Author Topic: Power Steering Gearbox  (Read 465 times)

OLDGOLD

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Power Steering Gearbox
« on: 30 April 2019, 02:01 PM »
Hello! My power steering gear box is leaking and after about 10-15 minutes of driving it begins to groan loudly at low speeds especially. It's not so bad while I'm moving, but once you start to steer at low speeds that's when she starts to make more noise. The steering feels pretty good, especially after replacing the coupler, and I had the PS pump resealed a few months ago, but this noise is starting to get pretty annoying and I'm afraid I'm going to hurt something if I keep driving.

I have the Febi reseal kit 1074600061 and I have a technician that can reseal it for about $300 cash. Should I have him reseal it? Or should I just buy a remanufactured or refurbished PSGB online? I saw one for about $300, but don't want to have to do this job twice if I don't have to if the cheap GB won't last.

Let me know ya'lls thoughts. Also, if anyone has used this kit with success or not, please let me know as well. I was told that these kits aren't as interchangeable as they seem sometimes. Once she's opened, I won't have time to procure more parts as this is my daily driver. Thanks in advance!

daantjie

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Re: Power Steering Gearbox
« Reply #1 on: 30 April 2019, 03:31 PM »
Are you running ATF or PSF in the system?
Daniel
1977 450 SEL 6.9 - Astralsilber

Alec300SD

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Re: Power Steering Gearbox
« Reply #2 on: 30 April 2019, 05:45 PM »
Swapping in a non-leaking unit would be the safest bet.
I installed a used Pick-n-Pull unit in 'Desert Rose' recently.

C&M Hydraulics has a good reputation for rebuilding MB steering boxes.
Not sure of current pricing as they changed their website.
79 W116 300SD 'Stormcloud' new as of 10/22/2017
78 W116 300SD 'Desert Rose' new as of 01/26/2014
83 W126 300SD 'Rena 2.0' with engine from 82 W126 300SD Rena' (SOLD and crushed 11-20-2017)

OLDGOLD

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Re: Power Steering Gearbox
« Reply #3 on: 30 April 2019, 08:18 PM »
Genuine MB Power Steering Oil  (Q1460001)

Randys01

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Re: Power Steering Gearbox
« Reply #4 on: 01 May 2019, 03:41 AM »
Try giving it a good bleed. J
1. make sure pwr stg pump v belt is tight.
2. Jack the car up.  {in a/w with proper safety procedure.} both front wheels off the ground.

Start the engine.  make sure the fluid level is at max and wind the steering slowly full lock to full lock at least 6 times each way.. .
return car to ground and drive. Determine if this has improved the groaning.

If the problem continues then potential by passing pump needs a pressure output check for a starters.

OLDGOLD

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Re: Power Steering Gearbox
« Reply #5 on: 01 May 2019, 05:52 AM »
Ok, I’ll give this a try. Could an air pocket cause the steering to groan?

revilla

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Re: Power Steering Gearbox
« Reply #6 on: 03 May 2019, 10:37 AM »
Yes, trapped air could cause that type of noise. But chances are low as the system is designed to flush air into the upper part of reservoir.  Maybe not what you want to hear but I personally think air is not the root cause of the noise; unless your pump is “weak” thus not capable to push the air pockets back to the reservoir.

Cheers
Robert
W116 1977 280SEL & 1979 280SE

floyd111

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Re: Power Steering Gearbox
« Reply #7 on: 03 May 2019, 02:11 PM »
Steering pumps can be very sensitive to oil levels, sometimes ridiculously so, not even allowing for 1CM in oil level drop in the reservoir. That sensitivity is noticed first when the wheels are turned outermost left or right as a grinding whizzing sound. Then, as oil levels drop further, the noticeable ailment moves from "outermost wheel position" to an ailment noticeable at the slightest touch of the steering wheel.
Brief, if you want to find things out, make sure you got perfect oil levels first. A tiny leak can cause a lot of trouble. Besides the steering pump, there really isn't anything in that steering system that could make that type of sound, not while parked/idle. For a guy like me, I would have it fixed by a specialist if it were to leak, and would surely send it to the same guy if it was noisy without having detected a leak first. I would say that a noise-without-leak would be a first for me, but I been driving 50 or so modern-ish Jap cars for decades, and may have  missed the state of affairs elsewhere.

