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?

[bbrock]

Hmm. I have PMB plated calipers that I rebuild myself per their instructions. Same for the pressure regulator. Porterfield pads and a 914R MC WITHOUT the EZ option (I never liked the look of that "improvement"). So, essentially the same setup as you other than the EZ option.

I initially bled my brakes using the gravity method that Eric describes on the PMB site, making sure to bang on the MC, regulator, and all calipers with a rubber mallet. I let the car set a couple weeks and followed up with a Motive power bleed and the pedal became rock hard. After bedding the brakes on the initial drive, I gave it another round with the Motive but don't remember getting much, if any, more air out. I do think the gravity bleed helped set me up for an easier power bleed.

I think I just got lucky but 6,000 miles later, the pedal is still firm and brake feel is excellent at all speeds although I still wish I had a 17mm MC. The other day I was driving at 70 mph on the frontage road and thinking of this thread and decided to punch the brakes hard. I heard the front tires chirp on the pavement within a second and let up and kept driving.

To be honest, I'm not a fan of the 914R MC and would go ATE if I had it to do again, but it does a good job of stopping the car and I'm happy with the overall setup. I've been paying a lot closer attention since this thread started, wondering if I had just gotten used to sub par performance but I'm confident I'm not. Even our resident brake engineer, @Superhawk996 has driven the car and didn't comment on the brakes. He may have been too preoccupied complaining about the steering (IMG:style_emoticons/default/lol-2.gif)

I really don't know why I had luck with my setup where others are having trouble. The only things I've done are get a good bleed on the system and bedded the brakes like I hated them (Of course I couldn't see it, but I'm pretty sure they were glowing red hot).