AO Platinum Member
Join Date: Feb 2002
Location: The land that Time forgot
Re: 155 rear brakes
The rear calipers seize up a bit these days, given the age of the cars. I doubt that just sticking new pads in will solve the problem but you never know.
First of all, there's a brake compensator valve under the car, near the silencer. It's held tensioned by a spring which sometimes rusts in the stretched position and therfore gets "loose".
Stick a new spring on there and tension the compensator properly (You have to loosen the lock-nut, hang a 10kg weight off the spring arm, and then tighten the lock-nut). That will ensure that the right amount of brake pressure is sent to the rear calipers (poor tension will send it all to the fronts).
Take the handbrake off before you touch the calipers. I don;t think you have to loosen the handbrake cable as it's supposed to be self-adjusting.
The calipers themselves are regular old Lucas Girling units. They have a wind-back adjustment on the pistons, so don't just lever them back with a clamp/screwdriver. Get a proper piston winding tool (£17 Halfords) and use that.
I'd work the pistons in and out a few times to try and free them up. Wind them in as far as they'll go, then pump the brakes to move the piston back out (mount the caliper back on the disc first, to stop the piston falling out of the caliper altogether!).
When you're happy they're as smooth as they're going to get, put your new pads in to gauge how much gap you need so that the pads fit over the disc and wind the piston back until you have just that gap. Fit the caliper and tighten the bolts. Repeat for the other side.
Once you've done both sides, then bleed the brakes. That's normal stuff. Finally.. adjust the handbrake (bolt under the lever itself, under the gaitor).
You may find the caliper pins are rusty. You can get yourself new pins in an overhaul kit (rather dear at £14 a side but you also get new rubber bellows etc.) or just emery yours until they slide in and out cleanly. Use lots of graphite/white grease on the pins (but clean out all the old grease and crap from the pin holes first).
Use copper grease on the backs of the pads etc. As you probably already know.
No bullets for Chaingun..