First off, thanks for the responses. To say that I'm in over my head is an understatement so any/all help is greatly appreciated.

Okay, so let me try to break it down and give you all a play by play. Warning, this will most likely be a long breakdown.

I had been driving the car for about a month and a half with what I was told was a minor leak in the front seal of the power steering pump. Eventually it started making a noise when I would turn the steering wheel while I was driving. The sound wasn't too loud or crazy sounding yet loud enough for me to know that I needed to do something about it soon or I should stop driving it until I could address it, which is what I did. I stopped driving it until I had an upcoming free weekend to work on it. I had been reading and watching a bunch of articles and videos about resealing it and felt I would give it a shot. I bought, what I thought was a power steering pump reseal kit from **************.com (more on this later) and I also bought an upgrade kit to flush out the old ATF fluid and switch to enhanced power steering fluid.

That free weekend arrived and I drove it to a friend's house so we could take out the power steering pump and reseal it. I should also mention that neither of us have much experience with cars in general let alone these specific cars. We have both done some minor tinkering on cars over the years but nothing too major. Anyway, we remove the power steering pump and I start to take it apart. I was worried about removing the pulley since I'd heard many horror stories about it but it came off super easy. Here's the part where I totally blow it and make a beyond rookie mistake of epic proportions... It turns out I did not buy a PUMP reseal kit, but a power steering BOX kit instead. The worst part is I don't realize this until way after the fact even though in the course of my "fixing" my pump there were plenty of red flags. Anyway, I take the whole thing apart and I can't find the right size o-ring for the back of the pump. I was annoyed but I decided it wasn't a big deal since the old one still looked fine and it was not leaking. I then realize the kit also doesn't include that little brass washer but again, not a big deal since the original is fine. Not sure if any of you are familiar with the power steering box kit from ************** but it has everything you need to reseal all the different types of w123 and 126 steering boxes from 1977-1985. So basically it comes with a ton of stuff. Still, although I'm confused as to why it doesn't have two of the things I need, I am convinced I have the right kit because it says "For all 123 chassis from 1977 to 1985" on it but somehow spacing on the fact that it says BOX on it and not PUMP. Deep inside I knew something was fishy but then I find a seal that looks like the front seal that I need so badly. For those who know there way around the steering box, you probably already know that in this kit for the box there is a seal that looks very close in size and style to the front seal in a power steering pump. I end up putting this incorrect seal into my pump and putting the whole thing back together and back into the car. At this point I elevate the front of the car so when the time comes, my friend can freely turn the steering wheel left and right so we can bleed out all the remaining ATF from the system in order to replace it with power steering fluid. So now the front end of the car is elevated and I start pouring in the fluid and immediately I notice it's leaking out of the front seal. I'm totally confused as to why the new seal isn't working, it seamed to fit in easily when I was installing it. After giving it some thought, I realize it popped in a little too easily. Which leads me to believe that it probably wasn't as snug as it should've been. At this point it's obvious that I need to order the correct seal and reattempt the whole thing at a later date when I get the parts in. But... here's where I get really, really stupid. I decided that since the car was already elevated and I already had my gallon water jug connected to the hose in order to drain all of the ATF, I should just keep pouring in the power steering fluid while I instructed my friend to turn the steering wheel back and forth in order to flush the system. Yes, although the pump was leaking, I figured I could keep refilling it while he turned the wheel so I could at least get all the ATF out, that way when the pump was fixed in a few days I could just reseal it, reinstall it, fill it up and be done. Okay, so as stupid as this idea was, it seemed to work. I was keeping the pump filled while he kept turning the steering wheel while all the ATF flushed out of the system. Once all the ATF drained out we lowered the car and we let all the fluid leak out of the seal and we were done for the night. The plan was to park it, order the correct seals and then repeat the process in a few days when the parts arrived. Defeated, we left for a few hours to grab dinner. When we returned I knew I couldn't drive the car but I did need to move it a few feet to park it on the street. I started the car and it started up fine, I put it in reverse and that's when I realized that the steering wheel wouldn't turn left or right at all. It wasn't the normal tougher to turn feeling when you are low on power steering fluid, it seemed locked. Granted, I was too scared to try to force it but it didn't seem to be budging. So we turned off the car, put it in neutral and pushed it straight ahead into my friend's garage. It wasn't until I got home later that I realized that not only did I not have the right pump kit, I didn't have a pump kit at all but instead the kit for the steering box. Unbelievable that I missed that.

