Clutch slip

[Dave Mann]

I've been asked to look at a Seven which suffers clutch only when negotiating a hill on a bend with no bother on a straight hill. Anybody any bright ideas as to what is going on?l

[Alan]

You sure it’s clutch slip and not wheelspin? Otherwise first thing I’d look at is are the engine mounts tight.

[David Witton]

Halfshaft key shearing on taper? Some years ago pal of mine had similar symptoms and that was the cause

[Ian Williams]

Agreed half shaft key failure, is the first thing I would look at.

[Dave Wortley]

Probably not much help Dave but my chummy also has this problem when exiting our drive. Very steep at the top bit and a full left hand lock. No slip anywhere else. I sold it to Tony Griffiths so he might know the cure.

[Tony Griffiths]

Probably not much help Dave but my chummy also has this problem when exiting our drive. Very steep at the top bit and a full left hand lock. No slip anywhere else. I sold it to Tony Griffiths so he might know the cure.

Indeed - it is very strange indeed. And no, it's not the half-shafts; I did the rear brakes a few weeks ago and the keys and tapers were in first-class-engineered-blue-split-pins-dead-in-line-through-the-holes-previously-assembled-by-an-expert order. No doubt, when it comes apart, we'll find out what the gremlin is!

[Alan]

When you apply left lock it unloads the LH rear wheel. Particularly if the dampers are a bit loose. With less load the wheel has less grip and if you apply sufficient torque it will spin. That’s what’s happening. The clutch doesn’t know if it’s in a corner or not.

[Tony Griffiths]

When you apply left lock it unloads the LH rear wheel.  Particularly if the dampers are a bit loose. With less load the wheel has less grip and if you apply sufficient torque it will spin.  That’s what’s happening.  The clutch doesn’t know if it’s in a corner or not.

There was a slight error in the reporting; it's not turning off-camber and so unloading the inside wheel and causing it to spin, but making a right-angle turn, left or right, before going straight up a steep hill that (sometimes) causes the clutch slip. Approach the hill straight on - and there is no slip.

[Alan]

So, to be clear, do you mean the slip takes place on a straight action of hill AFTER you have turned a sharp corner onto it? If so, is it instantaneous or does it last a while?

[Bob Culver]

I hope this gets sorted soon. The concept of a taper slipping to the extent that it can be mistaken for clutch slip is keeping me awake at nights!
(Sevens can produce curious effects. Decades ago a young mechanic apprentice lived near me. I was the only other Seven owner for miles so we often compared notes on our "motoring". Out one Saturday night there was a bang and his Seven mysteriously commenced to torque steer left and right.....all the way home. His Trade classes had not covered that.)