My 1999 Toyota Tacoma (Ext Cab, 4x4 TRD) has 162K miles and now the clutch pedal intermittently sticks to the floor. I have to pull it off the floor with my toes while driving and have also felt the pedal start to pull back towards the floor on its own while the truck is in gear.
I’m looking for some wisdom as a few blogs/websites point towards a master cylinder, others say the master and slave, and my local auto shop said I need to replace the entire clutch assembly and throttle bearing. My truck is no spring chicken anymore but I’d like to keep it running for a few more years…
The pedal spring is an overcenter design i.e. it holds the pedal up past the center up point but pushes it down when the pedal is past the center down point. The system is designed to have the clutch pressure plate spring return force push the pedal up through the master cylinder past the center up point after which the over center spring brings the pedal up to its rest point stop. Once the clutch pressure plate fails to push the pedal past the overcenter point, the master cylinder primary cup cannot uncover the compensation port and the piston slowly drops until the pedal is on the floor or the clutch will not disengage fully. You can manually pull the pedal up which allows the fluid to again get ahead of the primary cup through the compensation port and the pedal operates as usual until the next time.
Either the pedal rest point is adjusted too far out or the master cylinder is leaking internally. It could be a leaking slave cylinder but then you would have a low clutch master cylinder reservoir level. If the master cylinder leaks in bypass, there will not be enough fluid remaining ahead of the piston to push the clutch pedal up far enough so the over center spring will now drive the pedal down to the floot.
That is a very helpful explanation and seems to be what is happening most of the time. When the pedal sticks to the floor, I cannot get the truck in or out of gear without manually pulling the pedal up and trying the desired action again.
If the pedal is down to the floor and you can’t shift the transmission the problem is with the hydraulic system. Replace both the slave and the master cylinders.