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-   -   M46 Problems (kinda) (http://d24t.com/showthread.php?t=471)

nick 10-19-2010 01:59 AM

M46 Problems (kinda)
 
I just purchased a 1983 760 GLE, and drove it nearly 400 miles the same day with no drivetrain problems. The following day I could not disengage power to the transmission with the clutch (I could not shift gears by pushing in the clutch, even at a dead stop). I verified movement of the clutch fork, and even tightened the clutch cable to move the pressure plate even further off the clutch disk. I was about 50 miles from my house when this happened, so I just started the car in gear and floated the gears all the way home.

My wonderful fiancé assisted me in pulling the transmission out, and I found that the pilot bearing was trashed. The rollers were crumbs. It seems that this was causing the input shaft to be out of alignment and therefore angling the clutch disk, making it rub the flywheel and pressure plate.

All of the clutch components said "Made in Germany", "Sach and ....", "Volvo", and had the 4 Audi Rings. I figured the clutch could have been original, given the previous owner told me the car only had about 170k. I decided to go ahead and replace the clutch components and resurface the flywheel.

I tried jigging the flywheel up in a lathe, and was successfully able to center it up along the axis of the lathe, but I could not make the flywheel normal to the axis. After 2.5 hours I decided to take it to a company here in Jacksonville that has a diamond buffer designed for resurfacing flywheels. Fleet Pride did an excellent job, way better than I was expected to do with the lathe.

I could not find an OEM clutch kit for the car. I called about 25 different companies and emailed a few too. I finally decided to use after-market. I selected a Luk clutch kit, since they are OEM in a lot of vehicles now-a-days. Auto-zone offered it with a lifetime warranty (against wear too) for $205. This included the following parts: Luk (clutch disk, pressure plate) and Sachs and S... (throwout bearing), alignment tool, spline grease. I was excited to get the OEM throwout bearing.

I replaced the rear main seal while everything was apart. The car runs great now. No more clutch disengagement problems. It is definitely a blessing to have it back on the road. I really like this car.

v8volvo 10-20-2010 05:50 PM

Glad to hear you got it sorted out. It seems like the pilot bearing is one of the only weaker links in the D24T/M46 drivetrain. My first Volvo diesel, an '85 745 TD with an M46, had the same problem. I went around the loop adjusting the clutch, replacing the cable, worrying about a broken clutch fork, etc. Nothing helped, it still had intermittent disengagement issues. Finally pulled it apart and found a seized pilot bearing. At 200k the clutch itself still had plenty of life left. I think it would have made it to 300k or beyond if the pilot bearing hadn't given up first. Mine wasn't exploded yet, but all the grease had left the building and it was on its way there.

Luk is a good choice, their stuff is always good quality (except for those leaky PD TDI fuel pumps...). Did they provide a new pilot bearing with the kit? If not, what brand did you go with for that? Seems like a good one of those is hard to find.

They are indeed fantastic cars to drive, and under-appreciated. They got a bad rep from people who didn't know how to maintain them, but those of us who have them and understand how to take care of them know better...

nick 10-26-2010 02:50 AM

Yeah, the Luk kit came with a new pilot bearing. It had the same bearing number as the factor one that I removed. The clutch disk that came out of the car seemed like it had just as much meat as the brand new one.

I really like the car a lot. I get 37 mpg in overdrive and 28.5 mpg in 4th. I say this because I had to make a new wiring harness for the transmission while it was out since the old one was rotten to bare copper wires. I used Alldatadiy.com for the wiring diagram, but I obviously did something wrong...I no longer have o/d. I haven't had the time to do ANY troubleshooting.

nick 10-29-2010 04:28 AM

M46 Wiring
 
Does the output of the OD switch go to ground when in 4th gear? (open circuit when not in 4th)

nick 01-17-2011 03:35 PM

Yes, look at item 77:

http://dl.dropbox.com/u/11228964/Online/m46.jpg


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