W123 propeller shaft clamping nut loose? - PeachParts Mercedes-Benz Forum

biobenz617 · #1 10-09-2006, 06:22 PM

I'm in the process of replacing my flex discs while I'm there (replacing a rusted trailing arm is what started it all) and I've taken out the drive shaft. I somehow skipped the step of loosening the clamping nut while removing the drive shaft and was able to remove it nonetheless. Why does the service manual instruct to loosen this nut?? Does it clamp the splined connection together between the two propeller shaft halves and prevent them from moving or coming apart? if so, mine was loose before i started wrenching on the car

My splined connection fell apart while I was removing the whole shaft and luckily there are alignment marks on the two halves. I just hope that the service manual isn't lying when it says "On vehicles starting August 1982 the front and rear propeller shafts are pertinently identified." (41-050, 11) My car was manufactured November 1982

Old300D · #2 10-09-2006, 07:04 PM

If you loosen it, you can shorten the shaft length, making it easier to get it out of the way.

And I've never needed to mark the two pieces, as long as you align the flex discs when you fit it together. Same thing really, but I always forget to match-mark.

Stevo · #3 10-09-2006, 07:29 PM

I seem to remember the shop manual saying "after drive shaft work let the car down and roll it back and forth a little THEN jack it back up and tighten the shaft nut"

Should have a rubber "boot" covering the spline union.

I accidently pull one apart (78) and it wasn't marked

,had to replace the drive shaft

biobenz617 · #4 10-09-2006, 08:26 PM

Hmm, I guess mine was loose to begin with. We'll I made the cutoff by 2 months according to the shop manual. I'll see whether the driveshaft wobbles out of the car after I get everything back together

bgkast · #5 10-09-2006, 08:26 PM

When I did my drive shaft I never touched a clamping nut, of corse I was not following a shop manual though

. What does this nut do? When I put my shaft in I put in the rear section and tightened down the flex dist, then put in the front section and tightened down the front flex disk. Then I spun the drive shaft a bit and snugged down the carrier bearing bolts. Did I miss something?

Stevo · #6 10-09-2006, 10:30 PM

Quote:

Originally Posted by bgkast

When I did my drive shaft I never touched a clamping nut, of corse I was not following a shop manual though

. What does this nut do? When I put my shaft in I put in the rear section and tightened down the flex dist, then put in the front section and tightened down the front flex disk. Then I spun the drive shaft a bit and snugged down the carrier bearing bolts. Did I miss something?

The nut tightens down on the splines to hold the two halves together. I think its not out of the ordenary to find those nuts not tighten up . Just crawl under and if you can find a wrench to fit, tighten her up.

pawoSD · #7 10-09-2006, 11:08 PM

Quote:

Originally Posted by Stevo

The nut tightens down on the splines to hold the two halves together. I think its not out of the ordenary to find those nuts not tighten up . Just crawl under and if you can find a wrench to fit, tighten her up.

I had a vibration before, turned it over to the stealer, turns out that very nut was loose

He tightened it and the vibration has been gone ever since. (it was bad above 50-55mph)

Wallknight · #8 10-27-2006, 09:33 PM

Yeah, the cheap walmart pipe wrench is what I used, that and a pair of large ribbed pliers did the trick.

Oh, and i dont think the spline is ever REALLY tight. with the shaft off and all the torque I could put on the bolt, it only barely stayed in one place when I pulled it. I think that may be an additionall bit of stress relief on the shaft. Just loose enough to give if necessary.

my $.05 (inflation)