You are low on fluid or master check valve is failing.
Check clutch fluid reservoir on firewall, remove black insert, if it is low or empty you need to bleed the system after refilling.
If possible watch the fluid in the reservoir while some one pumps the clutch pedal, if fluid rises then Master's check valve is failing, replace master cylinder.
When you press down on the clutch pedal the fluid in the master cylinder flows out the hose and down to the slave cylinder inside the bell housing.
The slave cylinder expands and pushes on the pressure plate springs, the pressure plate springs are what hold the clutch disc against the flywheel.
With springs pushed in the clutch disc is free to spin at a lower speed not engine RPM speed(flywheel speed)
The clutch disc is connected to the input shaft on transmission, if you are stopped then transmission is stopped, so to get transmission into 1st gear clutch disc has to stop spinning completely.
If there is air in the system or low fluid then when you push in the clutch pedal the slave doesn't expand as much so clutch disc is still rubbing on flywheel so very hard to get disc to stop turning so you can shift into 1st gear while stopped, when you are moving it can be easier but still harder than normal to shift.
If slave is not expanded all the way then when you let up on clutch pedal disc will grab flywheel right away, no slowly engaging.
At the end of the master is the out hose to slave, AND the in hose from reservoir.
The reservoir hose has a check valve, when you press the clutch pedal down the check valve closes so all the fluid goes to the slave hose, when clutch pedal is up check valve is open so fluid from reservoir is free to flow into the master to replace any fluid that may be lost from a leak.
If check valve isn't closing fast enough or sealing completely some of the master fluid will go up the reservoir hose instead of down the slave hose, so slave doesn't expand fully.
Last edited by RonD; 12-31-2015 at 05:46 PM.