Recommended Brands for V-Belt & Powering Steering Pump
Thread Starter
Senior Member
Joined: Aug 2017
Posts: 393
Likes: 10
From: Ontario, Canada
2006 ML500, 2008 ML350
Recommended Brands for V-Belt & Powering Steering Pump
Hi fellow W164ers,
Appreciate anyone giving me an insight as to what brand to look for when searching for V belt and Power steering pump.
Thanks,
Appreciate anyone giving me an insight as to what brand to look for when searching for V belt and Power steering pump.
Thanks,
Thread Starter
Senior Member
Joined: Aug 2017
Posts: 393
Likes: 10
From: Ontario, Canada
2006 ML500, 2008 ML350
First thing in the morning everything is fine. However, once the engine is warmed up after say 20 minutes or so, that's when steering becomes stiff at idle or very low speed unless you push on the gas then it becomes easier to steer, otherwise impossible. Hydraulic fluid is fine.
There's also a whining noise when steering at low speed. The whining is also heard at the start when the engine is cold.
Thanks,
There's also a whining noise when steering at low speed. The whining is also heard at the start when the engine is cold.
Thanks,
Super Member
Joined: Jun 2014
Posts: 507
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From: Massachusetts
2014 Smart ForTwo Passion Cabrio
First thing in the morning everything is fine. However, once the engine is warmed up after say 20 minutes or so, that's when steering becomes stiff at idle or very low speed unless you push on the gas then it becomes easier to steer, otherwise impossible. Hydraulic fluid is fine.
There's also a whining noise when steering at low speed. The whining is also heard at the start when the engine is cold.
Thanks,
There's also a whining noise when steering at low speed. The whining is also heard at the start when the engine is cold.
Thanks,
MBWorld Fanatic!
Joined: Oct 2011
Posts: 7,107
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From: Bronx, N.Y.
2002 ML 320 & 2006 ML500
Replace the belt but don't be so quick to replace the pump. The whining sound is usually attributed to air being trapped in the P/S system. When the whining starts, remove the cap and look into the reservoir and see if there are any bubbles in the fluid. If need be have someone turn the steering wheel back and forth while you check for bubbles. Don't mistake wavy fluid as bubbles. If you see bubbles, you must replace the reservoir and O-ring.
Also keep in mind that an ML500 has Speed Sensitive Steering which has an SPS Valve Y10, attached to the rack and pinion.
This valve controls the looseness or stiffness of the steering depending on the speed of the veh.
Also keep in mind that an ML500 has Speed Sensitive Steering which has an SPS Valve Y10, attached to the rack and pinion.
This valve controls the looseness or stiffness of the steering depending on the speed of the veh.
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Thread Starter
Senior Member
Joined: Aug 2017
Posts: 393
Likes: 10
From: Ontario, Canada
2006 ML500, 2008 ML350
Great insight, I will look into it. However, how would you explain the stiff steering at low speed/during parking/idle when the engine is warmed up, not when it's cold. Is air an effect for this symptom.
How about the brands for v belt.
Thank you.
How about the brands for v belt.
Thank you.
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MBWorld Fanatic!
Joined: Oct 2011
Posts: 7,107
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From: Bronx, N.Y.
2002 ML 320 & 2006 ML500
In post #2 I have already said that Gates belt should be bought.
As for the SPS valve, it could be getting stuck.
Just do the test of the P/S fluid check for bubbles.
As for the SPS valve, it could be getting stuck.
Just do the test of the P/S fluid check for bubbles.
Thread Starter
Senior Member
Joined: Aug 2017
Posts: 393
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From: Ontario, Canada
2006 ML500, 2008 ML350
Ok I did the bubble test with the help of my son when the engine was hot. Revved up to 3000, no bubbles, turned lock to lock a couple of times at 2000, still no bubbles in reservoir.
one thing I noticed is that the whining/screeching is much less when the engine is warm.
If the speed is stuck, would it have the same effect.
Thanks
one thing I noticed is that the whining/screeching is much less when the engine is warm.
If the speed is stuck, would it have the same effect.
Thanks
Thread Starter
Senior Member
Joined: Aug 2017
Posts: 393
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From: Ontario, Canada
2006 ML500, 2008 ML350
Power Steering Test
Tested for bubbles at idle this morning when engine cold. Still no bubbles.
Please see the attached for the whining noise at the time.
I should add that while there is no apparent leak, I end up topping up the hydraulic oil around once a month, not much though.
Thanks
Please see the attached for the whining noise at the time.
I should add that while there is no apparent leak, I end up topping up the hydraulic oil around once a month, not much though.
Thanks
MBWorld Fanatic!
Joined: Oct 2011
Posts: 7,107
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From: Bronx, N.Y.
2002 ML 320 & 2006 ML500
Did you look into the reservoir while the wheel was turned?
That is not a bearing noise, it is a P/S noise/whine caused by air in the system. You probably have a small leak where the reservoir attaches to the pump because the O-ring has failed. Reservoir and seal must be replaced.
