Help with break calipers

[franklinhill]

just bought my first silver shadow rolls royce and i was in the process of checking / changing the break pads and i am stuggling with sorting out the calipers. The pistons in the caliper just wont go back (although the did come out further). I have tried easing the pressure of fluid, tried clamping, and tried force but nothing budged them. Is there a special tool i need or a particular way to do this anyone can advise me about. Any advice would be welcomed.

[dilbert]

franklinhill said:

just bought my first silver shadow rolls royce and i was in the process of checking / changing the break pads and i am stuggling with sorting out the calipers. The pistons in the caliper just wont go back (although the did come out further). I have tried easing the pressure of fluid, tried clamping, and tried force but nothing budged them. Is there a special tool i need or a particular way to do this anyone can advise me about. Any advice would be welcomed.

If the pistons are rusty where they stick out from the caliper, then it's unlikely that they will go back. If they are rusty, you may be able to clean them up, you may have to replace them.

Either way it might make sense to take the whole caliper off the car, so that you can work on it. That way you can replace the seals in the calipers while you're at it.

[franklinhill]

thanks for reply - have checked this and they dont appear to be rusted anywhere

[dilbert]

Hmm, well it's difficult to tell from here!


It could be that the pistons have become skewed in the caliper, especially if they have been withdrawn some way.

I don't know, there may be something specific to your particular car. Whenever I've encountered this sort of problem in the past, I've just dismantled the lot, inspected the parts, eradicated the demons, and put it back together again.

HTH. Maybe someone else understands what you're facing?

[F.M]

I take the cap off the master cylinder..cos the fluid will rise when they go back and need the room to expand then use a long bar with a tapered end to force them back...which sometimes doesn`t shift it...I then use my trusty ball joint splitter which again is like a chisel with a tapered forked end and hammer the barsteward in ..forcing the pistons back in ..always works ..no matter how rusty the pistons.. although the edge of the pistons can end up slightly dinged but they still slide in & out perfectly as any small dents/damage is limited to the outside edge which never goes back into the caliper bore...Not sure if I would do the same on very expensive calipers on a RR but time waits for no man...

Edited by F.M on Saturday 7th October 19:11

[m.lovell]

Sound like you need to remove the pressure from the brake system, it runs at 2000pis and will stop you pushing the pistons back in. I would replace the old pads pump the drake pedel with out the engine running untill the brake pressure warning lights come on for brake system1 and brake system 2. I think you will then find it quite easy to push the pistons in.
marc