Driveshaft question - PeachParts Mercedes-Benz Forum

rickg · #1 08-31-2004, 10:27 AM

Did a search and got too many results to read thru on this.
I was checking the SD over last night getting ready for a trip. Was under the car checking the driveshaft and could feel what I thought was slop in the center U-joint. Oh great! Took off the cover and found to my relief it was not the joint, but the spline coupling that was a bit sloppy.
So, the question. How tight should that nut be? I checked the repair CD, and it didn't really say. I just snugged it down until I couldn't feel and movement or slop in the spline. Is it supposed to be tight? Or should the spline be able to slip in and out at all? I would think not, since these cars have indie rear suspension.

R Leo · #2 08-31-2004, 10:37 AM

I just tighten mine as much as I can...probably 30-50ft/lbs

rickg · #3 08-31-2004, 10:53 AM

OK, thanks

Just wanted to make sure I wasn't gonna screw something up. Don't need any disasters on a trip.

skaa · #4 08-31-2004, 01:47 PM

RickG,
I'm reading this thread because I just replaced the driveshaft on my 1982 300SD last month after my front Flex Disc failed. I bought a new driveshaft from Driveline of Portland (www.driveshafts.com). While installing mine I had the same question about the slip nut, and spoke to the guy who actually makes and balances the driveshafts in their shop. He said when the driveshaft was at the right length during installation, just tighten the slip nut about 1/4 turn more past hand tight. He said some play (expansion and contraction) on the spline forwards and backwards was OK because of temperature variations that may occur under the car during daily (yearly) use. He also said that with a car as old as mine, 337,000 miles, that nothing in the drivetrain would ever line up as perfectly as it did from the factory, so a small allowance for self-adjustment wasn't a bad idea. I'm checking the whole thing every week or two for a while, but it seems fine. Just my $.02 worth...
SteveKaa
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1982 300SD 337k miles

rickg · #5 08-31-2004, 01:53 PM

Thanks Steve. I'll keep an eye on it. I don't think I went real tight with it. I just kept snugging it down a little at a time until the "clunk" went away when I grab hold of both sections and wiggled them around. So I think there's still some allowance for the splines to slip a bit if they have a mind to. I just thought it was kinda wierd the repair CD didn't give any kind of specs as they do for anything else on the car.
I was glad to see that the center support bearing looks fairly fresh, and the u-joint had no perceivable slop at all. The PO of this car really did take care of this thing as I was told. The more I get into this car, the more I see it was cared for.