Brakes don't Bite Options

[bkrantz]

As part of my rebuild I completely replaced the brake system:
calipers and rear pressure valve rebuilt by PMB
new ATE 19mm master cylinder
new hard and flex lines
new disks and Porterfield R4-S pads

I went through many (many!) episodes of bleeding, with different methods. The pedal feels very firm from the first push, and does not pump up. Rear clearance is set at .004". I went through the PMB bedding process, and have driven around a bit.

But the braking force seems weak. When I get on the brake pedal, I do not feel any "bite". Another 914 friend drove the car and also agrees.

Any suggestions?

[robkammer]

This is a thread I thought I would need to start. I'm having the same issue. Bought my 74 in Feb 21, pulled all of the brake parts except the steel lines. I sent the calipers to PMB along with the regulator. Bought an EZ MC from 914 rubber. Over the next 6 months (!) I was able to get it all together and start bleeding. And bleeding And bleeding. Over 2 quarts in all, lots of bumpy roads, hammer blows to the calipers and about 350 miles total. Finally the brakes were OK but would not lock up regardless of pedal pressure.

Then as I was putting the car away for winter I noticed that all 4 calipers nice new gold coating was pitted and looking like they were several years old. Crap. PMB sent replacements which I installed in January.

Bleeding wasn't as bad since I had fluid in the system, but still, after about 10-12 bleedings and 500 miles I still don't have brakes I would like to have. Soft pedal, doesn't pump up, push rod clearance is good, no leaks, Porterfield pads, venting clearance of 3mm.
When bleeding I can hear the regulator working, click click with the pedal travel, don't know if that's normal but it seems like that would indicate that it's working.

On my last spirited drive with lots of hard braking I pulled into the shop and took temp readings on all of the rotors. The were all within 2 degrees of the others.( 120-122F) That tells me all 4 are trying to stop the car.

I am really tired of screwing with these brakes. Bummed that I'm going to have to replace the lines from the reservoir to the MC if I go with an ATE MC. I'm thinking the Chinese EZ may be the issue.

Any input is welcome.

Other than that, life is good! Still a couple of good driving months left on the North Coast!

[Superhawk996]

On my last spirited drive with lots of hard braking I pulled into the shop and took temp readings on all of the rotors. The were all within 2 degrees of the others.( 120-122F) That tells me all 4 are trying to stop the car.

Hmm? What? 125F means you aren’t measuring before they cool down or they are not even working. That’s not even 40 degrees above ambient. Even 125 C isn’t hot for spirited driving or we have vastly different definitions of spirited driving.

The only objective measure is can you lock the fronts? If not - something is wrong.