The Death of a Flex Disc ... did I kill my 240D? - Page 2 - PeachParts Mercedes-Benz Forum

Bajaman · #1 05-07-2009, 07:45 AM

also check the centering bushing in the end of the driveshaft. It goes over the pin on the transmission yoke. If this bushing sustained damage from your catastrophe, it will not center the driveshaft properly. I would see if I could feel any lateral play without the flex-disk in there (just the centering bushing on the pin).

lietuviai · #2 05-07-2009, 11:32 AM

Quote:

Originally Posted by Bajaman

also check the centering bushing in the end of the driveshaft. It goes over the pin on the transmission yoke. If this bushing sustained damage from your catastrophe, it will not center the driveshaft properly. I would see if I could feel any lateral play without the flex-disk in there (just the centering bushing on the pin).

Yes X2 on this. There's a good chance the bushing got damaged in the process. That bushing is also what may have saved your car from further damage. It's easy to replace.

pawoSD · #3 05-07-2009, 09:18 AM

That was a lucky break, looks repairable by just replacing the discs....perhaps the weakling power output of the 616 saved you from catastrophe!

rs899 · #4 05-07-2009, 09:28 AM

Be prepared-compressing the driveshaft and getting the flex disc metal inserts out of the flanges can take some effort(once you get the bolts out) . They can be wedged (and rusted) in there pretty tightly. You may want to get under there a day in advance and soak everything down with penetrating oil.

Rick

JimmyL · #5 05-07-2009, 09:41 AM

Quote:

Originally Posted by rs899

Be prepared-compressing the driveshaft and getting the flex disc metal inserts out of the flanges can take some effort(once you get the bolts out) . They can be wedged (and rusted) in there pretty tightly. You may want to get under there a day in advance and soak everything down with penetrating oil.

Rick

Great advice, especially after your uca bolt.......

lietuviai · #6 05-12-2009, 06:18 PM

I've found using a small pipe wrench works fine on the nut. Try a sawzall on the nuts/bolts you can't get off. The new flex disc comes with new ones.

JEBalles · #7 05-12-2009, 07:37 PM

When I replaced my transmission, I didn't need to touch that big nut, despite what the Haynes manual said. Try compressing the shaft without loosening the nut.

BodhiBenz1987 · #8 05-13-2009, 12:59 AM

Thanks guys. I went to Lowe's and they didn't have any large enough adjustable wrenches, so I picked out a vice grip wrench that looks like a small pipe wrench. I used it on the lock nut and used a crescent wrench on the driveshaft and it worked great. That is, once I turned the nut in the right direction.

I did get the third bolt out of the driveshaft-flex disc. I can compress the shaft, but it's stuck to the tattered flex disc, which is still bolted to the tranny. I shot PB Blaster everywhere and hopefully the shaft will move off the disc tomorrow. If not, I'll try to get the other three bolts off and let the disc come out with the shaft. Really tough to get at the shaft/tranny bolts because of the flex disc wreckage. Long way to go, but at least I ended the night with some progress.

rs899 · #9 05-13-2009, 06:36 AM

Not sure if the little incident you had is making disassembly worse than "usual", but the flex discs do not just fall out of the flanges once you get all the bolts out. You will need to get a very hefty screwdriver or pry bar in between the flange and flex disc and pry them apart (forcefully!). The metal inserts on the disc are a tight fit into the flange (even without any rust or crud involved).

Rick

Mike D · #10 05-13-2009, 07:26 AM

Check this out!

What happens when you ignore that "little" driveline vibration!

dannym · #11 05-13-2009, 07:59 AM

Quote:

Originally Posted by BodhiBenz1987

Or how I could be dumb enough to keep driving it after I felt something amiss. The only thing I can say in my defense is that the car drove unbelievably normal.....

You have to be sensitive to the small signs. I once had a blow out on the rear tire doing 60 on the highway. I could hardly tell anything was wrong.
My daughter was sitting in the back seat too. I looked back and asked her if she heard anything and she could barely hear it.
I pulled over and found the side of the tire blown out. I couldn't believe how well it ran.

BTW I love vise grips! They've got me out of a lot of jams!

