Author Topic: Steering Coupling Question  (Read 10170 times)

116.025

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Steering Coupling Question
« on: 09 October 2006, 11:14 AM »
Greetings Gents,

I had noticed several weeks ago that my 116's steering column was starting to make a metallic rattle when I would go over big bumps.  As time went on, it got to where it was rattling over even the slightest bump.  So I finally got it up on some jacks and started poking around, and noticed in no time that the rubber in the steering coupling had perished and was also the probable explanation for the rather excessive amount of play that had crept in during the last 30,000 kms of use.

So, on to the question:  Is it possible to replace said coupling with the gearbox in place?  Or will I have to do fun things like remove the gearbox and recenter it and so forth?  All thoughts and suggestions welcome and appreciated.
Chad Johnson

'77 280SE Euro (4-Spd) Sold 1/5/09
'71 220D (4-spd)
'77 280SEL Euro (4-Spd) RIP
'89 420SEL
'78 350SE Euro
'86 300E 5-Spd RIP by Chevy S10
'83 380SL
"Don't Worry, Bobby, even a worn out Mercedes is better than a 2010 cracker-jack box

Tomi

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Re: Steering Coupling Question
« Reply #1 on: 09 October 2006, 12:42 PM »
yes, it certainly is possible to replace the coupling with the gearbox in place. I've done that with my 116. ( Before, with my 107 I did it replacing the gearbox and it was a pain, never again that way).

just take the steering wheel away and a  stop ring and pull the shaft up a small distance after unscrewing the coupling bolts. remember to keep the alignment.

(In fact if you wish, you can lock the gearbox to the straight wheel direction position: there is a bolt on the underside which when taken off, you can see a  hole when the wheels are straight aligned. It can be locked into position by placing a pointed screw in there. That is if you want to do it the right way and check your alignment ;) )
MB 450 SEL -80 (oldtimer for the class)
MB E220T -95 (daily driver)
MB 230E -82 (a present for my son)

s class

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Re: Steering Coupling Question
« Reply #2 on: 10 October 2006, 05:37 AM »
116.025,

common problem.  I am about to write up my procedure for steering box removal and refitment, plus centering procedure.  I haven't done it yet, but the pictures are all here http://gallery.w116.org/v/garage/power_steering/?g2_enterAlbum=1 in the gallery, with pretty detailed captions.  It may help you.  I must confess that Tomi's information about a pin locking arangement for centering is new to me, though.  Just proves that it doesn't matter how much you think you know about something, there's still more to learn. 

Ryan

'76 6.9 Euro, '78 6.9 AMG, '80 280SE, '74 350SE, '82 500SEL euro full hydro, '83 500SEL euro full hydro , '81 500SL

Tomi

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Re: Steering Coupling Question
« Reply #3 on: 10 October 2006, 12:40 PM »
sorry Styria,
some say its the steering gearbox (I think in US), and hence the short name gearbox which is totally misleading. Lets call it the steering box.

S-class and Styria and 116.025: The centering bolt can be read from page 5 of the (library) workshopmanual chassis-steering-section 46-412 removal and installation of the power steering.
And it really is there.

I would not even think of changing the coupling in any other way. in the 116 there is good space but in the 107 it is really tight. Its a good idea to change the rubber grommet of the steering shaft at the same time, since it gets deteriorated and leaks rain and noise through and it is cheap.

« Last Edit: 10 October 2006, 01:41 PM by Tomi »
MB 450 SEL -80 (oldtimer for the class)
MB E220T -95 (daily driver)
MB 230E -82 (a present for my son)

116.025

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Re: Steering Coupling Question
« Reply #4 on: 11 October 2006, 05:50 AM »
Sorry about the confusion, Styria, I suppose Tomi is correct in saying it is a US thing, since I generally hear them referred to as "Steering gearboxes".

Tomi, thanks for the great idea!  I'll be sure to implement it in the coming days.  I had seen the centering bolt thing in the service manual as well, but didn't really understand how to use it until you explained it.  This should turn what I was thinking would be an all-day (or two!) affair into a few hours  ;D

Ryan, I had been hoping you might chime in, since I knew you had done a bunch of steering work on your 280SE recently and figured you might have some good pointers.  The pictures are excellent, and looking at the comparative clearances, this might be the first time I wish my 116 was RHD!

In the meantime, I'll keep driving the 420SEL I picked up last week for USD $2700, since I don't want to take any chances with the coupling giving me a bigger issue.  I'll try to get some pics up somewhere in case anyone's interested in seeing it.  And I just want to get my OM615 reassembled...I miss my 220D!
« Last Edit: 11 October 2006, 05:51 AM by 116.025 »
Chad Johnson

'77 280SE Euro (4-Spd) Sold 1/5/09
'71 220D (4-spd)
'77 280SEL Euro (4-Spd) RIP
'89 420SEL
'78 350SE Euro
'86 300E 5-Spd RIP by Chevy S10
'83 380SL
"Don't Worry, Bobby, even a worn out Mercedes is better than a 2010 cracker-jack box

oscar

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Re: Steering Coupling Question
« Reply #5 on: 16 October 2006, 07:38 AM »
I've been wanting to bring up this subject for a while but I'm glad you did Chad.  Since I've had my car I have to remember to turn the indicator off after a left turn thanks to a misaligned steering shaft.  Ryan, I've just been thru your pics in the gallery. Fantastic!!  I'm going to finally attack this problem this weekend.

