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,

Eric has turned 3 sets of 308 calipers into 914-6GT calipers for me. Put them in a large usps priority box, send them to Eric, and get back the properly set up calipers. Eric has the machining all set up.

I have access to a machine shop and I will still go through Eric because I know he has this down pat.

Also, I get good money when I sell them because the buyers know that Eric knows how to do them right.

Here’s how PMB restored my 308 calipers, with some explanation on how they differ from the 914 ones…


https://www.youtube.com/watch?v=oUvYRPe2bDw

Mark and Ian thank you for your responses. Ian I have watched your video and enjoyed the content and knowledge exhibited.

Can the 308 caliper in its current configuration be used as a 914-6 caliper without doing the second bleeder valve or will it simply not work in our application? I have all the rebuild kits, everything has been plated - literally ready to do assembly. 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? Did everyone who used the 308 calipers have to do the extra drill and install of 2nd bleeder valve???????

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.

@jimdorociak @superhawk996 yeah spot on, I just went through this. I’m an idiot and put my early single bleeder front calipers reversed and had the bleeders on the bottom. I did 3 rounds of pressure bleeding and the front pads would not put any resistance on the rotors at all. Realized the mistake, swapped them and now very little pressure and they bite hard.

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

Cool video -- wish there had been an Interwebz when I had to do a caliper seal kit back on my 1st teener way back in the late 80's. So much good information in Ian's video's.

PMB makes it look so simple. Worth every dollar to have PMB do it if for no reason other than getting a nice Zinc / Yellow Chromate on the calipers that will help prevent future piston bore corrosion!

Call Eric and tell him what you have. Probably will be a fairly reasonable cost given the condition and already dissasembled state. Do it right or dont do it.

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.

I thought his price was very reasonable for a 100% proven solution. I had guys who own real 914-6 race cars, eager to buy the calipers, knowing they were done by PMB.

And then there's always that guy . . . ..

Very creative solution for an emergency situation. Hat's off to you on that one.

Thank you all who gave input and reasons why it must be done. I got it, was just surprised to find this out at the backend just before assembly but at least it was before everything was assembled or even me trying to bleed the brakes. I will send them to Eric to be drilled for the 2nd valve stem at the top of each caliper. Maybe this thread will help others understand the issues with all the explanations. Jim