P/S Maintenance
 

i am going to change the filter and flush the fluid in my p/s system this weekend, are there any caveats i should know about, or is this pretty straight forward? i read the DIY written by Herbert Rocha, any other tips?

The technique all-in all sounds pretty much ok. There's mention at the site about "clips", etc. inside the p/s unit.

On mine, you unscrew a large black plastic knob, remove, then the metal lid comes off. I then use a deep socket 10mm to remove a 10mm nut on top. With this off, a plastic piece and spring come off a rod. The filter can be removed using needle nose pliers. The fluid level indication marks are on the plastic piece.

Do be sure to remove the return hose and not the high pressure hose. I had to take the latter off once - it was leaking and had a heck of a time getting it reconnected. Didn't want to catch.

thanks for the reply, i would bet that my system is the same as yours since we both have 300SELs.

I read through the technique and I believe it is missing a few steps. During the flush procedure the helper should turn the wheel from lock to lock to flush all the fluid. At least this is true for rack systems -- I'm not sure if it's necessary for the worm screw type. If you turn the wheel from lock to lock, it is best done with the wheels off the ground to reduce the pressure of the fluid coming out.

I have always done it the less messy way... I always suck the p/s fluid out with a turkey baster...then change the filter..

I buy true power steering fluid...valvoline.... it is clear.... I add it back in.. then each week for the next 3 or 4 weeks i repeat the sucking procedure and add new. After about the 4th time, you have a clean system...and you can monitor the system by the "clearness" of the fluid. This takes next to no time.

I usually buy two quarts of fluid.

I tend to do the same with brake fluid in between pad changes... at a pad change, I bleed it down pretty good... brake fluid seems to stay pristine.

No mess, no fuss.

Of course I suck the oil out to change it, rather than draining it.

Tranny fluid, I do the traditional and very messy way... drain the converter and tranny, then drop the pan (the messy part-- and change the filter)

just my .02

Lots of thoughts on how to do this. I too like the simple turkey baster approach. I do it at every oil change.

However, the regular turkey baster you buy at the grocery store won't live long. They were not designed to work with chemicals. I've been through I don't know how many.

If this is the approach you want to take, go to Auto Zone or other mass-marketer auto parts store and buy a battery acid filler.

Here's a photo of one. You may have to click on the "expand photo" section.

I bought one of these a good while back and it's holding up much better than a turkey baster.

http://www.napaonline.com/cgi-bin/ncommerce3/ExecMacro/NAPAonline/search_results_product_detail.d2w/report?prrfnbr=15616585&prmenbr=5806&usrcommgrpid=

i thought turning the wheels might help flush the system, however i figured the pressure from the pump at idle would be sufficient?.?.

i like the idea of cleanliness, but i would like to get this done in one shot and not have to revisit it every weekend. how do you think the MB fluid stacks up against the valvoline? i already ordered the MB fluid...

Anything is better than Dexron, which is loaded with additives that aren't necessarily needed for power steering systems, and may even be too hard on the power steering system seals of older cars.

For the price ($8), I'm curious if the MB fluid is synthetic. The bottle doesn't indicate that it is synthetic.

At least on rack steering systems, you have top turn the wheel from lock to lock or you miss the fluid in the dead spots. I'm told this technique is actually covered in schooling for auto mechanics. Pump pressure at idle is more than enough to pump the fluid. That's why I suggest lifting the front wheels off the ground, to keep the pressure managable during this procedure.

[QUOTE=Kestas]Anything is better than Dexron

In some cases yes, but not all. Many Asian cars come from the factory with Dexron in their PS units and their associated shop manuals call for it as well.

I looked above and saw no ref to Dexron anywhere. Maybe I missed it. There was a ref. to Valvoline PS fluid.

I recall reading posts by Larry Bible on this subject. He merely uses regular PS fluid purchased from McParts; not the special MB PS fluid.

I use the MB fluid which is actually made by Febi. Comes in a dark blue bottle. Forget the part number.

I read a post on either this site or another some years ago that claimed the special MB PS fluid was made for MBs with serpentine belts. Traditional PS fluid could be used in the V-8s.

Who knows? These types of discussions end up being like the oil and coolant talks.

Don't put Dexron in any power steering system.... years ago, I think people did that...bought a 69 cent quart of p/s fluid and put it in..

people (including me with a 72 280se) wondered why seals and hoses would start weeping.

with experience and mistakes hopefully brings wisdom..

I haven't wised up to synthetics just yet however....

[QUOTE=lee polowczuk]Don't put Dexron in any power steering system.... years ago, I think people did that...bought a 69 cent quart of p/s fluid and put it in..

I realize this is an MB board and that Dexron is not the way to go, but to say "don't put it in any ps system" is wrong. As I just said above, many Asian cars come with it from the factory and use it in the maintenance process.

I don't think that is a sound method re: brake fluid, unless it is just to do it between bleeding all the fluid every 2-3 years (which sounds like it may be the case depending on quick you go through brake pads). you are changing the fluid in the m/c but you will never change the fluid in the calipers that takes the most heat and tends to be the dirtiest.

Few suggestions to Herbert's steps:

. Jack up the front or put it on stands for same reason as others suggested.
. Attach/connect a barb (3/4" I think) and a clear tube to the return hose & direct it to the waste containter - when clear fluid starts flowing out, you'd know it (changing in color)
. Turn steering wheel from lock to lock to disposed old fluid till no more coming out (without engine running of course) before putting in new fluid - you don't want to mix them up.
. Remove the EFI Main relay/fuse - you don't want the engine running as the fluid pumping out would be too fast (to adaquately refill the reservoir); but just cranking it instead.
. After reconnecting everything up - turn the wheel lock to lock to bleed all the air & refill if needed.

Frank.

re: brake fluid

I do the turkey baster method in between pad changes. I think brake fluid is an overlooked fluid change.