Steering coupler repair or replace

[Vintage]

Thinking replace but I have seen articles online about replacing bushings. Mine has a bit of play and seems a good first project. Anyone else been down this road already? My car is a '79 450SL.

Best to access from below? Looks like releasing the column support from inside the cabin will provide enough play to remove the coupling (rather than drop the steering box). Looks like the part is available online for $59.00. Have not found just bushings.

Thoughts?

[dkveuro]

Originally Posted by Vintage

.....................Anyone else been down this road already? My car is a '79 450SL.

Best to access from below? Looks like releasing the column support from inside the cabin will provide enough play to remove the coupling (rather than drop the steering box). Looks like the part is available online for $59.00. Have not found just bushings.

Thoughts?

Done several. Not a big job if you have a lift. Long extension for the Allen screw and a screw driver to pry open the collar slot to make removal easier.

You slide the coupler down and there's enough wobble to then get the coupler out.

Can be done from above too although you need a wobble head extension .
Just mark the steering shaft parts with White Out to make refitting without mistakes although unless you spin the s/wheel while old one out it's a simple job.



.

[mbboy]

Originally Posted by Vintage

Thinking replace but I have seen articles online about replacing bushings. Mine has a bit of play and seems a good first project. Anyone else been down this road already? My car is a '79 450SL.

Best to access from below? Looks like releasing the column support from inside the cabin will provide enough play to remove the coupling (rather than drop the steering box). Looks like the part is available online for $59.00. Have not found just bushings.

Thoughts?

Based on my personal experience and the experiences of many others, this job can be far more difficult than dvkeuro is leading you to believe it is. You can find some of the problems I and others have reported in the thread at: http://www.peachparts.com/shopforum/sl-forum/310593-stripped-coupler-bolt.html.

The biggest problem I had on my 380sl, and others have reported with their 107's, is loosening the rearward, 6mm Allen, since its recessed in the firewall. If you strip it, as a number of people have, you may end up having to drill it out, as Tony Baroso reportedly did in the thread he posted in MBworld.

Based on my experience, the best way to insure that you'll loosen that bolt without stripping it is to use a torx head socket (T-10, if I recall) and a 1/2" ratchet or breaker bar from inside the cabin, after you've 1) removed the flange covering the steering column, 2) soaked the bolt -- ideally overnight -- with penetrating oil, and 3) carefully torched it. Even after I partially stripped the bolt's head, the torx gripped it perfectly

Once you've done that, and removed the turn signal, as well as the bolts securing the steering shaft to the column, you can lift the shaft out of the coupler, and the coupler from the spline on the steering box.

Other people have removed the coupler by loosening and moving the steering box. But since the best way to loosen the rearward bolt is from inside the cabin, and the steering box is heavy, I think you're also better off removing the coupling from inside, too, using Tony Baroso's method.

When you replace the coupling and the steering shaft, make sure that the notch on the shaft is facing straight up, and the wheels are perfectly straight, or your turn signals won't cancel, and your steering wheel won't lock when you remove the key. In addition, make sure that you don't force the shaft into the coupling too hard, since the shaft is designed to collapse on impact, as another member reported after he hammered it in, and it later pulled out of the coupling while he was driving.

BTW, I rebuilt my coupling and another I got from a junk yard using brass bushings that will never wear out, and the steering is now tighter and more responsive than it was when the car was new. If you want the other one I rebuilt, email me, and we'll work out a trade for your old one. That way you can pop the rebuilt one in right after you've removed yours without having to run around finding the right fittings and drilling it out, as I did. But whatever you do, don't buy one of those cheap Chinese couplers, as you may end up having to do the job again sooner rather than later.

[nobby]

Originally Posted by mbboy

Based on my personal experience and the experiences of many others, this job can be far more difficult than dvkeuro is leading you to believe it is. You can find some of the problems I and others have reported in the thread at: http://www.peachparts.com/shopforum/sl-forum/310593-stripped-coupler-bolt.html.

The biggest problem I had on my 380sl, and others have reported with their 107's, is loosening the rearward, 6mm Allen, since its recessed in the firewall. If you strip it, as a number of people have, you may end up having to drill it out, as Tony Baroso reportedly did in the thread he posted in MBworld.

Based on my experience, the best way to insure that you'll loosen that bolt without stripping it is to use a torx head socket (T-10, if I recall) and a 1/2" ratchet or breaker bar from inside the cabin, after you've 1) removed the flange covering the steering column, 2) soaked the bolt -- ideally overnight -- with penetrating oil, and 3) carefully torched it. Even after I partially stripped the bolt's head, the torx gripped it perfectly

Once you've done that, and removed the turn signal, as well as the bolts securing the steering shaft to the column, you can lift the shaft out of the coupler, and the coupler from the spline on the steering box.

