Here's a “How-To” thread that describes how we do a 914 rear caliper rebuild. This is about a “top-end” caliper rebuild. If you have a 914 caliper and it's leaking through the handbrake lever I would consider getting a new core. Why? Rebuild kits are around $22.00. Handbrake rebuild kits are around $50.00. Now you’re in it for close to $80.00 with shipping etc. A rebuildable core should go for $20-$40 bucks… as these get scarce you may want to reconsider but currently they’re not too scarce. This job is not fun and it’s not all that easy. It’s not too tough either, it just requires some mechanical ability, patience, special tools and some “tricks of the trade”. Yes, we rebuild these so we're either loosing customers or gaining customers by writing this (I’m obviously not too concerned). Follow the thread. If it’s something you want to tackle then dive in. If not, you know where to go. Here are some of the tools you’ll need: Dental Pick R6 Ribe Driver (early single bleeder style) Torque Wrench 4mm Hex key Small and Large Locking Pliers Brake Grease Brake Cleaner Large Screwdriver Small Wire Brush 13mm Socket 11mm Deep Well Socket (to press the spring and cover into the inner caliper half) 11mm Socket MAPP Torch Air Wrench Pistol Grip Clamp Brake Caliper Hone Hand Drill Two Rear Caliper Rebuild Kits from Your Favorite Vendor (they must include all seals) 7mm Wrench (for the bleeder valve. I prefer to use a small pair if locking pliers though…) Here’s the “How-To” You’ll want to get all the fluid out of these before you dig into the task at hand. As mentioned above, take a pair of locking pliers and snug them down on the bleeders. Most are stuck and this is the only way to go. The 7mm wrench will rarely do the trick. If they're still giving you a hard time, use heat and lots of it.  Once you get them off, try to blow some air through them.  I like to mount these in a vise before I start the dismantling process. Next I start with the caliper half bolts. These are 11mm bolts on the later style (dual bleeder) or R6 Ribe bolts on the early calipers (single bleeder). The early calipers have 11mm nuts on them. These will sometimes seem impossible to remove. Here’s where the MAPP torch comes into play. Don’t worry too much about heating these puppies up. First of all, brakes get hot. Second, you have new seals in your rebuild kits. You just don’t want to heat up the parking brake area too much because as discussed earlier, that’s another $50.00 in parts and another rebuild. Heat the bolts and use your air wrench to hammer these off. If it's an early style, use the 11mm on the air wrench and the R6 Ribe to hold the head.  The reverse will result in a broken Ribe bit.  Split the caliper and remove the inner seals. While you’re at it, remove the dust boots and clamps using the dental pick.

Turn out the pistons.  I mention “Inner” and “Outer” caliper halves; The inner halves have the parking brake arm attached. For the “Inner” piston you need to spin the adjuster “CLOCKWISE”. “Outer” pistons turn COUNTER CLOCKWISE. For the outer adjuster you’ll need to loosen the 13mm lock nut and spin the adjuster with a 4mm hex wrench. For the inner adjuster you’ll first need to use the 4mm hex wrench to remove the adjuster cover. Many times this is stuck and the 4mm slot is stripped (has everything to do with the rusted thread surface area and wrech surface area). If this is the case you’ll need to slot the cover and pop it with a large screwdriver or chisel (see picture) Turning out the pistons is the part that I feel is “easier” than any other caliper rebuild. If your calipers are in decent shape the pistons should simply spin right out to the edge. Once you get the adjuster screws turned out to their limit (you’ll feel it and the piston will stop moving), you’ll need to pull the piston out the rest of the way. Do this by placing a shop rag over the piston and use a large pair of locking pliers to grab the top edge. Don’t dig into it and destroy the lip. Just snug. Now “rock” the piston back and forth while pulling. It only has about 1/8th of an inch to go. Here's a picture of the "inner" adjuster cover and the modification discussed above that is "usually" needed to get them off

4. Remove the adjusters. The outer adjuster will pop out after you remove the “clip” that is on the shaft just above the 13mm nut and the nut itself. Once the nut is off the adjuster simply pushes into the piston cavity. The inner adjuster is a bit tricky. It is set in with a hat, a spring and a clip that holds all that in there. (Are you sure you want to do this? It’s “really” fun putting it back!) Use the dental pick again and pull the clip inward and upward. I like to cover the piston cavity with a shop rag so the clip doesn’t go flying. Once the clip is out of it’s groove the adjuster, hat and spring should pull out. It comes out hard but it comes out. There should be a little “sausage” attached to the bottom of it with grease. The “sausage” may stay in the lever assembly but most come out with the adjuster. The “sausage” goes into a recess in the rod and pushes against the adjuster when you pull your handbrake lever. Next time you pull up on the handbrake, thank the “sausage”. Pull the adjuster gear out when you remove the 4mm hex key.

