Clutch misbehaving

[JJC]

The clutch on the 4 has always been a bit marginal. Almost on the floor. Suddenly its got a bit worse. Is there a possibility Ive got a mismatch between master and slave? Both new about four years ago. If so, how can I tell without chasing back through hundreds of Moss invoices to look for part numbers? JJC

PS I did check it doesnt need bleeding.

[PYU940F]

Hi

Mine was the same this summer. First top up reservoir and see if clutch pressure "pumps up" for a second or two. If it does then either slave or master cylinder. Look for leaks at both to determine which. (mine was the slave and cost a few quid for the kit. If it does not "pump up" it is probably mechanical and the clutch will need changing, unless the adjustment on the slave cylinder is completely wrong, By the way, the rod from the slave cylinder should be in the middle hole of the lever from the clutch housing.

 

Cheers

 

Simon

[Lebro]

Taper pin on cross shaft sheared ?

 

Bob.

[nigethomas]

+1 bob

 

Nige

[JJC]

Thanks for your suggestions. It’s virtually all new, no leaks, very unlikely cross shaft pin sheared. I have a vague recollection that there are two sizes of hydraulic systems but don’t actually know. That’s really what I’m asking. JJC

[BrianC]

Since "it's virtually all new" I assume this includes the flexible hose. If not, then check that it's not ballooning due to softening. This happened with mine due to oil contamination, although the clutch was still working fine. It's also worth fitting a s/s braided hose if/when you do change it as it is less likely to have this problem.

[JJC]

Brian good thought. I’ve been fighting an oil leak so checking the hose might be a good plan. JJC

[JJC]

If I’d looked in the Moss catalogue I could have answered my own question. There are two but that wasn’t the problem. Looks like worn clevis pin at the m/c allowing too much slack in pedal travel. Annoying as that’s one of the very few bits that weren’t new. JJC

[Steve Priest]

Thanks for your suggestions. It’s virtually all new, no leaks, very unlikely cross shaft pin sheared. I have a vague recollection that there are two sizes of hydraulic systems but don’t actually know. That’s really what I’m asking. JJC

 

I'm sure someone will correct me if I'm wrong, but I think the correct slave cylinder size is 1" bore. It is also possible to get a slave cylinder with a 7/8" bore, which is what I use on my TR4. The size is normally embossed on the side.

 

I found that the clutch on my 4 was marginal with a 1" slave, hence the change to 7/8" to get a bit more movement. If using the center hole on the cross shaft lever, a 7/8" slave does result in a very heavy clutch pedal. My solution was to use the bottom hole, which still gives slightly more movement than a 1" slave on the middle hole, but you don't need a left leg like a Russian shot putter to change gear.

 

Also, Revington TR (and probably others) do an adjustable rod/fork assembly for the clutch master cylinder, so you can raise the pedal up a bit and adjust out the slack to get a bit more travel (item RTR4136K).

 

http://www.revingtontr.com/product/rtr4136k/name/rod-assy-adj-tr4-4a-cl-master-cyl

 

Cheers,

Steve