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PS or Hydroboost issue...strg effort increases with rpm...

nvrstuk

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Just a Bronco driver for over 50 yrs!
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Parts-- Astovan HB, PSC P/S pump, 4x4x4 ported P/S box

Symptoms are the effort it takes to turn the strg wheel increases with the rpm when cornering... -up to a point as I haven't tried turning a 90deg turn at 4K rpm. :)

So... If I am sitting at a stoplight let's say or in my backfield idling I can turn the steering wheel with its normal amount of effort. If I accelerate as I'm going into the intersection and turning either left or right because it doesn't matter, then the RPM's at my engine might be higher and there is a noticeable increase in effort to turn the steering wheel and then it takes the same amount of effort to turn the steering wheel back to center..

I slapped a pressure gauge on the side of my ported box and as I'm turning the stg wheel the press is at 1350 at idle. If I increase the rpms the pressure is still at 1350psi and I can only test this while turning left since I dont have any AN fittings to splice into the system elsewhere. Although tapping into the left port does determine that myps box seals aren't compromised since I have zero pressure on the left port when turning the wheel to the right...

Is the bypass or porting in the AtroVan HB unit not allowing enough flow thru when putting more demand on

Possibly the box? Its always taken a Herculean amount of effort to turn the 37"s or 40"s off road...ever since I got it...

Ideas?

I have the ram disconnected so thats out of the equation
 
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nvrstuk

nvrstuk

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If I apply the brakes and try turning the steering wheel I get 1400 PSI and I can't turn the steering wheel all the way to the stop on the knuckle... weird that it has 1400psi and won't turn the tire.

This is a bit weird....
 
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nvrstuk

nvrstuk

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Forgot to add

- the hydroboost unit seems OK since I ran the simple pump pedal till hard with engine off, light pedal pressure, start engine and see if pedal moves to floor then quickly back up. Which it did. I don't have any typical HB booster issues...
 
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73azbronco

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Sounds like a restricted return issue. Do you have two or one returns to pump?
 
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nvrstuk

nvrstuk

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One return line since my large reservoir has 2 return ports one for hydroboost and and one for the cooler
 
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Hinmaton

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I agree with the restricted return issue thought. How do you have the return from the hydro-boost plumbed in?
Tee fitting? I recall there being a specific way to plumb a tee the fitting to resolve return issues. And maybe there was a potential of of and issue regardless? I can't quite recall at the moment.
I have 38's, Hydro-boost, a 4x4x2 box, HP pump w/ remote res, and ram assist. When I plumbed it I swear I recall there being a potential issue of spliced returns fighting for flow. Fortunately, I ran the second return into the res (not running a cooler).

Are you running ram assist as well?

I suggest re-plumbing your second return into the res by-passing your cooler temporarily, just to see if that solves it.
Maybe run the cooler inline with one of the returns?

Hinmaton
 
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nvrstuk

nvrstuk

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My earlier post wasn't clear..."one return line" .

Both the hydroboost AND the cooler have their own return lines to the large reservoir.

I'll put some air thru the line that flows thru the cooler and back to the reservoir..make sure it flows freely.
 

Hinmaton

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Now I’m confused...
Sounds like you have two return ports, but are dedicating one to the cooler?
It would also be helpful to understand how you plumbed your system.
Take a look at the attached document.
c396acee156ae11e80a0805c43f39751.jpg



Hinmaton


Sent from my iPhone using Tapatalk
 
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nvrstuk

nvrstuk

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My reservoir has two return ports.

1 is dedicated to the HB

1 is dedicated to the cooler

There is also a #10 or #12 AN feed line to the pump

There isn't any "T"s in any line anywhere.

I discussed the issues with PSC this am.

He tried telling me it could be caster, bad teflon seals in the box etc...BUT the fact that the gauge on the left port of the strg box reads 1350 when turning left and zero when turning right means there's no internal oil leakage around the teflon seals inside the box-so it "almost" rules out the box.

I'm going to see if any fluid is leaking past the spool valve inside the HB and will report back.

The reason that orienting the return line is important when using a T instead of having 2 separatw ports in your reservoir is that the HB only uses a teaspoon or so of fluid every time the brakes are applied. If you don't oriented the lines similar to your diagram above, the HB return line has a bit of resistance to flow and this impeded flow gives symptoms many have when first connecting up a HB into a reservoir with only one return port.
 
