Hi ' everyone,
I'been lurking on this site for a while now and I can say that this is the best place to spend my time (even some precius time). I want everyone know that I appreciate all the help that I got from you guys-too many to mention, including Fastlane ( Phil ) where I got all my parts without problem. Now the time comes that I can't figure-out whats wrong on my power steering system. I have a 1990 420 sel that I own since 1993 ( with 35k miles the time when I got it. I'm the second owner) with 97k miles @ present. Since day one I own this car the power steering is kind of hard to steer, not that hard but I believe it is hard enough to conclude that theres something that need to be fixed. Back then I thought it's normal. My question is , do I need a new one or even a re-built ( power steering pump ) will do. Here's what I did so far, flushed the system two times, replaced the filter with no change on the feel on steering wheel. All sugestion are welcome and will be appreciated.
I love working on cars, I'm self-learn mechanic, I manage to fast the test to be a licenced ( Sp. ? )mechanic (Pa.). If theres some one who need my help, just drop me a line. As you
notice English is my second language and please pardon it.
What I've done so far on my beloved garage queen from 1993,
I have replaced: brakes,ignition wires, spark plugs-2x, distributor cap and rotor,valve cover gasket, timing chain, camshop sprocket, timing chain tensioner and guide rails, replaced camshop sprocket keyway with 9mm keyway to put in the exact timing,fuel filter, air filter, smog pump and all the hardware, water pump-2x, water temp. sensor, adjust duty cycle to 45%-50%, all the v-belt 2x. I used to get 14-16 mpg. After timing chain replacement, I'm geting 18-20 mpg now. I love her so much that I think I will give it to my grand kid in the future. It run so smooth that you would'nt even hear the engine in the stop light. Well, thank you very much and sorry for the long post, this is my first one.

Welcome to the group and don't worry about the English. We have a joke in this country.
What do you call someone who speaks three languages? Answer: trilingual
What do you call someone who speaks two languages? Answer: bilingual
What do you call someone who speaks one language? Answer: A native born American

I'm afraid I can't answer your question, because I've never experienced it. Maybe another pro will chime in here. You said you flushed the system. What are you using for fluid? Also get the #s off the pump and post in case someone installed the wrong pump from a wrecking yard. you may also have the wrong pulley.

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i have a 90 350sdl. it has a relatively small diameter steering wheel. when the 126 bodies first came out they had the big old wheel. i think the small wheel just gives less leverage and makes it harder to steer. i squirted some grease into my ball joint boots with a needle on my grease gun. that seemed to help some.

tom w

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.

autozen, t walgamuth,
Thanks for the reply and sorry for the lack of important info. I believe the pump is original and so with the pulley, I said that because when I got the car it looks brand new ( and still is )-three years old and only 35k miles. I believe my pump is a ZF model. When I flush it I used ATF fluid, I know its wrong, it's too late when I found this web site. I've never driven other MB ( W 126 ) so I don't know the difference on the feel of the steering wheel of other MB. Could some one please tell me how's their steering system feel? I'm thinking of
getting a used one just for the heck of it. Thank you guys, I appreciate it.

autozen, t walgamuth,
Thanks for the reply and sorry for the lack of important info. I believe the pump is original and so with the pulley, I said that because when I got the car it looks brand new ( and still is )-three years old and only 35k miles. I believe my pump is a ZF model. When I flush it I used ATF fluid, I know its wrong, it's too late when I found this web site. I've never driven other MB ( W 126 ) so I don't know the difference on the feel of the steering wheel of other MB. Could some one please tell me how's their steering system feel? I'm thinking of
getting a used one just for the heck of it. Thank you guys, I appreciate it.

ATF is just fine. Let me see if I can look up the pump # today. Better yet I have a91 420SEL at the shop. I'll check the #s.

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Hi autozen,
Thanks for your time. so how's your '91 420 sel steering, I mean is't light or heavy to steer, or I guest what I want to know is what is "normal" feel for our w126? Thanks a lot man.

normal is a little on the heavy side. even by benz standards.

tom w

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.

If you haven't already done so, swap your tires front-to-rear. Then check that tire pressures are at least minimum, and test steering feel again. I have had tires that appeared to have a perfectly normal wear pattern, with plenty of tread left, cause hard steering.

If your steering feel seems normal after this, then check alignment.

Steve

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'91 MB 190E 2.3
'08 RAV4 Ltd 3.5
'83 Lazy Daze m'home 5.7

t walgamuth, that is exactly what I want to hear, I'm going to test drive a w126 maybe from a dealer to compare 'though I can consider mine is normal.Thanks a lot.
Sbourg, thank you for your time reading my post. I'm so sorry if I comfused you on the tittle of my post "hard to steer", what I mean to say is, the steering wheel is heavy compare to the car with a normal power steering system. Like t walgamuth said, it's on the heavy side.

benz makes the steering pretty stiff. also there is a lot of caster in most models which will make the steering a bit stiffer. the combination makes a car that wont go in the ditch on the autobahn if you sneeze.

it is a safety issue. it is comforting to me.

tom w

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.

I promissed to check the tag on the 91 420 a couple of days ago,but I keep forgetting. Sorry. I'll do better tomorrow. I'll check the 91 and two 86s.

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t walgamuth, you make me feel so relax and worry-free about my power steering now, it seem's that I won't even bother to test drive a 126 anymore.
autozen, I don't know how this # goes but here it is exactly the way I copy from the pump;
7672900446 ZF
3032879 590
1264601480 82 bar
Thank you guys, I truly appreciate your help.

I Finally remembered to check the cars. I checked three 86s and a 91. The MB part # you have is the same as 3 of the pumps. I didn't check the latest # from MB in the computer, because the # might have changed. The type # Matches 3 cars and all 4 cars say 82 bar. So I'd say you have the right pump. Since it is possible someone changed pulleys, I checked diameters. All 4 have a diameter of 127mm. Hope this helps.

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I'll check my pulley sometime today after work. I have an appointment @12:00 noon with a used car dealer today to test drive an '86 420 sel, I will let you guys know the outcome of the comparison. thanks a lot.