My '97 E420 is dripping a small amount of power steering fluid from the area just above the steering rack where it looks like the lines to and from the power steering reservoir come into. Is this the actual power steering pump, or is the pump right where the filler cap is located on top of the engine?

The area where it is leaking has two round pieces right next to each other with reverse torx bolts to remove two caps.

Thanks for any help you can provide.

Well I bought some Lucas Power Steering leak stopper and dumped some in the reservoir. Hopefully that will take care of the leak. I still don't understand where the power steering pump is as compared with the steering box. I think what I am seeing leak is the steering box which is just below the area where the steering column attaches to.

If yours is anything like my E300D W210, the pump and reservoir are one piece, attached to the engine. There should also be a quite noticable pully there, driven by the accessory belt.

The power steering fluid lines attach to the control valve on the rack. This valve sounds like where you see the leak. I haven't taken the lines off of mine, but they appear to be attached with banjo bolts (those large bolts that you mention). I'd check those fittings for leaks first.

If it is leaking at one of those fittings, the stop-leak probably won't have any effect.

Thanks Matt. Yes you are correct. The leak is around one of the reverse torx bolts with the large washer like surround. How would I go about fixing a leak from around those bolts?

remove both reverse torx fitings and you will see each has an o-ring that you may want to replace. very common leak on the 210s

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Paul Roberts
Mercedes Centrum Inc.
Bellevue,WA.

SOunds like an easy fix. Does anyone know how to describe these O-rings so I can pick up the parts from the dealer?

Sorry, I don't know the size of the bolt heads. You should get the seals from the dealer only (or from Phil).

Let me add that when I changed the return hose, I did somehow get air into the rack. You do not want to drive the car with air in the rack, as the steering damping effect is nearly eliminated. It is no fun.

To purge the air, the first thing to do after buttoning things up is to jack up the front end and turn the steering lock-to-lock with the engine off. You may want to do this after running the engine and turning the steering if you don't get all the air out. You *will* know immediately once you hit the highway if there is any air in your rack.

I've done tons of those O-ring repairs at the dealership, as it is a very common problem.

Not fun to get the bolts lined up going back in, but take your time and you should be fine, but you should run the car and turn the wheel stop to stop and keep checking your fluid until you get it topped off right.

Sometimes it takes quite a few miles to get all the air out of the system, but get the level good with no foam first in your driveway.

Some vehicles require that you drop the rack down for clearance to get the bolts out to replace those O-rings, and I can't remember if your 420 has enough clearance to do it.

I would get the O-rings from the dealership since they are familiar with the problem.

What size torx socket is needed? Is is E20 or something even larger?

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2008 S550
2010 GLK350
1997 E420 (retired)
2005 CLK500 (retired)

Thank you fo the write ups. It was very helpful.

I fixed my daughter's 1997 E320 last Sunday. I had already bought the power steering oil the day before from the MB dealer when it was open. I verified that the problem was a failed O ring at the steering column on Sunday.

I was determined to fix the problem on that Sunday as my daughter needed the car on Monday. Dealer was closed on Sunday for parts. I went to the local Auto Parts store, but no luck. I went to Lowes and was able to find the O rings very close or even exact to the size I needed.

You need 4 O rings total to change all of them while you are at it. They were very cheap at Lowes. about $1.20 for all four. Two in each package.

Look in the plumbing department area and look for the brand Brass Craft with part number 0542. O ring size that I bought is 1-1/4" I.D. (1-7/16" O.D.) x 3/32" wall.

You need an E14 external torx socket for the job.

There is usually a lot of crud and oily mud in there. Make sure you clean everything up before you reinstall for a tight fit and to make sure it will not leak.

Be patient as this DYI needs some finess and make sure you change all 4 O rings.

I'm aware this post is over 5 years old but its worth a shot. The EPC list 4 o-rings that are associated with the steering knuckle. I assume 2 for each side? The leak, I think, is coming from the driver's side because I've already replaced the shaft seal in pump. What are the tightening torque values? Yours or anyone else's valuable response is greatly appreciated.