Air in Power Steering

hurt4x4

hurt4x4

Well-Known Member
Joined
Sep 12, 2012
Location
Greensboro
I just had a PS conversion and hyrdo assist put on my 82' toyota and I cannot get all of the air out of the lines.
I've tried everything i know to do, witch involves lots of turning the wheel lock to lock and waiting. Ive tried engine off and engine on. No matter what I do there is still air. When it has sat and i first start it the pump is quiet as can be, but then about 10 sec. later it starts wining again
Its almost like the pump is sucking air from somewhere but i don't know where it could be.
any suggestions?
 
Your not running the fluid out in the reservoir are ya?
Single ended rams will make the fluid level rise and fall depending on which way you turn the wheel. If it falls enuff, It will suck air.

Another thing is the cooler. make sure you are running the fluid UP thru the cooler, not DOWN. DOWN will cause cavitation
 
My reservoir holds over a quart of fluid, so I don't think it could be running out. Also I have no cooler yet.
With the reservoir being so large it does sit lower than the pump, but the line does not seem to be collapsing. Can that still cause problems?
 
hurt4x4 said:
My reservoir holds over a quart of fluid, so I don't think it could be running out. Also I have no cooler yet.
With the reservoir being so large it does sit lower than the pump, but the line does not seem to be collapsing. Can that still cause problems?
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Output from the resi (suction side) needs to be above the intake on the pump or very close to that same plane. Otherwise it is trying too hard to pull fluid up into the pump. Also causes cavitation.
 
The wrong line feeding the pump can cause it too in higher end higher flow systems. I always plumb a larger suction line on all hydraulic systems and try my best to use suction specific hoses. Some pressure hoses are designed in such a way that the inner rubber (bladder if you will) can suck shut or even loose from the hose side wall. this starves the pump also causing cavitation. Another real good rule is to make the suction as short as possible on these small systems. The pumps aren't designed to pull a lot of head pressure. Just make pressure. keep it under 18 inches for the best results and I always shoot for 12 or less..
 
Take the cap off cycle slow to see if your draining it, if your sloshing fluid at this point it will never settle out, keep from cavitation, or run cool for very long. Cavitation can also occur with no air, simply starving the pump can cause it to basicly pound the fluid into tiny bb droplets that can actually shot peen and or destroy your pump. Its a type of hydraulic cavitation. I also run synthetic amsoil in all these low capacity very fast return flow systems, the fluid just doesn't see enough recovery time to work cool and efficiently otherwise.
 
Hmm. I guess I'll have to get a new reservoir because there is literally no way to get it higher unless it sticks through the hood haha. I have no clue what type of hose is going to the pump, but I'll check tonight and see if I see anything on it. I would say there is between 8 and 10 inches of hose going to the reservoi from the pump
 
I just reread your post, I was referring specificly to full hydro stuff..........sorry bout that, but the assist systems in my opinion would benefit from much the same..
 
I appreciate the help everyone. having to mess with the PS like this is relatively new to me, but i think I've got it figured out now.
With my reservoir being so large i tried to angle it slightly to get the feed line a little higher, this was causing the fluid level to fall below the return line. I think this is where my air was coming from. I believe there is still cavitation in the pump though.
I have a new reservoir that I can mount higher up and a cooler on the way. Hopefully that will take care of my problems.
 
OK i am at a loss with this steering.

Today I went through and made sure all my fittings where tight. I installed a PS cooler and made sure I was running the fluid UP through the cooler. And my reservoir is now mounted Higher than my pump.

It seems like i have all of The air bled out of the system. But at anything above 2,000 RPM the pump will start wining and then the fluid will foam??. The only thing i know to try now is to replace the pump??

Help anyone?

__________________
 
Something I used to do was use engine vacuum to pull the air out. It can be as down and dirty as wrapping duct tape around the reservoir neck and vacuum hose and routing it to an engine vacuum source. This will help remove air, it has worked on a lot of vehicles for me where nothing else would. Make sure the hose does not reach fluid and is just in the air space above fluid level. Start the engine and let it run while slowly turning the wheel.
 
Assuming you have properly purged the system, have you considered a pulley change?

Just thinking out loud, but you haven't mentioned a loss of performance just the wine and only at elevated rpms. When I changed pumps I had to trial and error different pulleys to keep higher rpm performance.
 
There is no loss in performance. I can turn the wheel with the press of a finger tip no matter the rpm. At idle I can turn the wheel, watch the fluid, it is clear and I can see no air in it. But as soon as I bring the rpm up the fluid will start foaming up.
I'm really not sure if this is from the system not being bled properly or what.
 
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Is your suction line and pressure lines all the same diameter? If so I'd start with the suction line. It needs to be larger than the pressure side. It also helps to use suction specific hose so it doesn't try to draw shut under vacuum. The longer the supply the bigger in diameter to make up for friction loss in the fluid. If your positive its bled its sounds like its starving for fluid. The foam may not be aeration but the fluid being broken down in the pump due to lack of intake flow.
 
The suction line is about 5-6 in of -10 AN,I assume it's not suction specific. The pressure lines are just factory toyota lines and appear to be a smaller line.
How can I be positive that the system is bled throughly?
 
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hurt4x4 said:
There is no loss in performance. I can turn the wheel with the press of a finger tip no matter the rpm. At idle I can turn the wheel, watch the fluid, it is clear and I can see no air in it. But as soon as I bring the rpm up the fluid will start foaming up.
I'm really not sure if this is from the system not being bled properly or what.
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I think this is your answer then.
If it will turn easy at low rpm, then you may be over turning your pump. There is a fluid velocity max. Essentially if your pump is pumping fluid too fast it can actually cause as many problems as too low a volume. Im not strong enough in fluid dynamics and its been too many years. But sounds like the same issue I had and I solved it with a larger pump pulley.
 
^^^and or to little supply^^^ good call Ron. Bigger supply to feed the pump or slow that thing down......Ron's suggestion would be easiest and more likely to correct the mismatch in flow. Especially if its running way to fast. Because with a limited orifice size, only so much will be pulled in no matter how large the supply line is. Fluid dynamics are cool. Designing a well balanced hydraulic systems are almost as much fun as putting in sexy welds.
 
Hmm Ok, this is a used pump. I know it is common for people to drill out the restrictor plate . If someone drilled out the restrictor plate too much could it be causing the same issues? Pumping too much volume for the reservoir to supply?
 
even if it is over drilled (who knows unless inspected) bigger pulley less pump rpm will help. Sure it was opened up by drilling?
 
Drilling the intake allows higher volumes of fluid to flow. You added an unintended cylinder to the factory equation. This upsets the balance of the system. So to counteract the needed extra volume some like you said modify the intake. If no air is present, something else is upsetting the fluid path. If the reservoir isn't to small and fluid isn't disappearing faster than it returns it just isn't ggetting enough to the pump. Or like Ron said, slow it down with a pully change. Problem solved. No starved pump, no excessive fluid drops in the loop. In a pressure sytem you can pump it faster than it returns. It doesn't diappear, it builds pressure. But if the end flow isn't balanced through the sytem something gets upset. Like a whining pump.
 
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