95 e300d steering box leak - PeachParts Mercedes-Benz Forum

connerm · #1 02-01-2009, 02:08 PM

I've had a few leaks on the garage floor in the past month or so. After removing the sound panels, I discovered a drop of steering fluid on the hex cap bolt on the steering box and one drop on each end of the steering stabilizer shock. I doubt the shock is leaking. The pic isn't great but it shows the steering box is wet. I took the pic from underneath. The drops on the garage eventually dry up and get sticky, but the stain remains. How to fix the leak?

sixto · #2 02-01-2009, 02:59 PM

Clean the steering box well then watch carefully for the source of the leak. Pay particular attention to the hose connections into the box, the adjustment screw atop the box and the input shaft from the steering column. There's also the plug for the steering lock at the bottom of the box. I thought mine was leaking from the pitman arm shaft seal, and very likely it was, but it was also leaking from the lower pitman arm shaft lower bearing carrier.

http://www.peachparts.com/shopforum/showthread.php?t=239322

Since that fix, my steering box is leaking from the steering box adjustment screw. I guess the seal didn't like supporting the full weight of the pitman arm shaft. I hope I can fix the leak without removing the steering box.

Looking at your first picture, I see seepage from the joint between the main steering box case and the pitman arm shaft lower bearing carrier. That's all I see though so it could be coming from somewhere else. But it looks just like mine did :/

The experts say you shouldn't separate the pitman arm from this type of steering box since it's a precision fit. MB doesn't sell separately a pitman arm for the 124. The FSM procedure for working on the steering box calls for precise measurement of the gap between the steering box and the pitman arm along the pitman arm shaft so the pitman arm can go back exactly the same way. I don't get it since the rest of the steering linkage can't be built to exacting tolerances for what they cost. Point is, the FSM shows you how to remove and install the pitman arm so you can get to the seals.

And make sure it's not windshield washer fluid dribbling from the reservoir if the reservoir sits over the steering box. The ACC auxiliary pump might be in that area as well.

Sixto
87 300D

connerm · #3 02-01-2009, 04:53 PM

Nothing is wet above the hex cap bolts just above the pitman arm. The fluid is to thick and black to be washer fluid. If the shaft and pitman arm have splines, why can't it be marked and put back exactly where it was?

What are next steps?

sixto · #4 02-06-2009, 08:42 PM

Quote:

Originally Posted by sixto

Since that fix, my steering box is leaking from the steering box adjustment screw. I guess the seal didn't like supporting the full weight of the pitman arm shaft. I hope I can fix the leak without removing the steering box.

For the record, I took a closer look and it's windshield washer dribbling down on the steering box. The steering box is tight

Sixto
87 300D

JimmyL · #5 02-06-2009, 11:21 PM

Quote:

Originally Posted by sixto

For the record, I took a closer look and it's windshield washer dribbling down on the steering box. The steering box is tight

Sixto
87 300D

sixto · #6 02-01-2009, 09:27 PM

It's not the clocking that's the issue rather the space between the bottom of the steering box and the top of the pitman arm. The FSM says to measure that gap and replace the pitman arm to the same position along the pitman arm shaft. The gap in my car was 17.6mm. I don't know if I'll ever forget that number

Of course clocking between pitman and and shaft is important too. In my case the etched mark in the pitman arm shaft was centered in the gap in the pitman arm.

Next step? Buy a pitman arm shaft seal and replace it. That's about all the FSM says to do. Measure the gap between the steering box and pitman arm, remove the safey circlip below the pitman arm, remove the tangential clamping bolt holding the pitman arm to the pitman arm shaft, remove the pitman arm (I used a common pitman arm puller), remove the seal (pry it out with a sharp object being careful to not nick the pitman arm shaft), installation is the reverse of removal. Well, not quite. You'll want to clean the pitman arm shaft with very fine abrasive. I covered the splines with plastic wrap to protect the new seal on the way up. The FSM calls for sealant or thread locking compound on the splines, I forget which. Tap the pitman arm back to the specified gap.

Do you have a copy of the FSM?

