Power steering pump seized?

[ericbeaumont]

Trying to identify a light grinding noise and a chemical burning smell from the front of the engine. It appeared after a routine 40-mile drive, during which the engine ran smoothly, steering was normal (no squealing) and temp gauge vertical.

When parking last night I discovered the start of the noise - constant light grinding. This morning I needed to move the car up the street to work on it, and the noise increased. It didn't want to turn over or start after that. Opened the bonnet and smelled the slight acrid burning; no obvious sign of the source.

Took the water pump off - it's had a slight leak at the top for a while, and I decided to do the job (again) and put on an SKF with a Volvo seal this time.

While the belt was off I tried (out of suspicious curiosity) to turn the power steering pulley by hand, and found it was exceedingly difficult, turning slowly in jerks but only with extreme effort; turning either way was equally hard.

Having googled a bit and discovered that power steering pumps should turn freely without the belt, my guess is that the bearings failed abruptly. PS oil is up to level; car is a 1997 945 on 122,000 miles.

I'd appreciate advice to confirm this analysis.

[360beast]

Sounds like your pump is definitely dead!

[ericbeaumont]

Originally Posted by 360beast

Sounds like your pump is definitely dead!

Had the weird idea they went on forever; what persuades the bearings to go?

[kiloran]

The donor engine Luke fitted for me came with a PAS pump which was monumentally shafted. I've always assumed that it's down to over-tight drive belts or like any bearing just some contamination. 120k isn't too bad.

[360beast]

Originally Posted by ericbeaumont

Had the weird idea they went on forever; what persuades the bearings to go?

I've not had one go on me before, but an overtensioned belt will put a lot of strain on the bearing.

[Steve 940]

Talking of over tight belts, have been trying to find guidance on checking tension, but Haynes mentions absolutely nothing.
Can recall back in 80's when working on various cars the manuals used to give amount of deflection, and where to take this measurement from??

Cheers
Steve

[Laird Scooby]

Originally Posted by Steve 940

Talking of over tight belts, have been trying to find guidance on checking tension, but Haynes mentions absolutely nothing.
Can recall back in 80's when working on various cars the manuals used to give amount of deflection, and where to take this measurement from??

Cheers
Steve

Ball park deflection on V belts is 9-12mm on the midway point of the longest straight section under "moderate" thumb pressure.

The poly-v belts (flat with ribs) should be much tighter so you can twang them like a bass guitar string and if you're musically talented, play the opening riff of Smoke on the water.

Over-tight V belts can cause bearing failure on water and PAS pumps, alternators etc. Also if a car has been laid up, the bearings can Brinnell and deteriorate but usually they are noisy before seizing. When i say noisy, i have a clutch bearing on my AC compressor on my other beast and it sounds like a noisy supercharger now!

[kiloran]

Laser sell a belt tension checker if you want to get really geeky about it

[griston64]

Originally Posted by kiloran

Laser sell a belt tension checker if you want to get really geeky about it

I have one..........It's called my thumb

[Steve 940]

Thanks for information re belts, i always used to go on circa 1/2" deflection on longest run, so will go with that.

Think thumb measuring device will suffice, at least you can't misplace it, well, assuming you don't get it trapped in running belts

Just noticed PAS belt getting really out of shape the other day when I was first looking at exhaust leak, flapping around like a mad thing.

Also had squeal for first 5 seconds after starting, should be picking 3 new belts up with all my exhaust leak parts , so will do asap, tensioners look to be partially seized, so more copious applications of penetrating oil over the next week.

Cheers
Steve