Leak in steering box 85 300sd - PeachParts Mercedes-Benz Forum

yuke · #1 08-31-2016, 11:19 PM

Yes I seem to have a fairly bad leak in the box. Seems to me you have to unhook the steering link on the bottom, unhook from the steering column, and then remove 2 bolts from the outside of engine bay tire side. Has any body had their box off and apart to put some gaskets in?

Stretch · #2 09-01-2016, 01:02 AM

Here's my experience =>

What a feeling it will be! A properly adjusted W123 / W116 / W126 power steering box

yuke · #3 09-01-2016, 06:16 AM

Wow stretch seems pretty complicated that you have to totally rip the whole box apart to put a couple of o-rings in it and seems you had a lot of trouble to remove the steering link on the out put shaft. I am going to do a lot more research including tryinging to find out exactly where it is leaking at. Just thought it would be a good time to address the leak as the engine is out right now and I have a lot of room to work in there. Was wondering if maybe just putting some power steering stop leak in there would make the o-rings swell up and stop leak. It worked great one time on a toyota I used to have. Hope to hear from other people that had same problem. Also trying to figure out how many mounting bolts there are I only saw 2 bolting it to the fender well.

Junkman · #4 09-01-2016, 09:22 AM

You have the engine out. Fix the box, adjust and be done. Other boxes that I've messed with have a bearing on the bottom with a seal. The bearing and seal need to be replaced and the box adjusted. It isn't difficult once you've gone through the learning curve.

Other vehicles running a Saginaw box have trouble with off the shelf remans. I always check the adjustment when installing any box. Many have a paint mark on the adjuster screw and you may void the warranty by messing with it. You can still measure the required torq and check for internal play and make sure that the box is centered before installing. The torq specs on my Cummins Dodge and 300SDs are similar even though the truck is more than twice as heave.

martureo · #5 09-01-2016, 09:46 AM

Quote:

Originally Posted by yuke

Wow stretch seems pretty complicated that you have to totally rip the whole box apart to put a couple of o-rings in it and seems you had a lot of trouble to remove the steering link on the out put shaft. I am going to do a lot more research including tryinging to find out exactly where it is leaking at. Just thought it would be a good time to address the leak as the engine is out right now and I have a lot of room to work in there. Was wondering if maybe just putting some power steering stop leak in there would make the o-rings swell up and stop leak. It worked great one time on a toyota I used to have. Hope to hear from other people that had same problem. Also trying to figure out how many mounting bolts there are I only saw 2 bolting it to the fender well.

There are three (3) 15mm (IIRC) mounting bolts in the wheel well. One is usually obscured by the brake line. I recommend backing these out but leave one with a few threads engaged. Grab hold of the p/s hoses with your left hand and as you remove the last bolt use them to lower the box to the ground. It's about 30lb and will drop like a rock if you're not in control of it.

You could try using a product to help the seals swell, but keep in mind that they are under a decent amount of pressure (65 bar = 945 psi, 82 bar 1189 psi). They usually leak at the pitman arm plate seal or shaft seal. DO NOT whatever you do try to seal the leak from the outside with silicone (don't ask).

Army's write up is amazing (I know, it helped me get started rebuilding these). But if your additive solution doesn't work I would recommend getting a professionally rebuilt box (~$400), getting a used box or getting someone like me (like an adventurous mechanic) to do it. It is quite a job to reseal one of these boxes. (Usually takes me around 5 hours)

Stretch · #6 09-05-2016, 05:32 AM

I think the phrase "there's no such thing as a free lunch" is appropriate for these steering boxes. They are lovely and wonderfully involved for what seems "just like" a leaky seal - but once fixed properly will last a blinking long time enabling users to go back to simple periodic fluid changing servicing...

DrLou · #7 09-05-2016, 12:29 PM

Stretch,

As always, thanks for your beautiful write-ups. I've been postponing the much-needed rebuild of my steering box; you've now re-emboldened me! (The leak is now getting bad enough that it's damaging bushings on the left side).

BTW, I still owe you a couple of dinners after the rebuild-entire-rear-subrame project last year!

After going there every October for several years, I probably won't make it to The Netherlands this fall - but it'll happen again soon.

Quote:

Originally Posted by Stretch

Here's my experience =>

What a feeling it will be! A properly adjusted W123 / W116 / W126 power steering box

yuke · #8 09-05-2016, 06:15 PM

I looked at the steering box very closey again today and yes it was still seeping while just sitting there without even a motor in it. I broke lose and then retightened all the bolts that I would have to if I was taking it off good time with no motor in the way. What I did was drain all the ATF out of it and I put in Lucas power steering stop leak and topped it off with power steering fluid. I wanted to take the easy fix first if it do'nt work I will be ready to pull it. Let everyone know how it turns out. I think ATF is more likely to leak then power steering fluid I will find out.

Stretch · #9 09-06-2016, 12:54 AM

Quote:

Originally Posted by DrLou

Stretch,

As always, thanks for your beautiful write-ups. I've been postponing the much-needed rebuild of my steering box; you've now re-emboldened me! (The leak is now getting bad enough that it's damaging bushings on the left side).

BTW, I still owe you a couple of dinners after the rebuild-entire-rear-subrame project last year!