OLDGOLD

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Re: Power Steering Gearbox
« Reply #8 on: 07 May 2019, 08:45 PM »
Thank you all for the feedback!

I took my car into the shop last night and filled the reservoir completely, then jacked up the front and turned the wheel to each side 6 times as you instructed. The noise was very much still present afterwards.

If I were to have the gearbox repaired, I would definitely send it to a professional as I've heard they're a bitch to reseal, even for the professionals!

The strange thing is that even with a completely full reservoir, the groan is just as bad. The steering is smooth as butter at first and gets louder as I drive. The groaning can be felt through the steering wheel and makes it more difficult to steer.

My biggest fear is having the gearbox replaced or rebuilt and the noise/roughness still be present. If I just had my steering pump resealed, the belt is tight and fluid level correct, what else could cause this if not the gearbox?

Alec300SD

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Re: Power Steering Gearbox
« Reply #9 on: 08 May 2019, 12:06 AM »
Next time the symptoms show, pop the hood and try to isolate the source of the noise.

If the noise comes fom the PS pump, it could be a failing spool valve (control valve), or just be entrapped air from the steering box leak causing low pressure in the PS pump.
This will cause the spool valve to complain loudly with 'groaning' until the pressure is raised to the normal level at higher rpms (or by topping off the fluid level in the PS reservoir).
https://www.yourmechanic.com/article/symptoms-of-a-bad-or-failing-power-steering-control-valve?PID=8980730&as=cj&mktg_channel=AFL_CJN&publisher=Autoblog


If the noise comes from the steering box, then there is binding of the steel ball bearings in the worm gear.


In either case, this can cause a steering failure at an inopportune time.  :(

79 W116 300SD 'Stormcloud' new as of 10/22/2017
78 W116 300SD 'Desert Rose' new as of 01/26/2014
83 W126 300SD 'Rena 2.0' with engine from 82 W126 300SD Rena' (SOLD and crushed 11-20-2017)

Randys01

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Re: Power Steering Gearbox
« Reply #10 on: 08 May 2019, 01:41 AM »
So you have pretty much eliminated air in the system. My follow up advice was to have the system pressure tested. Have you done this?

OLDGOLD

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Re: Power Steering Gearbox
« Reply #11 on: 08 May 2019, 01:31 PM »
I have not had the system pressure tested. I work at an MB Dealer in Dallas so it shouldn't be hard to find someone who can do that.

Also, where is the spool/control valve located on our cars? Is it in the pump?

Alec300SD

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Re: Power Steering Gearbox
« Reply #12 on: 08 May 2019, 05:22 PM »
The spool valve (aka shuttle valve) is located in the PS pump under the cap nut on the front lower left side (behind the pulley)..
https://lh6.googleusercontent.com/-aeyt_yCIIrY/TodY5EvintI/AAAAAAAAInM/SeMW_nKP5_A/s1280/IMG_20111001_111523.jpg
79 W116 300SD 'Stormcloud' new as of 10/22/2017
78 W116 300SD 'Desert Rose' new as of 01/26/2014
83 W126 300SD 'Rena 2.0' with engine from 82 W126 300SD Rena' (SOLD and crushed 11-20-2017)

OLDGOLD

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Re: Power Steering Gearbox
« Reply #13 on: 08 May 2019, 07:20 PM »
Ok, thanks! I found your thread on BenzWorld, very nice right up.

So do I just need to clean the shuttle valve or are there parts that need to be replaced?

It would be awesome if this fixed my issues.

Alec300SD

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Re: Power Steering Gearbox
« Reply #14 on: 08 May 2019, 07:43 PM »
That is not my thread, I just linked  to the image of the valve. :)

I think that gettting the pickup screen and the valve surgically clean may be all that is needed.
A speck of grit can cause issues, as reported by Stretch (FKA Army).
http://www.peachparts.com/shopforum/attachments/tech-help/86014d1287857865-w123-vickers-type-24-power-steering-pump-questions-vickers-shuttle-valve.jpg

Of course, replace the crush washer on the cap nut on reassembly.
79 W116 300SD 'Stormcloud' new as of 10/22/2017
78 W116 300SD 'Desert Rose' new as of 01/26/2014
83 W126 300SD 'Rena 2.0' with engine from 82 W126 300SD Rena' (SOLD and crushed 11-20-2017)