ChrisWhewell

Anyone know what the typical clutch life (in miles) associated with the dual-mass flywheel / clutch setup on an LT-1 propelled C4 is ?

GREGGPENN

90-120k avg

ZFDoc has one that's at 170k (and still passes the tension test).

PLRX

incredible

BAM92

Previous owner replaced clutch and flywheel at 115k.

pianoguy

At 47K, my disk looks like new.

ChrisWhewell

Mine's at 100k. Was previously owned by a rather mellow female who said she had it changed once already but I can't verify.

I'm wondering whether its worthwhile to get under there and change the clutch disc, before it goes out and takes the flywheel with it.

Or, is that not true that the cause of flywheel f*vkups is when the clutch goes ?

I'd like to preserve that DM flywheel. Other than driving nicely, is there anything one can do to extend flywheel life ? 1993 LT1 w / ZF6.

Thanks !!

MBDiagMan

I'm happy to read the responses to this thread.

Clutch life is determined SOLELY by the person managing the two pedals.

Itshakes

Just replaced mine at 68K. The flywheel was shot, and the clutch was 90% gone. replaced both (good luck finding a DM flywheel) along with throw-out bearing, pilot bearing (GM roller), pivot ball & keeper. Flushed the hydraulics, and changed the tranny fluid. This is NOT an easy job!!

2VettesMike

Bought my car with 48K and had to replace a slipping clutch at 50K. Used original DM flywheel with a new clutch and now I'm at 154K with no apparent problems.

Clutch kit at:

http://www.carolinaclutch.com/ShowIt...tch%20Kit.aspx

From a few threads it appears that the DM flywheel can have it's surface machined in most cases.

http://forums.corvetteforum.com/c4-t...esurfaced.html

http://forums.corvetteforum.com/c4-t...-flywheel.html

Good Luck,

Thanks,

Mike

ChrisWhewell

What happens to the DM flywheels on these ??? Just excessive wear ?

ChrisWhewell

Thanks a bunch for that.

Can't help but wonder whether a worn flywheel can't be electroformed with chromium or some other metal to restore its thickness, like Cal-Valves does to OEM valve stems, then machine them flat. Adding 0.020-0.050" by electroforming and machining flat should be no big deal and also very cost effective.

Itshakes

It was not the surface that failed on mine. It was the "Dual Mass" part- the springs, and the rubber piece between the two parts failed, and there was too much play in the two pieces. The surface was OK but the flywheel itself was loose, and would not return to center (too much horsepower, too much traction, too much drag racing!)

theadmiral94

ChrisWhewell,

Any chance the previous owner lady remembers where the clutch was done? If so, you could try contacting them to see if they kept any records or memory of the change.

Replacing the clutch disk will help (increases material and reduces heat build-up/transfer to DM flywheel -- just like brake pads).

Also, replacing the Clutch Slave cylinder (and maybe the master) and the hydraulic fluid can help substantially by reducing the stress on the clutch (only use GM dealer fluid it has special properties to help remove trapped air and reduce squeaking).

However, unfortunately, the DM flywheel has a finite life too. It has a fluid and seals which fail with time/heat as can the springs weaken (as mentioned by the earlier forum member). Usually in the 100K-150K range...

If you plan on keeping the car for many years, then keep your ears open for a new DM from some of the discount sources and buy one in advance of needing it (e.g. forum supporting vendors, partsladi on ebay, etc). BTW, the DM's are still available from the dealers, so in a pinch, you can still get them, albeit expensive...

ChrisWhewell

Very helpful, Sir. Thanks. I'm seriously considering putting in a new clutch disk. I spent a bit of time at zf doc's website, regarding master and slave cylinder issues, & cet. Did his recommended test and it passes, for now. I'm the pre-emptive maintenance type, as opposed to after the fact repair. I really appreciate your helpful reply. ::))