1986 535i Power Steering Problems

ArtHowle · 07-28-2003, 12:07 PM

I have lost power steering on my 86 535i. I replaced the pump with a rebuilt pump, but the problem remained. I can drive the car, but it requires effort to get the steering to return to center. It was suggested that I replace the power steering fluid filter, located in the reservoir as well as the accumulator, located under the pressure regulator. I cleaned the filter with compressed air, but got no positive results. How can I determine that the acccumulator is bad and would this part affect the power steering? The worst-case scenario is a bad steering gearbox, but I would like to be 99 44/100% sure that it is broken before replacing it. If it is broken, then I'm thinking of purchasing a used gearbox. What are some things to check for in order to better my chances of getting a reasonably good used gearbox?

Thanks,
Art Howle

Jared at Pelican Parts · 07-28-2003, 12:09 PM

Have you bled the system?

ArtHowle · 07-28-2003, 12:19 PM

I bled the system according to the Bentley repair manual. i.e. I rotated the steering wheel fully cw; then pumped the brakes aprox. 6 times; then rotated the steering fully ccw and again pumped the brakes 6 times. I repeated this procedure several times. I did not see any air bubbles in the reservoir.

Jared at Pelican Parts · 07-28-2003, 12:20 PM

How is the coupler between the column and the rack? There should be no free play at all.

ArtHowle · 07-28-2003, 12:25 PM

I'll have to check the coupler , but there doesn't appear to be any free play in the steering wheel. There never was any excess play in the steering.

Jared at Pelican Parts · 07-28-2003, 12:27 PM

it wouldnt be in the wheel, manually check the coupler by hand.

ArtHowle · 07-28-2003, 12:30 PM

I'll check it and get back to you.
Thanks

ArtHowle · 07-29-2003, 06:06 AM

On my vehicle, it appears that the flexible coupler is located within the steering column and requires removing the steering wheel and disassemblying the shaft assy in order to get to it. I gripped the universal joint between the gearbox and the firewall and tried rotating it back and forth. There did not appear to be any excess play. I'm no expert, but the problem does not appear to be in the steering column.

Jared at Pelican Parts · 07-29-2003, 07:14 AM

Ok the coupler is in the engine compartment where the shaft meets the rack.

ArtHowle · 07-29-2003, 08:03 AM

You must mean the pittman arm and the idler arm. I personally have not checked these; however, a mechanic at a local shop did disconnect the tie rods to free the steering linkage from the wheels and to rule out faulty strut bearings. He diagnosed that the steering gearbox was bad, but he never checked the hydraulics, which includes the power steering pump, power flow regulator, brake accumulator, brake booster, resevoir and associated lines. He quoted $1200 to replace the gearbox. I would like to know how the hydraulic fluid pressure is used to asist the gearbox operation. There are no diagrams of this in any popular tech
manuals. My next step may be to have a BMW mechanic checkout the hydraulic system.

BrianK3044 · 10-03-2003, 12:06 PM

Did you resolve the problem? I have a problem with my 535i . I replaced the ps pump, filter, power regulator and bomb, gear box, and master cylinder. The problem seemed 90% fixed for a few weeks but now is back in full force with lots of noise and heavy steering.