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bstratton
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Good morning gurus

I am very close to completing the restoration of my 71' R60/5. I noticed that my drive dog on my rear brake drum is loose. It is riveted to the drum. I have not been able to find anything about it in any of my service manuals. It looks like each rivet has a round head on the outside (hubcap side) of the drum and the end on the dog side was driven with a center punch.

First, I assume the drive dog should not be loose? second- does anyone know the correct procedure for re-securing the dog to the drum? Do I need to replace the rivets or can I just use a center punch to spread the dog side again? I think I could use my brass drift to keep the rivet head against the drum installing it between the rivet and my anvil.

Is this a common malady? Any insight would be helpful.

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Bstratton
1971 R60/5
1965 R50/2 (project)
MA

schrader7032
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San Antonio, TX
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Perchance do you have a

Perchance do you have a picture? I only know about "dogs" in the transmission...not sure what that is on the rear brake.

Have you looked at Duane Ausherman's website? He has quite a bit of stuff for /2 and /5 bikes.

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

bstratton
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I put the wheel back on the

I put the wheel back on the bike just for safety reasons. It is sitting on the center stand.

I am including the parts diagram. The dog is number 3 and the rivets are number 7.

It is the thing that slides onto the splined drive ring on the rear hub.

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Bstratton
1971 R60/5
1965 R50/2 (project)
MA

bstratton
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That didn't work. maybe this

That didn't work. maybe this will

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1971 R60/5
1965 R50/2 (project)
MA

bstratton
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this might help

this might help

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schrader7032
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OK, that helps...I guess I'd

OK, that helps...I guess I'd call those the rear wheel splines. Oak Okleshen has mentioned several times about replacing the riveted-on spline cup with one held on by 1/4-20 or better 1/4-28 plated allen cap screws about two inches long...they should have an unthreaded shank about 3/8 or 1/2 inch long. He also says that stainless is a good choice. Use wave washers and blue Loctite on the nuts. It's a tight fit and parts of the nuts might have to be ground to fit.

Snowbum has a discussion of this on his forum...he references the idea as provided by Oak:

http://bmwmotorcycletech.info/lesterwhls.htm

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

bstratton
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good stuff. thanks makes

good stuff. thanks

makes sense. just wanted to see what others did before I started experimenting on my own.

Excellent reference!

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Bstratton
1971 R60/5
1965 R50/2 (project)
MA

312Icarus
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Pean the Rivets?

You might try to pean the revits A good pean or punch, backed up with an anvil or heavy hammer ought to tighten them just fine. Peaning the rivets causes them to expand internally, filling the space and tightening the fitting.

I have peaned thousands of rivets on boats that leaked like sieves. After peaning they don't leak a drop.

Icarus

PS I believe the correct spelling is PEEN. But auto correct doesn't seem to like it.

Darryl.Richman
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You are right...

It is peen, whether your autocorrect likes it or not. (My autocorrect doesn't like "autocorrect"!)
https://en.wikipedia.org/wiki/Ball-peen_hammer

When I replaced the broken Hall sensor on my R65, the unit was riveted to its base plate, and the new one came with 2 rivets. I drilled the old one out and, with no previous experience, was able to flatten and expand the rivets with a regular flat punch (I have a cheap set from Horror Fright) on the anvil portion of my bench vise.

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bstratton
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That is what I did. I was

That is what I did. I was able to put a brass drift about 6" long against the heads of the rivets and placed an old piece of railroad track my great grandfather left in my basement as an anvil on the floor. I supported the drum above the anvil on the drift. I used a simple center punch to "peen" the rivets. they don't stick up past the face of the dog and the holes in the dog are tapered so I figured a punch would be best. It looks like that is what was used originally. It seemed to work. I'll check it in a few hundred miles. I'm just afraid the rivets might have become worn where they pass through the drum. I have no idea how long it has been loose. I figure that if it loosens up again I'll get new rivets and drill out the old ones.

Thanks for all the good info!

