C3 Clutch Pedal

[Forrest Gump]

The clutch on my ‘75 starts to engage when the pedal is only very slightly lifted off full depression.
I’m interested to know if this is the same on other C3s or if your biting point is higher on the pedal travel?

My linkage is correctly adjusted to give just a little free play. The car is fine to drive generally, I can’t detect any clutch drag, but sometimes it can be difficult to get reverse. The other thing is, and this is why I’m questioning the clutch set-up, is that I have now got a pretty shot synchro on 2nd gear after only a few thousand miles since a previous rebuild. Low road speed and engine rpm changes into 2nd gear are fine but if I gun it in 1st, the change into 2nd is getting really difficult (ie likely to crunch) I’m wondering if the clutch set- up could have contributed to the synchro failure. It could just be due to an inferior quality synchro ring and nothing to do with the clutch, but I don’t want to destroy another synchro after I’ve got the gearbox rebuilt again. Changes into 3rd and 4th are fine. The clutch is a RAM HDX performance, gearbox is Borg & Warner.

 

[Roscobbc]

Sorry to hear about that Andy......wonder if any of the clutch components are out of 'spec' and not allowing release bearing to disengage fully? - this was always a potential issue with the fluid relase mechanisms.....yours being mechanical obviously not that (unless it has the wrong release bearing?)......perhaps a posting on the American forum might pull up some potential answers relating to Ram clutches?

 

[Oneball]

The linkage adjustment isn’t just about free play. Have you followed the factory process for clutch adjustment? The floor is the clutch stop on a C3 so you need to follow the process to the letter.

 

[antijam]

This may be a stupid suggestion but do you have a loose mat in the footwell? These can get trapped and sometimes bunched up behind the pedal limiting the travel and not allowing full clutch release.

 

[Forrest Gump]

The proc

This may be a stupid suggestion but do you have a a loose mat in the footwell? These can get trapped and sometimes bunched up behind the pedal limiting the travel and not allowing full clutch release.

Nothing as simple as that I'm afraid - I don't actually have a mat in there at all!
That reminds me of when my wife phoned me saying her car had suddenly lost power. I got her to check the pedal first it turned out a small stone had lodged behind it. (floor mounted fly-by wire type pedal)

 

[Forrest Gump]

The linkage adjustment isn’t just about free play. Have you followed the factory process for clutch adjustment? The floor is the clutch stop on a C3 so you need to follow the process to the letter.

The process that I followed was as follows:
With the lock nuts wound clear from the pivot, apply 5lbs pressure to the actuating arm (to take up slack downstream to thrust bearing)
Set the back nut-to-pivot gap at 0.4"
Wind-in the front nut to lock pivot in this position.

I've not seen any other method or areas to adjust.

I did try reducing that 0.4" to virtually nil for a test but it didn't seem to make any difference to the bite point. If others tell me their bite point is near the middle of the pedal travel then I've definitely got something wrong in my set-up.

 

[Forrest Gump]

Sorry to hear about that Andy......wonder if any of the clutch components are out of 'spec' and not allowing release bearing to disengage fully? - this was always a potential issue with the fluid relase mechanisms.....yours being mechanical obviously not that (unless it has the wrong release bearing?)......perhaps a posting on the American forum might pull up some potential answers relating to Ram clutches?

That is the thing Ross, once you go with after market parts. As well as that, without experience of seeing others, it's difficult to know if any of the other parts are wrong like the ball stud length for example. I've got no reason to suspect any parts are wrong, but things do happen over the years.

Where is your clutch bite point?

 

[Oneball]

The process that I followed was as follows:
With the lock nuts wound clear from the pivot, apply 5lbs pressure to the actuating arm (to take up slack downstream to thrust bearing)
Set the back nut-to-pivot gap at 0.4"
Wind-in the front nut to lock pivot in this position.

I've not seen any other method or areas to adjust.

I did try reducing that 0.4" to virtually nil for a test but it didn't seem to make any difference to the bite point. If others tell me their bite point is near the middle of the pedal travel then I've definitely got something wrong in my set-up.

