Clutch Bite Point

[111Robin]

Just thought I'd upload these videos as there has been some discussion on clutch pedal travel and component wear. My clutch bite point is with the pedal just off the floor, hardly any travel at all. In the first video the first 4 movements are the pedal travel where it isn't operating the clutch, last movement is full pedal to the floor. In the second video the same travel in the pedal can be seen to not move the plunger at all. I will be replacing both arm and plunger as this would indicate ball/plunger wear. Stop screw is corrrectly adjusted, I can't vouch for the throw out adjustment as it's years since I rebuilt the engine but either way the movement would indicate wear in the ball/plunger. All clevis pins are new, there is no free movement in the pedal, as soon as it is moved it is operating the master/slave cylinders therefore the mechanical loss is at the end of the mechanism.

https://youtu.be/NvFiU5BvMMw

https://youtu.be/n-es76s6HWk

[bwaminispeed]

I have the oposite problem, mine engages almost right at the top of the pedal, may have to put a worn out arm in to fix it.......

[111Robin]

Sounds like a worn plate ?. Funnily I had the same when I test drove my Wolseley, didn't take up drive until the pedal was almost fully released so I assumed worn plate. As soon as I removed the cover I realised the problem, the arm was so badly seized on it's pivot pin that it was returning very slowly, lagging behind the slave and master cylinders, so although the pedal was at the top the clutch was way behind. Plate was fine.

[croc7]

While changing the throw out bearing, I was surprised to see how badly worn the plunger was from contact with the ball on the lower end of the clutch lever. I seem to remember reading somewhere that there should be 1/2", preferably 5/8", movement of the Arm at the Clutch Slave cylinder Pushrod. If you are not getting consistent movement of the clutch lever, I would look at the hydraulic components as well. Have you peeled back the dust boot on the slave cylinder to check for fluid leakage past the seals? How long has it been since the MC was rebuilt/replaced?

[111Robin]

While changing the throw out bearing, I was surprised to see how badly worn the plunger was from contact with the ball on the lower end of the clutch lever. I seem to remember reading somewhere that there should be 1/2", preferably 5/8", movement of the Arm at the Clutch Slave cylinder Pushrod. If you are not getting consistent movement of the clutch lever, I would look at the hydraulic components as well. Have you peeled back the dust boot on the slave cylinder to check for fluid leakage past the seals? How long has it been since the MC was rebuilt/replaced?

It's not hydraulic, the slave moves as soon as the pedal is touched so there are no losses from master to slave cylinder. As you see in the video there is significant movement of the arm before the plunger moves therefore the wear is at the ball/plunger interface. I'll do the easy bit first, remove the arm and slot in the new one to see if it makes any difference but I think I replaced the arm at some point years ago and it's hardly done any mileage since. I just can't ever remember fitting a new plunger so I'm assuming that's where most of the wear is. If the new arm gives an improvement I might just leave it for now. What puts me off is removing the radiator so I can jack up the engine, horrible job.

[bwaminispeed]

Have never removed a rad to do a Mini clutch, and, have done many in the car......Can't see why you would need to....

[111Robin]

Have never removed a rad to do a Mini clutch, and, have done many in the car......Can't see why you would need to....

So I can jack the engine up to enable the clutch cover to be removed. I've done it on later cars without the radiator shroud on the inner wing but there's no clearance between radiator and shroud to allow the engine to rotate as the other end is jacked up. I could be wrong, I haven't done this on an early car, just don't want to risk mangling the radiator or shroud that's all.

[bwaminispeed]

Once the motor mount is out (clutch end), you don't have to jack it up very much to get the cover off.......

If you are worried, you can just put a piece of cardboard between the rad and shroud......Just to prevent metal to metal contact....

BTW, my record for Re and Re clutch, including big red seal and release bearing is about twenty eight minutes start to finish......66 MKI station wagon with a standard Cooper 998 in it.....

[111Robin]

Once the motor mount is out (clutch end), you don't have to jack it up very much to get the cover off.......

If you are worried, you can just put a piece of cardboard between the rad and shroud......Just to prevent metal to metal contact....

BTW, my record for Re and Re clutch, including big red seal and release bearing is about twenty eight minutes start to finish......66 MKI station wagon with a standard Cooper 998 in it.....

