Monday, July 22, 2013

Clutch problem solved

Fellow Volvo enthusiast, Richard, arrived Sunday around 1:00.  Back in the 70's and 80's we both had 140s.  He a '72 145s, and me a '70 142s.  It was like old home day.  We had the transmission dropped out in under an hour.

Transmission removed

With the clutch removed, the problem became immediately apparent.  In the pictures below you can see that there is a 1/4" difference in height of the stacked pressure plate and release bearing between the new (and old) Sachs clutch and the National Clutch replacement that I was supplied.  Despite National Clutch claiming their product is a direct replacement for the Sachs clutch, it appears to actually be a replacement for the alternate Borg and Beck clutch.  The Borg and Beck requires a release bearing that is 6mm taller/longer than the Sachs.  Guess what 1/4" converts to?  Yup, 6mm.  Clutch problem solved.  The new Sachs kit that I bough is ready to install.

Transmission Removed

3-1/4" on National Clutch

3-1/2" on Sachs clutch
Then on to the oil leak.  The seal looked fine with no signs of leakage around the crank end.  Same for the oil galley plug and the crank shaft bore end plug.  All the oil appeared to be around the pan seam.  First check was the pan bolts.  The book quotes ft-lbs, but my torque wrench is in in-lbs, so a little conversion is required.  The result is that all the pan bolts were loose!  Maybe it's a result of gasket compression, or maybe I miscalculated when I originally assembled the engine.  But they tightened up a bunch.

Oil leakage around pan seam, not seal

Now the tough question was whether to take apart the rear seal housing, or leave it in place hoping that tightening the bolts would do the trick.  Removing the seal housing meant risking damage to the pan gasket, and the pan gasket can't be replaced without removing the engine.  But not removing the housing means a risk of not fixing the problem.  The decision was to leave the housing in place, and goop up the seam between the pan and block with RTV.

After reinstalling the flywheel and clutch, we offered up the transmission and completed the re-installation before 4:30.  I guess there is a benefit to having done this before ;-)

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