87-88 TC Rear Caliper Rebuild

1987 – 88 Thunderbird TC Rear Caliper Rebuild
By Boothe Gregory, a.k.a. Nitro_X

So you think you need to rebuild your rear calipers?  If you have a fluid leak, check the banjo fittings, rubber lines and bleeder-valves first.  If your emergency brake sticks on make sure the cables are free.  Do not attempt this procedure unless you are confident in your ability to do precision repairs on a critical system and you KNOW that the calipers are the problem. I make no claim that any of the following is correct, accurate or applicable to your situation. If you decide to do your own brake work, you do so at your own risk.  Other procedures may bring up the use of adult beverages when servicing a Turbo Coupe. Put the adult beverages away until after you're done!  Since the brakes stop the car, if you screw them up they can kill you and other folks!  If you insist on drinking while working on your brakes, please post times, dates and locations where you'll be driving.  That way the rest of us will know roughly where the scene of the accident will be and can detour to avoid it.

The emergency brake shafts were stuck on my ’87 TC and kept the brakes locked on. You have to completely dismantle the caliper to get to the e-brake parts, so it was time for a rebuild. Here it is from the top.  Get all the tools and parts you need together and prepare a clean work area.  The minimum parts you’ll need are rear caliper rebuild kits, new copper washers for the banjo fittings and new guide pin boots.  Optionally, you may need to replace the guide pins and hardware.

Spray the guide pin and banjo fitting bolts with PB blaster first. Remove the caliper from the car.  Lock it in a bench vise with the piston up and the outboard caliper hook facing you. I used aluminum jaw inserts to prevent damage (copper inserts or an old towel will work). Be careful not to clamp onto the bleeder fitting, e-brake lever or do any other unintended damage with the vise.

Use a suitable tool to remove the piston. Ford has a special tool for piston removal and installation but you probably won’t. You may be able to find a universal brake piston tool that will work. I just use a small spanner wrench ground down on the back to fit between the frame and piston (see Fig. 1). Some folks use needle-nose pliers, but they won't always do the job.  Don't even think about using a drift and hammer! You'll tear the piston face up and possibly damage the cylinder.

   

Fig. 1 - Removing the Piston

The piston unscrews off the emergency brake actuator shaft to the left (standard thread). You can unscrew it with the boot attached, pry out the seal and leave it on the piston for removal later. You remove the piston boot seal from the caliper body by slipping a small screwdriver under the lip and working your way around it prying up (see Fig. 2).

   

Fig. 2 - Removing the Piston Boot Seal

Now comes the fun part. The e-brake actuator rod comes up through a retaining cage for the piston return spring.  The spring is about the size of a small engine valve spring and just as beefy. The retaining cage has several fingers that fit into a recess in the bottom of the cylinder (see Fig. 3). It is held down with an internal snap ring. You have to compress the spring and cage before removing the snap ring. There is a special Ford tool to do this, but I don't have it.  So I used an 8" c-clamp and an 11/16" socket the first time I did this and it worked fine.  I know most DIYers won't have a c-clamp that big and they're expensive.  So when I rebuilt the passenger side caliper, I used a standard caliper piston compressor (you can pick one up at any parts store for a few bucks) to see if I could do it that way. It works, but does limit your access into the cylinder bore.  If you go that route, you may want to put it in place, scribe the tool’s backing plate around the caliper hook and cut off all excess metal.  It will make what follows easier.

   

Fig. 3 – Return Spring Retaining Cage

Compress the spring cage with the c-clamp or brake compressor on top of the socket (see Fig. 4).  Regular snap ring pliers won't clear to get in the cylinder. Use a small screwdriver to pop the snap ring out one side at a time. Once it's free, slowly release the spring cage. You will now be able to remove the spring cage, return spring; actuator rod, thrust washer, anti-rotation plate and e-brake link rod (see Fig. 5). Note the order they come out in for reassembly. Once the internal parts are out, remove the old cylinder seal (the flat o-ring in the in the cylinder bore recess) with a toothpick or small wooden dowel (like a manicure stick, see Fig. 6). This prevents nicks and scratches to the cylinder bore or seal recess that a screwdriver can cause.  Remove the old o-ring from the actuator rod the same way.

