jamesmartin
Well-Known Member
they would be m10 x 1.25 or 1.00 but i couldnt say which without checking, not easy to buy except from specialist bolt suppliers like bapp
JoelC
Active Member
Hmm there is a bapp not far from me, that might be a saving grace.
JoelC
Active Member
Managed to get some - Sheffield Nut and Bolt company, really helpful guys.
Anyway, got everything back together, but still pretty poor breaking performance, but I think this may be the servo, doing some research, it looks like they can crack around the bolt holes, which it looks like mine has, there seems to also be a loss of pressure from the joints where the two halves are joined together. New servo ordered, so we will see.
Anyway, got everything back together, but still pretty poor breaking performance, but I think this may be the servo, doing some research, it looks like they can crack around the bolt holes, which it looks like mine has, there seems to also be a loss of pressure from the joints where the two halves are joined together. New servo ordered, so we will see.
JoelC
Active Member
allmakes cailipers - only temporary while i refurb the AP ones, if i can get the pistons out of them.
Air line usually works for me - at least enough to get hold of them with a vice or mole grips.... presume you are fitting stainless ones ? ...
IME, the genuine seal kits are worth the extra moolah...
Air line works for me anorl. It pushes the easiest one out first, so you have to slide that one back in and then hold it in with something so the air pushes on the other piston.
+1 on the genuine seals and SS pistons and you want that nice red brake grease to put on the new components when you slide them together.
Good memoryYep ^^^, and nice red paint on the calipers too
JoelC
Active Member
Struggled with an airline. They are soaking in paraffin in my wash tank, see if that helps.
Typical eh?
try two bits of bar inside the pistons in this sort of shape \/- push the two bits apart to lock inside the piston, ... and rotate the piston - should come out enough to get hold of with mole grips .... maybe 
Flossie
Well-Known Member
It's easier to split the calipers to remove stuck pistons, I never bother doing them complete anymore.
However....a couple of tips to try if you don't want to split them.
1- try pushing the piston back in then reapply the air, piston back in, reapply the air and repeat, this usually works.
2- try and rotate the piston too whilst doing the above.
3- it is possible to weld a piece of bar to the top of the piston, avoid too much heat, just a tack with a MIG, this will give you a handle to wiggle/rotate the piston.
I've had a piston that took all the above including gripping the piston in a vice and pressing the (split) caliper body off.
I've always found the bores to be fine even on the really stuck one, use cotton bud things to clean the bore seal groove, there is loads of dirt in there usually. Spend time to clean/derust the Recess that the wiper seal sits in , the new steel ring/seal will tap home nicely then. I used a flat blade screw driver and a Stanley blade to get back to shiney metal.
However....a couple of tips to try if you don't want to split them.
1- try pushing the piston back in then reapply the air, piston back in, reapply the air and repeat, this usually works.
2- try and rotate the piston too whilst doing the above.
3- it is possible to weld a piece of bar to the top of the piston, avoid too much heat, just a tack with a MIG, this will give you a handle to wiggle/rotate the piston.
I've had a piston that took all the above including gripping the piston in a vice and pressing the (split) caliper body off.
I've always found the bores to be fine even on the really stuck one, use cotton bud things to clean the bore seal groove, there is loads of dirt in there usually. Spend time to clean/derust the Recess that the wiper seal sits in , the new steel ring/seal will tap home nicely then. I used a flat blade screw driver and a Stanley blade to get back to shiney metal.
Flossie
Well-Known Member
The paraffin should help, have you dug out the wiper seal first?
jamesmartin
Well-Known Member
if youve fitted new calipers , the pistons will retract after pressing pedal due to the seal ,until theyve done a few hundred or more miles, you can improve it by pulling one pad out pressing pedal so as the piston/pistons move out 10mm or so then prise pistons back till you can just refit the pad repeat on other pads
jamesmartin
Well-Known Member
id rather have pairs of new calipers and the cheap ones have been more than ok, they wont last as long but then you could fit stainless pistons to those , i used to rebuild hundreds of calipers but why bother if you can buy new
JoelC
Active Member
Ok, so I'm almost at a loss as to whats going on.
So far:
If i clamp off the brake flexi's one at a time, there is no change, there is no weeping from any of the joints as far as I can tell.
Only other thing I am going to try is to reverse bleeding the calipers to see if that helps.
Anyone else have any suggestions?
So far:
- Replaced
- Calipers (Allmakes pattern part)
- Master Cylinder (OEM)
- Brake Servo (OEM)
- Front Brake lines and flexi's
- Bled the system multiple times - cannot see any more air coming out of the system
- Vacuum is good - enough to hold the pipe on the end of my finger.
If i clamp off the brake flexi's one at a time, there is no change, there is no weeping from any of the joints as far as I can tell.
Only other thing I am going to try is to reverse bleeding the calipers to see if that helps.
Anyone else have any suggestions?
Faulty seal in the master cylinder.
Then I suggest, bearing in mind the statement below, the master cylinder is fubar - presumably it's a new one and you can return it ??
Which supports the MC being duff...
