cleanc

Sorry for starting a new thread for this but I need some help. I have seached the forum and couldn't find the answer... Since yesterday I have noticed that the steering wheel is very difficult to turn when my car is idleing. As soon as I touch the accelerator pedal, the wheel breaks free and turns as normal. I checked the power steering fluid and it is full. I was wondering if this could be caused by trash in the lines somewhere or what.. I hope I don't HAVE to replace the pump but I think I will unless someone has a better solution.

Glyn M Ruck

cleanc - see my PM

I've taken cleanc through all the standard top up & bleeding procedures etc. Belt tension check, noise issues, steering lock interference, leaks etc. etc.

I'm worried he might have a partially stuck pressure relief valve. This is a new one to me if all the checks achieve nothing.

Can we brainstorm a few thoughts on the forum as to possible causes - any sensible ideas or experience welcome

clean - for level see pics
https://mbworld.org/forums/c-class-w...-car-w203.html

cleanc

Thanks Glyn... I pm'ed back but maybe this is best done out here in case someone else has this problem. Everything checked out fine. I checked the fluid after priming the system... NO BUBBLES. It does however appear that there may be more fluid in the reservoir than is called for. It reads about 3/4 inch too high on the dipstick. Still only have PS with increased RPM's...?

cleanc

Anyone have any clues or suggestions?

mleskovar

Did you check the hoses for any crimping (especially the metal tubing sections)?

Glyn M Ruck

OK,
Here is our chat so far

Quote"
Hi,
Acknowledging receipt of your message. This is wierd - never heard of this problem. Don't go rushing out and changing pumps. Let me give this some thought & revert. In the meanwhile please do the following.

Ensure the Poly V belt is properly tensioned & not skidding on the PS pump pulley.

Make sure the fluid level is correct per the instructions I gave you.

Turn the steering from lock to lock at least 5 times to bleed the system

Recheck the fluid level & tell me if you see air in the fluid.

Does the system make any noise - Swishing, high frequency squeeling etc.?

Make sure the steering column lock is not interfering with wheel movement

If you have no leaks & no air in the system I'm worried you might have a partially stuck pressure relief valve



Thank you... I just went out and started car and turned wheel from lock to lock 5 or six times (my buddy drove by in his M3 and shouted that his was running fine today) I then checked the fluid and it is a full inch too high on the stick... This is crazy. I suddenly have extra fluid? No bubbles and no new sounds noticable.. A friend did mention a week ago that it sounded like the pump was whining loudly. Going to check fluid again now....... Still too much fluid. could this be the problem? All belts seem to be tight



This IS crazy - We can't gain fluid!!! unless it's been displaced by air??? and we have air trapped in the system somewhere in which case it should squeel loudly at full lock either left or right as the air goes through the pressure relief valves. Please do me one more favour. Climb under the car & check the steering rack rubber boots & make sure they are not full of fluid. Just give them a squeeze. We might have an internal leak in the rack.

Did you have to top up the PS reservoir recently?

Please suck some fluid out & correct the level dependent on fluid temperature. We can always top up later if it drops again. We'll lick this thing but this is a first for me with your symptoms. Weird "

unquote

Glyn M Ruck

ps - yes this is better out for all to see and comment. Many minds are better than just ours. I would have done a summary for the forum anyway, because that's the spirit of this endeavor.

mleskovar - any thoughts from you are most welcome. I've never experienced this before.

AND ANYONE ELSE OUT THERE PLEASE!! in advance

cleanc

Well... I will drain some fluid first thing in the morning... it is now dark here and about 30 degrees out.. and I have no garage. Glyn, what do I look for under the car that you said I should check for fluid? I have some experience with basic car stuff but I am not sure exactly what boots you are talking about.. I think I have an idea what it is but if you have time, please try to describe where I should look.

