My 1990 500SL has been sitting all winter, and I just tendered it and got it ready for the Spring. Upon starting it up, I noticed the steering wheel is nearly impossible to turn, and there is a groaning noise anytime I move the wheel.

My indy friend told me that it might just need a power steering pump hose, as this is common to leak on these cars. I noticed a very small leak on the garage floor which was not oil (as it was not the same shimmery consistency) and thought that was logical. He told me I should put some power steering fluid in and check to see if the noise dissipates, to help determine if it might be the pump instead.

The issue is that when I took the power steering fluid reservoir cap off, and checked the level, I had no guide to determine how much it should be filled. This 1990 seems to be lacking in the min/max fill line department in many of the reservoirs, and being as I am not a huge handy man, I am worried about over-filling.

I took a picture of the reservoir when the car was cold, and noticed it is completely below the yellow plastic guide which is in the reservoir. Photos online of people doing flushes seemed to show the fluid up to where the triangles peak on the bottom of the yellow plastic guide. I have attached an image.

Is this power steering fluid reservoir considered low? What is the correct cold level?


I might add, that even the original owners manual has no information on power steering other than to visit the mercedes workshop. There is no information about approved fluids, or even where the reservoir is located under the hood! They really didn't want people working on their 85k cars!

Having said all of this, I found Febi Bilstein (MBZ Approval: 236.3) Power Steering Fluid online (Part #: Q-1-46-0001-M36) and I am wondering if this will be sufficient for the fluid.

So two things:
1) Where should the level be when the car is cold? Is my level low?
2) Which fluid do you recommend for my 1990 500SL? Is the Febi Bilstein an okay recommendation?


Thanks in advance! I would appreciate some guidance as I'd like to get 'Kip' up and running for the 2019 summer.

 

Then it's likely the power steering pump- correct?

 

First of all, your image can't be seen. Use uploading attachments tool.

Secondly, yes it could very well be your ps pump.

 

I used the image uploading tool- I can see it in the post as well. But I will re-upload it:


I still haven't gotten a clear answer on where the level should be..

 

No one can answer these simple questions- really?

 

Your level should be no higher than where it is now, about the where spring belt is just under the yellow sleeve. As to ps fluid,, if you want to be sure, any Mercedes service or parts department should tell you if you call. Bilstein fluids should be fine.

 

I appreciate the response- I figured it was the pump and not the fluid- but I didn't want to overfill it, and my indy said to test adding fluid (to see if it was a leak out of the hose) before replacing the pump. I think I'll just go ahead and have the pump done $$. Hopefully it isn't an arm and a leg.