Had to replace discs and pads at the weekend, so decided to bite the bullet so to speak and do a refurb while they were off.
I got a rebuild kit from Biggred - the kits come as a complete set of rubbers for either front or rear axle.
Started by getting the old stuff off:
1) Loosen wheel nuts - easier to do this before jacking the car as you can use the weight of the car against it.
2) Jack up the car by the diff, and get axle stands under the subframe mounts or anywhere else stong and out of the way.
3) Remove the wheel nuts and wheels
4) Squirt some duck oil/penetrating oil/WD40 - your rust freer of choice :) on the main caliper retaining bolts - on the rear these are the 2 large 14mm nuts. I also lubed up the brake line where it joins the hardline, as I was taking this off the car and replacing with a braided line
5) Loosen the 12mm nut that retains the bottom of the caliper - it should be fairly free - but may need some penetrating oil on it as well.
6) With the nut loosened, pull it out a little way and then swing the caliper up - the pads may drop out - if not they are easily removed now.
7) Lube the nut\'s either side of the bracket that holds the handbrake cable on - you need a 14mm and a 15mm spanner to loosen the bolt - do only one side - it will be easier to locate the handbrake again afterwards.
8) Once it\'s loose, pull it up out of the bracket and forward to release it from the fork at the end. Move the cable somewhere out of the way.
9) If you\'re going to take the caliper off the car, then undo either the brake hose from the caliper or undo it at the junction with the hard pipe on the back of the wheel arch. Use a flared wrench for this - an ordinary spanner will round the end of the nuts and you\'ll be stuffed.
10) If taking the caliper off with the brake hose, then remove the clip that retains it once the brake fitting with the hardpipe is unwound. If you\'re leaving that hose intact, but removing it at the caliper - then cap the end off - you will need a new copper crush washer.
11) Move the caliper upwards and then slide it back into the arch to bring it off the top pin. If you\'ve left the hose intact, then you need to tie the caliper up on the suspension so that it doesn\'t stretch or split the cable. Otherwise take it off.
12) Now attack the large 14mm nuts that hold the caliper bracket onto the hub - you can get a large bar with a hexagonal socket on the top nut, but the bottom nut is quite recessed - for that find the longest ring spanner you can find and a nice mallet - not hammer - and gently tap it till it frees. If it\'s not moving - leave it to soak in some more lube.
13) With the caliper bracket off, you can now remove the disc. If your disk has retaining screws - then remove them - the easiest way to remove these will be to lube them and find a philips bit that will go in an impact driver - then it should come out. Otherwise drill it out. Once the screws are gone, give the disk a gentle tap at the back with a rubber mallet - it should come free.
14) With everything off, it\'s a good time to give it all a brush down, clean or whatever. Be careful with brake dust - wear a mask, use brake cleaner and put newspaper down that you can roll up and throw away. Don\'t get the dust in your lungs.
Refit:
So for refitting - I put the new discs on. I gave these a clean with brake cleaner to remove any oil from the machining. Don\'t handle the disc surface. I squirted some ceramic lube on the inner part of the disc - the face that mates with the hub - it helps to stop the disc binding on with rust.
Use a couple of the wheel nuts to hold the disc in position - it helps when lining up the caliper again.
Caliper paint:
I gave both calipers / caliper brackets a good brushing with a plastic bristle brush to loosen the dust and cack. Then using white spirits - give the caliper / caliper brackets a good clean. I then used a brass wire brush to remove any old / flaky paint and rust, then treated the caliper / caliper bracket with genolite on any rust spots.
After another cleanup with spirits, the caliper / caliper brackets are ready to paint. Mask off the rubbers, piston and so on - and make sure the bleed screws are covered - you need to be able to free these easily. For the caliper brackets, mask off the spindle that the caliper moves on.
I use Hammerite blue on mine - you can recoat every 15 mins, put several layers on and you\'ll get a good hard wearing finish.
