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Thu Mar 29, 2012 7:01 pm

I'm attempting to rebuild some late model calipers that I picked up, and it appears that both have at least one stuck piston. I've tried using my air compressor and even with it at 90 PSI, they aren't moving. In my searches, I've seen people use grease guns to get them to pop out. Has anyone tried this trick? Is it worth it due to all of the clean up with the grease in the caliper? Unfortunately the car is in pieces, so I can't just hook it up to the master cylinder and apply brake pressure.

Thu Mar 29, 2012 7:10 pm

I did it when compressed air wouldn't work. It works great. A mess to clean, but what else are you going to do? They don't come flying out like with compressed air either.

Thu Mar 29, 2012 7:21 pm

I bought new calipers when I was unable to solve the problem you have. :(

Fri Mar 30, 2012 12:57 am

if they are out
put Trans fluid in them for a day and take them apart and smack them back in
Then used compressed air OR the power of the pedal to push them out

Fri Mar 30, 2012 7:11 am

gtixpress wrote: I'm attempting to rebuild some late model calipers that I picked up, and it appears that both have at least one stuck piston. I've tried using my air compressor and even with it at 90 PSI, they aren't moving. In my searches, I've seen people use grease guns to get them to pop out. Has anyone tried this trick? Is it worth it due to all of the clean up with the grease in the caliper? Unfortunately the car is in pieces, so I can't just hook it up to the master cylinder and apply brake pressure.

Jim Adney actually uses water to push them out. It's easier to clean up too. :wink:

Fri Mar 30, 2012 7:41 am

I sent mine to Jim Adney for the complete rebuild - no muss, no fuss...

Fri Mar 30, 2012 8:58 am

Thanks for the replies. I guess I may just go ahead and try it. What do I have to lose, especially if they are stuck anyways. I thought about having them rebuilt but for the same price I can always just get new ones instead (and upgrade to the larger BMW calipers).

Mon Apr 02, 2012 12:27 pm

Well the grease trick worked. I was able to get the pistons our of one of the calipers and they look pretty good. Where is a good place to get rebuild kits, and is there a difference in them? I've seen some that are $12 and others that are $40.

Mon Apr 02, 2012 1:00 pm

I use the grease method every time, I usually just clean the pistons /bodys and reuse the seals there usually better looking that the ones in the rebuild kit.

Mon Apr 02, 2012 2:51 pm

gtixpress wrote: Well the grease trick worked. I was able to get the pistons our of one of the calipers and they look pretty good. Where is a good place to get rebuild kits, and is there a difference in them? I've seen some that are $12 and others that are $40.

The good NOS rebuild kits have the locator plates for the pistons. Hopefully you still have yours. If you do, I'd be tempted to try a set from rockauto as everything else appears to be there.

Mon Apr 02, 2012 7:44 pm

Yea, I still have the locator plates, pad guide pins and new mounting bolts. I'll probably try one of the cheaper sets and see how they are.

Tue Apr 03, 2012 12:37 pm

Famous Last Words
(especially when applied to brakes):

Quote: I'll probably try one of the cheaper sets and see how they are.

Tue Apr 03, 2012 7:49 pm

Have a better suggestion? Considering most kits probably contains the same exact seals. And I'm not going to buy a more expensive kit just to get extra pieces that I don't need. I've looked at kits from Autozone, CIP1, Rockauto, etc. They all appear the same, with CIP1 being the most expensive due to extra parts. And being original Type 3 calipers, they aren't available aftermarket (these have the pin behind the piston). Down the road I will probably upgrade to the larger BMW caliper, but that's an unneeded expense at this point in time. I would rather just get the car driving.

Wed Apr 04, 2012 4:57 am

gtixpress wrote: Have a better suggestion? Considering most kits probably contains the same exact seals. And I'm not going to buy a more expensive kit just to get extra pieces that I don't need. I've looked at kits from Autozone, CIP1, Rockauto, etc. They all appear the same, with CIP1 being the most expensive due to extra parts. And being original Type 3 calipers, they aren't available aftermarket (these have the pin behind the piston). Down the road I will probably upgrade to the larger BMW caliper, but that's an unneeded expense at this point in time. I would rather just get the car driving.

Joe, do you already have the late spindles and rotors for them? Just asking, because the late caliper won't bolt to the early spindle (mounting hole spacing is different).

