Steering Shaft Coupling & Gearbox

[bpossel]

Last year I replaced some seals in my old steering gearbox, only to find this a temporary fix.  [!]It started leaking again recently, so I decided to replace the steering gearbox and be done with this leak.

I finally was able to pull the gearbox out last night.  A slight bit of rust was holding the gearbox to the steering coupling.  Note: the box is heavy!  I am sure it will be a challenge to re-install and ensure that all the alignment marks are in the right spot…  I had installed the pin tool on the inside of the car, as per the BBB, but it fell out during my pulling on the box.  Also, I had to use the mechanical alignment (inspection) hole, vs the power steering hole, whereas only the mechanical hole was open all the way up.  No "inner" hole was visible in the power steering?  Not sure why?   :?: Any advice here :?:

Before I install the new gearbox, I am now thinking that, while its out, to go ahead and replace the bushings in the coupling.

I have the inside cover plate pulled up as far as it will go, which is not very far up.  So being able to see what I am doing is very difficult.  Also, from below (outside the car) and looking into the shaft hole opening, also very restricted.

 :?: My question is…  how do I remove the coupling to be able to replace the bushings?  Since I have to go by mostly “feel”, I am hoping that one of you that have done this job can provide me with some guideance and suggestions.

I will take some pics and post….

As always, thank you!
Bob


bpossel  (Memphis, TN.)
'71 280SL  /  '97 E320

[graphic66]

I have heard that you should also replace the mounting bolts as they can stretch and cause problems where the box mounts to the frame.

[George Davis]

Bob,

I may be wrong, but I don't think there are any bushings to replace in the 280 SL.  Perhaps you're thinking of the bushings that the earlier cars have?  The 280's have an all-metal u-joint, but no plastic parts down there.

Would you mind telling us where you got your new steering box, and how much?

Thanks,

George Davis
'69 280 SL Euro manual

[bpossel]

Hi George, you are correct.  The later 113’s seem to have a different coupling.  Seems that this later one is not serviceable, rather you must replace it….  Expense!

Here is a picture of the coupling on the car right after I removed the steering box.
Download Attachment: view-of-coupling.jpg
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Here is a pic of my new steering box and my old, leaky box...
New box, nice & clean!
Download Attachment: new-steering-box.jpg
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Old box... coughing up it's last bit of fluids...
Download Attachment: old-steering-box.jpg
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With a little more persuasion this afternoon, I was able to raise the steering column cover a bit more.  There was one 6mm allen bolt holding the coupling on the shaft.  I removed this allen and again, with some persuasion, pulled the coupling off.
Pic of cover pulled back.
Download Attachment: steering-column-cover-pulle.jpg
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Here is a pic of the coupling cleaned up.  It does have some rubber bushes, but mine looked good.  Maybe all the grease and crud protected them through the years?  I noticed a red mark on the coupling.  This matches the red mark found on the lower bolt holding the steering gearbox.  It also matches the red mark on the inside wheel well where the bolt attaches.  It also matches a red paint mark on my steering arm.
Download Attachment: coupling-up-close.jpg
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Here is a pic of the coupling with bolts that hold the steering gear box in place
Download Attachment: coupling-and-bolts.jpg
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Here is a pic of the new box installed
Download Attachment: new-box-installed.jpg
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Some other comments on replacing the steering gear box...
When I removed the coupling and cleaned it up, I then did a dry fit to the new box.  It didnt slide on...  I used a screw driver and carefully expanded the coupling a bit at a time, along with some antiseize paste, I finally was able to slide it over the shaft and onto the new box.  If I had not done this, it would have been impossible to install the box while trying to slide it onto the coupling.
I also did a dry fit (on the bench), with antiseize of all of the bolts, both large ones and the small 6mm allens for the coupling.  This greatly helped in reinstallation.  They slid in like butter during the re-installation...  I will replace the large bolts that hold the steering gear box at a later time. Will remove one bolt at a time and replace....  Also note that I was not able to slide the coupling over the steering staft or onto the new gearbox with the allen bolt slightly started.  They had to be completely off the coupling to install.  Then had to "blindly" install them because I still could not see behind the cover plate as I was working down there.

George, I bought this rebuilt box from Mercedesparts.com.  Cost me $427 (excluding core).  This was the cheapest I found.  The person who sold it to me said that they get them from C&M Hydraulics.  Supposedly a very good company who rebuilds and tests per factory spec.

Bob

bpossel  (Memphis, TN.)
'71 280SL  /  '97 E320

[rwmastel]

quote:Originally posted by bpossel

Hi George, you are correct.  The later 113’s seem to have a different coupling.  Seems that this later one is not serviceable, rather you must replace it….  Expense!

