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Old Yesterday, 01:21 PM   #1
Johnl48
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Join Date: Jun 2021
Location: West milford nj
Posts: 333
Hydroboost issues

I am running a disc brake conversion front and back on a 70 C20 4x4. I am just getting into the hydroboost troubleshooting. My lines are layed out as per diagram shown, and I'm using a disc/disc master cylinder. What's happening is, power steering is working fine, air is bled, the brakes work but pedal goes to floor then pushes back at me, and when stepping on the pedal I feel the steering wheel move slightly. Also when engine is off pedal feels fine. And yes brakes are bled
Any thoughts on this ?





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Old Yesterday, 01:51 PM   #2
bcfishon
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Join Date: Nov 2012
Location: canby,oregon
Posts: 357
Re: Hydroboost issues

Make sure the rod is adjusted perfectly inside cab
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Old Yesterday, 02:09 PM   #3
Johnl48
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Re: Hydroboost issues

Quote:
Originally Posted by bcfishon View Post
Make sure the rod is adjusted perfectly inside cab
What would be the procedure for that ?
The pedal feels normal with engine off
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Old Yesterday, 04:46 PM   #4
Joyridin
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Join Date: Sep 2020
Location: Cleveland, Ohio
Posts: 566
Re: Hydroboost issues

Have you tried taking the return line from the hydroboost and just putting it inside the reservoir instead of inline? I have heard that returning it like you have it can cause problems, although some people do it that way.
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Old Today, 08:55 AM   #5
A1971Blazer
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Join Date: Nov 2013
Location: East Tennessee
Posts: 2,212
Re: Hydroboost issues

Some people use the "T" in the return without issues and others seem to have issues.
I put an extra return in my reservoir just to be sure.
Also, is it a new hydro-boost unit or a used one? I had one on a truck once that was faulty.
It started by kicking back on the pedal like you describe, and then it self-applied the brakes and would not release. I had to replace it.
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