Clutch master cylinder or slave cylinder?
#3
10-17-2022
Welcome to the forum
Make sure clutch reservoir has fluid, take off the cap and pull out the "air dam" cup, leave it out and cap off
Go under the truck with a pan and open the Bleeder Valve on the slave
Should get a steady trickle of fluid, NO AIR
This is called Gravity Bleeding, works on Brakes as well
The Reservoir is "uphill" so fluid will run "downhill" to the slave with Bleeder open
Close bleeder
Now pump the clutch pedal a few times, reservoir cap still off
Make sure reservoir still has fluid and put cup back in and cap back on, cap is vented, just FYI, same as Brake master, or fluid couldn't run out to replace fluid if there was a leak
Start engine and see if things are better
If not then you may have air at the top of the master, its at a upward angle so if air ever gets in its hard to get it out
You can pull out the master and invert it, to see if you can clear out the air
As said the Pilot bearing allows the clutch disc and transmission input shaft to slow down to 0 RPMs while engine remains at 700 RPMs
This allows you to put transmission into a gear when rear wheels and transmission's gears are all at 0 RPMs, there is no disconnect for rear wheels and transmission, both maintain the same RPMs, when stopped that is 0 RPMs
So transmission input shaft must also be at 0 RPMs so a gear can "mesh" when stopped
Same for shifting gears while driving, RPMs must match for a gear to "mesh" but this is easier since both are spinning
The 0 RPMs at input shaft is hardest to achieve since clutch disc is sandwiched between the flywheel and pressure plate BOTH spinning at 700 RPM
,so even slight rubbing would cause clutch disc to not slow down to 0 RPMs OR a binding Pilot Bearing(this would usually make a noise)
Air in hydraulic system would cause clutch disc to rub because slave is not fully extended
Make sure clutch reservoir has fluid, take off the cap and pull out the "air dam" cup, leave it out and cap off
Go under the truck with a pan and open the Bleeder Valve on the slave
Should get a steady trickle of fluid, NO AIR
This is called Gravity Bleeding, works on Brakes as well
The Reservoir is "uphill" so fluid will run "downhill" to the slave with Bleeder open
Close bleeder
Now pump the clutch pedal a few times, reservoir cap still off
Make sure reservoir still has fluid and put cup back in and cap back on, cap is vented, just FYI, same as Brake master, or fluid couldn't run out to replace fluid if there was a leak
Start engine and see if things are better
If not then you may have air at the top of the master, its at a upward angle so if air ever gets in its hard to get it out
You can pull out the master and invert it, to see if you can clear out the air
As said the Pilot bearing allows the clutch disc and transmission input shaft to slow down to 0 RPMs while engine remains at 700 RPMs
This allows you to put transmission into a gear when rear wheels and transmission's gears are all at 0 RPMs, there is no disconnect for rear wheels and transmission, both maintain the same RPMs, when stopped that is 0 RPMs
So transmission input shaft must also be at 0 RPMs so a gear can "mesh" when stopped
Same for shifting gears while driving, RPMs must match for a gear to "mesh" but this is easier since both are spinning
The 0 RPMs at input shaft is hardest to achieve since clutch disc is sandwiched between the flywheel and pressure plate BOTH spinning at 700 RPM
,so even slight rubbing would cause clutch disc to not slow down to 0 RPMs OR a binding Pilot Bearing(this would usually make a noise)
Air in hydraulic system would cause clutch disc to rub because slave is not fully extended
Last edited by RonD; 10-17-2022 at 11:43 AM.
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