Random hard steering at low speed
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Junior Member
Joined: Jan 2019
Posts: 42
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2004 E500 4matic
Random hard steering at low speed
Our typically trouble-free 2010 GLK-350 (~160k miles) has developed an intermittent steering problem. Sometimes at low speed, like pulling into or out of a parking spot, the steering wheel will get hard to turn. It's very random and goes away as quickly as it appears. It's not throwing any codes, making they usually gawd-awful sounds that a dying power steering pump makes or losing any fluid. Fluid level is normal. Are there any speed sensors or actuators that might be in the process of failing?
Super Member
Joined: Feb 2023
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2011 GLK 350 4Matic
If one of your strut mounts was binding, it could do that (I'd guess usually with some sort of noise, but not necessarily). Without any obvious groaning noises, I doubt it's air in your power steering system (that normally produces a pronounced whining noise).
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Joined: Aug 2023
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From: MA Coast
W204 2010 C300 4matic Sport M272
What about swapping out the power steering fluid? I swapped out mine over the summer fairly easy. Once a day I used a large meat syringe and sucked out some fluid then put new fluid in. I did this until I went through a quart. The old fluid was dark brown, after the quart it was more like the color of new fluid.
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2021 GLB250 FWD, 2023 GLA250 FWD, 2013 C250, 2015 GLK350, 2005 ML350SE, 2003 E320
Try the other solutions first.
Look for black particles or debris when you change the fluid. That would mean the ps system needs to be flushed and hoses may need replacing.
If the previous suggestions don’t find anything, it could be the bypass valve in the pump. Test by standing on a level surface where the GLK will not roll in neutral without brakes applied. Apply the parking break. Jerk the steering wheel hard left then right a few times like performing an emergency avoidance maneuver. You should not feel any increase in effort. If you do this is a safety issue. Suspect the bypass valve, which will require a new ps pump. I’ve seen this in multiple brands foreign and domestic including Mercedes at high mileage. It could be a problem in the steering rack itself, but the pump is the first place to look.
Look for black particles or debris when you change the fluid. That would mean the ps system needs to be flushed and hoses may need replacing.
If the previous suggestions don’t find anything, it could be the bypass valve in the pump. Test by standing on a level surface where the GLK will not roll in neutral without brakes applied. Apply the parking break. Jerk the steering wheel hard left then right a few times like performing an emergency avoidance maneuver. You should not feel any increase in effort. If you do this is a safety issue. Suspect the bypass valve, which will require a new ps pump. I’ve seen this in multiple brands foreign and domestic including Mercedes at high mileage. It could be a problem in the steering rack itself, but the pump is the first place to look.
