Oversteer on Freeway bends - Mercedes-Benz Forum

Reply
 
LinkBack Thread Tools Display Modes
post #1 of 14 (permalink) Old 06-19-2017, 03:29 AM Thread Starter
BenzWorld Member
 
Neo7's Avatar
 
Date registered: Mar 2015
Vehicle: 2002 ML270CDI
Location: Sydney Australia
Posts: 150
Mentioned: 0 Post(s)
Quoted: 27 Post(s)
(Thread Starter)
Oversteer on Freeway bends

I've always felt that the steering on my ML270CDI is too light. But recently fix the HP Pump and have noticed a lot more power from the engine. I'm told by a friend of mine (who owned an ML320) that my ML has firmer suspension than most. But today I was on the Freeway, doing 65mph up a long hill. When I powered up the hill and steered into the left hand bend the steering went super light and the car seemed to over steer (which scared the cr*p out out of me!).

Any ideas whats going wrong?

Many thanks.
Neo
Neo7 is offline  
Sponsored Links
Advertisement
 
post #2 of 14 (permalink) Old 06-19-2017, 05:41 AM
BenzWorld Extremist
 
ArcticDweller's Avatar
 
Date registered: Jun 2008
Vehicle: '95 SL500, '99 ML320, '08 ML550 4MATIC w/Sport & Lighting Pkg, '12 ML350 4MATIC w/P2 Pkg & Pano Roof
Location: CANADA.... bbrrrrrrr!
Posts: 860
Mentioned: 3 Post(s)
Quoted: 95 Post(s)
Quote:
Originally Posted by Neo7 View Post
I've always felt that the steering on my ML270CDI is too light. But recently fix the HP Pump and have noticed a lot more power from the engine. I'm told by a friend of mine (who owned an ML320) that my ML has firmer suspension than most. But today I was on the Freeway, doing 65mph up a long hill. When I powered up the hill and steered into the left hand bend the steering went super light and the car seemed to over steer (which scared the cr*p out out of me!).

Any ideas whats going wrong?

Many thanks.
Neo

Hi Neo,

With 15 years on your ML270, I would check out your PSR (Power Steering Rack).

With age, the internal valves in the PSR wear out, and the result is a lot of "slack" in the steering.

At times, the steering will feel super "light" and the steering will shift either left , or right, on its own..... very unnerving.

This may be what you are currently experiencing.


God Bless, Arctic

..........
ArcticDweller is offline  
post #3 of 14 (permalink) Old 06-20-2017, 12:06 AM Thread Starter
BenzWorld Member
 
Neo7's Avatar
 
Date registered: Mar 2015
Vehicle: 2002 ML270CDI
Location: Sydney Australia
Posts: 150
Mentioned: 0 Post(s)
Quoted: 27 Post(s)
(Thread Starter)
Thanks Arctic

I haven't noticed any slack manoeuvring at low speeds and the steering feels just a light at low or high speeds but how do I go about testing the PSR?
Neo7 is offline  
 
post #4 of 14 (permalink) Old 06-20-2017, 01:28 PM
BenzWorld Extremist
 
ArcticDweller's Avatar
 
Date registered: Jun 2008
Vehicle: '95 SL500, '99 ML320, '08 ML550 4MATIC w/Sport & Lighting Pkg, '12 ML350 4MATIC w/P2 Pkg & Pano Roof
Location: CANADA.... bbrrrrrrr!
Posts: 860
Mentioned: 3 Post(s)
Quoted: 95 Post(s)
Quote:
Originally Posted by Neo7 View Post
Thanks Arctic

I haven't noticed any slack manoeuvring at low speeds and the steering feels just a light at low or high speeds but how do I go about testing the PSR?

Hi Neo,


First thing to do is make sure the Front End is okay..... Tie Rods, Ball Joints, Wheel Bearings, etc.,..... no play anywhere.

To check the PSR, this article is a good place to start:

Diagnose Rack & Pinion Steering


Hope this is of help.

