Hey Everyone,

As per usual what should just be a quick job (replacing rear brake pads and rotors on my '95 940T) is turning out to be not as easy or quick as it first looked like it would be.

First of all, one of the pistons in one of the calipers appears to be seized. The other 3 pushed back into the calipers with ease but one of them just refuses to budge.

What's the best/easiest way to deal with this ? Replace the caliper ? Or should I replace both just as a matter of course ? If replacement is the best option, where's the best place to get them ? Can you get refurb units or are they always new ? (It is an ATE caliper BTW). Can anyone get a good price on one ? (?

Secondly, I can't seem to get the @#*$$! rotors to come off. Bit of rust in there I suspect. I've tried beating on them with a dead-blow and prying a bit from behind with a long flathead screwdriver but nothing seems to be working. I sprayed some penetrating oil around the hub and studs to see if that will help. Letting the stuff work it's way in for a few hours now then will try again (Parking brake is released BTW).

What other tricks/techniques can I use ? Should I try and heat the hub part of the rotor with a blow torch ? Is there some kind of special puller I could use here ? Anyone have one that I could borrow ?

Any helpful suggestions/ideas would be most appreciated.

Thanks,

Roj

Heat and hammer is the only way I know, and let the penetrating oil sit overnight.

I'll try and get some prices for you after work. If you can't free up the piston, then you basically need to replace the caliper, unless you want to try rebuilding it. They're not expensive though, and they're usually refurbed.

To get the lines out I use penetrating oil, a torch and some 10 inch straight jaw vise grips

about $80 ea for front or rear calipers. $35 for front pbr deluxe pads.

To get the rotor off the hub.

Take a 3lb hammer to the face. A few solid blows and it should pop off. Don't hit the rotor surface, just the part where the studs pop through. Careful not to hit the studs.

This is how I get them off at work, even those rust bucket east coast cars will come apart this way.

Once the disk is loose on the hub, you might have a fun wiggle/pry time with getting the disk over the handbrake shoes.

Jordan

SInce the rotors will likely get replaced, I wouldn't be too worried about bashing the face. A brass mallet probably wouldn't even scar it...

Toss a spare set of lug nuts on the studs and have at it with a BFH. Mine came apart relatively easily, but you can see how it could rust on as the axle and the hat can get water inside pretty easily. Perhaps a smear of grease while installing will make this easier in the future.

What have you tried to get the piston out? I'd soak it down with PB blaster once the dust covers are off of course. Then try to drive it back with a C-clamp. If that doesn't work, try to push it out with compressed air using a piece of wood to stop the pisont from flying out. To do this you have to put the other pistons back in.

If any of this takes more than about 15 minutes - get the rebuilt ones.

Wouldn't be too worried about marking the rotor as putting a bunch of runout into it.

After a little work with the torch and a goodly amount of bashing I got one of the rotors off. Haven't tried the other one but I'm confident it shouldn't be too difficult to get it off.

I managed to get the sticky piston to move with a long crowbar. Then I put a set of well worn pads in, fired the car up and pumped the brakes. Then after wiggling the pads out I tried to move the sticky piston again and it was still very sticky. I couldn't get it to budge with a good sized pair of channel locks (which easily moves the other 3 pistons). After consulting with Volvord (he who knows all, sees all and foretells a good proportion ) on the issue I have decided to replace the caliper. I just priced one out through Bowness AP and Athal's price smokes 'em.

Guess I'll be checking the brakes on the 740 Ti soon to see if I need to be replacing any pads or rotors on that car.

Thanks for everyone's helpful suggestions. Much appreciated !!

Roger

just be careful with the brake line when taking the caliper off, use the method I said and you shouldn't have a problem. They seize up nicely and a lot of tools will just round the fitting or snap the line.

Will do ! Thanks Andy