2001 4.2 A6 brake caliper trouble
 

Hello,

While replacing pads and rotors I noticed the right outboard piston had seized. After a couple of days of saturating it with lubricant, the parts finally separated but the dust boot is wrecked. This is a Lucas 4 pad "floating" caliper system. The dealer says that rebuild kits only come with rubber for the two inboard pistons, and that I'd have to replace the caliper. At $770, I'm desperately trying to find another alternative. Has anyone found a replacement for this 50C piece of rubber?

Thanks,
plasma6

I'm confused.

These are HP-2 calipers?

Regardless, i dont understand what part you can't get. A floating caliper has one ( or two) pistons, on the inside. The other half of the caliper slides on guide pins, which can also be replaced or cleaned and greased. The pressure for the outer pads comes from newton's "equal and opposite reaction" - there is no piston (or else it doesn't float)

What part can't you get?

Before you spend $770 for a caliper, have you checked aftermarket? Typically calipers (BMW for example) can be had for about $250.

Grant

Those calipers don't have outboard cylinders; they only have two cylinders and they are both on the inner half of the caliper. If the rebuild kit has dust boots for the inboard cylinders, that should be all you need.

Grant,

Sorry about the confusion, I'm not sure what to call this part. My Bentley manual calls it a piston, and that is what it looks like. I realize that it is not hydraulically actuated, and it is more like a big guide pin located in the centre of the outside half of the caliper. It is the same size as the inside pistons, and has (had) a protective rubber boot. The "floating" caliper slides on the two conventional upper and lower guide pins, and also on this big, centre guide pin.

If you have the Bentley manual, it is pictured on P46-10, illustration A46-0120. The rubber dust boot is right above the tip of the screwdriver.

Thanks,
plasma6

i'll go look.

OK, got it. That's not a piston, that's the guide pin that the outer half of the caliper slides on. The boot keeps grease in and water out. I cannot imagine they are not available, but if you ask for the oputer piston rebuild kit, yea, they may send you for a bucket of steam or a left-handed smoke shifter. It is a guide pin kit. Will come with new pins and new rubber thingys. each is different. In fact, there may be mroe than one guide pin, i'm not sure. If you go to the tech section, and look through it, i wrote a tech article how-to on these, using a C4 rear caliper as the photo model. Go read it.

Call blau, ecs tuning, others that have goods OEM and aftermarket stock.

I generally just clean and re-lube. Obviously you can't. However, if you really ant get the part, clean adn lube what's there and get the closes possible thang and see how to attach it.

For the record, my bentley doesnt call it a piston. The pistons they refer to are on the far right, behind the inner pads. That's bentley with one "T" right?

What monkey damaged the grease cover? AIA if you.

Grant

Thanks for the help, I'll try to find the piston rebuild kit.

Yes, I'm the monkey...

What does AIA mean???

Apologies in Advance :-)

sounds like you need a piston rebuild kit (maybe, i dont recall you explaining why you need it) and clearly a guide pin boot, plus some high temp grease sold specifically for brake components.

Grant

Hi call this number 877 347-2225 his name is John. His company is called Goldline Brakes. Look at Goldlinebrakes.com. I think he will be able to help you. Tell him Ron from TX told you to call.

Thanks for the help folks, I'll give John a call.