What's the Best Power Steering Fluid? - PeachParts Mercedes-Benz Forum

Tom Evans · #1 10-10-2010, 08:46 PM

I've got to replace a leaking Power Steering Pressure Hose on my 1982 300SD. I figure this is a good time to change the filter and flush out the old fluid. I do have a slight fluid seepage around the seals

I heard that Dexron III ATF is not the best fluid to use. What is the forum's current thinking: Type F ATF, or some specific brand PS fluid?

I also have a bottle of AT-205 made by ATP, Inc. I have used it with great success on seal leaks on automatic transmissions. Has anybody used it for a PS seal leak?

vstech · #2 10-10-2010, 09:31 PM

I use valvoline powersteering fluid.

kinghais · #3 10-10-2010, 10:58 PM

If the steering gets hard Is that mean the oil fluid needs to b changed???

Jeremy5848 · #4 10-10-2010, 11:21 PM

Quote:

Originally Posted by kinghais

If the steering gets hard Is that mean the oil fluid needs to b changed???

Try that first. It could also mean that the seals are worn out and the pump needs replacement.

kinghais · #5 10-11-2010, 12:23 AM

How do I flush it???
I didn't c any in DIY

bustedbenz · #6 10-11-2010, 01:17 AM

Just about every auto parts store I've ever been in sells a few different cheap brands (as well as an expensive synthetic) of a product simply labeled "Power Steering Fluid." I've always used this and not worried too much about it. Not much on synthetic fluids myself so I buy the generic PS fluid and don't worry much about it.

@kinghais: The first thing to check is quite simply the fluid LEVEL. It does leak from time to time, and topping it off in the reservoir may solve your problem. It's not critical how full the reservoir is; obviously the filter needs to be covered. I usually fill to about 1.5 inches down from the top rim. There's a faintly etched line in some of them that's barely visible in others. Doesn't matter as long as a) the pump isn't dry and b) the return fluid doesn't overflow the canister and pump out through the lid or something horrific. (Never overfilled one but I imagine that's what would happen.)

MBeige · #7 10-11-2010, 01:27 AM

Quote:

Originally Posted by kinghais

How do I flush it???
I didn't c any in DIY

The gear box itself has a drain plug.

We just performed P/S service today with my mechanic (among other things). Drained gear box via small screw beside pitman arm (seen from below). While front wheels were jacked up off the ground, with key in position 1, turn steering wheel left and right until the fluid drains completely from the gearbox.

The reservoir will also empty. That gives you access to the filter, replace it and reinstall drain plug on gear box. Fill up reservoir with ATF.

My mechanic recommended Chevron MD3 ATF also for transmission service done today. Again turn wheel left and right to fill up the gear box with ATF. Then fluid level in reservoir will eventually stop going down, and top it off.

P/S hose is easy once fluid is out. Low pressure side is cut to fit, high pressure side is crimped on both ends.

jbach36 · #8 10-11-2010, 03:05 AM

I think the stuff I'm using is Valvoline. It has stuff in it to stop leaks, and the stuff really works. I heard if you get the stuff that simply puffs the seals up, that's really bad because it's a temporary fix, and one day, it fails and leaves you in a bad situation.

The stuff I have sort of rejuvenates the rubber, as opposed to just puffing it up.

ashedd · #9 10-11-2010, 03:36 AM

I have used any old ATF I had laying around since about 1990. At the end of the day it's all hydraulic fluid..

Some will disagree.

pawoSD · #10 10-11-2010, 07:35 AM

Quote:

Originally Posted by ashedd

I have used any old ATF I had laying around since about 1990. At the end of the day it's all hydraulic fluid..

Some will disagree.

That is a good way to make the seals leak.

P/S fluid of any type (non-synthetic tends to work better to prevent leaking) is what should be used.

-=DeanstuD=- · #11 10-11-2010, 08:10 AM

In the owners manual for my sdl, it says to use transmission fluid.

francotirador · #12 10-11-2010, 08:23 AM

Quote:

Originally Posted by Tom Evans

I've got to replace a leaking Power Steering Pressure Hose on my 1982 300SD. I figure this is a good time to change the filter and flush out the old fluid. I do have a slight fluid seepage around the seals

I heard that Dexron III ATF is not the best fluid to use. What is the forum's current thinking: Type F ATF, or some specific brand PS fluid?

I also have a bottle of AT-205 made by ATP, Inc. I have used it with great success on seal leaks on automatic transmissions. Has anybody used it for a PS seal leak?

How about MB p/s fuid? I'm surprised this is even an issue because the quantity needed and the cost are both negligible. I just paid $6.50 a quart at my local dealership. That's with my little discount, but even so, it's just $8.50 a quart list.