Help diagnose this pwr steering prob

Mrs. H’s mum’s car has an awful noise coming from the power steering pump. It happens under load (e.g. turning the steering wheel while stopped). The pulley stops turning and the belt slips when this happens. The fluid is topped up.

I don’t know anything about hydraulic steering, so I don’t know if the pump is dead, or what. Can anyone explain the power steering facts of life for me? (Gary T, are you out there?)

When I’ve seen this it has most often been caused by a worn or loose belt. If there are no other apparent steering problems, I’d recommend changing it, and making sure the new one is nice and tight. Also clean the pulleys while you’ve got the belt off. There could be some dirt or oil on them that’s keeping the belt from gripping them well.

If the pulley is stopping when a load is being applied to it the belt is either loose, worn, too narrow or glazed to the point that it is slipping. You can try adjusting the belt, but the best bet would be to replace the belt.
There is a slight chance that the pump is frezzing up, but the way to bet is on the belt first.

Also you might consider changing all the belts as they are probably of similar age, and if the PS belt is bad, the others probably aren’t far behind. A broken belt can make a bad day worse. (ask me how I know this)

As others have suggested, first make sure the belt is tight enough and in decent condition. If you only have noise when the belt is slipping, it’s likely only a belt problem.

If you have noise in the pump when the belt is definitely NOT slipping, it’s a pretty sure bet the pump is going out.

Be aware that in all systems, there’s going to be more noise when the steering wheel is turned to the end of its travel. At this point, the pressure in the system goes very high, and it’s best to avoid staying at full turn any longer than necessary. Just backing off to 95% of full turn eases the strain on the system.

The first thing I did was to take a (very cursory) look at the belt and I didn’t think it was that bad or that loose. But I suppose it wouldn’t hurt anything to replace 'em. Thanks all!

Any other suggestions?

To Expand on what Gary T said, the noise of a dying power steering pump is often a groan. (Not from you, from the pump).

They sell spray cans of belt dressing, which is pretty much a sticky stuff you spray on the belt to make it grip. It isn’t a cure by any means, but could be a cheap method for diagnoses of a slipping belt.

Yes, the missus put belt dressing on it before I even heard about it. I’m going to take a closer look tomorrow.