AU Sedan(6cyl) front brakes not releasing

[4ford]

Does anybody have any experience of AU2 front brakes not releasing fully, and thereby running hot, both sides.

I'm about to replace the master cylinder, which raises another question for anyone on the north side of Brisbane, where is the best place to buy/exchange a replacement.

I looked on eBay, but there is a distinct lack of m/cylinders to suit!

Any help with a good local place to go?

Cheers

[Ford Falcon XR6]

Have the Caliper slides been greased when pads have been replaced ???

[whiskers]

try repco at Morayfield, I replaced my rear callipers as an exchange unit they got them in for me the afternoon I wanted them. good service and price (can't remember the price though)

[AMB]

A common reason for the brakes dragging are the pistons partially seizing in the caliper. It happens when the fluid hasn't been flushed regularly (maybe never since new), rust develops and the pistons start to seize. Only way to check really is to remove the caliper and see how easy it is to push the pistons back in, they should move smoothly and pritty easily, if there's any sign of corrosion under the boot, very dirty, rubber boot torn and maybe slightly moist from slight seepage around the psitons then that's probably your problem. If you are lucky, they may only need to be dismantled, cleaned up thoroughly and replace piston seal and boot.

[GK]

You are able to buy a reconditioning kit for calipers from Repco and such places. Apparently it's pretty easy to do and not very expensive.

I haven't done it personally, but I know that JC has. You could PM him and ask about it, as he's a very helpful bloke.

Whatever you decide to do, all the best with it.

GK

[AMB]

Yeh easy, only one moving part, the piston(s). kit costs about 20-30 bucks. Depends on how bad any corrosion is, u need to thoroughly clean it up with 1200 (or finer) wet and dry and assess how bad the pitting is, you can get away with slight pitting (if you make it really smooth). A brake specialist will say no, but I've done it quite a few times with no problem for many years. The worse that can happen (if you know what you are doing) is that the pitting will slowly wear the seal, and it might start slightly leaking after 5-10 years.

[GK]

Thanks for that extra info AMB.

Are there instructions in the kits?

GK

[AMB]

No instructions, competency is assumed. Not much to know anyhow, a repair manual might give a few tips. Like if the piston is stuck/seized, you can use compressed air to blow it out, or if its really stuck or no compressor, you can use the car's hydraulic pressure to pop it out (leave the old pad on, and wrap the area in lots of rags so the piston is well protected when it finally pops out with force). Work in a clean area, fresh clean rags, final clean with metho, lube the new seal, piston and bore with fluid, push the piston in square and carefully so not to pinch the seal. You usually slip the end of the dust boot/cover over the piston before inserting the piston. Hard to get the boot in its groove once the piston is inserted. Make sure the dust boot is properly seated in the grooves, twist it around and push the piston all the way in to check the boot is seated in the grooves properly. Just checking the repair manual it says to lube outside of piston and boot with rubber grease. That's about it.

[mik]

or if your not confident just whip the calipers off and wizz them down to the local brake bloke (in another car) who would probably have them done in a couple of hours or less if he can do them straight away and for not much money.

[JC]

Originally Posted by GK

Thanks for that extra info AMB.

Are there instructions in the kits?

GK

The kits I bought years ago came with instructions, but they were fairly general with a definite level of assumed knowledge - 1st one took me around 90 mins, but after that, each one took less than 30, including sanding the piston etc.

[4ford]

Thanks guys for all the good info.

The reason I elected to replace the master cylinder, rather than the calipers, was because of the fact that both the fronts started to drag at the same time.

Is this a coincidence, I'm thinking the problem is something common to both sides, i.e., the master cylinder!

Your thoughts....

[AMB]

Yeh you're probably right. One caliper usually starts dragging first. I missed the bit "running hot, both sides".

[beAUtiful]

I rebuilt my caliper greased my sliders put new boots on and inner seals but my driver side piston just dos eat retract anyone have any further suggestions because I’m lost!

[AMB]

Originally Posted by beAUtiful

I rebuilt my caliper greased my sliders put new boots on and inner seals but my driver side piston just dos eat retract anyone have any further suggestions because I’m lost!

Hey probably good idea to start a new thread explaining what you have done. I'll ask admin.
Need more details. Doesn't retract when? If you have refitted the caliper, bled the lines, and its getting stuck then sounds like the master cylinder. With the rotor off, you should be able to push the piston slowly back in with a G clamp with little force. G clamp with a thread, the quick clamps you squeeze are usually not strong enough. Use an old pad to push against, not your nice new one!

[George V]

Hi Op,

It may sounds like a silly question. Did you check master cylinder push rod adjustment; plenty of threads on it.

If only one cylinder is not moving after servicing, then time to pop it out and check seal is sitting square or not.

Regards,
George V

[cairns27]

Bursons told me to put the steel pistons in and wouldn't happen again. $80 plus the kit.

bye