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Bstratton
1971 R60/5
1965 R50/2 (project)
MA

mark_weiss
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Using any sort of screw to

Using any sort of screw to secure the drive flange is a temporary fix, at best. When the rivets are set they expand to perfectly fill the hole in the hub (drum) and the flange. There are no gaps. Using screws, no matter how well they seem to fit, is a compromise. There will always be some play and eventually the fastening will loosen. Since the hub is the softest component of the assembly, it is the hub which will wear and that is not what you want to have happen. It is an expensive and entirely preventable repair.

Old rivets should not be drilled out, this risks damaging the holes in the hub and flange. Use a grinder to remove the rivet protruding from the flange and then drive the old rivet through.

The rivets are best supported by an anvil with a concave face and peened with a large, flat faced, drift. It is not the face of the rivet that you want to expand but the body passing through the hub and flange. Doing this manually takes a great deal of force and is VERY loud. The factory method probably used some sort of trip hammer.

Protective eyewear is a good idea.

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Mark
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bstratton
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The old timer at the local

The old timer at the local shop I use said the same thing. He doesn't like the screw fix.

He suggested that an air chisel with a punch ground flat worked well to expand the rivets. He also suggested some heat to soften the steel rivets. Even though the dog seems to be tight now - I am going to try that. I need to use a drift to back up the rivet heads. I support the drift on an anvil. It takes a couple extra hands but seems to work well. I"ll also grind the drift end to be as concave as I can make it. I'd like not to have to deal with this again and certainly don't want to have to buy a new drum.

Thanks for the sage advice

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Bstratton
1971 R60/5
1965 R50/2 (project)
MA

mark_weiss
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Be careful with heat. The

Be careful with heat. The temperature at which steel anneals is higher than the temperature to melt aluminum.

New rivets are annealed steel, they harden as they are peened into place. The air hammer sounds like a good idea, use hearing protection.
For rivets which are already set, the concave anvil is probably not of extreme importance, you'll probably just end up with a flat spot on the head of the rivet. More important is preventing the wheel from moving around.

I've replaced rivets in flanges which have had a few rivets break and fall out and have not found any damage to the brake drum. In fact, the drive flange has always been tight, even with missing rivets. On the other hand, I've scrapped a few drums which had the flange tightly bolted into place, but still worked loose.

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Mark
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bstratton
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I tore this bike completely

I tore this bike completely down and repainted all the painted parts, replaced worn stuff - re-spoked the rear wheel and cleaned everything else up. I had a valve job done including new valves, springs and guides - replaced rings and gaskets. Nothing more on the engine or tranny. It is all back together except the headlight bucket and wiring harnesses. It ran great before I tore it down except I noticed that it was clunky when shifting... It clunked when I engaged the clutch - unless I was extremely gentle. I wonder if the loose flange might have contributed to that?

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Bstratton
1971 R60/5
1965 R50/2 (project)
MA

mark_weiss
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That's when you would hear

That's when you would hear it.

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schrader7032
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Not sure about the rear end

Not sure about the rear end being clunky, but generally BMW transmissions are clunky, too. It can be helped a bit by cleaning up your shifting technique, preloading the foot lever before a shift and holding the shift lever all the way through letting out the hand lever.

As for the rear wheel splines clunking...seems to me that if it was that loose, it would only take a handful of clunks before the rivets sheared off. IMO the clunking wasn't the rear end.

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

mark_weiss
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It is doubtful that you'd

It is doubtful that you'd hear or feel a loose flange during shifting, unless it was REALLY loose. If noticeable at all, it would be felt just as the driveline loads up when pulling away from a stop. Maybe at low speed throttle roll-off, but that would be more likely to be other driveline free play.

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bstratton
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with any luck I'll be able to

with any luck I'll be able to test the theory soon. others have told me the 4-speed, in particular is clunky. feels like Play somewhere in the drive train to me but I didn't see anything a miss with the drive shaft or rear end other than the loose flange. I've been riding a long time and I'm sure my technique could be improved but it has never been an issue on other bikes. I did not tear the tranny down and have no plans to unless I believe there's a real need.

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Bstratton
1971 R60/5
1965 R50/2 (project)
MA

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