Technical Hydroboost problems

I just got the 34 Intl. hotrod going. I have a hydro boost setup on the brakes. With slight pedal pressure, it squeals very loud. Other than that the brakes and power steering work great. After dring it around the block the power steering fluid looks like it's in the beginning stages of foaming.
The unit is positioned under the floor boards next to the frame rail. It's lower than the power steering pump. The hydro boost low pressure return line is connected via a tee fitting with the return line from the power steering since the power steering pump reservoir has only one low pressure return connection
1. I'm wondering if the hydro boost spool valve may be hanging up and going full travel.
2. Could the hydro boost have air trapped somehow. I thought it would be self bleeding the way all the fittings are position on top of the unit.
I would appreciate your thoughts on the matter

 

If it is foaming it still has air in it. Let it sit for a little while and start it back up, top it off and turn the steering wheel lock to lock a few times, depress the brake pedal a few times, shut it off and let it set again (long enough for the foam in the reservoir to disipate). Repeat. If after the third time if it is still getting foam, it may be a problem with it being mounted that low, not sure. They can be difficult to get all of the air out some times.

 

I've been thinking about possibly bleeding the hydro boost unit itself by disconnecting the low-pressure return line located on top of the unit and running it into a jug to see if there is air trapped there. I just have to be careful and not let the power steering fluid get so low that I introduce more air into the system.

 

If that doesn’t work you may need 2 return lines in the reservoir

 

It bleeds itself

 

If it bleeds itself then why would it squeal? Air entrapment would be a likey culprit. What am I missing?

 

the fact that it is under the floor may make it more of an issue to bleed, as the pump is above the unit. a factory hydroboost has the unit above the the pump. It should bleed itself, but with the components location in different spots it may not. I would start it and carefully crack each line at the unit,to see if you can get any trapped air out. It will make a mess, it will be hot fluid so use caution. I had to do this to many hydro boost equipped chevy trucks when i was still in dealers in the late 90's. sometimes it just needed a little help.

The single return line with a T in it is probably also a problem. But that can be remedied with an 80s chevy powers steering pump for use with hydro boost. it will have 2 return line fittings.

 

Could be it’s position in your case but a PS system will bleed itself by turning the wheels lock to lock

 

Are the brakes, or the pump squealing?

 

It's definitely the pump squealing.

 

Thanks for all the input. I will proceed by doing two things.
1st I'll install a second return port on the power steering reservoir and separate the return lines.
2nd I'll bleed the hydroboost unit itself.
I'll let ya'll know how thing turn out once that's finished.

FYI, I'm using stainless steel braided TFE lines with AN fittings. They are easy to work with and I've had zero leaks. I use the same material on the tranny fluid lines and the fuel lines. This is great stuff.

 

Is it a pump for hydroboost?

 

In my intense research (reading a very good Hot Rod article) the pumps are basically the same Saginaw pump. The cans have an extra return and have a few different locations for them.
The heavy duty truck pumps are supposed to be able to produce more PSI. The pumps make pressure by the amount of fluid it moves.
if running as a brake booster only and no PS, you CANNOT plug the pressure line that would have been used for the PS box. That kills the pump. Just run it to the extra return line.
I read some guys on other message boards saying that combining the 2 returns to work with a single return pump caused some odd pedal feel issues.

 

My Old Power Wagon , I swapped in a Hydaboost powered by the Cummins pump . It has a Y fitting and one return from the PS and Booster . Seems if you get the steering in a lock position and the pump bypasses high pressure , you have no brakes with only one return . It’s on my list to find a can with 2 returns . The “ bubbles “ will work themselves out . But again use caution when applying the brakes with steering in a lock position , you will get a shock . Be safe

 

I have used a vacuum pump connected to the resevoir to bleed those. They won't always work the air out. Most of the time but not all of the time.