Can any good machine shop shorten a Mercedes driveshaft? - PeachParts Mercedes-Benz Forum

bosshog383 · #1 02-06-2009, 03:11 AM

It appears I need to shorten my driveshaft on my 420SEL. I've had them done on American cars before with no problems, just weld the yoke back on. The Mercedes shaft looks different, doesn't appear to be welded. Is it pressed on?Can these be cut off at the yoke and welded back, or is there a different method needed? Is it better to cut the spline end when shortening? At least that way if the weld failed, it would not tear up as much as the other end.

clm · #2 02-06-2009, 05:58 AM

Why does it need changed?

bosshog383 · #3 02-06-2009, 09:57 AM

I'm putting a 617 in the 420 body. When on the floor, both engine/trannys measured within a half inch of each other from engine mounts to tranny yoke/flex disc mounting surface. However, I had to swap tranny yokes in order to fit the 420 driveshaft. I'm going to measure those this morning to see if the 420 yoke is longer than the 300SD yoke. Everything is tight right now, with full compression of the splined end into the carrier bearing assembly,in normal operating position.There is no movement left at all, in fact it appears to be bending the flex disc slightly, which can't be good.

Stevo · #4 02-06-2009, 10:08 AM

There is only one place on the west coast I would send a D/S to. Dont know about other parts of the country but IMO, thats a job for a "specialist". Like not going to a GP for open heart surgery

TheDon · #5 02-06-2009, 10:20 AM

look in the phonebook for a driveshaft shop... yes there are shops dedicated to driveshafts and other driveline components...

winmutt · #6 02-06-2009, 10:32 AM

Bosshog: car-parts.com will have a proper DS if there are no SD's on the yards around you.

Bajaman · #7 02-06-2009, 11:24 AM

Most shops won't touch it because they are only set up to handle u-joint style shafts, even if they do claim to be driveshaft specialists.

rrgrassi · #8 02-06-2009, 11:27 AM

Call around to local drive shaft shops. It helps if you people that do racing on the weekends. They usually know of good, capable shops.

TylerH860 · #9 02-06-2009, 01:41 PM

Its probably cheaper to find a SD driveshaft.

sixto · #10 02-06-2009, 04:10 PM

See if an SD front shaft is sufficiently shorter than the 420 front shaft. An entire SD prop shaft won't work because the 420 is more than 1/2" longer in wheelbase. If an SD front shaft doesn't work, maybe a 300SE or 350SD front shaft is the right length.

If all you need is a half inch, maybe you can shave a quarter inch from the face of each flange/yoke.

Sixto
87 300D

bosshog383 · #11 02-07-2009, 12:45 AM

Today I went to my local machine shop that has done driveshafts in the past for me. He said he could do it, but didn't really know how it was put together, and could not guarantee anything. I need it to be 1" shorter. I called another shop that specializes in driveshaft shortening, they would not touch it. I then called Driveshaft Specialist in San Antonio,TX. They can't do it there, but work with a shop in California. Will give me a totally rebuilt(new u joint,carrier bearing),fully balanced, shortened shaft for around $525. Looks like I may go that route. They will also check my measurements out to see if any other stock shaft will fit, that would run about $367, depending on shaft.
I have my SD shaft still to check, but then would need balancing to be correct, so may still be better off with the rebuilt unit.

peterhardie · #12 02-07-2009, 09:34 PM

I had to shorten a shaft after putting a 4-sp in. It cost me under $200 (wholesale possibly), similar price on a similar job on a Grand Wagoneer years ago. Check your Mercedes specialists; a few guys I checked with first said they would not touch it, or said it could not be done. I found out who the dealers used.

The place I used did limos and trucks. Good job; no issues afterwards.

I would keep looking. Find someone who sounds totally confident.