No Biting Point

[paulob1]

if you get air in the hydraulic clutch system, upside of the clutch master cylinder..as the air warms up it expands, physics again, and it pressurises the system, effectively operating the clutch slightly and reduces the pressure it uses to engage and if sever enough starts to slip. And ruins the clutch...

 

[ScubaSteve]

Never heard of that, iv had leaking clutch cylinders and it makes the pedal spongy and clutch won't engage properly. Having read about your physics ideas elsewhere got anything to back that up? Infact I'd stick my.neck out here and say you are making that up to try and justify your previous flawed advice.

 

[ScubaSteve]

http://www.clarks-garage.com/shop-manual/ts-04.htm" onclick="window.open(this.href);return false;

No mention of clutch self engaging due to "expaning air" :roll:

 

[warrenpenalver]

if you get air in the hydraulic clutch system, upside of the clutch master cylinder..as the air warms up it expands, physics again, and it pressurises the system, effectively operating the clutch slightly and reduces the pressure it uses to engage and if sever enough starts to slip. And ruins the clutch...

upwards of the master cylinder?? the only thing upwards of the master cylinder is the pipe to the resevoir.....

the clutch system is NOT pressurised when the clutch pedal is not depressed. It is open to free flow into the resevoir. The resevoir outlet is just by the piston. The idea being expansion and contraction of fluid and a small leak will not effect clutch operation as excess fluid goes back into resevoir and any loss of fluid is replenished by the reserves in the resevoir.

As soon as you start to depress the pedal, the piston moves past the resevoir hole and the system becomes a closed hydraulic system.

Only a significant leak would be a problem as the fluid would leak out while the pedal was depressed.


your hot air idea is complete bollocks. Air is a compressible medium. The only thing air in the system does is make clutch actuation difficult due to the compression of the air reducing the movement of the slave cylinder.

The clutch simply cannot slip due to air in the system. The cutch is held engaged by the pressure plate. The only purpose of the entire clutch pedal mechanism is to release the pressure plate by opposing the spring pressure the pressure plate exerts on the drive plate, thus allowing the drive plate to free rotate relative to engine speed. The pressure plate being bolted to flywheel then rotates at engine speed and the drive plate, being on the gearbox shaft rotates at gearbox speed.

You can cut all your brake lines and the clutch system will operate fine due to the split resevoir design.

 

[paulob1]

whatever, there was no leak there was no air in the system it didnt slip and the clutch was just fine, i changed it because it was working perfectly...excellent glad I know that now...

 

[ScubaSteve]

Give it a rest and focus on giving out useful advice about what you know about rather then making stupid theories up to suit your bad advice. Knowing a bit is more dangerous then knowing nothing!

 

[paulob1]

okay, am sort of with you,

brand new clutch.
no oil leak and new clutch release unit.
it lasts less than 500 miles but slips noticeably only when the whole engine is warm after say 20 minutes of driving normally.
The history, the previous clutch release unit leaked and covered the old clutch in brake fluid. It would not work at that point of course and had to be replaced...
on removal of said slipping and now ruined clutch it was bone dry. no sign of brake fluid so no reason for it to slip..

why was it slipping.?

 

[ScubaSteve]

Did you clean up flywheel or have it skimmed?

 

[warrenpenalver]

could have been a manufacturing fault with the clutch itself, eg weak centre fingers or more likely incorrect assembly with the wrong bits by the manufacturer, or wrong friction material etc.

or

uneven flywheel

or

misalignment