Power steering - no return

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Ian Z
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Power steering - no return

Post by Ian Z »

Chaps
I have issue with no steering return. Power steering feels assisted when driving. Got about 3deg + castor after much messing. Engine off and wheels up, manually pushing road wheels left to right is very tough. Have to push in stages to move and feels like I’m fighting fluid pressure somewhere. Engine on and wheels up, steering feels free, assisted and balanced but still hard to push road wheels by hand side to side. Been through all joints, ok, and backed off box adjuster 1/2 turn for test. I can turn the box input shaft/column by hand easily with wheels up and steering column connected, engine off or on. TBH I think has always been an issue and I just got used to it. I suspect there’s a valving issue which prevents wheels from self centering. In the pump or in the box. Any experience of this?
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Dave999
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Re: Power steering - no return

Post by Dave999 »

this could cause you more pain so beware

the position of the fluid inlet manifold on the steering box case dictates the bias between left assist and right assist.
there are two inlets and a jiggly pin under here and its jiggle is bounded by a section of that manifold it need to be just the right amount 1 way or the other.

getting it in the right place means when turning right all the fluid helps with the right hand turn and vice-verca

if its not in the correct place by a very long way you have sterering the pins its self left or right as soon as you lift the wheels clear of the ground, and with enough froce to be dangerouse to anything in the way....

if its slightly not right you may i guess, have the issue you can feel...

but its a guess.......

otherwise
1) collapsing pipes
2) worn out seals in the pump or stuck pressure regulator valve. (if its a sagnaw this valve is in the hole behind the outlet (shims and spring on a small shaft, you can take it out)
3)worn out piston seals on the valve body around the worm shaft in the box causing binding or reduced assistance.
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Ian Z
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Re: Power steering - no return

Post by Ian Z »

Cheers Dave.
Power assist has never been a problem. It’s a one finger on wheel light and I have no problem with left/right power balance. I replaced seals in the federal pump due to reservoir seal leak last year. Also manually checked the valve operation in the pump body, ‘felt’ ok. No external leaks on steering chunk, but get your point. I believe this fed pump has two stage valve to reduce pressure at spin speed. Feels all good aside from the annoying lack of self centring. As i mentioned before, I get a strong resistance when I manually push the road wheels left and right with either engine off or on and front jacked. Is that usual? I assume not as when engine running and driving this feels to me like it’s working against the castor physics returning the wheels to centre after a turn. In my head, it feels as if there is a back pressure in the system that shouldn’t be there that fights the castor. Think I’ll drain fluid and see if I can manually move wheels Off ground. If that works then onto chunk seals and air leaks.
Involuntarius peristalsis rectum

"A true hotrodder wouldn't be content untill he had created a car so violent, so hairy, so totally sick that the very act of dropping the hammer would result in instant death. Anything less results in the need to go faster." - Tony DeFeo
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Dave999
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Re: Power steering - no return

Post by Dave999 »

MMM

well one thing that helps is a properly set up idler

the idler bush works like the upper control arm bushes i.e bonded rubber inner steel and outer steel case

if its all mangled it could be causing an issue
it acts as a steering damper and must contribute some action to self cenering when all is well

needs to be bolted in loose
steering centred
so that the rubber bush is not flexed

then clamped
so that the clmaping force is only applied by the bolt and bracket through to the centre sleeve of the bush. use a washer if need be
if the bracket is mangled or crushed it rubs on the outer case

obvioulsy you loose this action if you go for a urethane or ball bearing conversion

other than that as you say return valves somewhere not opening properly


i doubt your car is so low or high that the studs in the balljoints are rideing the edge of the hole they come through in the case
BUT they may if you jack up the car and have knackerd missing or incorrect upper A arm bump stops. On an A body they are conical rubber things that snap off.... they hit the bottom of the A arm at full droop. or maybe on the arm and hit the body..can't remeber. If snapped off, its easy to miss, or easy to assume nothing was ever there in the first place, just an obsolete square headed bolt left in place.

with no droop bump stop, on the top arm the suspension droops so far when jacked that the thing that stops it hanging lower is all joints at the end of their travel. this makes the steering really quite stiff. you can only see it if the seal is removed and its most likley to be the lowers, they have less angular deflection availble due to designed for the longer length lower control arm...

i.e you could be chasing part of the issue that is only in evidence when the car is jacked up...


Dave
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Dave999
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Re: Power steering - no return

Post by Dave999 »

one last thing rasing the front slightly will give you more + castor

more steering effort near either lock but more self centrering
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Ian Z
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Re: Power steering - no return

Post by Ian Z »

Thanks again Dave.
All ball joints low mileage and flickety free. Off the pitman, it’s free as a bird.
I did change (again) the idler arm as wasn’t happy with fitting in ears. New one has the ‘washers’ integrated with the spinny centre but is much better secure no wobble fit. It is a tad tighter being new.
I’ll go round castor etc again but I did have it better than ever been.

Ultimately if I have to put muscle into moving road wheels by hand left/right/left with engine on or off, its clearly gonna fight the ‘return to centre’ when driving. I just wasn’t sure if that fight was usual. It does feel like I’m working it against a pneumatic pressure which cant be right, as if a return is blocking flow. Otherwise the power assistance driving feels perfect and balanced, just no return to centre, zero, nada, at any position.
So I’ll order some seals just in case and start checking pressure flows. Will be sumting or nowt, maybe a flange race spring ball wotsit or dead cockroach in the return.
Involuntarius peristalsis rectum

"A true hotrodder wouldn't be content untill he had created a car so violent, so hairy, so totally sick that the very act of dropping the hammer would result in instant death. Anything less results in the need to go faster." - Tony DeFeo
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Ian Z
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Joined: Sun Jan 15, 06 9:33 pm
Location: Preston, oop north

Re: Power steering - no return

Post by Ian Z »

Had problem with air leak in hydraulics. Did vacuum test and found leak down in pump and cross threaded pressure pipe on steering box ally fitting. Strange that no fluid leaks. The air couldn’t bleed out and was causing pressure lock on steering return. Also, my cheap bubble gauge thing was telling lies and was ~1 +deg caster on full stock UCA adjusters and with 1/8” washers on LCA/ball joints. I’d already changed UCA bushings with stock but reckoned the Moog offset UCA bushings would not add enough caster. Fixed air leaks, new pump and pipe/fitting. I went with QA1 UCAs and getting just under 4deg+ caster. There is a coupl deg of rake on car which will take some castor out. Still refining adjustments but I get steering return albeit lazy. I may look at adjusting pump pressure for more road feel by splicing in a Heidts variable regulator. More washer on pump regulator (federal) would reduce pressure but also volume too. Need to get some miles on first and see how it feels.
Involuntarius peristalsis rectum

"A true hotrodder wouldn't be content untill he had created a car so violent, so hairy, so totally sick that the very act of dropping the hammer would result in instant death. Anything less results in the need to go faster." - Tony DeFeo
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