Inner adjuster pulled out... see the sausage? 5. Use the dental pick to remove the piston seals. 6. Optional. If you’re going to plate or paint your calipers (and why wouldn’t you while they’re apart) then you’ll probably want to take the handbrake spring off. To do this you’ll need to remove yet another clip, slide off the washer and then use the small locking pliers and grab the spring just past the bend and pull up. The tension is not that great so don’t worry about it flying across the garage. Next remove the spring rest from the shaft.

7. You Decide. You now have a totally stripped pair of caliper halves (or two pair). This is where I take them off to a local plater and have them “yellow” zinc plated to replicate the factory finish. Clear zinc will net you a silver caliper. If you decide to paint at this point, use a very high temperature paint. Rotor temperatures can exceed 1400 degrees. If you decide not to plate or paint this is where the wire brush and brake cleaner comes in handy. Spray and clean. 8. Ready to reassemble? Hone the piston cylinders with the brake cylinder hone and a hand drill. The hone can be purchased at any FLAPS for around $16.00. Don’t worry too much about the honing process, just don’t go too crazy with it. I find it best to hone enough to remove the plating that may have made it in there or to simply polish it to shinny metal. After the honing process spray some more brake cleaner in the cylinder and in all the brake fluid passages. Get them clean.

9. Install the piston seals from your kit. They don’t seem like they’ll fit but keep pressing them around and use that handy dental pick to position them. Soon enough they’ll drop right in the groove. I lube them up with brake fluid before I install them (as I do with all the seals). 10. Install the adjusters. Clean them up with the brake cleaner and the wire brush first. Remove the old seals and install the new seals from your rebuild kit. The outer adjuster simply pushes right in (use brake fluid as a lube on the seal). Install the 13mm nut and then reinstall the clip. The inner adjuster is a bit more complicated. First install the seal.  Use the brake caliper grease and load up the hole at the base of the adjuster where the “sausage” goes. Insert the sausage and spread some of the extra grease on the gear. Push the adjuster into position and make sure it drops fully into place. Place the spring over the adjuster and follow it up with the hat. Place the clip over the hat and your ready for the real fun stuff. Use the 11mm deep well socket and use the “Pistol Grip Clamp” to press the assembly in to place. Dental pick time again; use the pick to press the clip back into the groove. Once you know for sure that it’s snapped into place, release the clamp. Install the adjuster gear and use some new adjuster covers for the inner halves. Test the handbrake by positioning your thumb over the end of the adjuster and moving the arm.

Inner Adjuster Rig...

11. Install the pistons. I tape them off and bead blast the tops to bare metal. They tend to be a bit rusty. While they’re still tapped I put a coat of high-temp gray on them to replicate the factory finish. Once they’re dry you can remove the tape and use 600 grit wet-or-dry to polish the edges. Now you’ve got some nice pistons and they’re ready to “pull” into the cylinders. Here comes a little trick; install the dust boot now.

Next, use the caliper grease and put a light film on the piston and the cylinder wall. The adjusters go in the reverse direction to install the pistons.  Outer adjusters turn CLOCKWISE, inner go COUNTER CLOCKWISE. Turn the pistons in all the way but don’t crank them down too far. You can bust the springs on the inner piston assemblies. When they stop moving, stop turning. Install the dust boot clamps. Tip: Dust boot clamps are now coming untrimmed -or- a bit too large. Take a pair of stout wire cutters and trim them down to the appropriate size.

12. Reassemble the caliper halves. Use the two seals in the rebuild kit. Lubricate them with brake fluid. Position the half with the détentes horizontally in a vise, put the seals in and drop the other half on top. Install the bolts and torque to 7lbs. starting with the two inner bolts (2+3) and then the two outer bolts(1+4). Next, go back and re-torque to 17lbs. using the same pattern. 13. Install the spring rest on the shaft. Position the lever toward the outer caliper half and install the appropriate spring (the springs are left and right). If you get the wrong spring your handbrake will be on all the time (in theory). Use the small locking pliers again to grab the spring and position it in the groove. Use a screwdriver to push it the rest of the way on to the shaft. Install the washer and reinstall the clip.