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'83 300D, '85 300D
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5 Posts
Discussion Starter · #1 ·
Hello,

My '85 300D has suddenly become hard to steer left when starting to move or while moving very slowly. Turns right just fine. Steers fine both directions while moving faster than approx 10-15 mph. Would this be a problem with the power steering pump, or something else? A friend mentioned it might be some type of hydraulic assist in the front end.

Any help would be appreciated!

- Jon
 

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1977 W123.123 1995 W124.034
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3,915 Posts
Simple just make right turns :D

Seriously what is the condition of the tie rods and other steering gear? Do you have any issue returning the wheels to a straight ahead position after turning right?
 

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'83 300D, '85 300D
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Discussion Starter · #3 ·
Good one :)

No trouble returning to straight ahead. Haven't looked at tie rods and such, guess I hoped someone would magically know the answer. I'll get under the car and check it out this afternoon when the heat breaks. Will report back.

Thank you.
 

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'83 300D, '85 300D
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Discussion Starter · #4 ·
Ok, checked steering components under front end. I'm a machinist, not a mechanic, but everything seems to be in decent order. The rods seem fine, rubber is in pretty good condition. Couldn't find any play in the linkages.

Can a valve malfunction in the power steering pump in such a way that it only effects steering in one direction?

- Jon
 

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'83 300D, '85 300D
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Discussion Starter · #5 ·
I may have given the wrong answer to your question about returning to straight after a right turn. If moving very slowly, or not moving at all, returning to straight is just as difficult as turning left.

Basically, it feels like the PS pump went out, but only for left turning (or returning from right) at slow or no speed.

- Jon
 

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Registered
1977 W123.123 1995 W124.034
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3,915 Posts
I may have given the wrong answer to your question about returning to straight after a right turn. If moving very slowly, or not moving at all, returning to straight is just as difficult as turning left.

Basically, it feels like the PS pump went out, but only for left turning (or returning from right) at slow or no speed.

- Jon
Thats that I was looking for. I am no steering expert but I think the steering box itself my be the culprit. Army has a thread on rebuilding a steering box and hopefully he will see this and chime in.
 

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Premium Member
1967 250 SL, 1965 300SE lang
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3,150 Posts
I have a 1968 280S with leaking power steering. I filled it up and bled it and it worked fine, but liked like crazy. So I bought the money-back-guarantee Lucas Stop Leak Power Steering additive, which seems to just be very heavy weight oil. I added more and more of it and pretty much the system was running on Lucas mystery oil. Then the pump started groaning a bit. At this point I think I have power steering in one direction and manual steering in the other direction. My recommendation would be to flush and bleed the power steering fluid. The pumps on lots of MBs are very similar and probably the steering boxes are also. If a 123 is like a 108, there is a bleed valve on the top of the steering box and if you open that with a tube attached and start the car, the fluid will drain out of the tube and you fill with fresh fluid at the reservoir.

Oh, and I don't count the Lucas mystery oil as a success and I _did_ get my money back.
 

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1981 W123 300D non turbo, 1992 190E 1.8 <=> 2.0
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6,561 Posts
X2 for the fluid check - if it is black and grim drain and refill.

(If you don't know about the "drain screw" on the steering box have a look at post #5 here

http://www.peachparts.com/shopforum...justed-w123-w116-w126-power-steering-box.html)

Before you go ripping out the steering box - I'd remove the steering damper and see if that makes any difference to the feel. Take it easy when test driving - and you won't have to go far to see if it makes a difference or not.
 

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1985 300D Gone 1985 230CE Perfect, 1984 300TD Driver, 1981 300TD Bad engine
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1,421 Posts
Can a valve malfunction in the power steering pump in such a way that it only effects steering in one direction?

- Jon
I have a steering box in pieces to see how it works so I can say with certaincy: Yes. One of the pistons may be stuck. See Army's photo shoots of his disassemble of the steering box.
 

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'83 300D, '85 300D
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Discussion Starter · #10 ·
Thank you all very much for the replies. I'll delve into it after work today.

- Jon
 

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Simple just make right turns :D

Seriously what is the condition of the tie rods and other steering gear? Do you have any issue returning the wheels to a straight ahead position after turning right?
Hi my 300D started to be hard to turn left and fine when turning right
Anyone can help
 
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