Sixto
87 300D

connerm · #7 02-02-2009, 06:12 AM

Sixto, How did you measure the gap? I was thinking that stack of feeler guages might work. I have the repair and maint. CDs, but not the FSM. Do you know where I can get one?

connerm · #8 02-02-2009, 06:22 AM

Sixto,

You said, "Since that fix, my steering box is leaking from the steering box adjustment screw. I guess the seal didn't like supporting the full weight of the pitman arm shaft."

Would you elaborate on that a little more please?

sixto · #9 02-02-2009, 05:48 PM

[QUOTE=connerm;2097866]Sixto, How did you measure the gap? I was thinking that stack of feeler guages might work.

I used a Vernier caliper. See the attached image.

Quote:

Originally Posted by connerm

I have the repair and maint. CDs, but not the FSM. Do you know where I can get one?

What repair CD do you have if not the FSM? Phil can get you the FSM on CD through the Buy Parts link above. It's a collection of such poor quality scans that you'll wonder if it's worth the CDs it comes on. It's in section 46-3265.

Quote:

Originally Posted by connerm

You said, "Since that fix, my steering box is leaking from the steering box adjustment screw. I guess the seal didn't like supporting the full weight of the pitman arm shaft."

Would you elaborate on that a little more please?

Anyone who's asked me to elaborate has regretted those words. daw_two is my latest victim

I removed the 4 bolts around the pitman arm shaft seal to get to leaky o-rings. The pitman arm shaft lower bearing carrier held by the bolts supports the weight of the pitman arm shaft. My guess as to why it sprung a new leak is the adjustment screw seal didn't like suspending the pitman arm shaft. This won't be a problem if you don't remove the lower bearing carrier.

And it's Loktite 270 (red stuff) that goes between the pitman arm and splines on reassembly.

Sixto
87 300D

connerm · #10 02-04-2009, 03:55 PM

Sixto,
Is it any easier to remove the entire box and fix it on the bench? I rebuilt the pump a year ago.

sixto · #11 02-04-2009, 11:29 PM

Not for me. That thing weighs a ton. Not something I want to be lying under as I guide it back onto the steering column. Replacing the seal with fluid dripping on your face isn't fun but better fluid than a steering box on my face. Might be a different matter with have an extra pair of hands helping you from above. And you'll really have fluid flowing when you release the pressure and release hoses. Then you have to bleed the system...

I'm pretty sure you need a steering box locking tool if you're going to remove the steering box. You can make one by sharpening the tip of a ~40mm long M8 x 1.5 bolt.

Sixto
87 300D

gsxr · #12 02-05-2009, 10:33 AM

The steering box is a lot easier to remove than it looks like... pop the joints out of the Pitman arm, loosen the square shaft connector, remove the 3 bolts, and it should come right out. I'd much rather do this work on the bench. Removal also lets you fully drain the box of fluid, so when you re-fill the system you will have ~95% new fluid (assuming you also drained the reservoir, and replaced the low-pressure hose, which I'd also recommend... along with ONLY using the OE gold-colored fluid, not red ATF.)

Anyway, Sixto, the late-style box (as of 02/1990) does not have provision for the locking tool... there are external marks for centering instead. Also, the input shaft seal is about a million times harder to change as of 10/1987... you need to fully disassemble the steering box on those boxes! Click here to read the gory details. Note that there is 1 page for the early type, and 12 pages for the late type - ouch.

Click here for the Pitman arm seal replacement procedure from the FSM. It seems this is the same on all versions of the boxes.

connerm · #13 02-05-2009, 01:16 PM

I think I may just bite the bullet and buy a remanufactured unit. This is my daily driver and I don't have time for the rebuild.

gsxr · #14 02-05-2009, 01:29 PM

You may faint when you see the price of a rebuilt box. New, the box is $2300 MSRP. A dealer rebuilt is $1400 MSRP, or $1100 wholesale, with a $450 core charge. Aftermarket rebuilds appear to be about $450 with a $200-$450 core, depending on the vendor.

I would consider a good used unit instead, if you don't want to re-seal it. They're under $100. Or, see how much a local MB indy shop would charge to replace the seal. A few years ago my BIL had his steering box re-sealed at the dealership, it was under $500 (about 4 hours labor plus parts & fluid).