Gta rear calliper/handbrake

Well after years of binding rear brakes and trying to get the alpines through the mot with bad handbrake performance l thought I would try and understand what is the main problem.

Well firstly It is 30 odd years old so it has not done to bad, but once I got it apart it is a simple system and it just needs an overhaul, and the parts are cheap for once

First job read the manual ! then remove the callipers from the car, at the same time remove the handbrake cables and order some new ones, I sent my ones away and had them made by speedy cables, back in a week £80 plus vat and postage, then ordered the seals kits and new calliper sliders from Big Red £30 odd qid make sure you get the right seals for .4 brake fluid you are now ready to go

Firstly my rear calipers worked but where always a bit sticky to start with, but you can see from the photographs what actually probably causes most of the problems.

When you Peel the rear boot back the first two problems, the rear cylinder seal has started to fail and the pivot bush on the handbrake lever is corroded because of the brake fluid.

Was you handbrake cable corroded into the caliper?
I cant separate mine. I dont want to damage the caliper and I am thinking I need to make a tool to apply pressure (in vice maybe) while soaked in with penetrating oil and hopefully eventually push them out to then start working on them.

That is a problem and will tell you a story, but this will shows you what to expect.

Once the calliper is on the bench remove the Sir clip from the handbrake lever at the base and knock through the handbrake lever assembly, you will then see the central pin which is threaded into the back of the piston what I then did was to unscrew the pin but not all the way just so the seal is still in the calliper, I then added carefully some compressed air in the brake line feed, the piston then slowly comes out have paper around as there will be fluid, there are other methods but it’s about the thread in to the back of the piston.
Once it is out it is all self explanatory, you will then see corrosion around the end of the piston which will clean up which will hamper the movement of the piston.

[mettersl]

Custard,
Useful post, thanks, did you remove the compressed spring washers on the mechanism...if so how?
On the 610 there is an adjustment mechanism inside the piston...I chickened out and went for professional refurbishment when I realised this needed changing over to the new piston...did you find a way to do that too?
GTA looks like the same system as 610, but smaller....
Cheers
Lee

The spring washers slide of the shaft note there position and clean them, put them back on the shaft and then put the new small O ring on.
Then wash and clean the piston and I then put some light oil over the piston and wet and dry paper 1000 grit clean and came up like new, then thoroughly clean the calliper, l then removed the cast part of the calliper 2 bolts and put in the new main seal in.

Now get some brake fluid and coat the seal and piston, removeing the cast section allows you to then put the calliper and piston in a vise which will give an even pressure to put the piston back in, once home coat the small O ring and screw it back into the piston, then put the silicone grease supplied on the lever shaft, put the weird shape spring like clip in position slide the shaft in and you have to tilt the small metal peace in that Conect’s the shaft to the threaded shaft which is going into the back of the piston, it is obvious when you have taken it apart.

The next calliper sticking point is the calliper sliders if the rubber gators have perished water and dirt gets in, on mine the Crome platting was lifting of, so clean the calliper shafts remove the old rubbers l then applied the silicon grease to the new ones slid them in put on the new gators on job done.

Ok Simon the handbrake cables you will have a job to get it out of the calliper, one of mine was stuck I did all methods, soaking with oil, heat,made up tools. I found as you try to bang it out it expands and gets worse, so in the end I put a small hacksaw blade cut in the calliper above the cable then oil and heat it came out.

Then a good clean and down to get it ali welded as it is good ali it welded well, file back and you would not know, and no it does not distort or damage the calliper in any way.

Arh Ha! So a bit of a bigger to get apart.

Had to take the calliper of as the handbrake cable hole still needed a bit of weld filling of, you would not no that it has been done now all works perfectly never had a handbrake working so well, went out for a test drive and now the fronts are binding so new kits for them now.