   

Fig. 4 – Compressing the Return Spring Cage

   

Fig. 5 – Cylinder Internal Parts

   

Fig. 6 – Removing the Cylinder Ring

Now turn the caliper on its side in the vise for access to the e-brake lever and return spring. Use vise-grips to release the spring from the lever. Remove the spring / lever retaining post (you may need to soak it with PB Blaster). The e-brake cam assembly should now slide out of the caliper body.  Refer to Fig. 7 for order of operation of the major e-brake parts.

   

Fig. 7 - Emergency Brake Parts: Order of Operation

Pry out the old shaft seal. Clean the caliper body and all parts thoroughly with brake cleaner. Note that the e-brake link (between the bottom of the piston actuator rod and e-brake shaft) is lubricated with thick, sticky silicone grease. You will need to replace it for reassembly (check with your local Ford dealer).

Drive in the new e-brake shaft seal with an 11/16" socket. Lube the e-brake shaft cam cup with silicone grease (see Fig. 8). Reassemble the e-brake lever / shaft assembly, spring and post. Lock the caliper body back in the vise, cylinder up as before. Install the new o-ring, lubricated with clean brake fluid, on the actuator rod. Lubricate the actuator rod lower end cup with silicone grease. Stick the e-brake link into the lower rod cup allowing the grease to hold it in place (see Fig. 8).

   

Fig. 8 – Emergency Brake Cam & Rod Grease Points

Insert the link and rod (center it first) into the rod bore.  Be sure the link rod goes into the e-brake cam cup properly (see Fig. 9).

   

Fig. 9 – View of Cylinder Bore

Once the actuator rod is seated, reinstall the anti-rotation washer making sure that the raised pin drops into the hole in the bottom of the recess (see Fig. 9 again). Next reinstall the thrust washer, spring and retaining cage. Using the piston compressor (or c-clamp) and socket, compress the spring / cage assembly. Be careful that everything is lined up correctly or you may catch one or two of the fingers in the retaining ring groove and bend them up. If you do, remove the cage, straighten it and try again.

Once you get it properly seated and compressed, work the snap ring back in by pushing the rear of the ring into the groove with a small screwdriver. Now use two small screwdrivers (one to keep it from rotating) to pop the tips of the snap ring back in. Be careful and patient. It's a royal PITA, but can be done (even with the backing plate of the piston compressor in your way).

Next, install the new piston seal (lubricated with clean brake fluid) in the cylinder recess. Then install the new boot on the piston. Next plug the line fitting connection and fill the cylinder with clean brake fluid, about 3/4 full.

Very carefully thread the piston back onto the shaft (clockwise). Using the piston compressor (or c-clamp) put light pressure on the piston face. Turn the piston in until it is well within the seal area. Then turn the caliper in the vise, so the bleeder fitting is up. Crack the bleeder fitting open. Continue to turn the piston in applying pressure to its face with the piston compressor (or c-clamp) until it bottoms out. Let the air and excess brake fluid escape as you go. Close the bleeder. Now back the piston out until the anti-rotation slots are lined up for the pin on the brake pad.

Use a thin piece of flat-ended wood and a small hammer to tap the bottom seal of the piston boot back into place. Work your way around the lip until it seats. The caliper is now ready for reinstallation on the car.

Now is a good time to check the caliper guide pins and boots. Unless you've JUST done it, remove, clean and lubricate the guide pins and bores. Install new boots on the pins. It's cheap insurance for your rear disks and pads.

I also recommend doing a search on the NATO message board for “rear brake caliper” before diving in to this. Thanks to all the NATO members that posted additional information that helped me do the job and write this article. Here’s wishing you the best for your rear brake rebuild!