Other people have removed the coupler by loosening and moving the steering box. But since the best way to loosen the rearward bolt is from inside the cabin, and the steering box is heavy, I think you're also better off removing the coupling from inside, too, using Tony Baroso's method.

When you replace the coupling and the steering shaft, make sure that the notch on the shaft is facing straight up, and the wheels are perfectly straight, or your turn signals won't cancel, and your steering wheel won't lock when you remove the key. In addition, make sure that you don't force the shaft into the coupling too hard, since the shaft is designed to collapse on impact, as another member reported after he hammered it in, and it later pulled out of the coupling while he was driving.

BTW, I rebuilt my coupling and another I got from a junk yard using brass bushings that will never wear out, and the steering is now tighter and more responsive than it was when the car was new. If you want the other one I rebuilt, email me, and we'll work out a trade for your old one. That way you can pop the rebuilt one in right after you've removed yours without having to run around finding the right fittings and drilling it out, as I did. But whatever you do, don't buy one of those cheap Chinese couplers, as you may end up having to do the job again sooner rather than later.

Good post.

[abiby]

Nice write-up Mbboy, and I'm with you 90%.

IMO Mercedes put the rubber in the coupling to allow for minor misalignment between the steering shaft and the steering box, and perhaps a little vibration isolation. I'd go with a replacement coupler with rubber bushings rather than brass.

At the same time, I've read where someone was going to try injecting an elastic material into the old couple while still installed. If someone could perfect that, well, I'm certainly not a masochist (even though I own a 107) and would give it a try.

[Vintage]

Originally Posted by abiby

Nice write-up Mbboy, and I'm with you 90%.

IMO Mercedes put the rubber in the coupling to allow for minor misalignment between the steering shaft and the steering box, and perhaps a little vibration isolation. I'd go with a replacement coupler with rubber bushings rather than brass.

At the same time, I've read where someone was going to try injecting an elastic material into the old couple while still installed. If someone could perfect that, well, I'm certainly not a masochist (even though I own a 107) and would give it a try.

Thanks for all the great input. Forums like this are invaluable! I have to admit that the first thing I thought of doing was to attempt to "pack" the coupler with a urethane or butyl type compound as the rivets are intact and appear (famous last words) OK. I assume the original bushings were rubber and have simply desiccated in the heat. Life 6 inches from the manifold is probably warm...

[nobby]

Originally Posted by Vintage

I assume the original bushings were rubber and have simply desiccated in the heat. Life 6 inches from the manifold is probably warm...

Not to mention 33 years.

Even rubber has a shelf life.

[mbboy]

Originally Posted by nobby

Not to mention 33 years.

Even rubber has a shelf life.

For a detailed discussion of the advantage brass bushings have over rubber bushings, see this thread:
http://www.peachparts.com/shopforum/diesel-discussion/289876-116-steering-coupler-$6-00-upgrade.html

Based on my experience, the OP was right. OTOH, getting the parts and rebuilding the coupler is not as easy as he made it sound.

[meltedpanda]

as I have said several times in other posts , I would replace rather than rebuild, but either way, as I was shown works.
This is not an "easy" job but not over the top either. Plenty on the board about this project - read them all I'm just saying..

[sjefke]

For what it is worth, I did the coupler repair option on my '70 111 coupe and was surprised how easy it was.

To repair, you need the following parts:

2 x 912002010001 (lock washer) - $1.52 each
2 x 000137010205 (spring clip) - $0.80 each
2 x 1114620165 (bushing - listed as "seal ring P/S Pump") - $3.76 each

This assumes you have the repairable type early coupler, and not the later type.

Full post is here: http://www.peachparts.com/shopforum/vintage-mercedes/302392-111-280se-3-5-steering-coupler-repair-tips.html

To remove firewall allen bolt, I turned the coupler so that allen bolt was horizontal with bolt top facing towards the engine. Then I had enough space to put a 3/8 inch 6mm allen key socket on it, going at it from below the car. I did the same on a 450 SL in a scrapyard. I would not recommend trying to get this bolt out from the top. It will strip because you cannot get the socket on straight. Horizontally you can put good leverage on it and there is space between the bolt and block to put the socket in the bolt with your hand, at least in my car.

I went the way of loosening the 3 bolts of the steering box. Much easier than fighting my pedal assembly etc under the dash to get the column loose.

Bert

[Vintage]

Well, given the lack of time and a lift, I let the local MB dealer do it. Parts and labor came to $320. Money well spent. Steering is right and tight.

[Strife]

I can't overstate the importance of not stripping the bolts, at all costs. You will wonder why the fates have abandoned you if this happens. Avoiding this involves:

1. Using the highest-quality tools

2. SOAKING in Liquid wrench, etc and LET IT SIT FOR AT LEAST ONE DAY

3. Cleaning out the heads of the bolts with liquid wrench and a Q-TIP so that the tool can go completely and entirely as deep as possible.

4. Removing with even and constant downward pressure so that the tool will NOT clock out.