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Power Steering Cavitation

Stevsie

Stevsie

Well-known member
Joined
Dec 17, 2020
Member Number
3146
Messages
49
1985 22RE with stock steering other than an IFS box and high steer. I’m on my 3rd pump and every one of them foam my fluid up, blow bubbles, and scream like a banshee when I’m turning. I’ve bled my system six ways from Sunday with no luck. It just keeps puking fluid out of the cap.

Can a bad steering box cause air to enter the system? Starting to lean towards swapping the box out for another.
 
Sluggy said:
Are all the fittings tight and are you running a cooler?
Click to expand...
No cooler just the line that loops around in front of the radiator. And I just replaced the pressure line and it’s a tad longer than the original. But it was foaming before that.
 
Sluggy said:
Are you running big tires or a spool front?
Click to expand...
35’s and Detroit front with 5.29’s. The first/original pump was howling pretty good and had tough spots throughout steering so I swapped it out with a new one. Still got same amount of noise but steering was no issue. But was also frothing. Got annoyed with the loud pump and switched it again but with a used unit. Same deal, loud as hell but works by and is also frothing and blowing constant bubbles.
 
Maybe try a larger reservoir and/or larger cooler. It's possible the fluid is getting hot and doesn't really have a spot to settle out/ needs a little more buffer. Also is the supply line way below the pump inlet to where the pump is working harder to draw fluid in. Are you running power steering fluid, atf or hydraulic oil?
 
Sluggy said:
Maybe try a larger reservoir and/or larger cooler. It's possible the fluid is getting hot and doesn't really have a spot to settle out/ needs a little more buffer. Also is the supply line way below the pump inlet to where the pump is working harder to draw fluid in. Are you running power steering fluid, atf or hydraulic oil?
Click to expand...
He needs kicked in the dick if he’s running power steering fluid. I had the same issue of boiling fluid until I switched to tractor fluid. Is the box binding? Knuckle bearings tighter than a nuns (unt?
 
Aisin said:
He needs kicked in the dick if he’s running power steering fluid. I had the same issue of boiling fluid until I switched to tractor fluid. Is the box binding? Knuckle bearings tighter than a nuns (unt?
Click to expand...
By tractor fluid.. do you mean standard off the shelf tractor/hydraulic/transmission fluid like the crap I put in my leaky old hoe.
 
Aisin said:
He needs kicked in the dick if he’s running power steering fluid. I had the same issue of boiling fluid until I switched to tractor fluid. Is the box binding? Knuckle bearings tighter than a nuns (unt?
Click to expand...
Using ATF. No binding, I just had the drag link disconnected to do a TRE. I turned the axle and the box to center it and no binding.

I thought about doing a better reservoir but as is this setup should work the way it is with the tires being off the ground. I’ll try to get the supply line a little more horizontal and elevated to the pump. It does dip below the pump just a tad the way it’s routed.
 
blakes said:
By tractor fluid.. do you mean standard off the shelf tractor/hydraulic/transmission fluid like the crap I put in my leaky old hoe.
Click to expand...
Correct. Drag racers have been using it in auto transmissions for ever. It holds up to heat and pressure better than ATF. It also has anti foaming additives.
 
Clb said:
Start small or it will whine
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I’m more worried about the frothing than anything for now. It works the way it is but whines and foams up. When I pull the cap there’s constant bubbles being pushed up even after being bled 100 times
 
Look into each fitting for obstructions.
If hydro, check the steering box ports that were drilled , that the fitting is not interference fit inside of the box.
 
At the OP

I'm definitely interested in trying hydraulic fluid on my 98 K3500 that has a new reman pump and whines like a bitch.

But really, I think reman pumps are really hit and miss. I recently replaced the one on my taco twice. Got lucky on the third one. I run ATF in it.
 
I had stock pump and box on my SAS truck with a front Detroit and 37s. Had zero issues with what you are describing. Best it hard, would saw my way through 3-4' of snow all day on the rev limiter.

I used ATF Dexron III.

My buddy was running a conversion on his LR Series. Saginaw pump and Land Rover box. He had stiff steering and puking when cold. Think he switched to synthetic GM PS fluid which helped a lot.
 
I’m going to swap out the steering box with another that I have and see if that changes anything. That was kind of last resort because it’s a pain in the d!ck to do but I’m going to give it a try and I’ll report back.

blakes said:
At the OP
Click to expand...

blakes said:
But really, I think reman pumps are really hit and miss. I recently replaced the one on my taco twice. Got lucky on the third one. I run ATF in it.
Click to expand...
The first unit I replaced it with was a reman. The second unit was a used one that worked fine and was quiet before I put it into my truck.
 
Swepco 715 seems to have good success in the circles I run in.

For what it’s worth I had a buddy who had a pump that was giving him fits, he took it to a shop and they let it sit overnight and used a vacuum machine to pull bubbles out through the reservoir and that worked for him.
 
im running cheap ATF on a 86 4runner with a modified oem pump and home brew cylinder assist. zero pump foam problems. do you have a hard line thats bent/damaged slowing flow down making it cavitate?
 
Stevsie said:
I’ll try to get the supply line a little more horizontal and elevated to the pump. It does dip below the pump just a tad the way it’s routed.
Click to expand...
I think this could make a difference, maybe take a picture of your setup?
 
I'm not sure how it's so difficult to get the air out of you don't cavitate the fuck out of it to begin with.

I just installed a new box and pump. Turny turn turn a few times in the air. Start it up and do the same. Stop check fluid. So it again a few times slowly on the ground. You are probably 99% there with little air.

You cant just fill it and start running it up and not get a shit ton of bubbles.
 
Is there any specific type(weight) of the tractor hydraulic fluid y'all are running? AW32, AW68, J20?
 
for the trail gear pump:

"Use only standard power steering fluid with this product. The use of ATF fluid, semi-synthetic fluid, or full synthetic fluid is not recommended and will void the warranty"

psc [their bold letters, not mine]:

"#1 reason power steering pumps fail is due to cavitation aka fluid aeration. The #1 cause of fluid aeration is fluid temperatures in excess of 180°F.
SWEPCO 715 has a very aggressive anti-foaming formula and in testing with 15 other leading fluids used for power steering systems, it provides three (3) critical benefits:
1) Aggressive suppression of fluid aeration, especially as the fluid temperature increases
2) Quiet pump operation
3) Broad temperature range for a variety of climates

SWEPCO 715 is not readily available to me, are there any alternatives?
As an alternative to SWEPCO 715, PSC recommends using AC Delco Power Steering Fluid."

in this case, also check the pulley size
 
Update:

Just spent the day adding hydro assist and swapped in a newer box I tapped. Put a new pressure line in and made sure everything was right n tight.

Took my sweet ass time trying to bleed off all the air. Tires up and cycled until zero bubbles came out of the reservoir, cranked motor with coil wire off to prime pump, then cycled with motor off and until the bubbles were gone yet again. Fired it up and instantly foamed up and cavitating. Bleed it 15 different ways again over the course of 2 hours with zero luck, swapped out yet again another pump.

Idk what gives anymore.
 
Video of the pump pushing through reservoir
 

Attachments

  • IMG_9525.mov
    52.6 MB
That is definitely not right. I’m still a hydro fluid whore. Toyota did not use ATF at the factory. They used hydraulic oil. They spec’d ATF in the manual because it is mineral oil based and what is most common in garages.
 
Last edited:
How’s the filter screen at the bottom or the reservoir?
 
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