Here is a picture of the coupling on the car right after I removed the steering box.
Download Attachment: view-of-coupling.jpg
37.67 KB

Yes, very different indeed!

Rodd
Powell, Ohio, USA
1966 230SL, Euro, Auto, Leather, both  tops
1994 E420

[George Davis]

Bob,

nice pics and write up, and thanks for the info on where you got the new steering box!

George Davis
'69 280 SL Euro manual

[mdsalemi]

Hello Bob,

I for one, and probably quite a few others with original steering boxes, (albeit not leaky!   ) would be interested to hear what your driving assessment is with the new unit in place.  Did it "tighten up" the handling, or is it about the same, just without leaks?

Inquiring minds would like to know.

Kudos on the writeup and photos; good solid work indeed.

Michael Salemi
1969 280SL
Signal Red w/Black Leather
Restored

[bpossel]

Hi Mike,

Just got everything back together tonight.  Bled the system this morning and did a few other things while I had the front end up on jack stands... and while I had a vacation day today.

Very raining outside, so didn’t want to take for a "real" test, but I did back the car up this evening and repositioned it into its usual spot in the garage.  I can tell you that it really feels very different !  It feels a lot tighter than my old box.  With my old box I could wiggle the steering wheel back and forth and the wheels didn’t move.  With the new box, the wheels turn immediately.  I guess I would describe my old steering box as "sloppy" compared to the new box.  With my old box, if I turned my wheels to their full left or right position, the system would squeal a little.  Now…  nice and quiet!

Probably wont take it out until the weekend for a real test.  I will post an update then.

Bob

bpossel  (Memphis, TN.)
'71 280SL  /  '97 E320

[bpossel]

Hi All!

I called C&M Hydraulics Tech Support line last night.  I believe they are in Las Vegas, not in CA.?  I confirmed that they do not sell directly to the public, rather they sell through distributors.  The tech seemed very knowledgeable and said that they only work on Mercedes gear boxes and have been doing this for years.  I also discussed with him the leaks that I had in my old box and the fact that last year I just replaced the upper and lower seal.  The tech confirmed that if the upper and lower seals are leaking, that actually there are many other seals in the box that are probably leaking.  Many times the seals harden over time and just lack of use and proper maintenance (ie. Fluid changes).  So just replacing the outer seals many times will not resolve the leaks.  (Jeff, sounds like you did yours the right way!  Complete overhaul!)

When I mentioned that my old box felt a bit sloppy, he said that this is from my “leak by” condition and with the internal leak(s), the box was not building up enough pressure.  Sounds logical?

I asked him about the warranty on these rebuilt boxes and he said that it is through the reseller, so if you have a issue with the box, you work it out with the reseller that you purchased it from and they in turn deal with C&M and resolve it.  The tech also mentioned that it is very rare that he sees any of their rebuilt boxes come back.  

Just thought that I would share this add’l information with you…
Bob


bpossel  (Memphis, TN.)
'71 280SL  /  '97 E320

[ja17]

Hello Bob,

Those fine splines make it difficult to center the steering wheel unless you carefully mark exactly how it came off. Have you had any issues here?



Joe Alexander
Blacklick, Ohio

[bpossel]

Hi Joe,

I actually have not driven the car yet, except to reposition in the garage.  The C&M Hyd. guy said that I will need to get an alignment for sure.  He said that usually the toe-in will need to be readjusted after the install of a new box.

I used a homemade pin tool in the bottom of the shaft (per the BBB), and held it in place with some duct tape, so I was able to hold the wheel in the same place.  I also ensured the pitman arm was installed with the mark aligning with the shaft on the new box. The box comes delivered in its "centered" position.

So, I hope its all lined up....

Any other advice?

Thanks Joe,
Bob

bpossel  (Memphis, TN.)
'71 280SL  /  '97 E320

[ja17]

Hello Bob,

As long as the wheel is centered and the wheels are nearly straight, you should be OK.  If you are off more then a spline the wheel will be quite off center and the turn signal cancel will not work correctly. Unfortunatelly correction would require uncouping and adjusting as required at the splines. Very minor correction can be done with the tie rods lengths.

Joe Alexander
Blacklick, Ohio

[bpossel]

  Thanks for the guidance and info Joe!

As I removed and reassembled my steering box, it seemed to me that most likely when these cars were originally assembled, that they: installed the coupling on the gear box in its centered position; then installed the gear box on the car; then installed the steering column with wheel; then the pitman arm…?

Bob

bpossel  (Memphis, TN.)
'71 280SL  /  '97 E320

[Abbas]

Hi Bob,
  I have a similar problem - leaking Steering box .. do you remember what seals you changed. How many parts you had to open until you got to those seals - did you have to take the whole gear out as well.
I want to change the seals before I purchase a new one.

