Replacing the front pads is easy: remove the caliper, install the new pads, use a C-clamp or caliper tool to force the piston back into the caliper, replace the caliper. If the caliper won't fit over the new pads even with the piston fully retracted, try squeezing the pads together against the rotor with a C-clamp once.
The rear pistons screw into the caliper, using any tool (standard disk brake too, drag-link socket, big screwdriver, random piece of flat steel stock from the scrap pile, ....) that will engage the slot in the piston. The caliper won't bleed properly unless the smaller slot is horizontal and on top, so you'll always have to turn the piston in exact full turns to keep it properly positioned.
If you are having trouble bleeding your brakes (getting a firm pedal), it can be due to the flexible lines which come from the reservoir. These can go hard with age and kink where they enter the car through the fire wall. If they're kinked, fluid won't flow into the system and it will never bleed.
Bleeding with a pressure bleeding can also help, but check the above first.
--Dom. 22:10, 23 August 2009 (UTC)
Parking brake cables and adjustment
There is a small oval port on the understand of the car just forward of the plate from which the shifter rod and parking brake cables emerge. You use a 13mm GearWrench or equivalent to turn the lock nuts to make fine adjustments in the cables. This is a difficult and finicky process, so you only want to use it for the finest adjustment (one or two clocks on the lever at most) if you can't get it close enough using the coarse adjustment technique below.
Coarse adjustment is done inside the car by slacking the four bolts that hold the plate with the parking brake lever to the tunnel, and then moving the plate itself backwards or forwards. To set the tension:
- If you have installed new or rebuilt rear calipers, the internal parking brake self-adjustment mechanism won't have adjusted itself yet. Step on the brake pedal, hard, a half-dozen times so that caliper pistons will be properly positioned.
- Release the parking brake lever.
- Slacken the bolts and slide the plate backwards until the mechanism is slack.
- Raise the parking brake lever about halfway, typically about four clicks.
- Pry the plate forward hard (you're setting the parking brake, and means overcoming some fairly string springs) and tighten the bolts.
- Verify that the wheels are locked.
- Release the lever and verify that the brake has released.
This technique is also used to completely slacken the cables when you need to separate them from the rear calipers.
Rebuilding calipers does not take a lot of skill. The fronts are pretty simple. Hardest part of that is getting the piston out. Best way I know of that is to remove the pad, then use the pedal to pump the piston out. If you keep an eye on it and stop just before it pops all the way out you will not make a mess at all... if it does pop have a bucket under the wheel to collect the spuge.
Once you have the piston ready to come out, disconnect the bake line, your brake fluid will drain out unless you have some way to close the line.. I use an old caliper just cuz I have one laying around.
With the caliper off the car remove the piston, (remember the cavity behind it will be full of fluid), the bleeder screw and clean up the caliper as best you can. Brake cleaner helps, a parts cleaner is better. If you really want them to look nice a trip through the bead blaster will make them look like new. I use an old bleeder screw and banjo bolt to keep bead out of the cavity. I use a paper towel shop rag to fill the piston hole. A wash down with brake/carb cleaner spray after the beads will remove any residue. Some choose to paint at this point, or polish, if you paint use caliper paints.
Once the caliper body is clean, inspect the bore, if no serious gouges or cracks hone the bore and wipe clean. Be sure to remove the seal before this point. Also clean and inspect the piston. The reduced diameter portion can and likely will have scratches, and or rust, this is not a big problem, but if the large area is damaged I would replace it.
Be sure when you clean to use a scribe or small screwdriver to get the seal groove clean. You do not want any crap behind the seal.
Now that you have every thing nice and clean insert the new seal in the groove, it can be a little finicky to get it in there, just work it in to place. Place the piston in place but don't try to slide it in yet. Add a teaspoon or so of fresh brake fluid around the piston and press it in with your thumbs. You should get it to go in a half an inch or so. Once you feel the piston is in straight and not cocked at all, you can use the C clamp to press it in the rest of the way.
Now you can install the dust seal around the outer edge of the piston and you are done!
Be sure to check you flexible hoses carefully while you have everything apart, replace them if they seem too soft. The outer hose can look good, while the inner hose can have bulges that will act like check valves to the brake fluid. This can cause the brakes to drag or lock up.
Due to the E brake mechanism, these can be a tough job.
The piston is on a screw that actuates the E-brake. To get the piston out you will have to "unscrew" it all the way, also you will need to remove the rubber boot on the back, there is a large quantity of grease in there so this is a dirty sticky job. There is a snap ring that hold the E brake arm on, remove that then drive the arm shaft out of the caliper body. You will notice a small "key" in the slot on the shaft, also the head of the screw is stepped. Make note of how these are arranged. I always disassemble these one at a time so I have one to look at to get it right when I put it together. If the piston is not completely removed you can back the screw out the back of the caliper and remove it. Again make note of the way the bell washers are assembled. These are what make re-assembly a PIA. Once its all apart clean as above. Degrease the E brake actuation components.
There's a detailed explanation of how the e-brake mechanism works here.
Standard Reassembly Procedure
A specially modified C clamp is needed to compress the bell washers when you reassemble.
Assemble the washers and the screw (leave the piston out of the caliper for now. Slide the E-brake arm/shift into place ensuring that the key is in place. Also be sure to have the rubber boot in place or you will be doing it again. Using a C-Clamp (grind the solid end down so that it is small enough to fit on one side of the screw head compress the screw until you can get the shaft all the way over the screw head. Grinding the key to a slight wedge shape will help get things started. This can be tricky and likely the C clamp will fall off 50 time before you get it all together.
Once you successfully assemble the E-brake mechanism give it a good sized dollop of grease and fit the boot into place.
Insert the seal ring, start the piston like the fronts, once it has contact with the screw you will have to screw it into place. The groove in the face must be horizontal to the ground when the caliper is installed, and the scribed line should be nearest the bleeder screw (not critical but there is a relief in the edge of the piston to aid in bleeding).
Not an impossible job, but not a walk in the park either.
Andy Jossy Medford OR
Another Reassembly Procedure
I didn't have a C-clamp to sacrifice, so I tried an alternative approach. It worked for me, and you may find it easier.
Start the piston and its seal ring from the front, lubricated with clean brake fluid, and push it all the way in. Now you can insert the plunger from the back, and screw it all the way in. Start the shaft through one hole in the caliper, and you will have just enough play to tap the key into place with a light hammer and a cheap screwdriver. Once the key is place, use a block of wood and the hammer to tap the shaft the rest of the way in. As it goes in, it will compress the washers and you'll be able to forcibly line the end up with the other hole in the caliper and pass it through.
See here for a pictorial description of a Wilwood brake upgrade.
See troubleshooting page.