So now that I've told you all my embarrassing story, what is my next step? Is my steering box completely shot? Although I did drive it when it was low on fluid, I didn't necessarily drive it with zero fluid. Is it possible that I'll be able to turn the wheel again after resealing the pump correctly and filling the pump with fluid or am I screwed? Also, what steps should I take? Should I do it all in this order?

1. Reseal and reinstall the pump
2. Elevate the car
3. Fill the pump with fluid
4. Then start the car
5. Then try to turn the wheel while the car is still elevated

Anyway, thanks again for offering up any advice/suggestions.

Lifting the front wheels is preferable from an ease of turning the steering wheel / keeping hydraulic pressures low to reduce fluid aeration. It has nothing to do with preventing metal from deforming.

Depending on the pump type, it could suffer some damage due to being run out of fluid in the long term. In the short term, it might develop a buzz.

The steering box won't suffer any ill effects from being low on fluid unless lots of metal / dirt goes through the steering gear. If that happens, you will still be able to steer the car, this is part of a fail safe system.

Our guy likely never experienced a car that has lost power assist and thinks the steering is locked solid.


I have 40 + years in and around the auto repair business coupled with 20 + in industrial machinery repair. This includes hydraulic , pneumatic , electronic ( sometimes down to diagnosing / changing components on circuit boards ) , CNC , robotics, the list goes on. I've also repaired man lifts , ride on rollers , backhoes and countless other pieces of machinery.

The last job prior to retirement was Engineer.

I look at systems from an engineering standpoint and have an intimate understanding of how things work. I frequently take apart failed devices to see what actually failed. ( Example, electric fuel pumps ) Knowing exactly why a part failed helps diagnosis.

The steering gear return hose dumps fluid into the pump reservoir where it has a chance to deaerate. The suction side of the pump is immersed very near the reservoir's bottom. The reservoir is has an air space at the top and is usually vented to atmosphere. All this means is that there is no direct piping connection between the pump suction and return fitting on the pump.

In other words, excess fluid from the steering gear is dumped back into the reservoir not sucked in.

Pump damage, sometimes however it takes very little fluid to keep things turning.

Steering box damage, not unless the car is driven 10's of thousands of miles and even then, things will still turn.

Steering wheel damage? ! ? ! What specific part of the steering wheel do you feel will be damaged? The horn ring ? The splines ? The turn signal canceling cam ?

Locked in place with grease ? got a pic of that?

See my post 17.

You may have the solution. I've seen diagnoses get all out of sync ,even at a professional level, when someone if focusing too much on a perceived portion of the problem.

I spoke with the local Mercedes dealership, called in and basically stated what had happened and said it was my car. They recommended a few things.

-Paying the diagnostic fee, scheduling the old diesel in
-by the sounds of it, bare minimum power steering pump and they recommended box also
-I asked about steering wheel and mentioned I've never had the grease/oil changed on the steering wheel, and was concerned that with no oil in the pump or box that I forced the steering wheel and broke the spindle. I mentioned that I had never changed the grease/wax in the steering wheel. They were shocked and recommended a new steering grease/change etc.

So by the sounds of it - the dealer is saying exactly what I originally thought. Yes I may not be a certified mechanic with 40+ years experience but I know these cars very well.

__________________
1976 Mercedes 240D (Sold)
1985 Mercedes 300D Turbo Diesel: 500,000KM
1986 Mercedes 300E (Sold)
1988 Mercedes 300E (Sold)
2002 Mercedes C240 (Sold)
2008 Mercedes C350 4matic

A great site for purchasing industrial rubber products!

