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?

[gereed75]

Different car but maybe a useful data point - I had some unknown old and what appeared to be metallic very hard pads on my race car with Willword calipers. I called Willwood to get their recommendation for a pad. I gave them car weight, HP, typical track cycles (speeds braking from down to corner speeds how many times per lap and how much time between applications).

I was surprised when they recommended an aggressive street compound. They said my loading was just not enough to get sufficient heat into a race pad to generate good friction. My point is Race oriented compounds need a lot of heat to get into efficient friction ranges. The new ceramic street compounds are very good at generating initial bite with minimal loading while providing good wear characteristics.

Not sure what type of compound the R4S is, but you might be asking it to do something it is not designed for