Power Steering Problem???

[Denis O]

I have a 97 SL500 that has developed a really strange problem.
When turning the steering wheel to the right everything appears normal but when turning to the left it feels like I have no power steering. I did a 350 mile round trip yesterday and it was the same all day.
Any ideas?

 

[Robby]

Check your tyre pressures first- makes a surprising difference if one of your tyres is down by a couple of PSI.

 

[Denis O]

Checked pressure as a first option and it is correct. When turning to left lock there is a hissing noise all the way. The type of noise you get if you hold the steering on full lock. Perhaps there is some kind of pressure relief valve that on left lock is working continuously so no power to the steering that way.

 

[Benzowner]

Check your power steering fluid, sounds like it may be low

 

[Denis O]

Fluid is at the correct level. I think it's got to be the rack. It doesn't seem like the pump as it works one way.
Anyone know what a new rack will cost. I've checked GSF and Euro Parts but neither list the part. Could be stealer only in which case I'll probably have to increase the mortgage.