Wed Apr 04, 2012 10:13 am

Yes, I have the proper spindles for them. Managed to score an NOS set a year to two ago. New rotors and bearings are also planned.

Wed Apr 04, 2012 6:10 pm

gtixpress wrote: Have a better suggestion? Considering most kits probably contains the same exact seals. And I'm not going to buy a more expensive kit just to get extra pieces that I don't need. I've looked at kits from Autozone, CIP1, Rockauto, etc. They all appear the same, with CIP1 being the most expensive due to extra parts. And being original Type 3 calipers, they aren't available aftermarket (these have the pin behind the piston). Down the road I will probably upgrade to the larger BMW caliper, but that's an unneeded expense at this point in time. I would rather just get the car driving.

Get the complete best kit you can. Other than the anti-rotation plates..saving naything else is false economy. All the parts have huge heat cycles on them Get new sprerader springs and pins.

The difference is usually un the quality of the outer boot material and fit. You get what you pay for. Also with all of the current world problems with EPR, Buna and EPDM rubber...buy the best you can and take as few chances as possible.

A word about rebuilding them.....mix a small amount of muratic acid with water...about 50/50 or 60/40 water...soak the calipers in them and it will remove all rust period...just dissolves it.
And to those about to say it...no...it has no effect on the seals between the calipers. Then rinse with water and oil quickly with WD and wipe clean.

The inspection part: rust pits in the cylinder walls hurt notthing as long as rust pits that intersect the seal groove do not cross over and continue on the other side of the groove..either from the outside in or inside out. If they do the caliper is shot because fluid can pass across in these rust pits/grooves.

The piston....small rust pits are ok...as long as none of them are as wide or wider than the innser seal itself. If they are..they will bypass fluid.
The piston is more critical than the bore because the seal seals aginst the piston which moves through the seal.

Yes...you can use a hone....but its not necessary. You do not want honing marks in any brake cylinders. These are not piston rings. You want the surface very smooth.

I clean with 400 grit maximum to get the rough stuff off. Do not over do it. then lap it with 800 up to 1500 grit. Use 1000+ on the piston only.

Clean well in hot water...dry with compressed air and quickly lube with brake fluid. Then assemble immediatley. If you do not install immediately..tnen pump brake fluid through them, fill them, cap the port and keep them in a plastic bag. Do not wait too long as the fluid absorbs water. Ray

Wed Apr 04, 2012 7:58 pm

Thanks for the info. The calipers are actually in pretty good condition. I didn't see any real rust on the pistons or in the bores. I think they were just gunked up a little bit and that's why they wouldn't come out. I cleaned everything with Simple Green to get rid of the grease. Then washed them off and dried with compressed air. Then I sprayed the bores/pistons with some PB Blaster to prevent any flash rusting. I don't see any pitting on either the bore or pistons which is good. They are also stored in ziploc bags.

Is there a certain brand of seals to look out for? I haven't seen to many VW shops actually list the brand of seal kits that they sell. Sometimes the auto parts stores will.

Fri Apr 06, 2012 3:38 pm

gtixpress wrote: Thanks for the info. The calipers are actually in pretty good condition. I didn't see any real rust on the pistons or in the bores. I think they were just gunked up a little bit and that's why they wouldn't come out. I cleaned everything with Simple Green to get rid of the grease. Then washed them off and dried with compressed air. Then I sprayed the bores/pistons with some PB Blaster to prevent any flash rusting. I don't see any pitting on either the bore or pistons which is good. They are also stored in ziploc bags.

In the online sites you will likely find centric, Dorman, raybestos and occasionally Cardone. Oddly...Centric has been making quite nice rotors and calipers. I do not have expereince with their rubber kits but the rest of their stuff is nice.

Dorman is a fairly wel known supplier and is generally a B or and A quality.
Raybestos makes good stuff and poor stuff in the past two years. I use their pads only.

If you can find any original makes like ATE or FAG...those would be best.

Also most of what I have found kit wise through the Beck-Arnley World parts chain stores is excellent. Ray

Is there a certain brand of seals to look out for? I haven't seen to many VW shops actually list the brand of seal kits that they sell. Sometimes the auto parts stores will.

Tue Apr 17, 2012 2:19 pm

How about these kits?

http://www.thesamba.com/vw/classifieds/detail.php?id=1179514

Is that a good price?