After going there every October for several years, I probably won't make it to The Netherlands this fall - but it'll happen again soon.

If you make it to Holland please give me a shout again - but please don't feel you "owe" anything!

Quote:

Originally Posted by yuke

I looked at the steering box very closey again today and yes it was still seeping while just sitting there without even a motor in it. I broke lose and then retightened all the bolts that I would have to if I was taking it off good time with no motor in the way. What I did was drain all the ATF out of it and I put in Lucas power steering stop leak and topped it off with power steering fluid. I wanted to take the easy fix first if it do'nt work I will be ready to pull it. Let everyone know how it turns out. I think ATF is more likely to leak then power steering fluid I will find out.

Good luck with it - steering box removal isn't too too bad with everything back in you just need to catch it at that last moment when the last bolt gets removed!

BillGrissom · #10 09-06-2016, 01:21 AM

I don't know if anyone has had luck with p.s. stop leak, but of course all those motor mystery products sell because "cheap to try". I understand the stop leaks work by having strong solvents which swell the rubber seals. Probably just a temporary fix if it does work. I have removed and rebuilt p.s. gears on 60's cars (Chryslers). The one on my 300D looks nicer in many ways. The 3 mounting are easily accessible thru the wheel well, the input shaft head is secured w/ 4 studs, instead of a "mason jar" ring needing a special tool (think pre-chamber lock screw), and they even give you a place for a locating pin to center the gear. Downside is that rebuild kits are $$$ and almost non-existant vs $20 for my Chryslers. BTW, Harbor Freight has 2 sizes of cheap Pitman arm pullers that work well for other things like tie rods too.

martureo · #11 09-06-2016, 09:10 AM

Quote:

Originally Posted by BillGrissom

I don't know if anyone has had luck with p.s. stop leak, but of course all those motor mystery products sell because "cheap to try". I understand the stop leaks work by having strong solvents which swell the rubber seals. Probably just a temporary fix if it does work. I have removed and rebuilt p.s. gears on 60's cars (Chryslers). The one on my 300D looks nicer in many ways. The 3 mounting are easily accessible thru the wheel well, the input shaft head is secured w/ 4 studs, instead of a "mason jar" ring needing a special tool (think pre-chamber lock screw), and they even give you a place for a locating pin to center the gear. Downside is that rebuild kits are $$$ and almost non-existant vs $20 for my Chryslers. BTW, Harbor Freight has 2 sizes of cheap Pitman arm pullers that work well for other things like tie rods too.

A rebuild kit for the w123/r107/w115/w116 box is ~$25 for Hebmuller. The only thing it doesn't include is a circlip unique to the w126 box, but that's $2 through MBZ.

yuke · #12 09-09-2016, 12:23 AM

Well my steering box is still leaking it is leaking at the input shaft cover that is held on with 4 bolts. I was wondering if I pulled the box off and just took the input cap off if I could just replace the one seal stop my leak and throw it back on?

martureo · #13 09-09-2016, 10:15 AM

Quote:

Originally Posted by yuke

Well my steering box is still leaking it is leaking at the input shaft cover that is held on with 4 bolts. I was wondering if I pulled the box off and just took the input cap off if I could just replace the one seal stop my leak and throw it back on?

As per the email I sent you and the post above, the answer is no.

yuke · #14 09-10-2016, 08:03 AM

Ok maybe Matureo or Stretch can answer this another member has a box from an 83 240d 123 chasis the # on the box is AK3350 with 53 sideways since the first letter is (A) I read this means the box has an internal stop. My box off an 85 300sd 126 chasis the # is V5093 with 43 sideways would the box from the 123 chasis fit on my 126 chasis if I use the pitman arm that was with mine or are they not interchangeable? Since my 1st letter is (V) I think my stops are on the chasis cross member which I can see. Would the A box fit in mine but mine would not go in the 123 chasis. Am I clear that on installing another box that you keep a centering bolt in it so it does not get off center? I am working on installing another engine and am trying to clear up and stop leaks one being the steering box.

Stretch · #15 09-10-2016, 08:46 AM

Quote:

Originally Posted by yuke

Ok maybe Matureo or Stretch can answer this another member has a box from an 83 240d 123 chasis the # on the box is AK3350 with 53 sideways since the first letter is (A) I read this means the box has an internal stop. My box off an 85 300sd 126 chasis the # is V5093 with 43 sideways would the box from the 123 chasis fit on my 126 chasis if I use the pitman arm that was with mine or are they not interchangeable? Since my 1st letter is (V) I think my stops are on the chasis cross member which I can see. Would the A box fit in mine but mine would not go in the 123 chasis. Am I clear that on installing another box that you keep a centering bolt in it so it does not get off center? I am working on installing another engine and am trying to clear up and stop leaks one being the steering box.

Check in the FSM but I'm pretty sure you'll be alright if you have the correct Pitman arm for your car. (Removing a Pitman arm might cause the average DIYer a bit of grief - might need some carefully applied heat - which of course can damage seals...)

The FSM has the ultimate say on this - I think the fixings on the casing are the same so it should bolt up.

May be Matureo can add in more about the swapping between W123 and W126