A few questions.

Tomi- you said about pulling the shaft out a little after unscrewing one of the coupling bolts.  I've attempted to align all this ages ago but never got anywhere.  Referring to the pic below, I took both inner and outer rings off and undid the 4 hex screws and couldn't move the shaft towards me.  Any ideas what I'm not doing?




Also, does the centering pin go into the drain plug?




Lastly, Ryan or anyone for that matter, my steering feels really good but how do I know if the coupling is worn?  There's no rubber that I can see on my coupling that you guys talk about. 

I took the best photo I could and BTW, FYI, the rust is from when the master cylinder spewed brake fluid over the right hand side of the engine bay before I got the car. It's usually covered in fish oil as a stop gap.  I know it doesn't look flash but apart from the misalignment, there's no steering complaints.

1973 350SE, my first & fave

oscar

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Re: Steering Coupling Question
« Reply #6 on: 16 October 2006, 08:07 AM »
I just checked your new coupling again Ryan and I have to say it looks nothing like mine re the rubber.

Here's what I assume I need to buy if I need to replace mine, but again I can't see the rubber.  If I get this thing off, because I'm wondering now whether the rust has fused it to the steering box spline, I'll give it a closer inspection and better pics.  Is this a flexible coupling BTW?  I can't see the need for rubber or how this thing can become worn. (Unless you get brake fluid on it ::) )

1973 350SE, my first & fave

Tomi

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Re: Steering Coupling Question
« Reply #7 on: 16 October 2006, 09:34 AM »
Hi Oscar,

that is the coupling, the pic above. That flex disk coupling I have seen on some W123's.
I think the best way to see if you have a bad coupling is to see if it has any visual flaws and then have someone move the steering wheel back and forth while you look at the coupling and see if you notice any looseness.

Yes, if I remember correctly, when the 2 stop rings are out and the 4 screws, that plate (on the pic) can be taken off, from the edge with a knife.

 BTW the screws have to be totally out of the coupling before pulling the shaft (since there is a restriction in the steering box axle and the coupling would not move anywhere if the screw is in place, even if loose.
You can also try to widen a little the gap in the coupling with aa big screwdriver once the screws are out.

this should work. ;)
« Last Edit: 16 October 2006, 09:37 AM by Tomi »
MB 450 SEL -80 (oldtimer for the class)
MB E220T -95 (daily driver)
MB 230E -82 (a present for my son)

116.025

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Re: Steering Coupling Question
« Reply #8 on: 16 October 2006, 09:51 AM »
When I did the job on Saturday, I never even got the inner ring out, and was able to move the bearing bracket, once I loosened the shaft side bolt on the coupling, I even managed to nearly pull the entire shaft out of the column since I was using a bit of force to get it to slide out.  Though, I did slide the wheel back on and use it to initially withdraw the shaft, since the coupling had a bit of a hold even with the bolt loosened.

Aha, I knew I was overlooking something...you MUST disengage the turn signal switch mounting screws and the two horn wires from the turn signal switch to withdraw the shaft, as well.  And yes, Tomi's suggestion of a screwdriver was exactly what I did to get it off of the box (see Styria, I even managed to not say gearbox  ::)) splines. 

No flexibility here, that I can see, Oscar.

My only annoyance was that even after lining up the centering hole and the shaft notch, my steering wheel/shaft was about 25 degrees right of center.  :'(  So since it was getting dark and cold, and I needed to check something on the 420, I just moved the steering wheel over and decided to get it right later.  I'll try to get some pics of my worn coupling, since the last bits of rubber fell out of it after removal, I can illustrate clearly where it goes and the problems it causes when it perishes.

But man, what bliss to drive without ridiculous amounts of play and loud rattles from the steering column! ;D
« Last Edit: 16 October 2006, 09:54 AM by 116.025 »
Chad Johnson

'77 280SE Euro (4-Spd) Sold 1/5/09
'71 220D (4-spd)
'77 280SEL Euro (4-Spd) RIP
'89 420SEL
'78 350SE Euro
'86 300E 5-Spd RIP by Chevy S10
'83 380SL
"Don't Worry, Bobby, even a worn out Mercedes is better than a 2010 cracker-jack box

oscar

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Re: Steering Coupling Question
« Reply #9 on: 17 October 2006, 01:54 AM »
Thanks Tomi and Chad.  My guess is that I didn't loosen the coupling enough.  Armed with your advice, I'll do this job this weekend and report back.  Thanks for your help.
1973 350SE, my first & fave

s class

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Re: Steering Coupling Question
« Reply #10 on: 17 October 2006, 11:38 PM »
Oscar,

The pictures you show of the new steering coupling ar ethe correct W116 item.  The upper and lower halves of the steering coupling are connected by the rivets you see.  What you don't see is that the rivets are bushed with rubber.  The squidginess of the rubber provides some flexibility to the coupling. 

