Rear Brakes -Reconditioning
The following is the procedure I took to recondition my brake calipers.
It is a bitch of a job because of the handbrake setup, but is well worth doing yourself.
Parts required[edit]
- 2 x PBR K1488S R31 Skyline rear caliper seal kits (do both at same time) approx $30
- Rear brake pads
- Methylated sprirts (1 litre +)
- Brake fluid
- Silicon grease (the workshop manual recommends using this, maybe not necessary.. read below)
- PBR rubber seal grease (definitely get some of this)
- New cotter pins for the handbrake cable.
- New discs if they are less than 9.4mm thick. ($55 each) (do both at the same time)
Tools required[edit]
Usual mechanical tools. Tool for turning the caliper. I would recomment a piece of aluminium the same size as the big slot in the piston if you wish to make your own. Circlip pliers (with fairly small points) 10mm open ended possible) 15 mm socket. 13mm socket or spanner. Big screw driver
- TIP-
- Before you start, inspect all the rubber seals in the kit for imperfections.
- One of the guide pin seals in mine was deformed so I had to use one of the old seals.
Procedure[edit]
Remove U shaped clip securing the handbrake cable first, before you remove the caliper. I use the biggest screw driver and prise or lever it off.
Remove cotter pin from the handbrake cable and remove the washer. Remove handbrake cable from caliper.
Undo caliper bracket bolts using 15mm socket Loosen bolt holding brake line half a turn. Be careful not to twist brake line too much. Now the caliper should be free from the car so unscrew the caliper off the brake line, don't twist the brake line.
Now the caliper should be off.
Take the caliper off the caliper bracket. Clean the bracket and guide pins in kero or degreaser.
Remove bolt from back of caliper where handbrake lever attaches. (13mm I think) Remove Seal.
Use 10 mm open ended spanner to undo piston. RH caliper undoes clockwhise, LH anti-clockwise. Push the handbrake adjusting screw through the caliper. If this is seized you may have to put it in vice and hammer it with a piece of wood.
There is a thrust washer and bearing on the handbrake shaft so dont lose them. Remove seal in inside of caliper with toothpick. I used two toothpicks, one to unseat the seal, the other to stick underneath so it doesn't pop back into the groove. Try not to use anything metal incase you damage the housing bore.
Now take piston, remove circlip.
Tap out contents of the piston, there should be a few washers and another thrust bearing.
Remove the bleed valve from body of caliper. I cleaned the main caliper body with degreaser and kero, then cleaned it thoroughly with metholated spirits. Use compressed air to clean the bleed valve and the brake line hole. I didn't have compressed air so you can blow through it to remove some of the gunk. Metho doesn't taste very nice though. You might like to clean the caliper more thoroughly, perhaps with spinning metallic brush on a drill and maybe even paint it. Note: I did not paint my calipers but I would clean them with the wire bush attachment because it is best to clean the caliper housing thoroughly so when you install the piston it doesn't get dirty.
Clean all other brake parts with metholated spirits. Dry with compressed air or leave to evaporate. Use 600 wet and dry paper to smooth any scuffs on piston or caliper. If the piston is badly damaged, buy the kit to replace it. I soaked the pistons in metho overnight to remove the gunk built up in the grooves. It comes out easily after soaked.
Use 600 wet and dry on the adjusting screw shaft where it mates with the caliper housing (before you put the seal on, as pictured) and also sand back any caked on crud or rust on the caliper where it touches the handbrake shaft.
This is why the handbrake seizes, crap gets past the seal and rusts or gunks up this surface.
File:SealOnShaftArrow.jpg File:CaliperMainSealArrow.jpg
Discs should be smooth and at least 9.4mm thick. Because my handbrake was siezed and had scored deeply in the disc, I replaced mine. To remove the disc you may have to find some screws which fit in the small holes on the disc. Screw them in and they will force the disc off the wheel.
Install the stuff inside the piston, and put the circlip back on
Place the thrust bearing and washer on the screw shaft and put the little seal on.
Screw the adjusting screw shaft into the piston (one is for the RH and the other LH, the threads are different.
Now dip the main seal in brake flue and install the inside the caliper body (the large thin ring seal)
Grease the caliper seal with rubber grease. I tried forever to get the piston in without it but it slides straight in with a little grease.
Then place the piston dust seal over the piston, and stretch out, so the end (the bit which fits in the groove of the caliper body) is overhanging the end of the piston.
Now install the seal while it is attached to the piston into the caliper body.
Align the adjusting screw shaft with the hole in the caliper body and push the caliper through until it is seated.
Ensure the piston groove is vertical with the caliper and the screw shaft where the handbrake attaches is correctly positioned.
Put some silicon grease on the seal and then place that and the handbrake lever on the caliper. Screw the bolt on. I put some locktite on this bolt.
Put the spring back on the handbrake lever.
Screw the bleed screw in.
Get the caliper bracket and use silicon grease on the guide pins and install the new seals.
If you are replacing the disc, install that now. Use a wire brush to clean the hub face thoroughly so the disc seats true and correct.
Install the caliper bracket onto the car.
Screw the caliper onto the brake hose. Tighten now it now because when its bolted on it is difficult to tighten.
Position the new brake pads and put the caliper on with the new bolts from the seal kit. Service manual says to replace these each time you undo them.
Install the handbrake cable, washer and new circlip
Check that you or I haven't forgotten to install or tighten anything.
Now you will need to replace the fluid and bleed the brakes.
NOTE: The front brakes would follow this same procedure, except it is much more straight forward because the handbrake mechanism is not on the front calipers.
Compiled by
Julian Simmonds