Did you make sure the clutch pedal was fully up and against the stop when you did it.
Your pedal bite point should be about an inch from the floor give or take. The floor is the clutch stop to stop you over extending the diaphragm and that’s the usual rule of theme for setting clutch stops. I’ve actually got and adjustable stop bolted through the floor in mine.

 

[Forrest Gump]

Did you make sure the clutch pedal was fully up and against the stop when you did it.
Your pedal bite point should be about an inch from the floor give or take. The floor is the clutch stop to stop you over extending the diaphragm and that’s the usual rule of theme for setting clutch stops. I’ve actually got and adjustable stop bolted through the floor in mine.

Oh really. I reckon my bite point is an inch from the floor too - and was questioning wether that is correct. If you think that is how it should be then I'm good.
I've read on the US forums that bite point might be at mid-pedal travel. I'm way off that and got me thinking there could be a connection with possible clutch drag and over-working the synchro?

 

[Oneball]

Easy way to test if the clutch is dragging. If you Jack the rear up and put it in gear with the engine running and the wheels stop turning when you press the clutch it’s not dragging.
In my experience with gearboxes baulk ring failure so soon after a rebuild is usually a tolerance or machining issue.

 

[Roscobbc]

That is the thing Ross, once you go with after market parts. As well as that, without experience of seeing others, it's difficult to know if any of the other parts are wrong like the ball stud length for example. I've got no reason to suspect any parts are wrong, but things do happen over the years.

Where is your clutch bite point?

Bite-point is certainly not 1" from the floor - not 100% sure without going out and driving it but its probably 2/3 rd's travel (which I would have have thought is normal. Mine is a Centerforce dual friction.....which is much the same as any other diaphragm clutch (other than differering materials on each side of the clutch disc)
Having said all that......when I installed put the new clutch in I replaced everything.....so new flywheel, release bearing, bearing in back of crankshaft for 'box shaft, clutch arm (I think) and the ball stud........that didn't work.....it was either too long (or too short) and would fit/and allow best angle of clutch arm (if I remember?)

 

[Mad4slalom]

The proc

Nothing as simple as that I'm afraid - I don't actually have a mat in there at all!
That reminds me of when my wife phoned me saying her car had suddenly lost power. I got her to check the pedal first it turned out a small stone had lodged behind it. (floor mounted fly-by wire type pedal)

Whattt? No mats? Most c3 owners have mats on mats and That can be an issue. Occaisionally I think my battery is flat as nothing happens shen i turn the key, then I realise I havent pushed the pedal down far enough and the safety switch stops it turning over. Need to build some leg muscles

 

[Forrest Gump]

Thanks fellas, some further investigation required. I'm now not too concerned there is any major clutch problem after Tims comments.

 

[Roscobbc]

Thanks fellas, some further investigation required. I'm now not too concerned there is any major clutch problem after Tims comments.

Clutches, expecially diaphagm clutches when 'on the way out' from my experience seem - depending on whether 'wear' is loss of friction material.....or diaphragm 'tangs' lost 'temper' (due to exessive clutch slip and subsequent overheating)......so 'bite' point will be close to pedal full engagement.....or......close to floor......combined perhaps with clutch 'drag' perhaps.

 

[teamzr1]

Being a bit off the floor is fine
What you do not want is mid-pedal and that means any further down and the pressure plate is being over clutching and causes
more pressure springs and on the fingers of plate

I have done for many years, esp for racing is mounting an L bracket to arm of clutch pedal with a bolt mounted by two nuts point to the floor
I can then adjust the length of bolt so that it stops the pedal from any more downward travel

 

[Forrest Gump]

Being a bit off the floor is fine
What you do not want is mid-pedal and that means any further down and the pressure plate is being over clutching and causes
more pressure springs and on the fingers of plate

I have done for many years, esp for racing is mounting an L bracket to arm of clutch pedal with a bolt mounted by two nuts point to the floor
I can then adjust the length of bolt so that it stops the pedal from any more downward travel

Thanks, it looks like my clutch set-up is about right then. I got concerned it was too near the floor and maybe not right. There is some bad information out there!
My clutch is quite switch-like on or off engagement especially compared to modern road cars that tend to be softer and engage over a wider pedal travel.