Danny

whunter · #12 05-13-2009, 11:38 AM

Driveshaft, Axle & Wheel bearing
Driveshaft, Axle & Wheel bearing

BodhiBenz1987 · #13 05-18-2009, 01:44 AM

Just a little update: Everything is out, after much fighting and a few minor injuries. I ended up getting the shaft off the disc (and tranny/diff) using a chisel and hammer to knock the little metal cuffs out. Lots of work in a tight, dirty space. Getting the bolts off involved holding a wrench on the nut with both hands while lying on my side and pushing my foot on the breaker bar to break the bolt lose. Good thing I'm flexible ... it worked on every bolt. I did have to buy a 6pt 15mm socket to get the sheared bolts off.
Damage assessment is pretty much what I thought before: Nothing catastrophic. The bushing at the front of the driveshaft was damaged so I will replace both of those. There are some minor scuff marks on the yoke of the driveshaft and tranny, but very surface. I will dab some POR15 on there to make sure it doesn't progress to rust down the road. Center support is a wreck, but I was going to replace that anyway.
One question: The grease boot on the center of the shaft was cracked and there was grease oozing from it. I got a new one, easy to install, but do I need to put any grease inside it? Manual doesn't mention it, but it also doesn't assume a busted boot.
I will be trying to complete this tomorrow if time allows before I have to go to work. Hopefully I'll remember to snap a few pictures for entertainment/educational purposes.

kmaysob · #14 05-18-2009, 02:26 AM

Quote:

Originally Posted by BodhiBenz1987

Just a little update: Everything is out, after much fighting and a few minor injuries. I ended up getting the shaft off the disc (and tranny/diff) using a chisel and hammer to knock the little metal cuffs out. Lots of work in a tight, dirty space. Getting the bolts off involved holding a wrench on the nut with both hands while lying on my side and pushing my foot on the breaker bar to break the bolt lose. Good thing I'm flexible ... it worked on every bolt. I did have to buy a 6pt 15mm socket to get the sheared bolts off.
Damage assessment is pretty much what I thought before: Nothing catastrophic. The bushing at the front of the driveshaft was damaged so I will replace both of those. There are some minor scuff marks on the yoke of the driveshaft and tranny, but very surface. I will dab some POR15 on there to make sure it doesn't progress to rust down the road. Center support is a wreck, but I was going to replace that anyway.
One question: The grease boot on the center of the shaft was cracked and there was grease oozing from it. I got a new one, easy to install, but do I need to put any grease inside it? Manual doesn't mention it, but it also doesn't assume a busted boot.
I will be trying to complete this tomorrow if time allows before I have to go to work. Hopefully I'll remember to snap a few pictures for entertainment/educational purposes.

no grease needed, the bearing is sealed. its just a dust boot.

BodhiBenz1987 · #15 05-20-2009, 09:08 PM

Update and some pics:
Well, I finished everything this evening. Yesterday I spent most of the day removing/replacing the bushings at the ends of the driveshaft (that included two trips to Lowes and a trip back to my house). I drilled a hole in each one, per Haynes manual procedure (bought a new set of Bosch drill bits that could handle the thickness), stuck a mini allen wrench through it and tried to pry it up using screwdrivers with the shaft in a vice. Upgraded to giant pry bars, no go. So I bought a torch and heated it ... they came right out. You can see the damage on the front one.

Today I put the center support back on, had to tap it on using a wide PVC pipe. The real tough part was torquing on the 12 bolts for the flex discs. My torque wrench is too big, everything kept slipping, and I had no space under there. Plus I have the strength of a preteen girl. But, I toughed it out and got them all done, despite lying in what was clearly not just mud under the back of the car.
Took it for a drive, everything seemed OK.
But here's the kicker (you knew it was coming, right?). When I was cleaning up a I picked up one of the old bolts, which still had the washer on it ... and realized I put the washer on the wrong side of every single bolt (i.e., I put it under the nut. Why? I have no idea). I doubt that will lead to immediate catastrophic failure, but the washers go under the bolt heads for a reason, and I have to go back and re-do all 12 bolts. It makes me so mad, because if I'd stopped and thought about it, logic alone would compel me to put the washer under the bolt head. And I was so careful about everything else. Oh well, it could be worse ... at least it doesn't look like this anymore ...