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

tangofox007 · #16 05-07-2009, 08:34 AM

Quote:

Originally Posted by kerry

Rotate the yoke on the transmission. Needs to be in neutral. Block the wheels well before climbing under there. There wont be any resistance to rolling in the drivetrain.

How is the driveshaft going to rotate if the wheels are blocked?

At least one rear wheel needs to be elevated and free to rotate.

pawoSD · #17 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 · #18 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 · #19 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 · #20 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.

kerry · #21 05-07-2009, 11:44 AM

Quote:

Originally Posted by tangofox007

How is the driveshaft going to rotate if the wheels are blocked?

At least one rear wheel needs to be elevated and free to rotate.

No need to rotate the driveshaft if the transmission turns unless you want to spin the driveshaft for better access to the bolts. Blocking whatever wheel is on the ground would work.

BodhiBenz1987 · #22 05-12-2009, 06:11 PM

Started this job today ... not going so well. First problem: I can't get the large nut on the shaft to turn. I did get it about a half-turn, but the tools I'm using are impossible. I don't have the giant wrenches so I'm using a crescent wrench and pipe wrench, both extremely heavy and will barely fit. Is there anywhere to buy the 41 and 44 mm open end wrenches, and are they really expensive? Having the right tools would make this job doable, I think. The Haynes manual says you need about two turns of the nut to compress the shaft ... is that about right?

I'm also having a bear of a time getting the bolts out of the flex discs, although I've gotten the three out of the rear that attach it to the shaft, and two from the front. I'm pretty sure I've broken part of my knuckle, but I guess better that than the car, right?

I just got overwhelmed after 3 1/2 hours and went home. Ugh.

lietuviai · #23 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.

dieseldan44 · #24 05-12-2009, 06:24 PM

BodhiBenz,

You need two wrenches like this for optimal operation on the driveshaft nutes: http://www.hardwareandtools.com/invt/u714904

You can get them at Lowes, Home Depot, or your local harware store - they are around $15 a piece.

You can get big wrenches from NorthernTool.com - I have a 46mm open end wrench and it looks like a cartoon it's so big.

If you need more torque with the smaller handle adjustable wrenches, get a piece of 12" long 1" black iron pipe to use as a 'cheater'. Slip it over the existing handle for a longer handle and more force :-)

For the nuts on the discs themselves, I found that a gear wrench was very helpful as a back up wrench. It helped me put the most force to get them loose. Don't forget to douse them in PB Blaster beforehand.

If you are going to go for the full center carrier + bearing replacement you will need a 3 jaw puller to extract the bearing and a correctly sized PVC pipe section (i forget what size) to tap the bearing in.

Good luck - I did this two years ago on the '82 and Im already fuzzy on it.

Thanks to you I looked under my '85 and saw a small crack (big enough to see white thread) in my flex disc, so I'll be doing this again shortly. Thank you again.

Do you have the FSM? I remember the article on this job being very helpful along with the Haynes manual.

dd

JEBalles · #25 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 · #26 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 · #27 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 · #28 05-13-2009, 07:26 AM

Check this out!

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

dannym · #29 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 · #30 05-13-2009, 11:38 AM

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