at a loss,

[Gazz270]

couple of weeks ago i changed the power steering pump on my 2001 ml 270,
since then ive had a constant groan from the steering pump,ive now swapped the pump again for another new one,thought the first one might be faulty and swapped the reservoir but still groaning and gets worse the warmer it gets.
Its got genuine mb oil in it and all genuine parts,there doesnt seem to be any air in system(no bubbles in reservoir),ive jacked it up and gone lock to lock engine off and on but still no success,
im kind of at a loss now,

anyone else had this problem,

regards

gazz

 

[AndyPCD]

What was the colour oil that you put in the system.

 

[Gazz270]

its a very light almost clear brown hydraulic oil,came from a local mb independant

 

[grober]

Why did you feel it necessary to change the pump in the first place? Working on the chicken and egg principle. Symptom sounds like the pump is labouring. This could be due to it not getting enough power from the V belt- partially seized air con compressor?? or its being asked to do too much- hub swivels/ball joints partially seized? Might not show up when they are unloaded/jacked up?? If you could get a drive of another ML270 might be useful to compare the steering feel in both cars?

 

[Gazz270]

bearing had gone in the original,

ill pull the belt off and try the compressor,but it seems the same with the air con on and off,if the air con is off though wouldnt it just freewheel anyway,

 

[Gazz270]

had the belt off now and everything seems free enough,