w124 Power Steering Effort / Hard / Difficult - PeachParts Mercedes-Benz Forum

mcguirjf · #1 10-27-2008, 11:57 AM

Greetings,

I replaced the power steering pump, replaced tie rods, damper, drag link, rebuilt the idler arm, and everything else but the damn lower ball joints. I don't have any leaks and the power steering pump I just replaced doesn't whine and provides the same resistance. I've got about 300K miles on the odometer.

Other than the lower ball joints and the steering box adjustment (CW to loosen), is there any other possible causes to steering resistance? I have to turn the wheel just to staighten out the vehicle when exiting a turn. The steering is not notchy or binding. The power steering is worse than a nissan sentra's!

Should the steering effort be the same as a w140? I test drove one with low fluid (whinning) and that was better!

I have a 1990 300D W124.128.
Thanks!

emerydc8 · #2 10-28-2008, 03:38 AM

If some of the pump blades (I think there are 10) were inserted in the pump backwards (rounded edges toward the center), I was told by an MB tech it will decrease the power assist. Was the pump rebuilt?

Also, if there was a tiny protective rubber plug in the output side of the pump and it was not taken out when the pump was installed, it could create a restriction and end up at the entry of the gearbox (ask me how I know). You can take the line off between the pump and the gearbox and check for restrictions.

The first picture is the way the pump came with a tiny plug to protect the outlet port. The second picture is where the plug was found (melted) after spending 15 hours trying to figure out why no power assist.

mcguirjf · #3 10-28-2008, 12:15 PM

Thanks for the reply!

I purchased the PS pump rebuilt from autozoo. The nice thing it does come with a lifetime warrantee.

I will definately go over the PS lines and check for kinks. I'll even run some pressurized air to see if there are any blockages. Great idea!

Thanks again. I'll report back with my results.

MDE3 · #4 10-29-2008, 03:16 AM

I have removed working power steering pumps..vane type..left them on the bench for a couple of weeks while working on other thngs, and voila..when put back in the car, no power steering..had no problems pryor to removing it from the car.

Removed it again and opened it....the old oil had turned to a varnish and basically locked up the vanes in the rotor while sitting on the bench drained...looks like the air reacted with the ancient steering fluid and turned it into a varnish....Pulled them all out, cleaned thoroughly and replaced everything...pump re-installed and works like new....

How many of us ever think to drain and replace power steering fluid...mostly just add as needed right...

mcguirjf · #5 10-31-2008, 05:05 PM

I got an email from BillyBob on the possibility of soon to fail lower ball joints! I have all the front end parts. I'll post any findings.

mcguirjf · #6 11-04-2008, 10:45 PM

I'm putting the new bushings and ball joints into the arms now. I used a picture of a control arm assy to see how the bushings are aligned into the arm. The two numbs are side ways up front and the three numbs are up and down on the rear side of the control arm.

Please let me know if I'm wrong.

hages · #7 05-25-2013, 02:38 AM

Quote:

Originally Posted by mcguirjf

I'm putting the new bushings and ball joints into the arms now. I used a picture of a control arm assy to see how the bushings are aligned into the arm. The two numbs are side ways up front and the three numbs are up and down on the rear side of the control arm.

Please let me know if I'm wrong.

4 years later and no update if the heavy steering was due to the ball joints...hmm!

I test drove a '93 Cabriolet and it had heavy steering. The seller claimed it was because the cabriolets are heavy cars. I was immediately skeptical.

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