Diagnosing Hydroboost

Mark Bradley

Da guy in Newbury
**** Solved ***
Howdy all. I just converted my ‘68 Camaro to a Hydroboost system and am questioning if there is something wrong with the unit.
I purchased a rebuilt Hydroboost for a 2003 Astro van from A1Cardone as the core of the effort. It is in and it stops very well although I can feel the brakes drag after applied.
I used the existing master cylinder and custom made the rod between the Hydroboost and the master cylinder because it did not come with one.
I measured the depth into the Hydroboost and then accounted for the depth the master cylinder sets into the Hydroboost.
I have also made sorter and longer ones just to double check.
Here is what I see...
With the master cylinder laying aside and then I start the motor The Hydroboost creeps out to its limit. Once the motor is off I can push it back.
With the master cylinder on and the motor off the car can role easily. Once I press on the brake then release it it is locked but if left alone for about 10-15 seconds it rolls freely.
I’m the same test above if I power off the car it then rolls easily.
Any thoughts?
 
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I’m doing some research and wonder if I need a return spring on the pedal. If I pull the pedal up it seems to release.
 
I assume you connected to your power steering pump.
If you teed into the single return line, instead of creating a separate return,
I believe the pressure back-feeds and slightly drags the brakes.

I will try to find the article for you.
 
The newer electric boost systems interest me but my power steering pump that came with billet specialties tru-trac says no hydro boost
 
Update:
Seems very positive results from testing so far. As a test I capped off the T that I inserted into the powersteering return and ran the Hydroboost return into the top of the power steering reservoir.
Now when I release the brake pedal the brakes release pretty quick.
More details shortly.
 

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All done.
I took apart the powersteering pump and added a return to the side of the reservoir and that is where the hydroboost now returns without intersecting the powersteering return and the brakes work great.
Looks like I also got a powersteering flush and some new lines out of the exercise... I guess that is not so bad.

Cheers
 
Few photos of the location of the new line.
I drilled the hole and cleaned the surface. Then sanded a washer clean and soldered it to the outside. Then I sized the washer to allow the brass fitting to just slide inside. I the used another washer on the inside and used a compression nut without the ferral to sandwich the stack together. Then insoldered the entire stack and brushed off and extra solder. Should be plenty strong and sealed without any chance of ever coming apart.
 

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Great job. Plus you gotta love it when the fixes are that easy.
I'm glad I remembered that for you.
 
Mead well... I had seen a post that mentioned that and dismissed it. Funny that I presumed it had to be harder than that.
I’ll bet some people run a T with success. I had one guy say he ran a Y and was fine.
GM uses a pump with two ports so that sells me.
 
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