explanation of the Ferrari 308 vs 914-6 caliper, differences and necessary mods to use 308 caliper Options

[jim dorociak]

Ok - I started down a slippery slope and now am faced with exactly what to do to wrap up my calipers.
Initially had refurbished 4 cylinder calipers and wanted to split and run vented rotors, well the spacers from 911 calipers do not fit, so I decided to look for 914-6 rear calipers knowing that I already had the spacer blocks from the 911 calipers - and then I ran across some Ferrario 308 calipers and thought I had the final solution as they already have spacer blocks and started a restoration of these calipers. I managed to get them disassembled, and all the parts gold zinc plated and am ready for assembly only to bump into Eric Shea at the last swap meet in LA last weekend and he mentioned that the bleeder valve was in the opposite end of the caliper compared to the 914-6 and the proper way was to have the caliper half drilled in the 914-6 location and run two bleeder valves - So is it the need to have the bleeder valve at the top of the caliper as the -6 caliper is so it works properly or could you just not do the modification to drill and run 2 bleeder valves - a convenience factor or must do to properly bleed the caliper?

Who used the 308 calipers and did you do the dual valve set up???

I look forward to any discussions and experiences you guys can share.

Jim. jdorociak@gmail.com,

[ClayPerrine]

Would a bleeder valve on the bottom of caliper instead of the top like our 914-6 calipers were designed actually work - can you bleed the air out or is it impossible?
Jim

That is a very bad plan. The caliper bleed needs to be at the top because the air bubbles rise within the caliper to the high spot.

It will be virtually impossible to get a good bleed without the bleeder at the top where it belongs.

As previously recommended, just send to PMB and have it done right.

Bleeders need to be at the top or you have paperweights.

Not 100% true. You can do it, but it is a pain in the ass to do and get to work. I found this out the hard way. On my Jeep Pickup, I had a caliper go out on the left front, and I needed it running to get to work. Called all the auto parts stores in the area. Nobody had a left caliper for it. One place had a right caliper. The calipers were interchangeable, but the bleeder was in a different location. I sucked it up and bought the right caliper and installed it. To bleed the brakes properly, I had to unbolt the caliper, and stick a block of wood between the pads. Then I turned it so the bleeder was on top and bled the brakes. I put the caliper back on the truck, and it worked fine for years after that. When I finally replaced it, I was able to get the correct caliper for that side.

This is NOT a recommended procedure. I was desperate to get the truck up and running for work. There is a big difference between a single piston floating caliper on the front of a Jeep and the rear caliper on a 914. The 914 is much harder to remove and reinstall, so I would never do this on one.