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Matt, Mechanical Engineer
Category: BMW
Satisfied Customers: 22748
Experience:  BEng hons Mech engineering, in auto industry 22 years
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Hi, I have got BMW 735i 1999. Power steering became stiff.

Customer Question

Hi, I have got BMW 735i 1999. Power steering became stiff. I have changed ATF fluid recently. Please would you advise what the problem could be?
Submitted: 5 years ago.
Category: BMW
Expert:  Matt replied 5 years ago.

its possible that the steering is actually OK and that you've got a failing strut top bearing

To feel if there's a worn strut top bearing then lightly hold the spring by hand and have your assistant move the steering from left to right with the wheel on the ground - a worn bearing will feel 'notchy' through the spring. The wheel needs to be on the ground for the test to load up the bearing

if this is OK then give all the steering column joints a good squirt of WD40 and work the steering back and forth and squirt again - squirt each joint in turn and try the steering

if this helps then you know to replace the joint which was squirted with oil last
Customer: replied 5 years ago.

Thanks for your advise. I will give a go and see what happens.


Just to share some more info with you. Firstly, power steering started to become stiff if I was getting over 30 miles speed, but if I shut off engine and start again I was getting normal power steering back until I would reach 30 miles speed again. It went like this for a few weeks until it became stiff all the time. Do you still think it might be the same problems you mentioned?




Expert:  Matt replied 5 years ago.
Hello Raimus

thanks for the extra information this could be a faulty pump in that case

if the fluid was black and discoloured then this also points to the pump may be faulty

I'd still try what I'd suggested 1st as this is a lot cheaper to put right

but if these are Ok then consider replacing the pump