It feels like my brake master cylinder is going bad on my 1974 2.0. Since I've never rebuilt one or replaced one on the 914, I'm looking suggestions and parts sourcing. Any help out there?
Thank you.

I looked high and low for a rebuild kit and my understanding is they have been NLA for awhile. I bought a new one from 914rubber but haven't installed it.

I checked out the 914Rubber site. Did you buy the easy install option?

Perfect time to upgrade to a 19mm master cylinder, unless you already have one.
Add some Stainless steel brake lines while your add it.

I did not and may regret it. But my car is completely stripped so it will be going in without the fuel tank so I think I'll be okay. From what I hear, if you are installing in an assembled car, get the EZ option.

What makes it feel like the MC is failing? When was the last time the system was bled with new fluid? Over time, DOT 3 & 4 brake fluid pull humidity from the air, which leads to decreased braking response. If it hasn't been changed in a while, that could be the cause.

The 19mm MC is a great upgrade regardless. Here's the install video I made for the 914rubber one...hope it helps.

https://www.youtube.com/watch?v=N6ZHK5f_9bE

go for the 19MM from 914Rubber

Second that!. Made an immediaite difference.

You may just have soft rubber flex lines that need replacing. Rubber or SS flex lines are good. Pelican carries a good set made by Troutman for about $80.
Rebuild kits have not been available for years. Discontinued as the bore can be bad and a mechanic have a lot of time to R & R a master cylinder and bleed the system.

I went with the 17mm Ate from Pelican Parts. $294 not cheap, but I could not find a better price. A 19mm will require more pedal effort. Not what I wanted. Bench bleed before install. I did not and had to use a pressure bleeder to get the air out.

I would do the soft lines at the same time. They don't get better with age and if you don't know when they were done, its probably time.

I agree on the soft lines. They degrade from the inside and choke the line like a clogged artery.

I don't know if people have commented about increased pedal effort with the larger m/c upgrade ,mines an ATE 19mm I find it great.
The 914rubber m/c looks like a great piece and well worth considering,if you could find a rebuild kit you would be lucky to cleanup and hone a 40+yr old cylinder with good result.
My local brake shop offers a service of resleeving m/c's with a stainless steel liner but this is mostly done for very old classics where the part has been long out of production,they don't recondition any parts off newer cars anymore.

I looked for ages for a kit for my 19mm but could not find one. Ended up buying a new ate 19mm unit instead.

As above i did find someone to refurb it and they had kits but would not sell one. They sleeve the cylinder too. But mine was spotless inside so don't think it needs a sleeve.

To much liability to sell rebuild kits to people who have never (and are not qualified to) rebuild a master cylinder.

I've always been curious about this. Why would the liability for rebuilding an MC be different from rebuilding a caliper? It's a genuine question because I've never rebuilt an MC so don't know what is involved. Seems weird that DIY caliper rebuild kits are okay but not MC though. Plus, you can get rebuild kits for other ATE MCs, some for cars as old as our 914s.

Thanks, Cuddy.
I just had 4 PBM Performance calipers installed. Lines were bled many times. No leaks in the lines or at the caliper. My mechanic and I are assuming the master cylinder. I had to take the car home and do this research. Sounds like my MC...doesn't it.

If everything is new, it could be that the pads haven’t fully bedded. Def check with Eric at PMB. A new master never hurts tho. And the “extra force” required for a 19mm is negligible on my car...

Do you have two bleed nipples on each caliper? Or, do you have one?


If you have two bleeders on each caliper, do both or you will be fighting this until the earth explodes into tiny particles.

I use the tool from Phoenix Systems. On man operation.

I thought the master was bad on the one we have in now....nope.....just was an extra challenge to get the air out. Now it stops as it should.

Thank you, Cal44. There are two bleed nipples, but I can only assume that my mechanic checked this. (Yeah, I know "assume" can be challenging.) I'll look into this.