Light Steering
Thread Starter
Junior Member
Joined: Dec 2022
Posts: 48
Likes: 16
2009 ML350 4matic
Light Steering
Recently I replaced tires (new Michelin Defenders), struts/springs front, shocks back and then had a bad clunk in front. Ended up replacing the bushings on the two bolts/nuts that hold the steering rack in place. Got the car aligned. Now everything seems great except the car now seems to wander a bit at highway speeds. Steering is nice and easy at all speeds and no leakage at this point from steering reservoir/pump. Do you think that the sps valve could be defective and not allowing more contact with the wheels at higher speeds to keep the wandering down? I have an Autel Pro but have not run it yet since a CEL did not come up. Any other thoughts? The rest of the suspension items all seem solid from inspection while car on lift.
As always, thanks to all that respond! 2009 ML 350 4matic.
As always, thanks to all that respond! 2009 ML 350 4matic.
Thread Starter
Junior Member
Joined: Dec 2022
Posts: 48
Likes: 16
2009 ML350 4matic
UPDATE NAPLES:
JULY 2023 - 3 months ago I posted about my ML wandering just a bit at highway speeds but no comments. Since that time I was researching whether my truck was equipped with an SPS solenoid (also referred to as a Power Steering Proportioning Valve and controls fluid pressure to the steering rack). While all of this going on, my 1700 mile trip in August from Naples to Montreal to visit wifey family for a month has been roaring down the tracks and I've been getting more and more nervous about the truck being trusted for the journey.
To make matters worse, last week we drove 3 hrs to Tampa for Dr. appt and the truck barely made it home with steering getting very very stiff. As I pulled up to my house, I parked on the blacktop in case of needing a tow. Least of my issues. Truck dumped PS fluid all over. Next morning I called all around, including the MB dealership, to understand my options for getting this fixed. I figured it was the PS pump even though the local dealership had replaced the pump/resy 4.5 years earlier. In the end, I found a local Indi and determined if I could coax the truck 5 miles to his shop, that's where I would go. If I had to tow it, it would go to dealership 2 miles away. Luckily, I was able to drive to the Indi.
After listening to the terrible whining, he said he was 98% sure it was the PS pump. He replaced the entire assembly (pump and resy) with new and it cost me $875 plus tax and that's here in Naples where everything is expensive!.
Couple of items:
1. My guy mentioned the rack can be an issue in these situations and can go anytime without notice on a truck with 160K but said it looked good at this point. After replacing the pump with NEW (not resy) part, he flushed extra PS fluid thru the system to make sure no debris in there before completing the steering wheel stop to stop bubble purging procedure.
2. He visually determined that no SPS solenoid on my truck.
3. As I mentioned above, my previous Indi (before he just retired) replaced the bushings on the rack (a real bear of a job he told me) and said that some leaking from the PS pump probably contributed to the bushings deteriorating. I had noticed some drop in the ps fluid a few months earlier so put some stop leak into the resy and the leak stopped. Guess I didn't get it in time and the leak not only killed the bushings but it was also the beginning of the end for the pump itself.
4. Now that my pump replaced, I can't tell you how happy I am that it also fixed the wandering of my ML at highway speeds. Now at 70-80 mph, the steering tightens up a bit and tracks straight and true.
Now the hope is no further issues between now and the trip to Montreal in a few weeks. Hope this is helpful.
JULY 2023 - 3 months ago I posted about my ML wandering just a bit at highway speeds but no comments. Since that time I was researching whether my truck was equipped with an SPS solenoid (also referred to as a Power Steering Proportioning Valve and controls fluid pressure to the steering rack). While all of this going on, my 1700 mile trip in August from Naples to Montreal to visit wifey family for a month has been roaring down the tracks and I've been getting more and more nervous about the truck being trusted for the journey.
To make matters worse, last week we drove 3 hrs to Tampa for Dr. appt and the truck barely made it home with steering getting very very stiff. As I pulled up to my house, I parked on the blacktop in case of needing a tow. Least of my issues. Truck dumped PS fluid all over. Next morning I called all around, including the MB dealership, to understand my options for getting this fixed. I figured it was the PS pump even though the local dealership had replaced the pump/resy 4.5 years earlier. In the end, I found a local Indi and determined if I could coax the truck 5 miles to his shop, that's where I would go. If I had to tow it, it would go to dealership 2 miles away. Luckily, I was able to drive to the Indi.
After listening to the terrible whining, he said he was 98% sure it was the PS pump. He replaced the entire assembly (pump and resy) with new and it cost me $875 plus tax and that's here in Naples where everything is expensive!.
Couple of items:
1. My guy mentioned the rack can be an issue in these situations and can go anytime without notice on a truck with 160K but said it looked good at this point. After replacing the pump with NEW (not resy) part, he flushed extra PS fluid thru the system to make sure no debris in there before completing the steering wheel stop to stop bubble purging procedure.
2. He visually determined that no SPS solenoid on my truck.
3. As I mentioned above, my previous Indi (before he just retired) replaced the bushings on the rack (a real bear of a job he told me) and said that some leaking from the PS pump probably contributed to the bushings deteriorating. I had noticed some drop in the ps fluid a few months earlier so put some stop leak into the resy and the leak stopped. Guess I didn't get it in time and the leak not only killed the bushings but it was also the beginning of the end for the pump itself.
4. Now that my pump replaced, I can't tell you how happy I am that it also fixed the wandering of my ML at highway speeds. Now at 70-80 mph, the steering tightens up a bit and tracks straight and true.
Now the hope is no further issues between now and the trip to Montreal in a few weeks. Hope this is helpful.
