111 280SE 3.5 steering coupler repair - tips?

[sjefke]

So I got back from holiday and decided to investigate the massive steering play I have been experiencing for the past couple of months in my coupe. I thought the steering box might have to come out (following Tony H and GGR's lead), but crawling under the car, I realized that the coupler is the cause of the play. I am missing a lock, spring washer and noticed a lot of play in the bushing (or whatever is left of it - it may have fallen out) on one side.

Couple of questions:

1 - Should I order a complete new coupling or order just the bushes?
I found complete couplings online at various sites ranging from $70-$110. (don't know Fastlane price because Fastlane parts does not have my car model on its site...). Have not looked for bushings yet (might get those from MB, but have not checked EPC yet)

2 - If it is "just" a bushing, is that easy to push in with the coupler left in place? I suspect the clip fell off, followed by washer, and that finally the bushing worked its way out. It looks like I could just push a new one in from below the car, but please advise.

3 - How easy/difficult is this to replace the whole coupler? Should I prepare myself mentally for a day of torture, or is it a 1/2 hour heavenly experience of accomplishment?

Any tips are appreciated.

Thanks,

Bert

[Mike D]

There are two types of couplers. One has replaceable bushings. If you can see the coupler you can tell. The replaceable style has locking flat spring retainers on it. The bushings are about $10 US. The other style runs about $95 US.

Before you pop out and get the replaceable bushings you need to get the coupler off and inspect it for actual metal wear in the bushing sockets and that is why they made two types. One for the Joe who knows the condition of his car and one for most of us who don't want to piss about and take the chance of finding a bad metal housing on a car someone else has been, ahem, "maintaining"..

The spring clips are on the two pins which provide the actual pivoting part of the coupler.

[werminghausen]

Bert
If you have the clips (and have the replaceable coupler bushing type) then it is relatively easy to change the nylon bushings which are cheap.
I just did this job on my W109 and it is very tight place to work. I think other cars have more space.
First remove the 2 bolts that clamp the coupler. Then...
In order to get he coupler out I had to lower the gear box .
Remove the 3 (17 or 19mm., forgot) screws accessible at the wheel well with wheel removed. Then lower the box as much as you can with all the connections still in place.

With airsuspension and the 3.5 I had limited room to move and I needed to pull the steering shaft (in order to get enough play to slide the coupler off the shaft) by removing the steering wheel /removing the spring ring which holds the ball bearing of the steering wheel in place. Then you can pull the shaft and this frees up the coupler.

When you Reassemble make sure you DON'T put the two screws in the coupler before the coupler is in place because the screws not only clamp but also secure the couple so it can't come off in case the screw come loose.
Guess how I know.

[meltedpanda]

just make sure you fully seat the steering shaft and that you mark positions of the shaft spline so that the steering wheel is straight upon rebuild

[sjefke]

I have the earlier type with clips.

I just placed an order with MB for new bushings, clips, etc. A new coupler will get me a new type with non-replaceable bushings. I figured I'd try the "repair" mode with bushings first. I can always change the complete coupler down the road. They seem to be the same for a bunch of MB models anyway, so not rare at all.

And yes, I am fully aware of making markings. I have had my share of disassembling steering systems to know. Unfortunately, my coupe's steering wheel is already off by a notch courtesy of a prior owner's maintenance by a "professional" garage. I know I would have done better...

Bert

[Mike D]

The best way to do is to pull the plug on the top of the box. Grind a bolt into a slight "tip" shape and screw it into place (there is a small detent you'll see at center) to hold the box at center. I'm thinking it's an 8mm fine thread.
_______

[GGR]

Bert,

all what the others said. It's also a good opportunity to reseal the steering box in case it leaks.

Originally Posted by Mike D

The best way to do is to pull the plug on the top of the box. Grind a bolt into a slight "tip" shape and screw it into place (there is a small detent you'll see at center) to hold the box at center. I'm thinking it's an 8mm fine thread.
_______

That's hard to do on V8s as the exhaust maniold is in the way.

[Mike D]

Oops! Sorry about that, I forgot he was working on a V8.

[sjefke]

Yes, I can only get to it from the underside. I plan on raising the car high up on the left front side (on sturdy axle stands) and see whether I can push the new bushing in without taking the coupling off the shafts. According to the section view drawing in the workshop manual, it should be a straight hole all the way through so I am hoping a little pushing and wiggling might get the bushing in (famous last words...).

Down the road, I plan to get the engine out sometime, and that would be a good time to do check the whole coupler and steering box in depth. I vaguely recall that a PO replaced the steering box one time, so it should be fine.

Bert

[Mike D]

In one of the threads someone posted the easiest way to do the coupler in the V8 models is to pull the steering column and go at it from the top. Leave the coupler connected at the steering shaft end and remove the bolt at the box end. If I remember correctly you don't even have to loosen the box bolts.

[gs sparhawk]

Did my '79 6.9---a tight fit in there. A buddy's lift was the biggest blessing. rotated the steering box down and away from the coupling after disconnecting the coupling from the box shaft. Then pulled the whole coupling off the steering shaft and took it to the bench. The sparse remains of the old bushes came out and then used the vice to squeeze the new bushes in. Not bad with the controlled force. "Reassembly is in reverse of above." Made a world of difference and was worth the strain of getting the box bolted back up.

[sjefke]

Just a quick update. My plan A did not work. Turns out the the new bushing is longer than the gap between the coupling and the steering box. It's only about 3 mm longer and I was tempted to shorten the bushing but decided against it (if MB had just made the gap a bit wider...).

Now I'll have to go with plan B, which is either pulling the steering box out of the way (seems to be the easiest access), or pull the column like Mike D suggested (although there is not much room).

I'll make sure I have plenty of time (and refreshments) ready when I start to do that because it looks like a bit of a pain. V8s are wonderful to drive, but do result in cramped working places.

Bert

[Mike D]

Yeah, it's a 7.8 on the PITA meter and about a 4 on technical skills. Persevere and you'll be fine. Take it slow, don't force anything, if something gets sticky then walk away for a few minutes.

[sjefke]

Finally decided to tackle this job (procrastination? me?). Workshop manual advises to do it from the bottom by removing steering gear. Got the bolts loose and was able to slide coupler up, but there is simply no way that the bushings I got from MB will fit without some major presswork. Not sure who made these, but they seem to be larger in diameter than the hole.

So, plan B will be to order a complete new steering coupler and put that one in. Also because the second bushing in existing coupler is complete mush/absent too.

Inspecting this, it seems easier to do this from the bottom in my car because I worry that if I take the steering column out (seems to be an ordeal) that I may still not have enough room between gear shaft and firewall to pull/put the new coupler on.

Good news is that at least all bolts have been loosened so next time should be easier. And why MB loves those (bendable) clips everywhere instead of nuts is beyond me.

Bert

[GGR]

Originally Posted by sjefke

And why MB loves those (bendable) clips everywhere instead of nuts is beyond me.

And why MB stuck so long to steering boxes instead of rack & pinion is also beyond me. That steering box on V8s is a real PITA.