEM backing plate is straight within .010", I had to straighten it so I know it is. The operating cam is new so is the bushing. and the pivot stud is assembled correctly. There is just not enough clearance in the drum. Back to the machine shop monday and I will take about .025 off of that face, hopefully that will be enough.

I definitely prefer the cast over the stamped drum but on my bike at least it is not "bolt in". Good thing I am a machinist.

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