PeachParts Mercedes-Benz Forum - View Single Post - Two-Mass Flywheel failure

Greg in Oz · #5 06-21-2006, 08:12 PM

Tom,
The dual mass flywheel is effectively two flywheels coupled by springs and a damping mechanism. The primary mass (which includes the starter ring gear) is bolted rigidly to the crankshaft. The secondary mass is that to which the clutch is attached and thereby provides the drive to the gearbox. In the case of the 4-cylinder M102 up to +/- 40 degrees of movement is allowed between the two masses (up to +/- 15 degrees on the 6-cyl M103 & M104). This "soft" coupling is intended to remove vibration and noise from the driveline and to improve smoothness, particularly at low engine speeds. Unfortunately, repair it is not so straight forward as replacing bolts (they are actually rivetted pins). I actually have access to a machine shop and we investigated the possibility of a repair but decided that the labour involved would be extensive and the end result questionable. The holes for the pins which have sheared have elongated due to movement around the broken pins and would therefore need to be enlarged and larger pins fitted. Other parts such as the bearing between the two masses is worn. I decided that for such a critical component of the car it was not worth it.

Brian,
As you mention your '86 M103 still has a conventional flywheel. MB introduced the dual mass versions in late '89 for the '90 model year (except on the performance oriented 190E 2.5-16 which retained a conventional flywheel with a weight well under half that of the dual mass). When I discovered mine had failed I looked at the possibility of fitting a conventional flywheel. Studying the EPC revealed that whilst the same crankshaft was used on all the 2.3 litre M102 engines, the gearbox input shaft and guide tube were shortened to accommodate the thicker dual mass flywheel. I liked the idea of a lighter conventional flywheel providing a slighty more "sporting" drive as whilst the dual mass is very smooth its huge mass and the momentum it carries means gear shifts cannot be rushed.

M.B.Doc,
A102 030 3105 is indeed the correct part number for the flywheel which replaces the original A102 030 2605 flywheel fitted to my car. Hopefully the new part number indicates a design change that will hopefully prevent a repeat of the same failure. The prices you quote are similar to those I have been quoted to get the parts directly from Germany. The $2516.23 my local dealer quoted me for a flywheel (and the $445.30 for a clutch disc and $495.80 for a pressure plate) just goes to show how much we here in Oz are being reamed up the you-know-what by MB on parts prices. Thankfully I don't also get reamed on labour as I do all that myself.

Thanks for the replies,
Greg