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Yeller

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What size lines are you running? I'm in the return line restriction camp. Is it possible that the return line has a "flap" inside causing a restriction when flow increases? I've had a few systems that acted funny until we went to #10 hose on the return. But those were full hydro. Also if your cooler has internal fins they could be flexing at higher flows causing a restriction, seen that with trans coolers before
 
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nvrstuk

nvrstuk

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Plate style cooler.

With my Reservoir with 2 separate return ports on it the Hydra Boost line comes in at the top. I scooped a little fluid out of the top of the reservoir so the port was exposed so I could see what was gping on. . At idle a little bit of bleed by fluid was coming out the hydro boost return line and with the brakes applied there was enough coming out that I could not cover the port with my thumb as the pressure was way too high and I can spray the fluid with the amount of pressure bypassing the hydro boost with the brakes applied. I have Eddie at Van CO and West Texas off road and PSC already gave up
 
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73azbronco

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FYI with hydro at that pressure I would not try to cover anything with a finger, it could inject into your body, not good.
 
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nvrstuk

nvrstuk

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Its the return non-pressure line. Only a teaspoon at a time should come out when releasing the brakes.

It had a very slight dribble literally oozing out of the line so to see if it was under pressure I covered the port and it had enough pressure to spray the fluid.

Dont worry, I've worked with hydraulics enough to know not to try to plug off a 1,000 psi hose with my pinkie! :)
 

Yeller

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I would bypass the cooler and see what happens, coolers sometimes do weird things. But that being said I do 2 things that a lot of steering companies disagree with, I always use a cooler and a spin on filter. I use a quart size hydraulic filter with base that has a 15psi bypass that is rated for 25gpm+ never had an issue and even had clean fluid after catastrophic pump failure.
 
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nvrstuk

nvrstuk

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Ill try bypassing the cooler tomorrow...it is totally isolated from the HB line but I will bypass it tomorrow...Been wheel barrowing concrete for a pole barn... so I'm done for the night.
 
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nvrstuk

nvrstuk

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Sorry Steve, #6 AN lines for return lines both from the HB, from the cooler and the box.

Update after phone calls...

PSC who I bought the pump from years ago, referenced me to Eddie at VanCo who I've dealt with prior... PSC was stumped, like myself...

Eddie at VanCo was great, but also stumped. He's doing some research and going to call me back. He said that sometimes with Hi pressure pumps that HB units will leak fluid when not releasing the brake. essentially the spool valve and seals can't handle the very high pressure that we modify the pumps to work at...PSC was adamant (until the very end of our conversation) that a HB should never have fluid bypass it unless the brake pedal is released... then I called West Texas Off Road...tech guy gave me an answer and the real tech in the back is supposed to call me in the am...

We shall see...

Thanks for the ideas guys....
 
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nvrstuk

nvrstuk

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Update...

NOBODY has a clue yet... lol

Welding up anti-wrap bar for a buddy so I'm behind on this but....

Doing some more testing and with the brakes applied I cant move the strg wheel at all. I mean not even an inch. I dont remember this as an issue before but I remember it being harder but not impossible...

Going straight down the country road at 50 moh and I stab the gas and the steering is noticeably stiffer/harder to turn... what the heck is going on...?
 

Yeller

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my guess is your fff.....d; I work for FFF so i guess I'm an expert....LOL

just kidding but still puzzling. it almost like the piston inside the box is leaking, other than you say there is zero line pressure turning opposite direction from the gauge, ruling that out. Not being able to steer with the brakes applied leans me towards faulty HB.
 
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nvrstuk

nvrstuk

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That's where I'm leaning also... I can push on the brakes and have NO possibility of turning the strg wheel.

So I hopped in my HB equipped diesel truck, literally stomped on the brakes and I can turn the strg wheel easily...

Talked with Eddie again at VanCo and he's still working on ideas...

My question is...has anybody ever had to send a hydroboost out to VanCo to be ported to essentially change the brake bias proportioning and allow more flow? Eddie has not been pushing this but I"ve talked to him months before about this and some Pirate guys have done this with good results.... super spendy ...
 
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