God Bless, Arctic

..........
ArcticDweller is offline  
post #5 of 14 (permalink) Old 06-20-2017, 04:50 PM Thread Starter
BenzWorld Member
 
Neo7's Avatar
 
Date registered: Mar 2015
Vehicle: 2002 ML270CDI
Location: Sydney Australia
Posts: 150
Mentioned: 0 Post(s)
Quoted: 27 Post(s)
(Thread Starter)
Thanks Arctic ;-)
Neo7 is offline  
post #6 of 14 (permalink) Old Yesterday, 12:58 AM Thread Starter
BenzWorld Member
 
Neo7's Avatar
 
Date registered: Mar 2015
Vehicle: 2002 ML270CDI
Location: Sydney Australia
Posts: 150
Mentioned: 0 Post(s)
Quoted: 27 Post(s)
(Thread Starter)
Ok, After inspecting what I thought was all the suspension and steering bushes today I was at loss what the problem could be. The PO had told me that I could always ask Mercedes to do a "Complementary Condition Assessment Inspection" so I called them and they now charge $250 for that. But I got chatting to the guy on the phone, got half way through my description and he interrupted me with "The Steering Rack Bushes are worn". So checked them out, with the wife rocking the wheel, and he was bang on!!!

So now my big question is .... Is it possible to change the bushed without unbolting the tie rods ends and hoses? In other words can I unbolt the 2 mounting bolts (and possibly steering shaft coupling) shift the rack out a bit and swap-out the bushes? .... Someone please give me some good news lol!


All the best.
Neo
Neo7 is offline  
post #7 of 14 (permalink) Old Yesterday, 03:22 AM
Lifetime Premium Member
 
mattml430's Avatar
 
Date registered: Sep 2008
Vehicle: 2000 ML55 , 2008 C200k Elegance 2006 C180k sports(sold)
Location: Melbourne Australia
Posts: 3,200
Mentioned: 3 Post(s)
Quoted: 496 Post(s)
Lifetime Premium Member
Would be easier to just disconnect it at the outer ball joints and steering knuckle spline. Make sure you mark exactly where that comes off. Also check where the spacers are aswell. Put them back they way they come out.
I had to replace my steering rack with similar systems to what you have. Try it first with the bushes and see what happens.


Sent from my iPhone using Tapatalk
mattml430 is online now  
post #8 of 14 (permalink) Old Yesterday, 02:21 PM
BenzWorld Elite
 
art_arev's Avatar
 
Date registered: May 2013
Vehicle: ML 500 2002 RHD, ML55 AMG 2003 RHD
Location: Harare, Zimbabwe
Posts: 3,443
Mentioned: 3 Post(s)
Quoted: 585 Post(s)
Send a message via Skype™ to art_arev
the rack has to come out to change the bushes. It is not possible to do it while the rack is still on the car but slightly pushed forward. So, remove inner + outer tie rods, then the rack & have the alignment done afterwards.
Was the rack & the bush moving or the rack is moving while the bush is not mobile?
I would tighten the bracket bolts first before removing the rack. They might be loose.

Art
art_arev is online now  
post #9 of 14 (permalink) Old Yesterday, 02:43 PM Thread Starter
BenzWorld Member
 
Neo7's Avatar
 
Date registered: Mar 2015
Vehicle: 2002 ML270CDI
Location: Sydney Australia
Posts: 150
Mentioned: 0 Post(s)
Quoted: 27 Post(s)
(Thread Starter)
Thanks Matt.

I'm thinking that with the steering knuckle disconnected and the front wheels off the ground (allowed to turning outwards in opposite directions) then there should be "Slack-around-the-Rack" lol! ....and I might be able to move it forward enough and to knock the bushes out.
But the things I don't know is ...
  • Once the mounting bolts and steering knuckle are disconnected how hard will it be move the rack forward (with the hoses still connected too)?
  • Will there be enough room to get the bushes out?
  • How hard will it be to remove the old rubber bushes?
  • Do the new bushes need to be bench pressed into the rack or would a G-Clamp do the trick?
All the best.
Neo
Neo7 is offline  
post #10 of 14 (permalink) Old Yesterday, 02:51 PM Thread Starter
BenzWorld Member
 
Neo7's Avatar
 
Date registered: Mar 2015
Vehicle: 2002 ML270CDI
Location: Sydney Australia
Posts: 150
Mentioned: 0 Post(s)
Quoted: 27 Post(s)
(Thread Starter)
Hi Art,

Just seen your reply... thanks.

Yes the rack is moving from side-to-side a few mm as the steering is rocked. ... I will recheck the bolts today thanks.

All the best.
Neo
Neo7 is offline  
Sponsored Links
Advertisement
 
Reply

  Mercedes-Benz Forum > Mercedes-Benz Vans/Trucks/SUV/Others > W163 M-Class

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Mercedes-Benz Forum forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:
OR

Log-in









Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.




Currently Active Users Viewing This Thread: 2 (1 members and 1 guests)
jac9f
Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode



Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

 

Title goes here

close
video goes here
description goes here. Read Full Story
For the best viewing experience please update your browser to Google Chrome