Hope someone can help (Eric Shea? are you out there?). I rebuilt the rear calipers on my 71, and went to adjust the venting clearance on the right side and ran into a problem. The adjuster on the outside half just spins without pushing out the piston. I am guessing I assembled it incorrectly but when putting it back together I swear everything was working (2 weeks ago), now it just spins.

Hope someone comes up with easy solution, or else tomorrow off it comes and I will tear it apart and check it out.

Oh, by the way, thanks Eric Shea for the rebuild write up in the Classic Forum, could not have done it without you.

Jim

I assume you are turning it in the correct direction.
Does it spin easily or with significant effort?
Did you reassemble the internal mechanism correctly and get it seated in the groove? If it is not seated in the groove then you have to adjust it until you hear it snap into place. With some effort you can get the whole assembly to spin within the piston, but if so, I'd have to say you did not do the rebuild correctly. Both Eric and I put a lot of effort into the rebuilds so that the customer does not have these problems. Lots of custom tools and trick required, and tons of experience. Even then it is not a trivial matter. Each caliper takes hours to disassemble, clean, and reassemble.

sounds familiar.

http://www.914world.com/bbs2/index.php?showtopic=74724

Sounds like you dont have the "C" clip on outer threads. Without that it will just spin and go nowhere.

It spins easily in both directions after the lock nut is loosened. The inner piston is working but not the outer. When you say 'internal mechanism' you are talking about the adjusting screw? Is it possible to have the piston too far into the bore to the point the adjusting screw won't "catch" the piston to adjust it out? And the c-clip is installed.

It's not the end of the world to disassemble it tomorrow, FWIW the left side works great after the rebuild. I can now appreciate how much time you guys put into rebuilding them, and for the price you charge I don't know how you make any $$ . It was a rewarding project though, I guess I will have to have a second go at the right rear if there is no more wisdom.

Thanks to all, keep the ideas coming!

Jim

a parts breakdown of the external adjuster

note the position of the circlip in the mechanism, you must not invert the mechanism in the piston otherwise the snap-ring will not go in the groove.

by the way, please do not totally wear out your pads or you may see this

Thanks for the pics davep. I will have check and make sure it is set up correctly.

Jim

LOL I have one of those on my bench as well

I'm "guessing" the spring mechanism in the lower left hand corner of Dave's previous picture may not be snapped into place where the 90 degree bend at the top (in that picture) is.

I haven't seen the "Crusty One" weigh in here but he would say do not pull them in without a thumb on them. This helps aleviate the strain on this spring preventing it from popping out.

You can drop a stop piece down the adjuster hole and screw the adjuster in as seen in the last picture posted here. Once the adjuster hits the stop piece it will begin pull the mechanism out of the piston. This is kinda advanced stuff and I don't really recommend you try it without knowing what you're getting into.

It may simply be the internal mechanism spinning. You may want to try high speed bursts with an air wrench in the "COUNTER" clockwise direction. Believe it or not, this has been known to get it moving. Try that "first". If that doesn't cure it, PM me and I can get you another piston.

You "can" get that pitson out without it working. Simple take the clip and nut off and tap the adjuster in with a plastic or brass mallet. You will see the piston begin to move out as the adjuster taps in. Once the adjuster gets close to the caliper surface, back it out and tap it again. If it keeps spinning simply tap the piston out with a long 4mm hex. Make sense? This is how I remove all of my outer pistons as I simply don't like using the adjuster on old grundgy calipers. It helps save the adjuster for future use.

Good luck.

Eric,

You rule! The air wrench trick worked. Funny thing is I was gonna disassemble the darn thing today, but got busy with the family and put it off till tomorrow. I saw your reply and went out to try it, and once again you saved me a bunch of time.

Not sure how my neighbors felt about hearing the air tool at midnight but hey, I needed to try it

Thanks everyone for the help!

Jim

Way happy that it worked for ya!

There is nothing to stop the adjuster from spinning in the piston, just friction. If you lube it up too much during assembly, then there is almost no friction. Spinning with the air wench may scuff away some of that lube and increasing friction to the point that it works as intended.

Yup.

I never grease that assembly. I do however put a dab on the adjuster shaft. I think the high speed spinning is enough to overcome the inertia of the mechanism and the adjuster.