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?

Anyone?

Seals for the power steering hoses where they attach to the steering gear.

Thanks! Is there anything special I need to do after I refill the reservoir after the repair? Any sort of deairing/purging procedure?

Never done it on mine yet, but I'm seeping fluid from flexible return hose, so that will happen soon enough.

Here's what I plan to do:

1: Drain fluid from the reservoir by removing the leaky hose and aiming it into a container. Reattach new hose.

2: Replace the filter. We're lucky to have one. Most cars do not.

3: Refill the reservoir with fluid. I'll get mine from the dealer. I'm sure that you can get the proper fluid elsewhere, if desired.

4: Start the engine and listen for any noise from the pump. With the reservoir full, it shouldn't run dry for very long, if at all.

4a: See below.

5: Check the fluid level. If it appears to be at a safe level, drive the car for a few miles to heat up the fluid. Then fill to the mark.

Since you will be removing the pressure hose from the rack, you need an additional step at 4a. After starting the engine and running a minute or two, turn the steering to full lock (but don't force it - you don't need to make the belt slip) on each side several times. This is to purge any air from the rack.

Turning the steering lock-to-lock is probably not essential in your case, since the rack really shouldn't get that much air in it, if you let the pump circulate fluid for long enough to purge the control valve before turning the steering wheel. But just in case, I'd take the extra couple of minutes. It's clearly not helpful in my situation.

Thanks Matt, that was very helpful. Good luck with your repair too.

My 96 e300d has developed a steering fluid leak. I'm planning on replacing the seals behind the reverse torx bolts. Does anyone know what size socket is needed?

I may have this problem. Do I need to go to the dealer to find these o-rings. Wouldn't a hardware store have what I need?

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

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.