Hey Gang, Here's the build thread for a pair of 308 rear calipers. We had a previous thread going where a customer of ours was looking for a pair of rear calipers for a project of his. St@ven here was nice enough to sell him these calipers. And while they have quite a bit of "patina" (St@ven's feeleings were hurt when we called them ugly in the previous thread so... patina is the new code word), they are very rebuildable and should come out shiney new. Others wanted this to be a "live" thread so, I'll do my best to post in segments and allow plenty of room for question & answer time. There's a few basic steps in the process that should allow us just that. We have to 1) Disassemble. 2) Recondition (plating etc.) and, 3) Reassemble. Here's the "Disassemble" part. I'll try to list out all of the tools needed to do the job right so those following along at home can assemble the right stuff "before" they decide to tackle this job: Bench Vise 11mm Socket 13mm Socket 3" Extension 1/2" to 3/8" Adapter Air wrench R5 Ribe Bit or Wrench Dental Pick Assortment Small Vise Grips Large Vise Grips 7mm Open End Wrench Dremel w/Carbide Cut-Off Wheel Large Screwdriver Small Screwdriver Torque Wrench (I'm sure there will be a few things I forgot. I'll update this section as I go along) Here's what we had to start with: Crap... image tags don't work? This is going to take a while. You can follow this on Facebook as well: http://www.facebook.com/album.php?aid=245424&id=72240238192&l=f5e7f17a0c Image Unavailable, Please Login
Missing some parts here... more patina Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login
Odd hole drilled into the side of the handbrake Welch Plug... wait until you see what we found under here. This was a strange plug as well. Not factory at all. Image Unavailable, Please Login
Alrighty... we've seen what we have, let's dig in. Our trusty dental pick begins the action by removing this clip on the spring washer. Once the clip is off, the washer comes off. Small Vise-Grips grab the spring and you just wiggle back and forth until it's off. The spring seat bushing is next, it usually pulls right off. You may have to take a thin screwdriver and pry the bottom off the arm to get it started: Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login
Before we go any further, this is a must. Always use the correct "Ribe" tools. This is an R5 wrench. These are "not" torx fasteners. These are NLA M7 Ribe fasteners and you don't want to damage a SINGLE one. Image Unavailable, Please Login
I'm fairly certain I mentioned here somewhere, how much I love painted calipers (and fiberglass underwear). The paint was so thick on these that I couldn't get the wrench in. Again, this is "VERY" important because these fasteners are NLA and, the wrench has to be firmly seated before you begin to remove the 11mm nuts. I used the dental pick to get in there and gouge it out. I even used a torch to burn it out. Multiple layers of paint on these. I sprayed a little brake cleaner on them (look what happened to that fabulous caliper paint). To seat the wrench I used a 2lb hammer. That wrench has to be in there all the way or you can damage the bolt. Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login
The bolts are out and the caliper is apart. Patina encrusted spacers are shown here. You can see from the spacers that the calipers true color is yellow zinc. Image Unavailable, Please Login
Next it's on to the outer piston removal. This caliper is missing the clip to hold the lock nut from coming off the shaft. That being the case, I basically spun it off with the air wrench and will tap the adjuster and piston out. By tapping lightly on the adjuster you can simply force the piston out. This can save the internal piston mechanism and the small 4mm hex because they won't have to work at all to get the piston out. This is especially helpful when dealing with old calipers that have sit for years. You can see from the 4th picture down, the piston starts to come out. Use the 4mm hex to turn the adjuster back up and tap it again. Repaet until the piston and adjuster comes out. Use the dental pick to remove the bore seal. Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login
Let's get the bleeders out. A word about bleeders. NEVER try to remove a 7mm bleeder with a 7mm open end wrench. Always start with a pair of Vise-Grips. Set them "very" tight and push lightly until it breaks loose. If you get too much resistence, use a MAPP torch. Once it breaks free, use the 7mm open end to finish it off. Image Unavailable, Please Login Image Unavailable, Please Login
On to the inner piston and the inner adjuster. Here's a fancy way to deal with on inner adjuster cover. Looks like Goober cut into the back of the caliper (sorry St@fen if that was you, then again you may not know who Goober is in the Netherlands. Google "Goober Mayberry RFD"). A cold chisel is the best way to remove these. A few whacks with the 2lb. hammer and it spins. The inner adjuster gear hides under this cover. Out with the old and in with the new. The "new" has a deeper and larger (5mm vs. 4mm) hex. Once this cover is off, we can get at the inner adjuster gear and begin to get the inner piston out. Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login
Remember how we tapped the adjuster to get the outer piston out? With the inner piston I like to use the handbrake arm itself to do the work. BEFORE you even attempt to use the inner adjuster gear, tap the arm all the way back. With old grungy pistons, this will break the bond... Be carefull not to tap the arm back too far. Only far enough to get it close to the stop pin... go too far and you will snap off this pin. So... tap the arm back - spin the adjuster clockwise (watch the arm slowly go back to the forward position). Once the arm is full forward again, tap it back and then turn the gear. Again, this method is good for old stuck calipers. You're using the leverage of the arm vs. the more delicate internal adjustment mechanism to get the piston out. Here's the gear that's doing all the work. This comes out once the piston is cranked out all the way. Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login
