Steering getting stiffer

[Zantus]

Are there any known steering problems on the ML?

My 3.2DiD's steering has been getting a bit stiffer lately. I had the wheel alignment checked and checked the tyre pressures, but it still feels stiffer than it should be.

Before I take it to the agents, I'd like to find the problem myself.

[Jitsukablue]

Yes, the early models, '07/'08 had power steering pump problems. I had mine replaced early on.

Then there is the infamous "characteristic" where the power steering is reduced above 2000 rpm, which is a great idea if you want to go in a straight line. It's a bit like turning the tap down a bit because you want to save water, but still try and fill the same container... not sure what they were thinking.

My steering is actually quite a bit lighter since I went to a taller narrower tyre, so did you change to fatter tyres?

[Zantus]

The change in powersteering had nothing to do with changing tyres, I changed those about 4 months ago.

It's exactly as you say, above 2000rpm, usually at speed the power steering is reduced. Mine was built in October 2008 here in South Africa, which means the pumps come from the same source as the Thailand plant. The vehicle has 22 000km on the clock.

[Homer]

Hey Zantus, mine is sept '08 build and has the updated power steering pump, but it is a Thailand model so don't know if or when SA changed them over.

They still have the progressive power steering in the new pump, but by all accounts not as noticeable in the new one - unless you are taking evasive action, then the steering locks in your hand .
Have a go at driving in 1st gear with your engine revs at about 2500rpm and swerve your steering quickly from left to right and back.
I believe they had a hotfix for a replacement pump if it does the same thing at 1800rpm from memory. Worth checking out.