Need Brake Master Cylinder Piston

[red911]

Hello all,

I am switching my 1967 911 coupe from a single master cylinder to a dual master cylinder. I need the shorter piston from a pedal cluster if anyone has one. Here is a photo of the one that is too long.

Thanks in advance, Tom

Attachment 87568

[ajwans]

Hi Tom, I can't help you with the piston, sorry.

Would you mind listing all the parts and steps
required to do this swap? I would like to make
this mod also.

andy

[MarkS]

Tom, I did the same on my 67 and if I remember correctly (old and forgetful) I threaded down until I had length I needed and cut off what I didn't. If you can't locate one and what to get on the road you may consider.

[Flieger]

You mean a dual-circuit master cylinder, not a dual master cylinder setup (as is used on racecars with a bias bar), correct?

[304065]

Call Will Pringle at CSP, he markets the kit.

[red911]

Hi Andy,

Hi Andy,

I start with a 19 mm dual circuit master cylinder from a mid 70's 911 or 914.

Then since you need to plumb the front differently from the rear, I do the following from Classic Tube in NY state.

I bring new stainless steel brake lines forward from the rear. Easy for Classic Tube to bend, then once I am to the front, I take three feet of welding wire and bend the parts from the the dual circuit master cylinder to the front and the middle brake line. I also move the brass banjo fitting from the old single circuit to split the front brake lines. None of the lines from the single circuit work any more.

The reason for the new piston shaft from the pedal cluster is the single circuit longer than the dual one. So, I need a shorter one from a slightly later car.

I hope this helps.

Tom

[typ901]

guys... was a resolution here? I am in the same boat. i *can* thread & shorten the SWB piston, but another part would be SO much easier. I was sold a piston from (i think) an SC, but it's too short.

[edmayo]

I recently did the same to my 67. I just used the pushrod from a 68-73 pedal cluster. I used a master cylinder reservoir from Zim's. It has the center divider that you need to supply fluid to both circuits of the master cylinder. The reservoir comes with a molded on bracket that I cut off, and an additional fitting on the side that I sealed up. This then leaves you two outlets out the bottom, then ran the blue silicone hose to the master cylinder and used their two plastic angle fittings into the master cylinder that you just clamp the hose onto. Much easier than the original flared metal ends you have to push into rubber grommets. For the brake lines I just used the OEM lines from a dual circuit car. The tricky part is that the 67 isn't wired for the brake light switch on the pedal cluster, so I had to use an extra banjo to plumb in the pressure switch at the master cylinder. Haven't got the brakes working yet so not sure if this will all work as planned! The nice part of the reservoir is that it is round and fits in the original clamp with a plastic spacer for the longer clamp bolt. Don't have pictures of the underside plumbing, guess I need to take some.

[typ901]

hi Ed;
here's where my project sits. 19MM dual circuit MC leaves me w/ a question mark re; how to wire the brake lights (dual brake light switch) also, re: the piston the original is too long (we already knew this) the one i received from a parts recycler is too short. they claim this is the 'in between' unit & that the only other one available is shorter still. by playing the mix-n-match game I can get a workable set but with only 3-4 threads engaged. (see detail) I'm wondering if this is recommended. I can also shorten the original w. Mr. Grinder.

[edmayo]

I see you're using the later power brake 21mm master cylinder, I used the 68-75 19mm non power brake cylinder. You have a totally different piston length requirement than I had.