Caliper refurb:
I took the opportuniny to replace the rubbers when I had the calipers off - the biggred kits have all the rubber parts that are on the rear caliper - you get dust boost, seal, o-ring, bottom seal (for handbrake lever), and the 2 rubber parts that protect the caliper mountings. Use grease on these last 2, but for the other parts use brake fluid only. Don\'t use metal tools to remove or replace the seals - you will damage them and end up with leaking calipers.
As Haynes say - refit is reverse of removal !
Follow on steps:
1) When you\'ve replaced the rubbers in the caliper, you will have drained all the brake fluid. You need to bleed the system using the bottom bleed screws.
2) I ended up bleeding form both screws, as air was still trapped after a full bleed from the bottom screw.
3) Don\'t be suprised if you have to bleed the front brakes as well, you will lose a lot of fluid when the brake hoses are off.
4) I found the rear brakes took a day before they properly sealed - seems the rubber seals swell in the new brake fluid and form a good seal - when wearing the brakes in go gently and allow more time to stop - I didn\'t get my brakes back to full strength for a couple of days.
5) Don\'t leave it too late to replace the discs - I had drilled / grooved discs - and was going to replace the discs when the grooves had all but gone, but scraping noises made the decision for me - you can see in the photos that the inner surface has worn more than the outer - so don\'t go by what you can see !!
nice write up Prof - just intime for me to do mine tomorrow :D
doesnt look tooo bad of a job ( fingers crossed !! )
although i had to admit - i forgot about the handbrake cable side of things
Just remembered one other gotcha !
I replaced the brake hoses with braided ones - Goodrich lines. I found that the end of the braided line that mates with the hard line seem to have an issue whereby it can\'t pass through the bracket on the back of the arch far enough to get the spring clip in to retain it.
When you look at the profile of the connector at that end - there are two \'nut profile\' sections - one thick and about 1cm long, and one about 1-2 mm in length, then a round secion of smaller diameter that mates with the hard line. The thinner nut profile section has a slot either side one of which the spring clip should go into.
The problem is because of the smaller nut profile section, the hose can\'t pass through the bracket far enough for the spring clip to go on. The solution to this was to file the nut edges of this section down until it can pass through the bracket, then you can get the spring clip on with no issues and the line is made secure.
i already have braided lines on mine - looks like they just tie-wrapped them to where they should be clipped :(
gonna get changed and have a play with the car for a few hrs - see if i can get the rears done :D
Dave,
i\'m starting my conversion and i need to change some of the hardware for the handbrake cable, i had to remove the large spring and arm that the cable sits in as i am replacing all this, my new set up doesnt have the spring and the arm the new braket sits on move in and out 5-8mm (on both calipers) is this normal?
Nice write up Dave. Thanks for taking the time to do it as above I\'m doing mine in the near future so this will come in handy.
Quote from: mpk490p;606372Dave,
i\'m starting my conversion and i need to change some of the hardware for the handbrake cable, i had to remove the large spring and arm that the cable sits in as i am replacing all this, my new set up doesnt have the spring and the arm the new braket sits on move in and out 5-8mm (on both calipers) is this normal?
Isn\'t the spring required ? It brings the brake back to normal position when the handbrake is released. Because of the tension on the spring, that section doesn\'t move - probably not having the spring is why it moves in and out. That lever operates the brake piston mechanically.
the kit i have says you dont have the spring, it comes with another that sits over the cable to pull the level back in postion. if it is mechanically opeated then both are not working!?
i didn\'t know if they pushed a rod that needed pressure to operate the piston? dont remember it working before i pulled them apart!:3Confused
When I took mine apart, the handbrake lever mechanism rotates a needle bearing which has a small hole in it. The hole has a small rod that operates the back of the brake piston mount.
Did you take the caliper apart, or were they supplied like that ?
i only changed the piston seal and dust cover, i then removed the stock handbrake lever set up and put the new hardware on. ive a feeling i may need to strip them completey now:reallymad i have tryed to look for a strip down pdf but no joy