I have a question, for the past week the clutch pedal pressure seems much greater than before, ie. it takes more effort to push down the clutch pedal before shifting. It's not a problem, in fact I like it better this way, but I am wondering what might be the cause of this, and if it is foreshadowing a problem down the road. I recently seafoamed the h^%l out of the '4runner in the vacuum line, which caused a LOT of smoke to billow out as usual and I am seeing better power, but I have never felt a change in the clutch pedal. I am worried this might be a master/slave cylinder issue

 

well, chances are it is the throw out bearing. this is the bearing that allows the clutch to slide in and out on the tranny input shaft. as the throwout bearing ages, looses lube, wears, the clutch gets harder and harder to push in. the clutch master and slave cylinders are very cheap, 38 bucks for master, and 18 for slave, and they are easy to swap out, bleed, and adjust. but i doubt this is your problem. with the throwout bearing making a noticeably stiffer pedal, it could last for another 5 years, or go out tomorow.

 

The release bearing spins between the release fork and the fingers of the pressure plate and has no bearing (unintentional pun) on the feel of the clutch pedal. when the release bearing goes bad you will get a whirring noise when you depress the clutch pedal.

As far as increased effort. this is usually something that slowly increases over time and is usually caused by the gradual change in geometry as the clutch wears and the fingers of the pressure plate move outward. this changes the effective fulcrum length of the release arm.

Other problems that could do this more quickly are problems with the hydraulics that cause the clutch to release closer to the floor, or with the pedal or it's mounting point on the firewall. some trucks crack the firewall around the master cylinder mounting location.

Hope this helps.