Dragging clutch

v8alex · Post by **v8alex** » Sat Dec 22, 2007 3:26 pm

I've noticed when the engine is running the output flange on the box is spinning too when the box is in neutral. I have a new clutch (AP heavy duty) which has not seen any use yet.

Yesterday I connected up the propshaft and the rear wheels turn slowly with the engine running, but I could hold them still with one finger. So I guess the clutch is dragging slightly and will settle down once a few miles have been driven and the friction plate has bedded in.

However, on starting the engine today, the rear wheels started turning again, but with much more force than yesterday and it was almost impossible to stop them turning using my hands. The clutch hasn't been bled yet, so I've been unable to use the clutch pedal to see if this will stop things.

So things seem to have tightened up a bit overnight. The car is up on axle stands at the moment, so I guess when it's on the ground the weight of the car will hold things still, but thought it wise to ask the question - Should I be worried ?

Alex

Post by **katanaman** » Sat Dec 22, 2007 4:47 pm

I am confused here, you say your clutch is dragging but you also say you cant release it yet because you haven't bled the hydraulics? Or do you mean its in neutral but still turning and you cant stop it?

ian.stewart · Post by **ian.stewart** » Sat Dec 22, 2007 5:04 pm

If the flange is turning round with the box in neutral, the only thing that can do this is the viscosity of the oil and friction in the bearing in the input shaft or perhaps a sticky syncro cone, with the pedal up on the clutch there is CONSTANT drive to the gearbox
it was colder last night than the night before, I wonder if the gearbox oil has stiffened up over night, especially if you had the been working in the garage all day the ambient temp would have increased compared to how it would have been this morning and you probably had the engine running longer to enable heat transfer to the gearbox for longer.

v8alex · Post by **v8alex** » Sat Dec 22, 2007 5:08 pm

OK sorry - to be clear, the hydraulics have not yet been bled so I cannot operate the clutch to free up the friction plate. The gearbox is in neutral at all times.

With the engine off I can turn the output flange by hand, no problem.

Start the engine and the output flange spins with the engine.

Connect up propshaft and rear wheels spin slowly, but gentle hand pressure stops them.

After an overnight spell, running the engine again and wheels were spinning again, but now very difficult to stop by hand.

So what I'm saying is in neutral, no hydraulics and it's very hard to stop the rear wheels spinning after an overnight break.

Hope this makes a little more sense.

Alex

ian.stewart · Post by **ian.stewart** » Sat Dec 22, 2007 5:19 pm

dont think its anything to worry about!!!!

Post by **katanaman** » Sat Dec 22, 2007 5:19 pm

Yup makes sense now. As Ian says really as its nothing to do with your clutch. Don't know what box you are using or the type of oil in it either but thick cold oil can make the box drag in neutral as well. Let it heat up and you shouldn't have any problems although its still common for there to be a slight drag so don't panic if there is. If its an LT77 you should be using Dextron II or similar weight of oil and not EP80 or something as thick as that

v8alex · Post by **v8alex** » Sat Dec 22, 2007 5:29 pm

Just went to the garage and gripped the prop and rear wheel together and it freed up with a sharp twist and now spins freely again. Guess there's something sticky in the box as you say, oil or more likely a syncro piece.

The box is an R380, reconditioned from Gearboxman so should be a good one, but like everything else in the kit car, not yet seen any real use. It is filled with MTF94.

Hopefully when the things all built up a quick blat up and down the road will shake things out.

Thanks again, your comments are appreciated.

Alex

ian.stewart · Post by **ian.stewart** » Sat Dec 22, 2007 5:43 pm

If Bernie built it, its a good bet its a good one