Power Steering Pump Failure?
08-10-2020, 02:07 PM
#1
Junior Member
Thread Starter
Power Steering Pump Failure?
Lately I have been finding unfortunate power steering oil puddles under my 2003 ML350. I first noticed it when I turned the car on and it made a horrific noise when turning the wheels. I went ahead and added Pentosin CHF11S Power Steering fluid and it fixed the problem for a while.
I still noticed my fluid was leaking out from somewhere so I followed a video on YouTube on how to replace the contoured O ring on the power steering reservoir. During this process, I pumped out all the old oil out of the reservoir so I wouldn't make a mess, replaced the O ring, and then replaced the oil. I jacked up the front of the car and put the key in and didn't turn it on. I cranked the wheel from lock to lock to burp the system and then lowered it down and made sure the fluid was at the right level and all was well.
Later that night, I am still having leaking. I put some more fluid in and zip tied some paper towels around each end of the return hose which I suspected was leaking. I drive home and call it a night.
Well this morning I got up to go to the bank and I have ZERO power steering. I checked the levels and they are good. There was a little smoke coming out of the reservoir when I was checking this morning.
I think I either blew up my power steering pump somehow or I just had a pump going out. It has 181000 miles on it so there's a good chance its just donezo. I checked the paper towels and there was zero oil on them.
My question: Does anyone have any method to diagnose which part is actually failed? The reservoir is cheap enough to replace, and so is the pump (with non-oem), but I don't want to just go replacing stuff if I can diagnose what the actual failed part is.
I heard that the check valve in the pressure hose can go bad which can blow up pumps too. I was planning on replacing the pump, reservoir, and both hoses. Does anyone have any better ideas? I am all ears.
Thanks!
Will
I still noticed my fluid was leaking out from somewhere so I followed a video on YouTube on how to replace the contoured O ring on the power steering reservoir. During this process, I pumped out all the old oil out of the reservoir so I wouldn't make a mess, replaced the O ring, and then replaced the oil. I jacked up the front of the car and put the key in and didn't turn it on. I cranked the wheel from lock to lock to burp the system and then lowered it down and made sure the fluid was at the right level and all was well.
Later that night, I am still having leaking. I put some more fluid in and zip tied some paper towels around each end of the return hose which I suspected was leaking. I drive home and call it a night.
Well this morning I got up to go to the bank and I have ZERO power steering. I checked the levels and they are good. There was a little smoke coming out of the reservoir when I was checking this morning.
I think I either blew up my power steering pump somehow or I just had a pump going out. It has 181000 miles on it so there's a good chance its just donezo. I checked the paper towels and there was zero oil on them.
My question: Does anyone have any method to diagnose which part is actually failed? The reservoir is cheap enough to replace, and so is the pump (with non-oem), but I don't want to just go replacing stuff if I can diagnose what the actual failed part is.
I heard that the check valve in the pressure hose can go bad which can blow up pumps too. I was planning on replacing the pump, reservoir, and both hoses. Does anyone have any better ideas? I am all ears.
Thanks!
Will
08-10-2020, 10:28 PM
#3
Junior Member
Thread Starter
I actually introduced air into the system last night when messing around with the return hose so we bled that air out again and got the power steering working.
We FOUND the leak (or at least one of them), it was on the rack and pinion. I will post a picture. It was POURING out if you even touched it and little bit and there was a ton of play on the passenger side but not the driver side. We tightened the torx bolt holding it in place and I assume there is a seal behind it. From what I gathered, that seal often goes bad and you can replace it instead of replacing the rack and pinion.
Spoiler
08-10-2020, 10:34 PM
#4
MBWorld Fanatic!
So my dad and I brought the Mercedes to our garage and jacked it up and bled the system again. We added some more fluid so we can try to find where it is leaking.
I actually introduced air into the system last night when messing around with the return hose so we bled that air out again and got the power steering working.
We FOUND the leak (or at least one of them), it was on the rack and pinion. I will post a picture. It was POURING out if you even touched it and little bit and there was a ton of play on the passenger side but not the driver side. We tightened the torx bolt holding it in place and I assume there is a seal behind it. From what I gathered, that seal often goes bad and you can replace it instead of replacing the rack and pinion.
I actually introduced air into the system last night when messing around with the return hose so we bled that air out again and got the power steering working.
We FOUND the leak (or at least one of them), it was on the rack and pinion. I will post a picture. It was POURING out if you even touched it and little bit and there was a ton of play on the passenger side but not the driver side. We tightened the torx bolt holding it in place and I assume there is a seal behind it. From what I gathered, that seal often goes bad and you can replace it instead of replacing the rack and pinion.
Spoiler
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