Bubbles in power steering

Reply Subscribe

Thread Tools

Search this Thread

Nov 11, 2010 | 09:52 PM

dailo

Thread Starter

Racer

Joined: Dec 2003

Posts: 349

Likes: 0

From: Hong Kong

Bubbles in power steering

Hi

My 91's PS pump started to groan when turning the wheel, it gets louder as rpms increase, but is not too loud at idle. Noticed a lot of small bubbles in the PS reservoir whilst the engine is running. No power loss in steering.

Changed out the fluid with some new power steering fluid from mercedes benz (thats all we have in Hong Kong) that didnt do the trick, so changed to ATF, seems a little better, but the bubbles are still present.

Ive done some searching and the most common answer was cavitation in the pump, could this air leak be in the pump itself, or likely somewhere in the lines?

Thanks!

Nov 11, 2010 | 10:33 PM

oldalaskaman

Le Mans Master

Joined: Aug 2010

Posts: 9,272

Likes: 17

turn your steering wheel lock to lock,several times, could be it just got to low and needs to be bled

Nov 12, 2010 | 01:01 AM

dailo

Thread Starter

Racer

Joined: Dec 2003

Posts: 349

Likes: 0

From: Hong Kong

Thanks, but have tried that as well. there is no fluid leaking out anywhere.
Do you know the common places that air could get in?

Nov 12, 2010 | 07:23 AM

AGENT 86

Team Owner

Joined: Jan 2003

Posts: 20,333

Likes: 263

From: Summerland B.C. Canada

If air was to be introduced into the system, I would have to think it would be on the low pressure inlet side of pump, such as the hose and fittings from tank to pump.

Nov 12, 2010 | 07:54 AM

Brian Smith

Advanced

Joined: Sep 2009

Posts: 51

Likes: 2

From: Flower Mound Texas

Bubbles in power steering

I would agree. Air is being sucked into the system on the suction side of the pump somewhere. As suggested check all clamps, hydraulic fittings and hoses. If you have a leak on the high side you would have found it in short order due to the mess is would make. With a leak on the suction (low pressure) side you might be able to track it down by seeping after sitting a while.

Nov 12, 2010 | 03:14 PM

coupeguy2001

Le Mans Master

Joined: Sep 2006

Posts: 6,050

Likes: 147

From: Phoenix AZ

2021 C4 of the Year - Modified Finalist

I would replace the suction hose as it may be disintegrating internally, and that restriction would be hard to detect.

Just as a note, the suction side may be creating a vacuum as the fluid is being drawn into the pump, and the air that is entrained in the fluid would be drawn out and noticed in the reservoir as bubbles.

Nov 12, 2010 | 10:00 PM

dailo

Thread Starter

Racer

Joined: Dec 2003

Posts: 349

Likes: 0

From: Hong Kong

Thanks guys ill have a look at the hoses later on and try and see where air could be leaking from.

Could the internal seals of the pump itself be bad and allow air to enter? seems to get better as the fluid warms up though..

Nov 15, 2010 | 01:46 PM

coupeguy2001

Le Mans Master

Joined: Sep 2006

Posts: 6,050

Likes: 147

From: Phoenix AZ

2021 C4 of the Year - Modified Finalist

well, you understand that the leak, if it was pump seals, would bypass from the pressure side of the pump to the suction side of the pump, and you would not be able to tell except by a pressure gauge on the pump pressure side and it would be noticed only on movement of the tires on the ground exerting a force. you would have to know what a healthy pump pressure was unloaded, then loaded pressure and compare to yours..
If not pump seals, then it would be an external leak in which you would have puddles and run out of fluid.