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#1 Rear calliper leaking?

Posted: Tue Jul 29, 2014 10:42 am
by peters3103
Hi all,
Well after several months of refurbishment my 61 fhc rear suspension has been reunited with the car. I removed it to have the differential rebuilt as it was noisy and had started to weep from the LH driveshaft seal. I took the opportunity to replace wheel bearings, radius arm bushes and replace seals and boots in the brake callipers. Also sandblasted and repainted everything and fitted GAZ height adjustable shocks and new springs. Had my first drive today and all was well until I noticed brake fluid dripping from the left rear. I've not yet jacked it up and had a close inspection but fear the calliper is leaking which means removing the whole IRS again. BLAH! Oh well at least it's nice and clean to work on and the nuts and bolts are new.

#2

Posted: Tue Jul 29, 2014 10:57 am
by christopher storey
Don't despair yet ! It may just be that you have not done up the unions sufficiently tightly, and these can be tightened without removing the suspension. I tested mine before I put it in the car, with compressed air and soapy water on the unions, and I was surprised just how tight they had to be done up to stop bubbles appearing even with as little as 20 psi

#3

Posted: Tue Jul 29, 2014 11:08 am
by peters3103
Thanks for the encouragement. I'll certainly be checking everything thoroughly before pulling the IRS out again.

Cheers Pete.

#4

Posted: Wed Jul 30, 2014 10:53 am
by peters3103
I've checked all the unions are tight and cleaned the brake fluid away. Looks to be leaking from the outside piston on the left calliper. (Not the brake pipe union). If I'm not mistaken it seems that piston can be removed with the calliper in situ. You get good access to the four bolts once the front rear shock absorber is removed. Does this sound right? Not sure why it's leaking as the callipers had new rubbers fitted.

#5

Posted: Wed Jul 30, 2014 12:43 pm
by christopher storey
Yes, you should be able to undo the four small fasteners and take cylinder and piston out . As for leakage, I'm afraid it's not uncommon for the seal to be trapped/kinked/turned over as the piston is inserted into the cylinder, and if this happens leakage is almost always the result. When you remove the piston you should be able to see if the seal is damaged in any way . If it is undamaged , use plenty of lubricant - preferably red rubber grease - and with the seal correctly positioned reinsert the piston dead squarely into the caliper. It is best to use gentle sustained pressure e.g. from a drill press to do this rather than a succession of light taps

#6

Posted: Wed Jul 30, 2014 8:31 pm
by peters3103
Thanks Christopher, will see how it goes.

#7

Posted: Sat Aug 02, 2014 10:20 pm
by peters3103
Ok, outside calliper cylinder/piston easily removed and dismantled to reveal the seal having been damaged during assembly. A 10 centimetre piece sliced off the edge. I have a new seal which I will install today once we get up a little from -6 degrees.

#8

Posted: Sun Aug 03, 2014 4:35 am
by peters3103
Apologies that should read 10 millimetres not centimetres

#9

Posted: Tue Aug 05, 2014 7:35 am
by peters3103
Calliper piston now with another new seal fitted and re-installed on car. Bled the brakes and all is dry! Glad I fitted remote bleeders - makes for a much easier job.

Pete

#10

Posted: Tue Aug 05, 2014 8:45 am
by christopher storey
Excellent, Pete. Good luck with it all