Clutch Biting Point

[Mad Mart]

On my TVR the clutch biting point is right at the top of the pedal travel but, on the Tolly Sprint I've just been working on, the biting point is right at the bottom of pedal travel. I believe both have new clutches. I always believed that the clutch friction plate was worn down if the biting point was at the top of the pedal travel?

[yorkshire_spam]

Mechanical or hydraulic clutch? Any adjustment in the clutch? On the Spitfire the position of the slave in the "clamp mounting" makes a difference to the bite point regardless of the state of the friction plate.

[MIG Wielder]

Hi Mart, I can give you experience of 2 very different cars here in the garage.
If the MGB gets a clutch biting point ( with a hydraulic clutch ) close to the top of the clutch pedal travel then I know It's getting time for a clutch plate change. I've never had to bleed the MGB clutch.
O.K. I know I'm lecturing the professor, but for the listeners the clutch driven plate wearing down to the rivets means that the clutch cover plate is furthur in. Which means the release bearing is furthur back in the bell housing which means the clutch biting point is higher up. And the next sign of clutch wear is that you get clutch slip in 3rd / 4th.....
Time for a new clutch plate.
One slight difference is on the Lotus Elite where the clutch is cable operated and there is an adjustment to set the clutch cable free play. If this is ignored you get clutch slip if the biting point is too high. Time for adjustment or a new clutch driven plate.

Now on the Dolomites I've never got to the state where clutch wear has changed the biting point. It's always been a reason to change the clutch because of a replacement gearbox. On SWK ( an 1850 ) if the clutch biting point is quite low then a quick bleed of the system restores operation about 1/2 way down. I've never found out why.
HTH,
Tony.

[sprint95m]

What an interesting question you have posed Martin.

I am thinking your TVR has a better design of clutch cover than the Toledo?
The reason I am of this opinion is to do with the T2000 original clutches where two makes were used
and one was better than the other (Laycock v Borg and Beck).

On hydraulic clutches it is possible to use a bigger bore master cylinder to reduce the pedal movement
(required to get the clutch to clear)
but this makes the clutch heavier to operate.


Ian

[Mad Mart]

The TVR is a hydraulic system. No adjustment, although I can adjust the height of the pedal!

Some good thoughts there. I'll have to double check that a new clutch was fitted though.

[naskeet]

What an interesting question you have posed Martin.

I am thinking your TVR has a better design of clutch cover than the Toledo?
The reason I am of this opinion is to do with the T2000 original clutches where two makes were used
and one was better than the other (Laycock v Borg and Beck).

On hydraulic clutches it is possible to use a bigger bore master cylinder to reduce the pedal movement
(required to get the clutch to clear)

but this makes the clutch heavier to operate.


Ian

I dislike heavy clutches, having once had to contend with one on a Bedford CF van. The clutches on my 1974 Triumph Toledo 1300 "HL Special" (hydraulic clutch) and 1973 VW "1600" Type 2 (cable-operated clutch, with butterfly adjustment nut) have always been light and progressive in engagement; just the way I like them.