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Steering Problems on 87 300td
I have recently rebuilt the suspension of my 1987 300td. I am not a mechanic but through reading this board was able to accomplish the job including resealing the tandem pump, resealing the steering pump, and getting the self leveling system to work. When I finished I had a problem where the car felt bouncy. Not like the pods were bad but it bounced around more then it should. I finally diagnosed it as air in the hydraulic system. I was able to fix that by having my son and three of his friends bounce on the rear bumper of the car while I held the throttle to 2200 rpm. That bounce is now gone.
I have another problem that I can not diagnose. When I turn the car hard to the right the the steering kind of locks in place as if it has come hard against a stop and doesn't "bounce" back to the center. It doesn't take any force on the wheel to get the steering off of the "stop" but I know it is not right. I was careful to measure the pitman arm and have it back in the right place to on the steering pump. I am wondering if 1) the pitman arm may need to be adjusted in or out on the shaft of the steering pump or 2) when replacing the seals in the power steering pump could I have incorrectly aligned the gears inside the pump. The mark on the pitman arm does align with the mark on the power steering pump. Any help with this would be appreciated. I took the car into the best independent mechanic that I know of (he goes to Germany on vacation and does research for Mercedes in their vaults) and he could not diagnose the hard "stop" on the steering. Now that the air in the hydraulics is cleared up the car drives much better but I can now feel a different problem. When making a turn on a windy road and the road is flat the car feels fine. When there is a bump on the road during the turn the front end bounces a little and the car doesn't track correctly. I am not sure if this happens on both right and left turns or just on right turns. It is very subtle but unnerving. Is there anyone who can help me with these problems? |
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We should get our terms straight. To most folks here, the steering pump is the device driven by the engine serpentine belt that delivers pressure to assist in steering. In the case of your TD, the steering pump is in tandem with the pump that provides pressure to the SLS. The device that takes a signal from the steering wheel and is assisted by the steering pump is the steering gearbox or just steering box. The pitman arm attaches to the steering box.
I have difficulty understanding the problem you describe but it sounds like you reach a point in right turns that the steering linkage doesn't naturally return to straight ahead when you release the steering wheel. That's unusual. My questions at this point: 1) Did you touch anything in the steering linkage? Tie rods, center link, idler arm, etc.? 2) How far into the steering box did you go? Did you replace the pitman arm shaft seal and call it a day, or did you take it apart completely and set preload to the inch-pounds specifications? If you removed the steering box from the car, did you use locking compound on the bolts (which you're not supposed to reuse)? Is it still firmly attached to the frame? 3) Did you do any work to the front suspension that might have altered camber, caster or toe settings? 4) Did you bleed the power steering system? 5) What motivated you to touch the steering system in the first place? What problem were you addressing? Having asked all that, someone will come along and suggest you flip some switch to make it right Sixto 87 300D |
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I will keep my eye on this problem as i have the same thing on my 87 wagon when you go fully to the stop on the steering it does not self return! However since it turns back with normal pressure on the steering wheel i never gave it much thought.Maybe we will hear from some of the many other 87TD owners here. Don
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Red Green "This is only temporary,Unless it works!" 97 E300D 157000 miles 87 300TD ?141k? miles |
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I recently had this problem (not self-centering) on my 91 300D. I had all sorts of suggestions, including alignment and steering damper....it was very frustrating In my case, it turned out to be bad ball joints. Though there were neither loose nor squeaking, they were in fact bad. As a safety precaution if nothing else, if your ball joints have never been replaced, replace them.
Anyway, either your alignment is off or something is binding, preventing the steering from self-centering.
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14 E250 Bluetec "Sinclair", Palladium Silver on Black, 153k miles 06 E320 CDI "Rutherford", Black on Tan, 171k mi, Stage 1 tune, tuned TCU 91 300D "Otis", Smoke Silver, 142k mi, wastegate conversion 19 Honda CR-V EX 61k mi Fourteen other MB's owned and sold 1961 Very Tolerant Wife |
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I replied to this post but I had all the text inside the quote so perhaps that is why it got lost.
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14 E250 Bluetec "Sinclair", Palladium Silver on Black, 153k miles 06 E320 CDI "Rutherford", Black on Tan, 171k mi, Stage 1 tune, tuned TCU 91 300D "Otis", Smoke Silver, 142k mi, wastegate conversion 19 Honda CR-V EX 61k mi Fourteen other MB's owned and sold 1961 Very Tolerant Wife |
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Thanks Shertex
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I'd go and look at the control valve. As far as I know that's the only thing that could be providing the bounce you want. As you have seen from the W123 steering box there's no return spring in there - I think the W124 steering box is of a similar breed.
http://www.startekinfo.com/StarTek/outside/12264/disc_2/Program/Chassis/46-0238.pdf Found from Mercedes-Benz Model 124 Service Manual Library I think you'll have to remove the steering box to access it though. Keep on looking through those online PDFs and you'll find the FSM chapter to help you with that.
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1992 W201 190E 1.8 171,000 km - Daily driver 1981 W123 300D ~ 100,000 miles / 160,000 km - project car stripped to the bone 1965 Land Rover Series 2a Station Wagon CIS recovery therapy! 1961 Volvo PV544 Bare metal rat rod-ish thing I'm here to chat about cars and to help others - I'm not here "to always be right" like an internet warrior Don't leave that there - I'll take it to bits! |
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This thread by Army is very well presented. It'll bring a tear to your eye
http://www.peachparts.com/shopforum/diesel-discussion/303379-what-feeling-will-properly-adjusted-w123-w116-w126-power-steering-box.html Which brings up another question - when you installed the steering box and had the wheels aligned, did you use the centering tool? Not many alignment shops are aware that MB requires this tool. Sixto 87 300D |
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Thanks Army and Sixto. I have the original steering box ( with the flaw) on the bench right now. I will have a look at it and see if I can replace the control valve. I got a new set of sockets for Christmas so this will be a nice way to break in my new toy.
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keep in mind, the 87 has the strut bearings up top, they could be damaged, or old, and keep the steering from returning as well! Mine squeak when I turn... so I know I'll need a set soon...
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John HAUL AWAY, OR CRUSHED CARS!!! HELP ME keep the cars out of the crusher! A/C Thread "as I ride with my a/c on... I have fond memories of sweaty oily saturdays and spewing R12 into the air. THANKS for all you do! My drivers: 1987 190D 2.5Turbo 1987 190D 2.5Turbo 1987 190D 2.5-5SPEED!!! 1987 300TD 1987 300TD 1994GMC 2500 6.5Turbo truck... I had to put the ladder somewhere! |
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VS Tech thanks for that piece of information. The timing is great. I just heard the front end squeaking as I went over some speed bumps. The speed bumps were in the tire shop where the mechanic said I should look into changing my front struts.
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