Industrial Rubber

Please elaborate on this "grease/wax" in the steering wheel. Last I checked, the steering wheel is just that....a metal hoop with some rubber or leather wrapped on it. If you're talking about the steering column itself, that usually is not serviced unless it is binding (common to ANY car, not just Mercedes).


Your postings seem to contradict your claims.

__________________
Current stable:
1995 E320 149K (Nancy)
1983 500SL 120K (SLoL)

Black Sheep:
1985 524TD 167K (TotalDumpster™)

Gone but not forgotten:
1986 300SDL (RIP)
1991 350SD
1991 560SEL
1990 560SEL
1986 500SEL Euro (Rusted to nothing at 47K!)

Why would you bother calling the dealership?

I'm willing to bet there isn't a single person on that staff that would know how to service these cars. At best, they're looking at the FSM docs and going by that.

Ain't no one got bucks to do that!

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-Typos courtesy of my mobile phone.

I have an old box off of a 83 300D that has been sitting on my shelf for a couple years (with fluid in it and not leaking) that I'll let go very reasonably. Message me or answer here in this thread if you are interested.

__________________
2012 Mercedes ML350 Bluetec 91K (hers)
2005 Corvette 55K (fun car)
2002 VW Jetta TDI 231K (mine)
1998 Volvo S70 T5 Turbo 196K (kids)
1994 Ford F150 4WD 249K (firewood hauler)
1983 Mercedes 300D 376K (diesel commuter)

FYI, I posted this initial thread and I responded yesterday but my response just got approved and it popped a few responses back (assuming in the order of when I originaly posted it) Scroll up a bit and you'll see the post where I explain the whole situation. Thanks everyone!

Sorry, I wouldn't usually post just to tell everyone that I made a previous post but I thought my response might get lost in the shuffle since it didn't come up as the most recent reply.

Your post likely got put on hold due to competitors web links in the text. ( Peach Parts / Pelican Parts sponsors this site ) Usually the links just get blotted out with **** but I bet there is a new poster filter when a link is posted. No big deal in you posting.

Good to know. Thanks!

Thanks, I might have to take you up on that. Let me put my pump back together with the correct seals and I see where I stand and I'll let you know.

No worries, I read over your post.

Moral of this story is to post here with questions first about your project and then tackle it if you're not sure

Someone would have caught your mistake and directed you to the right thing.

From what everyone has written, I think your power steering BOX is probably fine. Though, I'm sorry to say that your car is definitely out of service for the time being. I would plan on bumming rides, Lyfting, or getting a rental care for the interim.

You can purchase the correct seal kit and try again. Given what you've written about your abilities in doing car repair I wouldn't advise that. No offense intended, but even I don't attempt rebuilding things like pumps, steering boxes, calipers, MCs, etc. I'm too lazy and let other people do that. Avoids shenanigans like this.

I would instead purchase a rebuilt PUMP (notice the emphasis of what I am writing ).

Where in the world are you based? Your location will dictate the next advise I will give you.

Firstly, go to google and look for your nearest Napa Autoparts. They sell a rebuilt version of the pump for your car. Here's a link https://www.napaonline.com/en/p/PNB381384

Check if they have it in stock. If not, give them a call. They've surprised me previously with what they can get me in a very short amount of time. I've gotten calipers and MCs in under a day which is astounding for $128.

If you're based in California, I recommend you look at our forum sponsor for a rebuilt pump.

If you're not in CA and someplace else, check around for a rebuilt pump.

If you DO decide that you're up for doing this resealing correctly, may I recommend you look at this page here: https://www.pelicanparts.com/techarticles/Mercedes-W123/52-ENGINE-Power_Steering_Pump_Rebuild/52-ENGINE-Power_Steering_Pump_Rebuild.htm

This is an instructional on how to rebuild the power steering pump. On the right there are links to the seal kits you can purchase.

I would take a picture of your pump serial number and call Pelican to make sure that you're getting the right part. Since the seal kit is really cheap, I would opt for overnight shipping and just pay for it. Call off work, get your PS oil (don't use ATF), remove the pump, and be ready to reseal it using the instructions above.

Bleed the system and come back here to tell us your success.

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-Typos courtesy of my mobile phone.