Hydro boost helll p ?

[impalamonte]

Needing some professional direction. Love the hydros difference in pedal feel and stopping power! But , it is giving me " heartburn"!!


4 wheel disc brakes. Front , Baer two piston 13" rotors. Rear , Just Right Manufacturing kit, 11" rotors.
Master cylinder for 4 wheel disc and junction block.
Stainless lines through out. Steel braid out to wheels.


Using a 2000 year model Hyrdro- boost from a g2500 3/4 ton chevy van.


Rebuilt my Hydro boost .
Installed upside down.
Dedicated return line to reservoir.
Running in-line Magna-fine filter. ( as cheap insurance)
All fittings AN style , sweeping 90 degree. No lines binding or kinked.


I have taken material off the "plug" in the rear of the master cylinder. Did not solve rear brakes dragging thinking the rod in the hydro was too long and applying pre-load on the master cylinder.
As a check , I started with one washer between the master cylinder and hydro boost. Then graduated to a total of 3 washers ( totaling .190 inches). After each test drive, very apparent rear brakes still dragging.


I lifted the front end of the car and the front brakes do not drag with the car running and manually turning the front tires by hand.
After each subsequent test drive testing the washers as spacers...I could not put my finger on the webbing of the rim and leave it there as the webbing was so hot. The fronts were warm and I could hold my finger on them.
Roughly ( 1 mile) test drives. And the car is noticed , laboring to overcome the drag.


I probably have 10 hours in troubleshooting all possible potential offenders....per the internet. I did have a "T" in the return and went to a dedicated line and still have the issue.
I have noticed a small amount of pressure when I remove the reservoir cap. But, it is small , barely audible.




I feel defeated.

[WallaceMFG]

Put a better vent in your reservoir. Any pressure in the "leak" (that is what Hydratech calls the 3rd line from the boost unit) circuit will cause the boost to apply a little pressure, and the rear brakes will drag. Try lifting up on the pedal to take all pressure off the boost rod and see if the brakes stop dragging.

Our Chevelle had the same issue, but seemed to get better and go away once the PS fluid warmed up. We had a T fitting with a check valve in the line to prevent back feed into the boost unit leak fitting. We replaced our return lines and reservoir so we had a direct line from the leak line and the problem went away. We also did a new PS pump at the time since we had issues with several pumps before.

Also make sure your reservoir is big enough and it is not aerating the fluid. What are you using for a PS pump? What size AN lines? Filter location?

[thinkfastroth]

Are you sure you have a disk/disk master cylinder?
Who and where did you get the hydroboost unit or kit from?
Are you sure you have the right accumulator on the hydroboost unit? I found out that there are differences depending on original application.
You might contact Elliott at Custom Power Brake http://www.custompowerbrake.com and see if he can point you in a right direction, he builds hydroboost custom kits and brackets.
Dan

[thinkfastroth]

In my last post I mentioned the accumulator, but that's just going to give you a shot of pressure to get you to stop if you lose your pump pressure.

[impalamonte]

WallaceMFG & thinkfastroth......

Thank you for your input. I wanted to run some tests before I responded again. With all the trouble shooting...tired of swimming in PS fluid !!

I removed the cap from the reservoir and drove around. I cut a slit in a denim rag and placed the caps long end through the slit and placed the cap on top of the reservoir to breath. Up and down the interstate 3 miles each way. With the finger test. The webs on the front rims, warm. The webs on the rear rims , warmer than the front. But I do feel like it helped. Therefore , I will be acquiring a vented cap. Suggestions ? Is the cap from a mid-nineties Astro van vented ? Would drilling a small hole through mine work ? Very small though. I dont want it all over the engine compartment.

I went a step further and removed the inline filter. NO appreciable difference. Drove the same route again.Same results.

Pulled into the garage. Then heat sink set in without the air flow around the rear rims while driving. Webs on front rims , warm. Easy to leave my finger there as long as one would want. Rear rim web , considerably warm and increasing as the heat progresses from the rear rotor to the rim. But able to keep my finger held to it. BUT WARMER...WARMER.