That's fast, impressive. I'll certainly give it a go . Is there any need to disconnect the exhaust from the lcb ?. I haven't changed a clutch withh an LCB before, just not sure if there's enough freedom of movement to jack the engine up without disconnecting the exhaust.

[Polarsilver]

Just to let you know your not alone .. yesterday i got my 1275GT uncovered from its 10 months in storage .. The Engine stated up with no issues thanks to the product from Briggs & Stratton "Fuel Fit" this is good stuff that i added to my e petrol way back when
Then the gears engage without an issue but the Clutch activation is now super Low .. ok i may need a slave cyl;bleed.. but i did measure the wear on the the Clutch Arm lower Ball & it is worn oval by half a mm.. so onto Minispares .

[111Robin]

I'm fitting a new arm today to see how much it improves on the slop but I'm assuming I will also need the new plunger. Better to be busy I suppose.

[111Robin]

Well the new arm has made a slight improvement on the slack before the plunger moves although if there is any wear on the ball on the old arm it's imperceptible really at least visually. I'll probably just run like this until it starts to bother me enough to replace the plunger.

[Polarsilver]

Got my new Minispares Clutch arm fitted with new Clevis Pins + new Push Rod + arm Stop Bolt re-set up & the length of throw Nut & Locknut re-set + Slave Cylinder Bleed & still my Clutch action has a too Low Pedal & quite an aggressive Clutch action .. there is no evidence of oil loss from the clutch cover drain hole .. so my next thought is to strip out the clutch & check there is no binding on the splines.
Questions..
1. My Clutch Friction Plate is at least 30 years old ( maybe older ) ..it looked good last time i re-installed the Clutch .. maybe this Friction Material has lost its performance capability due to old age ,which may account for the aggressive clutch feel..
Do you Guys throw out old Friction Plates because of old age ?

2. Is there any wear tolerance acceptable on the Clutch Diaphragm contact point area ? .. yes it is another over 30 years old component

[imack]

I'm currently running a 30 year old orange clutch cover and AP centre plate, no problems. I'm reluctant to fit modern offerings in case they're rubbish.

[111Robin]

Got my new Minispares Clutch arm fitted with new Clevis Pins + new Push Rod + arm Stop Bolt re-set up & the length of throw Nut & Locknut re-set + Slave Cylinder Bleed & still my Clutch action has a too Low Pedal & quite an aggressive Clutch action .. there is no evidence of oil loss from the clutch cover drain hole .. so my next thought is to strip out the clutch & check there is no binding on the splines.
Questions..
1. My Clutch Friction Plate is at least 30 years old ( maybe older ) ..it looked good last time i re-installed the Clutch .. maybe this Friction Material has lost its performance capability due to old age ,which may account for the aggressive clutch feel..
Do you Guys throw out old Friction Plates because of old age ?

2. Is there any wear tolerance acceptable on the Clutch Diaphragm contact point area ? .. yes it is another over 30 years old component

Is there actually any slack pedal travel before you feel that you are operating the clutch ?. I had a couple of inches on the pedal, not completely slack but only taking up the mechanical wear from pedal through to plunger. Fitting the new arm reduced the slack considerably. If the slave rod moves as soon as you touch the pedal then you have no hydraulic issues. If the pedal feels perfect with almost immediate resistance but is only engaging/disengaging just off the floor then the mechanical losses must be within the diaphragm, straps etc.

[woodypup59]

That's fast, impressive. I'll certainly give it a go .

I expect that the lower/rear bolts of the chinese hat have been left out.

These can be a cow to get at, and are usually omitted upon rebuild.

[Blacktulip]

I've read that if the master cylinder gasket underneath the foot of the canister has been replaced it could be this being too thick which raises the master up so the pedal travel is reduced.

[Polarsilver]

With a new Clutch Arm fitted .. my clutch bite point was still very Low .. so i strip out & all components they looked good to be used other than i notice printed onto the Clutch Plate is showing "August 1978" the date clutch plate was manufactured .. so i thought after 41 years it was worth the chance to buy a NEW Clutch Plate .. yes problem is solved i now have a good feel to the Clutch Bite Point