I have never had to add fluid and my mechanic would have let me know if he had added any (if not by spoken word, then in the form of $$$ on the bill. haha)

I am very thankful that I have found this forum and people like you to help me bang through these crazy situations.

cleanc

mleskovar- I looked and saw nothing out of the ordinary... thats not to say that there is not some crimping somewhere, but it is just below freezing here and I admit I didn't want to lay on the ground and stuff for very long. I'll check again in the morning and see what I can find.
Thanks

Glyn M Ruck

See pic & boots highlighted in yellow

Glyn M Ruck

You need to remove the undercover (skid plate) to check metal & rubber hoses - see bolts in pic

cleanc

looks like fun!!! gonna have to borrow some real tools i guess

mleskovar

My power steering problems have been limited to slipping belts and leaking hoses or connections. At what RPM does the power steering start to work? What is the idle speed? I know the tach isn't real accurate unless you go into dyno mode but estimate as best as possible. To test it you need specs and a gauge. I'm also curious if this just happened all of a sudden or slowly built up to where it is now over a period of time. And does it always act this way now?

FrankW

wish i can chime in, but other than a leaking seal that was replaced I didn't have any other issues with it.

i would suspect that you need a new power steering pump, but that's just my wild guess.

Glyn M Ruck

WAGS are greatfully accepted - this ones got me puzzled. Maybe the pump is not producing enough pressure at idle. Trouble is if we've got dirt in a valve we might replace an expensive pump for nothing. Hmmmmm

FrankW

that's my guess (pump dying and not able to produce enough pressure on it's own). if there's dirt in a valve somewhere I would think that after you are on the throttle and more power is produced by the pump (evident that the power steering is back) the dirt would've been floating around in the system and it would randomly clog some valve instead of the symptom he describe as no power steering until he pick up speed. again my non-scientific guess..lol

Glyn M Ruck

Yep - who knows. I've seen valves fail partially and give you heavier than normal steering because they are venting off system pressure all the time, but you can usually hear them even with no air in the system, if you know what to listen for.

cleanc

Okay guys, I checked the hoses and the rubber boots under the car. All was in order. I checked the fluid level after sitting all night in the cold. It was still WAY too full. I drained it to the cold minimum level and drove around the block a few times and turned from lock to lock to prime the system fully... no bubbles in the reservoir... still no power steering at idle(600-750 RPM) When the RPM's go to 1000 or so, the steering is fine. Thanks for the ideas. Gonna keep working on it I guess.

Glyn M Ruck

re my PM here is pic

cleanc

That was the problem... I needed a new PS Pump. Got it replaced and it drives like new. Thanks for all who have tried to help.

Jack_2001C240

How many miles do you have on your 2004 C240. I have a 2001 C240 with 33,000 miles and I recently notice a slight whinning noise when I make a U-turn. I wonder if it is normal for a power steering pump to fail on a 4 or 5 year old car.

I have a 1990 Toyota Celica and 1990 Honda Civic with their original power steering pumps. Never had a problem with either power steering systems. And I had the power steering fluid flushed on both cars last year for the first time after 18 years of use.

Glyn M Ruck

I know of PS pumps on 240s at 700,000Km & 550,000Km never replaced. If it whining at full lock it's the pressure relief valve venting. If it's loud there is air in the system & likely low level in reservoir.

Glyn M Ruck

Good news - hope it was not too expensive

cleanc

I have nearly 110,000 miles on this car. I have been very pleased. The only other issue that I have had is the drivers side rear door lock flickers. I will search for this later. I'd say these are fairly minor problems to have.

02C240

I suspect a small Power Steering Fluid leak, but I can't pin point the source. I suspect the area between the pump and pulley as it's greasy in that area and the drivebelt also gets wet but only on the inside grooved side. The outside edge stays dry.

I also see evidence of fluid splash on the plastic undercover (skid plate) on the left side between the center jacking point and the 8mm bolt to the left that holds the plastic cover in place. I checked all the hoses and no leaks coming out of them.

Has anyone had a similar situation? Does it sound like I have a bad seal between the pump and drive pulley?
Has anyone tried Lucas “STOP LEAK” without ending up in more damage to the pump?

Any input is appreciated.