Our piston is almost out. If you have bad, stubborn pistons (like these) you may have to pull them the remaining 1/8" or so. Don't tell anyone, this is a little vise trick I have. I cut notches in the vise face to grab the piston tops without damaging them. There's a similar notch on the opposite vise face. I put the caliper in the vise with the piston in the jaws. Then I tap the housing off the piston... Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login
Next the internal adjuster mechanism needs to come out. You can see the c-clip at the base of the adjuster hat in the first picture. Our trusty dental pick gets tasked with the c-clip. Pull it inward toward the center of the caliper bore. You may have to flick this a few times before the clip come out of it's groove. In the 3rd picture the clip is about to fly out. I always put my thumb over the end of the adjuster so the clip doesn't go flying across the shop. Here's the assembly out of the caliper with the components that make up the inner adjuster. From left to right: Pushrod-Adjuster-Spring-Hat-Clip. Yank the bore seal with another dental pick. Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login
Now for the final bit; removing the welch plug and handbrake arm. IMPORTANT: Don't waste money here. This step is only required "if" you have a bad wiper seal under your handbrake arm. If you have fluid leaking from your handbrake arm, this is not the fix. The seal on the handbrake arm (directly under the lever) is only a wiper seal meant to keep things like dust and water out... not brake fluid in. Skip this step now if your arms move easily back and forth once the inner adjuster is out. That said... the hole in that welch plug we showed in the first few posts is cause for alarm and these arms need to come off. I like to use a Dremel with a carbide wheel. I cut two lines side-by-side (to get a large screwdriver blade in there). You have to just cut through the plug and avoid cutting the arm inside. Once the notch is cut use a large screwdriver to pop it out. All cleaned up. There "is" a clip under there. The clip is out and the handbrake arm pushed right through... Shwon is a wiper seal. These are in good shape but, because that one caliper had the hole, I decided to remove both arms. Again, if you're doing this yourself, you can skip this step (the removing the arms step) if these seals are good. And again, these are not fluid seals...they are just wiper seals. If your calipers are leaking from this area... your inner adjuster seals are bad. Pop this seal out with the dental pick. Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login
I'll leave you with this. Remember that welch plug that had a hole in it... Please weigh in with any questions you have. It will be a while before we get these back from plating. Mark's calipers will be used on a special 3.2 liter 914-6 GT build. That means we'll have to modify the calipers by installing a second bleeder on the opposite end of the caliper. This was done later in ATE production for the 1973-76 914 calipers so it's not a mystery. I believe this was an economy of scale issue that allowed the calipers to be used on different vehicles. Once these come back from the machinest, they'll go into plating and be ready for reassembly. ATE used "Yellow" zinc on "all" of their calipers. They did not use cadnium. This is a common myth because so many of the other small parts on these cars were cad plated. The caliper came from ATE and they used zinc. Be prepared for a shock when you see the transformation of these bits from patina to paradise. Image Unavailable, Please Login
I must admit that this is the ugliest caliper that I have ever seen. I assume it will look brand new when you are done. Good luck.
Just kidding on this end as well. These are actually very rebuildable cores. I've seen worse. Throw any questions you have at me, over the next few weeks I'll mess around with the pistons and internals to get those cleaned up and the keep the thread rolling. Thanks Guys!
Sorry PMB but I don't get it. Too many super close up shots maybe to get the whole picture. I'm sure you accurate but I would recommend anyone trying this job to look at the procedure on BIRDMAN FERRARI site. I followed that step by step with good results. Maybe you should look at that and revise for clarity
Nice thread so far - sometimes it's just good to see another point of view on the same rebuild. I rebuilt one of my rear calipers a few years ago and the only real problem was the Ribe fasteners - I think one head stripped out, but I did get them all undone in the end. Superformance as we know sell all the bits you will need: http://www.superformance.co.uk/a-308/brakes.htm including M7 Torx which are a valid replacement to the Ribe bolts I reckon. I tend to use a small 7mm deep hex socket on the bleed screws if they look ok and I use a short hand wrench with the socket - like 100mm wrench so try and avoid snapping the thin off. There's nothing particularly complicated about these calipers, you just need threads like this to take the mystery out of them and adding a few tips for problem areas. Lee
You're Right! I forgot about Collin selling the Ribe fasteners! I think (not sure) his are Ribe and not Torx though. The issue with Torx tools is... they fit... sort of. They're close enough to give a false sense of security. That's how the heads can strip. Also spot on with the deep well 7mm. Not too many people have them so in these kind of threads I like to pose "workbench" solutions. Most of the 7mm bleeders we see have had an open end to them and they're trash can fodder. Also agree on the complexity. There are a few tips we've learned over the past 10 years of doing these. I'll share all of those here. Some of them may be buried (like using the adjusters and the arms to tap the pistons out vs. trying to turn the bad ones and stripping the adjuster heads) but, if people follow along and try the methods side by side, they'll see. The main trick will be the inner adjuster. That method is still pretty standard over the years. I've had special tools made up over the years and still, the 12mm deep well works the best. Badman - There's a big heavy box here from Mass...
