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Discussion Starter · #1 ·
I have a question some of you may be able to help me with. I have a hydro boost setup with a 96 GT m/c. I bench bled the m/c before installing, all of the calipers are on correctly such that the bleeder screw is at the top of the caliper. None of my hard lines run above the m/c. I do not have a factory distribution block being used.

I bled my brakes yesterday starting at farthest away and working up to the driver front. After getting oil coming out of each corner I started over at the rear and bled till all air bubbles were gone then going to the next wheel and repeating. I bled with the m/c cap off and had the pedal pushed down and held then cracked open the bleed valve, waited, tightened the bleed valve, had pedal released and then repeat the process. Topped up the m/c resvoir any time it got close to half way down.

Problem is, the pedal is still going to the floor; the pads grab enough that one cant push the car but I did a small test down my driveway which has a slight slope for 20 feet and the car will not come to a complete stop right away. My driveway is sloped such that it goes down 20 feet and then up a bit into the garage so I placed the car in the driveway with the rear higher than the front and bled again, then I placed the front higher than the rear and bled again. With the front higher than the rear,I did get one tiny air bubble out of the front psgr and driver side. All other conditions I got nothing but brake fluid. So my question is should a hydroboost setup, brake like a manual brake setup prior to the hydroboost being supplied with hydraulic power (b/c I am still engineless)? If so, is there anything I have overlooked in bleeding or should I try a vacuum bleeder b/c I expected the pedal to be solid after an inch or so of depression.

Thanks in advance,
 

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From what you said you should have pedal. It should not go to the floor. Try bleeding the master cylinder in place. If it's like a 99 there should be two bleeders on the master cylinder one for the front and one for the back. Same process. Have someone pump the brake pedal and hold it then open the bleeder. Pedal goes to the floor and hold it. Close bleeder and do it again. It took me several times bleeding both the master cylinder and the lines before I got a good pedal.
 

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The pedal should be hard even without the motor running. The stopping force will be less, but the pedal should not go to the floor.

My wife and I bled mine with the exact method you mention above and I have had no issues for 8000 miles.

Are you using a donor MC or a new one? IT the brake line are bled well and the pedal still goes to the floor I would think bad MC.

Bobby
 

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Are these all new/refurb parts that have never had brake fluid in them? When we installed our hydroboost kit from Hydratech braking we did the exact same steps as you. Bench bled the master first, gravity bled the whole system, and then bled each wheel starting with the farthest from the master. When we were done (twice) we still barely had a pedal. In talking with Paul at Hydratech he commented that the all new parts will have thousands of trapped air bubbles and to let them gravity bleed more (simply open the bleeder screw and let them "breathe" and he also suggested hitting all four calipers with a rubber mallet to dislodge the air bubbles and get them to move to the highest point (the bleeder screw). I did these steps, then bled one more time, and now the pedal is great.

Try these steps (on level ground if possible) and let us know what the outcome is...

HTH...
Mark
 

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Discussion Starter · #5 ·
Cheers Jeff!!! Went out and bled the m/c and it had air in it. Guess my bench bleeding wasn't what I thought it was


Bled front and rear m/c ports and my wife was amazed at what a few air bubles difference made.

Re-did my test run down the driveway and it stops instantly anywhere just as I thought it should without power assist.

Thanks again to all the help the forum members provide!
Dave
 
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