Hydroboost help please!!!

[jeremy92555]

Ok, here is what I did. I put in a 1993 hydroboost out of a Astro Van. I used the the master cylinder off the astro van as well. The master cylinder has a MF sticker on it if that matters. But, I did not use the proportioning valve. My hoses off my stock master cylinder fit right into the Astro M.C so I did not change anything there. When I bleed the system with the truck off it seems to bleed like normal. But, when I start the bronco and press the pedal the pedal pushes back and seemed to find a weak point in my break lines and also causes a leak at a fitting near by rear axle. What is causing the pedal push back? Why dont I have a normal pedal. Any help would be greatly, greatly appreciated because I am now frustrated and I am sure it has something to do with what I did or didnt do.

 

[ransil]

air in the power steering system.
I had to bypass the hydroboost and bleed the power steering when that was good, i then bled the hydroboost.

 

[jeremy92555]

Is there another way to bleed the power steering system other then turning it lock to lock. how do I bleed the hydroboost?

 

[nutter3]

http://hydratechbraking.com/Hydratech/braketech1.html

This is a pretty good article. Also read somewhere to disconnect your drag link at the steering box so you can turn the steering box fully from lock to lock.

 

[TOFIC]

The pedal push back is fairly normal with a new install. H boost should not cause brake line leakage, a new pump might but not H boost. It is parasitic and dormant when not used. You have air in the brake system somewhere. There is one other way to bleed power steering, drive it on a mildly rough road. the bouncing and vibration should take out the air in the system. Make sure you have brakes though, fix the leaks. if this does not work you have some contamination in your PS fluid and will have to change it out.
TOFIC

 

[jeremy92555]

Just to make sure this is the same, the push back i get is instant. When I push the pedal in it is extremely hard. I think I can only push it in approx a inch or two because it is so hard. The brake line leak never occured until it was under preasure so that is why it concerned me. I have never had a line leak until today.

I will work on trying to bleed the powersteering some more, fix the leaky line, and see if that helps. I wanted to make sure that the cause had nothing to do with the master cylinder used, not using the P-valve etc. Unfortunately, I will have to wait until Friday to work on it again which will make for a long week. Thank you very much for the responses.

 

[DanWheeler]

based on your description the pedal feel is about right i'd say but with a new system you should have air in it so you should spend some time bleeding it out anyway. You may not be used to it yet. It doesn't feel like a master cylinder because your not actually pushing on a master cylinder (directly) Sometimes the hydroboosts can feel a little bouncy but thats not a bad thing.

Astro vans are disc/drum but I would guess all the proportioning is done on the ABS block on the Astro firewall. I've always wondered if the Astro M/C puts out the same pressure from both ports. If so, and you have rear drum brakes, they are going to lock up too soon which can be dangerous.

btw - if you hadn't figured it out already, the front port on the astro M/C is for the rear brakes. large reservoir goes to the front discs.

the leak is probably just a result of the increased pressure put out by the hydroboost. Which fitting is leaking? If there is a leak, it could be letting air into the system causing other issues.

btw - one problem i had with the astro M/C is I would accidentally run the small rear reservoir down to empty then suck air into the system. You can pick up another reservoir from the junkyard so both front and rear reservoirs are the larger style. just cut the 2 reservoirs apart and the large one plugs right in where the small one was. you have to rotate the new larger reservoir 180 degrees. Dont forget to grab the rubber o-rings from the junkyard.

 

[jeremy92555]

I will definately spend some more time trying to bleed it out to see if it gets softer. I kinda expected to feel somewhat like a pedal on a newer vehicle. But, it is far from feeling like that right now. The fitting that is leaking is at the rear on the frame where it is connected to a stainless line to get get down to the rear axle. I will try to tighten it up some more but may have to replace something if that does not work.

 

[TOFIC]

Just to make sure this is the same, the push back i get is instant. When I push the pedal in it is extremely hard. I think I can only push it in approx a inch or two because it is so hard. The brake line leak never occured until it was under preasure so that is why it concerned me. I have never had a line leak until today.

I will work on trying to bleed the powersteering some more, fix the leaky line, and see if that helps. I wanted to make sure that the cause had nothing to do with the master cylinder used, not using the P-valve etc. Unfortunately, I will have to wait until Friday to work on it again which will make for a long week. Thank you very much for the responses.

Fix the leak in the brake line first, I would surmise that is one of your big problems solved and will go a long way to fixing others.
As to the line leak, I am not surprised. Hboost will put a lot of pressure into the application of the brakes. If system is not up to snuff, you just found out what can happen
get rid of the Pvalve from the astro van use the bronco hblock for your front rear distribution.
As to the pedal, leave it alone, I have a feeling things will come together once you get leaks plugged and air out of system
TOFIC

 

[Lebe]

I use the complete Astro braking components, i.e. H-boost, MC, p-valve. Once properly bled it works fine with my D60 front discs, D70 rear drums.

 

[jeremy92555]

I will work on the leak first, and probably replace all power steering fluid with 100% fresh stuff. I think I will unhook the drag link this time when bleeding and make sure that all air is out of lines. I better double check the master cylinder to make sure I got all the air out of it as well while I am at it. Thanks again for all the feedback.

 

[barronj]

just cut the 2 reservoirs apart and the large one plugs right in where the small one was. you have to rotate the new larger reservoir 180 degrees. Dont forget to grab the rubber o-rings from the junkyard.

I used the MC reservoir off my 93 Astrovan MC on the 79 Malibu MC I'm running, but had to cut them apart to get them to fit in the closer spacing on the MC... What rubber o-rings are you talking about? Do they go on the male end/bottom nipple of the reservoir where it plugs in to the MC?