Steering: heavy steering, intermittent assistance

[1965shelby]

Hi all, can anyone advise on what might be causing stiff steering when stationary and loss of assistance when turning sharply, off throttle. Tyre pressures are high, PAS fluid changed, revving the engine when stationary doesn't help so I am guessing that would rule out a failing pump. No visible leaks and no seized suspension or steering joints. I am wondering if this is a speed sensor failure or more likely to be a seal within the rack failing and allowing fluid to bypass a ram seal. Any ideas or advice please!

[gudgeonpin]

Aux belt not slipping is it?

[AndySaxton]

I had similar symptoms. Would drive along the street with my foot on the accelerator, lift to turn into my drive and the steering would suddenly become heavy - turned out to be the Power Steering pump

l also had a pulsing sensation from the steering wheel when going round roundabouts or taking long sweeping corners - turned out to be the steering rack, now replaced.

[ampmaster]

Originally Posted by AndySaxton

I had similar symptoms. Would drive along the street with my foot on the accelerator, lift to turn into my drive and the steering would suddenly become heavy - turned out to be the Power Steering pump

l also had a pulsing sensation from the steering wheel when going round roundabouts or taking long sweeping corners - turned out to be the steering rack, now replaced.

Hi,
What was the cause in the end? Oops, sorry. posted to wrong person.

[ampmaster]

Originally Posted by 1965shelby

Hi all, can anyone advise on what might be causing stiff steering when stationary and loss of assistance when turning sharply, off throttle. Tyre pressures are high, PAS fluid changed, revving the engine when stationary doesn't help so I am guessing that would rule out a failing pump. No visible leaks and no seized suspension or steering joints. I am wondering if this is a speed sensor failure or more likely to be a seal within the rack failing and allowing fluid to bypass a ram seal. Any ideas or advice please!

Hi, Did you ever pinpoint the fault?

[moorgate]

I had pulsing like this, lots of noise and occasional assistance failure. Turned out that the *return* pipe was actually loose enough that air was being sucked in, which was returning from the reservoir to the pump and then compressing the air not moving the fluid. The actual part that has to be exchanged is not the pump or the rack; it's the header tank. Flush through with new liquid and it's all good. Mine was on my V70 but I'll make a bet the XC90 has the same bits.

[ampmaster]

Originally Posted by moorgate

I had pulsing like this, lots of noise and occasional assistance failure. Turned out that the *return* pipe was actually loose enough that air was being sucked in, which was returning from the reservoir to the pump and then compressing the air not moving the fluid. The actual part that has to be exchanged is not the pump or the rack; it's the header tank. Flush through with new liquid and it's all good. Mine was on my V70 but I'll make a bet the XC90 has the same bits.

Thanks for the info. The symptoms of this one are different though. I have completely flushed and replaced the fluid, checked all pipes and reservoir. The steering feels as though the power is only working at 50% with tights spots as you steer where it drops off altogether. If you try and turned the steering quickly you cannot. There is no assist at all.
At first I suspected the pump but it only marginally improves with higher revs. With the car turned off and the wheels jacked up, trying to turn the wheels from lock to lock from the road wheels results in very tight spot where it jams and a huge effort is required to get it moving again. Pretty sure it is a rack problem. It is a low(ish) mileage XC60 that has always been dealer serviced but come to me as a non runner. I was not expecting a problem with the steering.

[TruckbusUK]

Originally Posted by moorgate

I had pulsing like this, lots of noise and occasional assistance failure. Turned out that the *return* pipe was actually loose enough that air was being sucked in, which was returning from the reservoir to the pump and then compressing the air not moving the fluid. The actual part that has to be exchanged is not the pump or the rack; it's the header tank. Flush through with new liquid and it's all good. Mine was on my V70 but I'll make a bet the XC90 has the same bits.

Hello moorgate, slightly off topic and I don't want to hijack the thread, but how did they discover the issue?
I assume it was not leaking or weeping from the joint at the header tank.

[ampmaster]

Originally Posted by TruckbusUK

Hello moorgate, slightly off topic and I don't want to hijack the thread, but how did they discover the issue?
I assume it was not leaking or weeping from the joint at the header tank.

Hi Truckbus,
Not sure about Moorgates diagnosis but I have watched a few youtube videos about general power steering issues to try and gain some extra knowledge and they often recommend changing the clips from the spring loaded type you squeeze together with pliers to a jubilee clip. As the pipes (and clips) age they get slightly looser and apparently can suck in air which creates a wide range of problems.

[TruckbusUK]

Originally Posted by ampmaster

Hi Truckbus,
Not sure about Moorgates diagnosis but I have watched a few youtube videos about general power steering issues to try and gain some extra knowledge and they often recommend changing the clips from the spring loaded type you squeeze together with pliers to a jubilee clip. As the pipes (and clips) age they get slightly looser and apparently can suck in air which creates a wide range of problems.

Hello amp, yes I have seen that, but moorgate mentions replacing the fluid reservoir/header tank ....so I'm assuming there was something wrong with that, rather than a pipe crimp/jubilee clip issue.

Re your issue, there was a XC90 recall for internal PAS pipework around 2011, that resolved mysterious fluid loss (giving the symptoms you mentioned, not the hose fitted with a ty-wrap nonsense from 2009-2012.)
Not sure its your problem, or if it indeed was also an XC60 issue but it may help if your also having assistance loss.