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Air being sucked into power steering.

9K views 22 replies 6 participants last post by  AstroWill 
#1 ·
Hey fellow astrosafarians, I've been trying to pinpoint an air leak in my power steering and I'm stumped. I replaced the power steering pump and pressure lines a couple weeks ago. I did the wheel lock to lock bleed procedure, but the pump was pretty noisy. I then got a handheld vacuum pump and made my own reservoir adapter. When I pump it up to 15-20 I can hear bubbling in the reservoir and the vacuum won't hold. I proceeded to change all low pressure lines to no avail. It seems to be coming from the hydroboost side. I had been planning on re-sealing the hydroboost because of very slow seeping, so I did that today. When I was pulling it out, I found a broken o-ring on the line from the gearbox, so I assumed that was the culprit. I replaced it and put everything back together, but when I put the vacuum on it again, it still won't hold a vacuum and I can hear bubbling in the reservoir. There are no visible fluid leaks, all connections are tight and all the hoses and clamps are new. The only other thing I can think of doing is replacing all the o-rings on all the connections and hoping that fixes it. Any thoughts and input would be most welcome, I really can't think of where the air is getting in.
 
#4 ·
albrow100 said:
I've never had good luck with the vacuum bleeders holding vacuum for a while.

I typically just pull vacuum several times and keep bleeding normally
Then let it rest for a few hours and resume until all the air is out.
Do you normally hear air bubbles coming up in the reservoir when you've done that? It just seems like I pump and pump and the air doesn't stop coming. That's what makes me think it's getting in through one of the lines...
 
#6 ·
MechBob said:
I would ignore using the vac pump. I have seen limited success with them, on older vehicles, like ours. What makes you think it is sucking air? Does it blow fluid out the cap, every time you drive it?
The pump is quite noisy, whenever I turn the wheel or press the brake pedal the pump whines. The steering feels a little bit stiffer than it should, and the brake pedal jumps a bit sometimes when I press it.
 
#9 ·
Interesting development while doing more testing today. I found that when I draw a vacuum on the reservoir, with the engine off, if I press the brake pedal the bubbles stop. That makes me think the hydroboost is the problem. Does that seem likely? :shrug:
 
#10 ·
I think there are assumptions being made.
BTW.. the PS system is a recirculating "open" system.. gravity fed to the pump.
Part is under pressure.. the part at the reservoir is not
 
#12 ·
MechBob said:
You have not even given a logical answer as to why you think you have air in your P/S system. Until you do this, why ask inane questions?
From what I've read on this forum and in the factory manual, groaning noises from the pump indicate air. The manual also says that when bleeding with a mityvac, vacuum drop off indicates air entering the system. Maybe I'm misunderstanding the whole thing, but this is my first time dealing with a power steering system. I'm not trying to be annoying, just trying to figure it out. In your experience, what would be accurate indications of air in the P/S system?
 
#13 ·
Mmusicman said:
I think there are assumptions being made.
BTW.. the PS system is a recirculating "open" system.. gravity fed to the pump.
Part is under pressure.. the part at the reservoir is not
That's what I'm worried about, I don't want to make assumptions and just throw parts at it. I'm just not sure how I should troubleshoot it at this point.
 
#14 ·
When I'm using the pump it just seems to never hold a vacuum. Not sure if it's bubbling a lot or not.

Does the fluid look foamy still? It's possible the hydro boost could leak vacuum but not
Pressure I guess. I know that when I've opened the system on my van it takes forever to bleed out. Start by turning the wheel back and forth with the engine off 10 times. The press the brake 40 times. Let sit for 1 hour and then repeat until there isn't any foamy bubbly fluid
 
#15 ·
Being an "open" system.. air naturally escapes while being recirculated though the reservoir.
If the bubbles are tiny, churned up by the pump, it takes much longer. Larger they can escape.
This is why you do the steering wheel back and forth a bunch of times first (without running the engine).
This does push the fluid.. and does push out the larger bubbles.
When you finally do first run the engine, do so only at idle, still moving steering back and forth a few more times.
Once you churn up the air, it's harder to get it out.

I am not aware of the "vacuum" system (never used or needed one).. or if it even works with our PS system.
I've always done it the regular way.
Putting a vacuum on the hydroboost "may" not be a good thing.. since that part is not a sealed system.
I don't know. Mine drips sitting (with engine off) feeding from reservoir.
I'm certain if I put a vacuum on the reservoir, it would draw air in the leaking seal.
It doesn't leak running... none of the pressure lines leak either.

PS: I had a PS pump that groaned for years. It never stopped until I replaced it.
There was NO air in the system, it was simply internally damaged.

Once you run them empty, you "may" cause some irreversible damage, usually just noisy.
 
#17 ·
Mmusicman said:
"This is why you do the steering wheel back and forth a bunch of times first (without running the engine).
This does push the fluid.. and does push out the larger bubbles.
When you finally do first run the engine, do so only at idle, still moving steering back and forth a few more times.
Once you churn up the air, it's harder to get it out.

PS: I had a PS pump that groaned for years. It never stopped until I replaced it.
There was NO air in the system, it was simply internally damaged."

I wish I'd read that last year, or at least understood it better. Thanks for posting the tips. I'll keep them in mind in the future.
Replaced my power steering pump last August, and the whining finally died down. Had to replace the hydra boost just prior. Both are much better now. I did replace most of the hoses and all of their o-rings. My mistake was starting it up to turn the wheels side to side. That probably aerated the oil real nice-like. But I just let it sit for a couple days before driving.
 
#18 ·
Sorry if I was a little rude. I have reread this thread, and checked some old info. I think you have approached this OK, esp, with replacing the hoses. However, it is possible you did not get the hydroboost sealed correctly,i guess there were certain model Fords that had air getting in from the unit. However, i highly suspect the problem might be the replacement pump.
 
#19 ·
MechBob said:
Sorry if I was a little rude. I have reread this thread, and checked some old info. I think you have approached this OK, esp, with replacing the hoses. However, it is possible you did not get the hydroboost sealed correctly,i guess there were certain model Fords that had air getting in from the unit. However, i highly suspect the problem might be the replacement pump.
No problem at all my friend, I didn't do a great job of describing the situation and the steps I had taken and I do appreciate the input. Sometimes I get ahead of myself and do things based on assumptions. I kinda wish I hadn't touched the hydroboost until checking and replacing all the hoses. I'm also wondering if I just got a bad pump...
 
#21 ·
Hey guys, I thought I'd give an update on my power steering issue. It is fixed! Turns out it was the hydroboost after all. I'm not exactly sure how it was letting air into the system, and from my web searches it seems like it is a rare occurrence. I bought a new hydroboost from rockauto, installed it, flushed the ps fluid and replaced it with royal purple. Then I thoroughly bled the system and it has been working just fine. I will say that bleeding takes a lot longer than one would think. I did the wheels up, lock to lock method about 25 times and also used the vacuum pump on it several times over. The pump is still a bit noisy at times, but nothing like before, and the fluid looks clear and foam-free. I can definitely live with it. Thank you all for taking the time to reply and for sharing your knowledge. Cheers!
 
#23 ·
abelram57 said:
It is fixed! Turns out it was the hydroboost after all.... I bought a new hydroboost from rockauto, installed it, flushed the ps fluid and replaced it with royal purple. Then I thoroughly bled the system and it has been working just fine.
Fan-freaking-tastic! Glad to hear that you got it figured out, the reward for being persistent.
 
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