Power Steering Fluid
 

I am the second owner of an '88 560SL, which is in excellent condition and I've not been required to do much self-help work. Recently, however, I'm getting that moaning sound traditionally characteristic of low power steering fluid. I checked and sure enough, it needs some. Problem is the manual only specifies MB power steering fluid; it does not go into the usual "SAE approval", etc. Unfortunately, the nearest Mercedes dealer is 25 miles away and I'm afraid they might not have the right MB fluid anyway. I've been working on cars for many years and have found that using the manufacturer's fluids—which they want one to do for obvious reasons—is usually not required. Further, local auto parts stores have a plethora of power steering fluids and I'd rather go with one of them if there's no down side to doing so.

Can anybody help? Is there an off-the-shelf national brand that can be used in this car? Does anyone know the proper class/spec for the fluid in question?

I have been using bottles of fluid labled "Power Steering Fluid" which can be found at any auto parts store without any ill effects. My car is only 6 years older than yours, and specifies ATF, though new ATF has come a long way since 1982 and has caused leaks in some cars of my vintage that specify ATF. Usually when MB specifies to use their fluid only, such as SLS fluid or coolant, they've got a pretty good reason, so I'd follow their spec this time. If 25 mi is too far to drive, I'm sure Phil can take an order for you and ship it to your front door.
Order here:http://catalog.peachparts.com/
Power Steering Fluid is part number 000-989-88-33.

Benzoboy, thanks for the information. Based on your input as well as the results of some additional research, I bit the bullet today and made the drive to the Mercedes dealer. The parts lady confirmed what you'd said, citing the fact that one could use Dextron ATF in older MBs ( a good friend has a '78 450SL and he does this), but that a newer one such as mine (19 years old is newer?) needed the special MB fluid. I put it in and, Presto! problem solved.

I had an independent Mercedes-Benz mechanic do this service only to fine out he used ATF transmission fluid. I checked with Mercedes-Benz sources and was informed that it would be OK, but that they recommened factory Fluid for the system. I had a good friend of mine help me purge the ATF fluid completelyby disconnecting the return line hose and using a small bucket to catch fluid from the system while pooring in Mercedes-Benz power steering fluid until it ran clear. Then put a new filter in and toped off to the correct line.
I am much more satified nowing if that this service was done properly even though I do not drive the car much and it has low milage under 40,000 miles.
I beleive following recommended service will help protect the mechnical parts of this car.
Strangely I do not see any recommendations for changing Power steering fluid in the Mercedes-Benz service guide for my car 1992 300-E.
Bob Geco

The mechanic that replaced my steering box seal said he looked in "the manual" and it said to use "Dexron", so thats what he used. I have NO IDEA what "manual" he was referring to, but I am pretty sure that the owners manual does not state that. :confused:

A search will turn up several threads on this subject. It has been brought out that the Dexron of today is a lot different than the old formula, and it's being changed again right now as it evolves into a new form of Dexron V.

What I took away from my reading is that some have continued to use the Dexron without a problem while others have experienced failure of the seals. It was pretty much agreed that the Dexron is a gamble at best but the Power Steering fluid should be a sure thing that can be used worry free.

I flushed my system six months ago with STP Power Steering fluid. So far, so good.