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,

[jim dorociak]

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

[Superhawk996]

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.

[barnfind9141972]

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.

@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.