So we've had an apparent braking problem for the past year or so. Although while on shorter tracks, the issue is much more manageable, the problem really surfaces on longer tracks (Road America). So here's what the issue is... The pedal is relatively spongy for the first couple inches of travel in our FE. Usually after a bleed the pedal firms up, but that feeling can come and go throughout a session on track. Under hard braking as seen in the video the car is violently uncontrollable as if the left to right braking power is significantly different OR the rear bias is cranked through the roof. Immediately after the session in the video at last year's Cat Nat, we replaced BOTH master cylinders thinking there was something wrong with one of them. Evidently, the problem is still there as we have only been on much shorter tracks where the speeds aren't as high and braking pressure isn't as hard. This past weekend at the June Sprints, I had several episodes of the car getting out of shape under braking. Although none put me into the wall or did any damage, the feeling was the same and lead to us not qualifying or racing the entire weekend. After bleeding the brakes Friday night after practice and finding bubbles of air in the line, there were bubbles found the next day as well.
http://ift.tt/1l4ErKp
What we know:
1) both master cylinders were changed last year after the first time this happened under braking.
2) We used new (sealed) Motul 600 brake fluid once we suspected some kind of problem. We are very careful not to use old fluid that could be able to absorb moisture out of the atmosphere.
3) Air found in line within hours (15) of being bled with a lot of fluid.
4) No obvious leaking anywhere to be found. Fluid level staying consistent.
5) All piston seals were replaced two years ago and then over the weekend at the Sprints, the front piston seals were replaced since most of the air bubbles were coming from the front calipers.
6) Brake bias checked and rechecked to be within a good starting point (60% front)
7) Floating rotors are kept within a small window to float and potentially knock back the pistons to require an extra pump to bring them back into contact with the rotor.
Our next step is to start replacing the brake lines, fittings and possibly the bleeder valves (one way bleeders). My question is, is it possible to get air trapped in the line without leaking fluid everywhere? What else can it be? We are stumped.
http://ift.tt/1l4ErKp
What we know:
1) both master cylinders were changed last year after the first time this happened under braking.
2) We used new (sealed) Motul 600 brake fluid once we suspected some kind of problem. We are very careful not to use old fluid that could be able to absorb moisture out of the atmosphere.
3) Air found in line within hours (15) of being bled with a lot of fluid.
4) No obvious leaking anywhere to be found. Fluid level staying consistent.
5) All piston seals were replaced two years ago and then over the weekend at the Sprints, the front piston seals were replaced since most of the air bubbles were coming from the front calipers.
6) Brake bias checked and rechecked to be within a good starting point (60% front)
7) Floating rotors are kept within a small window to float and potentially knock back the pistons to require an extra pump to bring them back into contact with the rotor.
Our next step is to start replacing the brake lines, fittings and possibly the bleeder valves (one way bleeders). My question is, is it possible to get air trapped in the line without leaking fluid everywhere? What else can it be? We are stumped.
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