Now onto the answer the question that you gentlemen had asked.
WallaceMFG: The reservoir is a factory unit from a 1993 Camaro Z28 . I notice no frothing of the fluid ..its clear. At the correct level.
My motor is actually a 1993 LT1 , Blown and meth injected. Running the factory PS pump. There is no whining /sounds come from the
NEW Borgeson Steering gear or the Hydro-boost.
All lines are 3/8th"
Filter location is the last thing on the return line before returning to the reservoir. Do I really need to run a filter ? Opinions ?
No trouble to return it back in line.

Thinkfastroth : I am sure it is a disc / disc master cylinder. 4 month old TUFF STUFF part # 2018nb. I purchased it as in the description it said disc /

disc compatible.
The hydroboost unit is from the junk yard from a 2000 model G2500 Chevy 3/4 ton van. Rebuilt on my bench in "clean room" like

conditions.
I was very aware of the importance of cleanliness with this part. Understood and maintained throughout the rebuild.
Rebuild kit was from Southwestern Performance Parts.
Accumulator is gold.
I will contact Elliot at Custom Power Brake to get his insight.

[thinkfastroth]

Are you also running an oil cooler?
When I was doing the research for my set up, I found it was recommended to run an inline cooler, that's why I ask.

I have a similar pump and boost unit set up in my 84 Grand Wagoneer but, I do have drum rears.
Im running a 94 LT1 power steering set up from my Z28 but with a C4 Corvette remote reservoir, 1997 3/4 ton boost unit with a gold accumulator, inline filter and an inline oil cooler and Im on 37" military tires. That sucker stops on a dime.

I think contacting Elliot would be a good idea or, contact Hydratech Braking http://hydratechbraking.com. Hydratech also has some really good info on their tech page http://hydratechbraking.com/tech.html.

Hope some of this helps.
Dan

PS, you have a really good looking car!

[impalamonte]

Thank you Dan!

We are running very similar set-ups and puts me more at ease that I don't think I have done anything wrong in my set up. I most definitely like the feel of the stopping power now for this 4000+ car. And I do not want to resort back to my vacuum set - up...ugh!!

Yes , I am running an oil cooler , much like a GM PART # 26083109. But it is from a mid 2000's Chevy truck in the same orientation / location on the front of the core support as the truck. 2 row pass as suggested by others.

My filter is / was located as the last piece before going to the reservoir as well.

I will make contact with those resources but will also accept anyone's insight to "point " me towards the potential source of issue.

Mark

[impalamonte]

Hey Dan,,,

For clarity , are you also using the reservoir cap for the C4 reservoir ?

It looks like it could be vented.

IF it is from a 90-96 Vette, our reservoirs are very much similar sized.

Mark

[thinkfastroth]

Yep, sure am.

PM me your email and I will send some pics later today.

Hey Dan,,,

For clarity , are you also using the reservoir cap for the C4 reservoir ?

It looks like it could be vented.

IF it is from a 90-96 Vette, our reservoirs are very much similar sized.

Mark

[thinkfastroth]

Mark,
I went out and looked at the Waggy.
I'm wrong, I am running the 94 Camaro cap and reservoir. My cap does not appear to be vented. I also looked at the reservoir and cap on a 93 Vette I have, it does not appear to be vented either.

[impalamonte]

Ahh , ok. Thanks.

Ours are just alike then.

I definitely am holding some pressure though.

PM SENT.

[impalamonte]

Just to do a quick revisit and report that I have resolved the issue with the assistance of Hydratech.
Due to my setup , the bypass line off the Hydro Boost was not allowed to make its way back to the reservoir "cleanly".
There were no kinks or restrictions.....other than low pressure.
I had to change my routing as my reservoir is set up on the passenger side of the car with my dedicated return line to the reservoir.
As the flow is very light out of the Hydro-boost bypass , the fluid would not make its way back " up hill" as I had the line routed under the engine
following the cross member and then to the reservoir. That inability to get back to the reservoir created a resistance and thus the rear brakes were "dragging" .
I could have installed a "T" in the low pressure return line. I tried that and found the when I did the brakes did not release quick enough and it made my steering " not smooth" .