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34 Ford typical under floor brake system. I have ECI brake stuff. Front calipers are small GM Rear calipers are Corvette. M/C is Corvette, 7" single Booster. The problem I have is the car doesn't stop well in a panic situation. Under normal braking like coming to a stop at a stop sign works fine. I have the 2 psi residual valves, proportioning valve / distribution block all from ECI. I just checked the booster and all is fine except for the air tightness check.The test is, start the car and let it run for a few minutes then shut it off. Then step on the brake pedal several times and the brake travel should increase with each depression. Mine stays in the same spot each time I step on the pedal. They say it could be the check valve. I tested the check valve and it is fine. It holds vacuum forever with no leak down. They say it could still be the booster is bad. What are your thoughts?
 

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I did a 70 buick GS a few years ago,used the same type of booster had the same problem.Istalled a vacuum pump and can still had the same problem,called the company replaced it still had the same problem.We used 6 piston willwood in the front 4 in the back.Called willwood told them the problem, they sent me the one they recomened but made it manual .After that no matter how fast of how hard you used them they would clamp down.
 

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34 Ford typical under floor brake system. I have ECI brake stuff. Front calipers are small GM Rear calipers are Corvette. M/C is Corvette, 7" single Booster. The problem I have is the car doesn't stop well in a panic situation. Under normal braking like coming to a stop at a stop sign works fine. I have the 2 psi residual valves, proportioning valve / distribution block all from ECI. I just checked the booster and all is fine except for the air tightness check.The test is, start the car and let it run for a few minutes then shut it off. Then step on the brake pedal several times and the brake travel should increase with each depression. Mine stays in the same spot each time I step on the pedal. They say it could be the check valve. I tested the check valve and it is fine. It holds vacuum forever with no leak down. They say it could still be the booster is bad. What are your thoughts?
It sounds like the booster is not working correctly.Check the vacuum with guage on the hose at the booster.I have heard quite a few rodders with the same set up as yours and they all have the same complaint, normal stopping ok, but not enough braking in a panic situation.Some rodders are using a 12 volt electric vacuum motor to add vacuum to the booster.also as side note: what bore size m/c do you have and also make sure the m/c rod at the m/c is the correct ratio and not on a bind or angle.
 

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It sounds like the booster is not working correctly.Check the vacuum with guage on the hose at the booster.I have heard quite a few rodders with the same set up as yours and they all have the same complaint, normal stopping ok, but not enough braking in a panic situation.Some rodders are using a 12 volt electric vacuum motor to add vacuum to the booster.also as side note: what bore size m/c do you have and also make sure the m/c rod at the m/c is the correct ratio and not on a bind or angle.
I did check vacuum at the engine and it is 18 inches. The tube is stainless all the way to the booster then a short piece of hose to the booster check valve. So I would assume the vacuum would be sufficient, but I will check it. The M/C is Corvette with a 1 1/8" bore. The pedal ratio is correct, but I have to check the rod adjustment. Thanks
 

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some of the lower MC's get air trapped if the cals. are higher than the MC-you might need to drop back to a 1" piston, or maybe a 7" single
booster just doesnt have enough
you might want to ck pressure at all wheels
 

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some of the lower MC's get air trapped if the cals. are higher than the MC-you might need to drop back to a 1" piston, or maybe a 7" single
booster just doesnt have enough
you might want to ck pressure at all wheels
Made a couple of calls today and as noted above by Jim (forced02) the 1inch bore worked for several guys,much better response on panic situations.
 
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