Tomi is correct that the coupling in my car is a W123 item.  They are physically interchangeable, but I don't recommend it as the W123 item is much inferior.  The W116 coupling is "fail safe" because even if the rubber perishes completely, you still have a physical connection between the steering column and the steering box.  In the W123 item this is not the case.  If the rubber fails, the upper and lower parts of the coupling become detached from one another.  Way uncool situation to be in. 

I agree with Tomi's suggestion for diagnosing play in the coupling.  You can also try holding your hand around the coupling to feel for play whilst an assistant jiggles the steering wheel. 

This pic here shows a W116 coupling that has lost its rubber.  YOu can actually see the bare rivets which should be encased in rubber. 

Take encouragement Oscar and 116025, I was astounded at how light, crisp and precise my steering felt once I had the steering wheel, shaft, steering box and pitman arm all centred with respect to one another. 

Ryan

'76 6.9 Euro, '78 6.9 AMG, '80 280SE, '74 350SE, '82 500SEL euro full hydro, '83 500SEL euro full hydro , '81 500SL

oscar

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Re: Steering Coupling Question
« Reply #11 on: 22 October 2006, 06:57 AM »
So much for a quick job realigning the steering shaft.

I spent 2hrs trying to get the hex nut loose on the steering gearbox side and ended up rounding it.  I jammed a bigger hex fitting in and used a ratchet gun and the bugger still wouldn't budge.  i've had the other nut loose before but I need this one off the spline.  The area's too tight to get multigrips around the head of the hex screw.  I can't even get a drill in there to drill it out.

Any ideas?   I'd like to avoid removing the steering box if possible.
1973 350SE, my first & fave

Tomi

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Re: Steering Coupling Question
« Reply #12 on: 22 October 2006, 12:10 PM »
hi,
sorry to hear that Oscar. One way or another you will have to get those screws out.

You should spray some wd40 or equivalent oil on the screw for the night. I dont remember how much space there is to work there. Try it with the hex , but if the screw has rounded the alternatives are few. Many times in a case like this the 'Russian technique' might work, with a sharp chisel+hammer hit the screw from the side counterclockwise it usually opens bit by bit. Another possibility could be heating the coupling (a bit dangerous). It all depends how much space there is to work.

BTW I just did the aligning of the steering shaft for my sons W123, and it was really simple. Once the coupling screws were out, it could be just sliden up the steering shaft. No need to dislocate the shaft. Possibly it could work with the w116 like this, I never thought it this way before.
MB 450 SEL -80 (oldtimer for the class)
MB E220T -95 (daily driver)
MB 230E -82 (a present for my son)

Papalangi

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Re: Steering Coupling Question
« Reply #13 on: 22 October 2006, 09:01 PM »
If it is held by a thread locker like Loctite, heat will break it loose.  It doesn't need to be smoking hot but hotter than you can touch.

You may also try acetone or MEK to dissolve the thread locker if you can see the end of the bolt.


Michael
1976 450SEL, 116.033  Sold it to buy a '97 Crown Vic.  Made sense at the time.
1971 250C, 114.023      Sad but true, it's gone to a new home.
1976 280C  Stolen by the City of Seattle, sort of.
1970 250/8, traded in on a 1993 Land Rover Disco

oscar

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Re: Steering Coupling Question
« Reply #14 on: 23 October 2006, 05:32 AM »
I did it!! ;D

Thanks one and all. I went for the heat idea with a butane torch and bashing for a while until I could smell the coupler's rubber burning.  So yes, my coupler definitely does have rubber (still I hope). I don't have any acetone and the MEK I've got is quite thick and I could see myself making a huge mess.  In the end I struggled for a while to come up with a way to make a tool fit the threaded hex screw. 

Eventually I was able to slice a gap near the middle of the head with the flexible attachment of a dremel, used a tall flathead screwdriver and attach multigrip pliers as a lever to the screwdriver's handle.  With a few attempts and all my weight it finally gave way.  For RHD car I had to remove the brake booster vac line, the battery and the 4 ignition leads to give me enough room.  Most of my screwdrivers have rubberized handles and were unsuitable to attach the multigrips to so I ground the head of the biggest plastic handled flathead to fit the screw.

To realign I suspended the front end, judging each side by comparing the front wheels' position to the rears.  I found the leading edge of the fronts were further apart than the trailing edge.  Is that called toe out?  If so, is that normal?  As handy as the centering pin option is, I don't trust my jacks or blocking methods to go under the car. 

My only hassle reattaching the shaft and coupling to the steering box spline was that the shaft kept collapsing before the coupling made it's way to the steering box.  Eventually I levered it on and I'm happy to say the alignment seems to be spot on. 4hrs it took.

« Last Edit: 23 October 2006, 05:34 AM by oscar »
1973 350SE, my first & fave