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312Icarus
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I just put new (NOS, that I have had for 40 years in my parts box!) brake linings on the rear of my 68 R50 US. I backed the adjuster off nearly completly to get the wheel (drum) back on. All good so far, but now I’m trying to adjust the pedal free play and here is the problem. I have to back the nut on the pedal rod so far that nearly no threads stick out to get the tire to spin. Before, it was projecting beyond the nut by ~1/2”. The old linings are nearly as thick as the new ones, (they were grease soaked due to a final drive leak).

So the question is...do the new linings need to be “arced” the way old school auto drum brakes were. I can’t imaging that I have to take the entire linkage apart to gain a few mms of travel.

Once again, thanks for all the good advice,

Icarus

312Icarus
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PS. The new linings are 4mm

PS. The new linings are 4mm thick, the old ones a bit over 3mm, nad are very consistent thickness over their length. I would think that the additional 2 mm over the circumference of the drum would be enough to make such a huge difference on the adjustment.

Icarus

wa1nca
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VBMWMO #8374
Ashfield Ma.
Joined: 09/27/2012
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Brake shoe linings

Just checked and new linings should be 4mm
If the brake linings are seated ok on the brake shoe and are uniform in thickness and return all the way then you may have to remove the brake lever forward a little to get freeplay when the pedal is released

Ps
At least you didn't have to shim bearing pack

Tommy

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Tommy Byrnes
54 R51/3 55 R50 64 R27 68 R69US 68 Sears Allstate 250 (Puch)

312Icarus
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I’m going to have to figure

I’m going to have to figure out how to move the pedal forward. Thanks Tommy

Tony (Icarus)

wa1nca
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Ashfield Ma.
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Rear Brake Lever

Reposition rear brake lever # 3 in diagram
Remove nut and brake lever

Move forward 2 notches
Dont try to seat it all the way
Start nut and tighten to draw the lever into brake shaft

Tommy

  • bmw-r50-to-r69s-rear-brake.png
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Tommy Byrnes
54 R51/3 55 R50 64 R27 68 R69US 68 Sears Allstate 250 (Puch)

312Icarus
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I actually put some 120 self

I actually put some 120 self stick sand paper on the drum, marked the linings and ran it around a few times and it is much better. The shoes make full contact, and after a test run, the rear brake is better than ever. The adjuster is still a bit further back than I would like, but I have some thread coming through now so I think I will let sleeping dogs lie.

Thanks for the advice,

Icaruis

schrader7032
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As Tommy said, that shackle

As Tommy said, that shackle is normally marked with a punch relative to the splines so it gets put back the way it came off. I don't know if this was a parts box bike so there might be no way of knowing. The best position of that shackle is such at as the brakes are being applied, it makes a 90 degree angle with the brake rod. That's the point of maximum power.

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Kurt in S.A.
'78 R100/7 '69 R69S '52 R25/2

wa1nca
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New Brake Pads

Very nice
I am sure someone else can learn from this tread

Tommy

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Tommy Byrnes
54 R51/3 55 R50 64 R27 68 R69US 68 Sears Allstate 250 (Puch)

312Icarus
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It is not a “parts box” bike.

It is not a “parts box” bike. I have had it for over 40 years, but it has been idle for more than 20 until a couple of years ago. I’ve never had the brake rod or arm off in the entire time I owned it. The final drive seeped as it sat and soiled the shoes. I burned them off to run it for tests not wanting to soil a new set. Alls good with the final drive, so I decided to recline the shoes.

I think it is good enough, I have some pedal free play, some threads showing after the adjuster nut, the cam fully retracts, and the rear brakes are better than ever.

Thanks all for the advice.

Icarus

wa1nca
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Cluth Adjustment

Yes Kurt
Same goes for adjusting the clutch bolt
It should just start to engage the clutch when the clutch lever is at 90 degrees

Tommy

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Tommy Byrnes
54 R51/3 55 R50 64 R27 68 R69US 68 Sears Allstate 250 (Puch)

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