Here is an attachement of the Steering parts if you do not mind pointing me to the ones you changed back then. Thnks

Download Attachment: Steering.gif
37.61 KB

Abbas

280SL W113 1969 Ivory
E280 W124 1995 Silver

[bpossel]

Hi Abbas,

Hard to see which seal by the diagram, but the seals I replaced was the one seal directly under the large round disk on the top of the box and also the seal directly under the lower end, under the lower plate, around the shaft area.  You can see the replaced seal (blue color) on the lower end my old box (refer to attached pic).

When I did this last year, I left the box in place and only disconnected the pitman arm and unscrewed the allen bolts.

Overall a total waste of time!!!

To do it right, you really need to pull the box out and dismantle it and replace all seals.  At that point I think it would also need to be adjusted per factory spec.

Jeff removed his box and replaced all the seals and had success!

I would recommend either leaving it alone and living with the leak or replacing the entire box.  This is only my personal opinion based on my experience.

Bob

Download Attachment: old-box.jpg
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bpossel  (Memphis, TN.)
'71 280SL  /  '97 E320

[jeffc280sl]

Bob,

I'm glad your steering box replacement went well.  I can't imagine a reason for needing an alignment after doing this job.  I don't think any of the geometry changed.  You removed the pitman arm and put it back in the same location.

Attached is a diagram of the box where your system leaked.  The red o rings or seals are the parts you replaced.     Anything is possible but maybe the leak occurred where I have marked in blue because the o rings marked in green were not replaced.  That's the only thing I can come up with.

Jeff C.
1970 280SL 4-speed

Download Attachment: steerbox.jpg
54.1 KB

[bpossel]

Hi Jeff,

Actually, Joe was right!  After his post last night in regard to the steering wheel alignment, I thought I would drive it to work this morning (first real test drive due to havy rains over the weekend).  Ended up turning around after a block.  Anyway, the steering wheel is not lined up.  Its off by about 15-20 degrees.  So I will have to disconnect the coupling again, and move the steering wheel and then reconnect the coupling.  I want to get it all as close as possible and then "maybe" do another front alignment?
  Bummed!
Bob

bpossel  (Memphis, TN.)
'71 280SL  /  '97 E320

[jeffc280sl]

I thought you were referring to a front end alignment, camber and stuff.  I understand the need to align the steering wheel.

Jeff C.
1970 280SL 4-speed

[Abbas]

Jeff and Bob,
  Many thanks for this nice colored photo of various seals. Are these standard O-ring types. I guess the middle Semi-Rectangular is needs to be purchased from MB directly.

Abbas

280SL W113 1969 Ivory
E280 W124 1995 Silver

[jeffc280sl]

Abbas,

I would buy the MB repair kit.  It used to be $24 or so.  That way you get the correct o rings, oil seals and gaskets.

Jeff C.
1970 280SL 4-speed

[rwmastel]

quote:Originally posted by Abbas

Download Attachment: Steering.gif
37.61 KB

Abbas,

I don't know what manual this picture is from, but it looks like part #117 is a major (complete) reseal kit.  It points to a lot of parts!

Rodd
Powell, Ohio, USA
1966 230SL, Euro, Auto, Leather, both  tops
1994 E420

[Abbas]

quote:Originally posted by jeffc280sl

Abbas,

I would buy the MB repair kit.  It used to be $24 or so.  That way you get the correct o rings, oil seals and gaskets.

Jeff C.
1970 280SL 4-speed

Jeff is there a part number for this kit I could reference.

Abbas

280SL W113 1969 Ivory
E280 W124 1995 Silver

[bpossel]

Abbas,

These kits are available at many suppliers.  The dealer and also others.  Arizona Autohaus sells them for $21 US.
http://autohausaz.com


Download Attachment: steering seals.jpg
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bpossel  (Memphis, TN.)
'71 280SL  /  '97 E320

[Abbas]

While searching the Steering gear parts, I found that there is yet another filter in this car that is new to me. The steering filter (as in the attached image). Steering Filter.jpg 29.61 KB

Is this filter fitted inside the oil reservoir or somewhere else. How can you replace it ... do you also need those seals around.

Abbas


280SL W113 1969 Ivory
E280 W124 1995 Silver

[ja17]

Hello Abbas,

The filter is below the metal plate in your power steering fluid canister. Remove the spring under the lid and pull the plate at the bottom of the reseviour out. The part sequence in your illustration is wrong.  The plate is actually on top of the filter.

Joe Alexander
Blacklick, Ohio