Repair Question for W114 broken bolts on steering gearbox - PeachParts Mercedes-Benz Forum

bruno64 · #1 01-09-2011, 10:47 PM

I have a 1973 w114 "280cp". Vin 11407312004868. My steering gearbox bolts broke. I posted an earlier thread that was not very specific so decided to post a new, more specific thread.

Need some additional advice on fixing my steering problem on my w114 1973 280c if someone could help. Here is what I accomplished so far and where I am stuck. I removed the gear box and carefully tapped out the broken bolts. I fabricated a metal plate out of two inch wide by 1/4 steel welded. I did not weld this to the frame but plan to just place it over the frame and bolt to it. Should this be welded to the frame? Not really the problem. When I set the gear box in place there is a gap between the coupler and the steering column ( I don't really know how to explain this). Am I missing a bushing or something? It looks like the pins on the end of the steering column that fit into the coupler have grooves in them like once inserted you slide a clip over them to hold them in place but there is about a 5/8 gap there? Can anyone tell me what is missing or where am I going wrong here to fix this problem?

Thanks Bruno

pj67coll · #2 01-12-2011, 01:41 PM

Why did they break? Simply loosened up over time or is there rot inside the chassis box section so that they are screwed thru a soft rusty mess? I ask because my 108 suffered a snapped steering shaft because the box section was so badly rusted they entire steering gear box was moving around when I turned the wheel. I had a repair done by welding new metal in to the box section. Not sure if they actually cut out the old metal first though. This was years ago. I do know that this is a critical repair which must be done right.

- Peter.

bruno64 · #3 01-12-2011, 03:01 PM

Thanks for the reply/question.

Apparantly this is a common problem. My guess is the bolts were just loose and will break at low speeds with turning the wheel, which is exactly what happened. The bracket that was fabricated should add stability to the gearbox but I can't get it to fit properly. Tough ordering a manual to find out what the problem is, so I was looking for advice from any members with knowledge or experience with this.

Thanks

Bruno64

pj67coll · #4 01-12-2011, 07:05 PM

Every Mercedes manual says the bolts must be correctly torqued at regular intervals. I doubt that they are ever done as they should be. If you have fabricated a bracket does it fit directly over the box section? If so they gearbox will not align properly with the steering shaft.

- Peter.

Mark DiSilvestro · #5 01-16-2011, 11:39 PM

Not sure if failure to retorque causes the initial problem, but after so many years, what develops on these cars is the frame-rail fatigue-cracks around the mounting bolts. Then the rail starts flexing under heavy steering loads, generally at parking speeds.
Once that happens, the bolts will keep on snapping repeatedly, regardless of how well they're torqued.
It might work-out to weld that 1/4" reinforcing-plate to the outside of that frame-rail, then use longer bolts for the steering-box.

As for this new 'gap' between the steering coupler and steering box, I've seen where the telescoping steering-shaft was disturbed during steering-work, and had collapsed slightly. Could this have happened in your case?

Happy Motoring, Mark