I had mentioned in a previous thread that I would post about my experiences in rebuilding my rear brake calipers. Well, here I go...

First, let me say that if you have never tackled a job like this, don't - save yourself a lot of hassle by either replacing the calipers, or having a mechanic rebuild them for you.

Second, the Chilton manual - either the new version, or the old one, details most of these steps, but negates to mention that the snap ring pliers needed for the snaprings inside of the caliper, for the e-brake arm assembly, are virtually non-existant...we have to fabricate our own from a pair of cheap, LARGE, needle nose pliers, to reach down far enough, using a bench grinder. As a part of the reassembly, the manual also fails to mentions you will be trying to installing these snap rings under spring tension...not an easy task...

To perform this task, purchase the Beck and Arnley rtebuild kit...it comes with everything you need.

OK, here we go...

After the caliper is removed from the car, use a pair of needle nose pliers, and turn the piston counter-clockwise, to remove the piston. Set the piston aside for the moment. If the have not already done so, remove the old boot. There are a total of three snap rings per caliper...two are the exact same size...the third is a little bit larger, and is the outer most snap ring, located in the caliper body. Use a set of snap ring pliers to remove this ring. A spring, cap, and a washer, which is used a spring seat, will come out. set these aside. Now, using your snap ring pliers again (the long ones, that we had to fabricate), reach further down into the caliper body, and remove the smaller snap ring. then, you will have that threaded rod in the center ready to come out - but note, it has an o-ring at it's base, so it'll be stiff coming out. When it comes out, it will also bring with it a key plate, and a much smaller rod. Remove the o-ring from the threaded push rod, and discard it, as well as the two snap rings you have removed. Now, release the return spring from the cam at the back of the caliper, using a flat screw driver. Then, remove the nut that it encircled. This will allow you to pull up on the shaft, and remove the cam plate from it. There is a small, grommit looking seal on the caliper, helping to hold this shaft in place. Once this seal is removed, discard it. Clean the caliper body thoroughly. If you need yto, hone the inside of the cylinder LIGHTLY, and then clean again, to remove any dust/ material left from honing. You'll notice in the hole that you removed the last cam from, there is a series of roller bearings. After cleaning the body, and blowing it dry with air, apply a thin, even coating of grease to these bearings, aligning the open section with the shaft leading to the cylinder. Thoroughly clean all removed parts, except for the piston. Install the NEW grommit like seal (Note, the kit includes a total of four of these - only two are used). Lubricate it with a little bit of brake fluid, and then push the cam bolt through the hole carefully, making sure to keep the concaved side facing the shaft leading to the cylinder. Once that is all the way in, drop the small rod into the shaft at the bottom of the cylinder, which should seat it in the concave portion of the cam bolt we just installed. Then, Install the new o-ring on the end of the push rod, and lube it with a little brake fluid. Now place the key plate over the push rod, and guide it into the cylinder, making sure the little convexed 'key' on the keyplate is facing down, so it'll fit into the 'divot' in the bottom facing of the cylinder. Firmly push on the rod, to seat it, and the o-ring, into the shaft. Using the snap ring pliers, install one of the smaller NEW snap rings - please note that these snap rings have a beveled edge on one side, to aid in installation - make sure this slightly beveled edge is facing down when installing, or it could release while under pressure. This snap ring will hold this previous assembly in place. Now, install spring seat washer over the threaded portion of the push rod. It will not rest on the key plate - it sits on a shoulder on the rod, about an 1/8" of an inch above the keyplate. Now, for a trick we found that helps in assembly. Place the spring cap over the spring, and LIGHTLY squeeze it down onto the spring, just enough to hold it in place. Now drop the spring and cap over the rod, centering it on the seat below. Now, here comes the FUN part (This is a fascious statement). You have to find a way to compress that spring, and it is a tight spring - it has to be, to hold your brakes on. This spring has to be compressed a little, to allow the larger snap ring to be installed. Once you have that much done, set the caliper body aside.

Now to disassemble the piston. Using the snap-ring pliers again, remove the final snap ring, and discard it. Inside of this is a small shaft, with a couple of spacers and washers on it. Pull it out of the piston. Clean the piston well, inside and out, and the spacers / washers. On the small end of the shaft, where it fits into the bottom of the piston, is a small o-ring type of seal. Remove it. Clean the shaft, and then install the new seal. Note the new seal ius not an actual o-ring, and has a 'cut' side, so a cross section would appear to be v-shaped. The open end of this seal faces toward the cam on this shaft, and the longer end. Lube this seal, and then press it into the piston. When you removed all of the washers, etc, from the shaft, there was a small bearing race...install this with the open side of the race facing up, out of the piston. The, install one of the star shaped spacers. Next, install the wave type spring spacer, and then the final star spacer. Now, install the last NEW snap ring.

Now, install the new piston seal into the caliper body groove. Lube it thoroughly with brake fluid, and then set down. Take the new boot, and lube it on the inside lip, and the outside lip. Push it onto the piston. Make sure you have it oriented correctly, to fit the out lip into the ridge in the caliper body. Keep it by the bottom end, not the ridged end. Set the piston into the body enough so you can insert the outer lip into the ridge for it, on the caliper body. Now, using needle nose pliers, push down straight, and firmly, until you feel the piston hit the push rod. Now, while still pushing down, turn the piston clock-wise. It will likely take a couple fo turns to get it set on the rod. Then you'll know, because the piston will turn easily, and within about 2 full turns, will be fully reseated, all the way into the caliper. Now, reinsatall the cam plate on the bolt at the rear, and the nut to hold it on. Then, reinstall the return spring. Now, you're almost done. To ensure you'll have no problmes bleeding the brakes, go ahead and loosen the bleeder valve, just to make sure you won't have problems there. When you reinstall the caliper, remember, you need to also replace the two brass 'crush washers' - one goes between the bolt head the brake line, and one goes between the caliper, and the line.

That it the entire procedure for one caliper. Due to the problems in fabricating the pliers needed for the snap rings, and the spring compression issue, it took me and my dad about 9 1/2 hours to rebuild both calipers. If this procedure is worhtwhile for you, go for it.
Otherwise, I would highly recommend just replacing them with rebuilt ones, or having a brake shop rebuild them for you. Just for a positive note, once we found the tricks involved for us, we were able to do the second caliper in 2 hours...the first took us the 7 1/2...trying to learn the tricks involved.

The front calipers are by no means that complex...Fom the time I jacked the front up, to the time we dropped the front to the ground, was a total of 1 hour, and that included new pads & rotors, and cleaning all the hardware.

I hope this helps someone else.

 

Ill be adding this to the FAQs great job maxwgn.

You know what instead of using Needle nose pliers to squeeze the calipers there is actually a cube shaped tool that is used for that purpose. My dad has it at his house. It works alot better you attach it to a Monkey Wrench.

 

I've seen the tool. The only problem is, when removing the piston, there isn't really enough room for it between the piston, and the outboard pad retaining arms...But for reinstalling the piston, or pushing it back for pad replacement, they work great.