Before replacing anything, inspect the area of the pump and reservoir for fluid leak.
Thread Starter
Senior Member
Joined: Aug 2017
Posts: 393
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From: Ontario, Canada
2006 ML500, 2008 ML350
I did check for bubbles turning the wheels lock to lock. There is absolutely no bubbles.
There was a leak on o ring last year . I replaced the o ring and the reservoir. The leak stopped. And there is no leak there right now, nor under the car, but somehow it's lost, very small amount, over a month or so.
Would this very small amount of fluid loss be the cause of this noise and the very stiff steering at idle. At idle, when the engine is hot, steering is impossible to turn, even by the slightest amount.
There was a leak on o ring last year . I replaced the o ring and the reservoir. The leak stopped. And there is no leak there right now, nor under the car, but somehow it's lost, very small amount, over a month or so.
Would this very small amount of fluid loss be the cause of this noise and the very stiff steering at idle. At idle, when the engine is hot, steering is impossible to turn, even by the slightest amount.
Thread Starter
Senior Member
Joined: Aug 2017
Posts: 393
Likes: 10
From: Ontario, Canada
2006 ML500, 2008 ML350
Thread Starter
Senior Member
Joined: Aug 2017
Posts: 393
Likes: 10
From: Ontario, Canada
2006 ML500, 2008 ML350
You were absolutely correct. I removed the belt and checked the P/S pump pulley. It would turn smoothly with a slight push of a finger and very quietly too, no noise or screeching or any play in/out direction, as you would expect from a bad bearing. So for sure it's not the pump, at least it's not the bearing.
Then I removed the under cover to look at the rack and pinion. There I noticed everything was covered in oil, almost the entire left side (driver's) of everything under the pump were covered in oil, and the other side was completely dry.
I checked the low pressure hose, high pressure hose connections, no leak was found. where else would a pump be vulnerable to leak?
don't know whether they are the remains of the old leaks last year. I sprayed the area with brake cleaner and am going to drive the car to see if I still get the oily surfaces. Point is, as for the steering fluid, I lose very very little. I'm sure the extent of the splatter could not have been due to the p/s fluid leakage; we'll see later on.
So, what would you think would be the problem. I managed to reach the electrical connection to Y10, it was sound and firm. With the present feel of the steering, how do you think I can test Y10.
I do appreciate your input.
One more point of notice; I lifted the front wheels and starting turning lock to lock slowly; when I turned right, passenger side, slight movement on the fluid in the reservoir, more like a suction movement; then when I turned left, the fluid rose. like a push from under, and every second time, it even overflowed. This is with engine off and cool, and turning the wheels very slowly. Starting fluid level was under the lower neck of the reservoir.
Thanks
Then I removed the under cover to look at the rack and pinion. There I noticed everything was covered in oil, almost the entire left side (driver's) of everything under the pump were covered in oil, and the other side was completely dry.
I checked the low pressure hose, high pressure hose connections, no leak was found. where else would a pump be vulnerable to leak?
don't know whether they are the remains of the old leaks last year. I sprayed the area with brake cleaner and am going to drive the car to see if I still get the oily surfaces. Point is, as for the steering fluid, I lose very very little. I'm sure the extent of the splatter could not have been due to the p/s fluid leakage; we'll see later on.
So, what would you think would be the problem. I managed to reach the electrical connection to Y10, it was sound and firm. With the present feel of the steering, how do you think I can test Y10.
I do appreciate your input.
One more point of notice; I lifted the front wheels and starting turning lock to lock slowly; when I turned right, passenger side, slight movement on the fluid in the reservoir, more like a suction movement; then when I turned left, the fluid rose. like a push from under, and every second time, it even overflowed. This is with engine off and cool, and turning the wheels very slowly. Starting fluid level was under the lower neck of the reservoir.
Thanks
Last edited by anavabi; May 2, 2018 at 05:57 PM. Reason: Last sentence added
MBWorld Fanatic!
Joined: Oct 2011
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From: Bronx, N.Y.
2002 ML 320 & 2006 ML500
If the leak is at the head or one of the boots are leaking, you must get a rebuilt or used rack and pinion. The boots are only dust covers so don't think that replacing the boot will correct the leak.
Regardless of what rack you choose, replace the reservoir and O-ring at the same time. As previously informed, the bleeding must be done prior to starting the eng.
Thread Starter
Senior Member
Joined: Aug 2017
Posts: 393
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From: Ontario, Canada
2006 ML500, 2008 ML350
Please have a look at the last paragraph on my last post and the relevant video. Looks like suction and discharge action when turning lock to lock.
Thanks,
Thanks,
Last edited by anavabi; May 3, 2018 at 10:50 PM.
Thread Starter
Senior Member
Joined: Aug 2017
Posts: 393
Likes: 10
From: Ontario, Canada
2006 ML500, 2008 ML350
I ran the engine, no leak anywhere, it must be the overflow that causes loss of fluid.
it would be so frustrating had I replaced the pump, thanks to your guidance.
