1988 Acura Legend, 2.7L 6 cyl., 181,000 miles only do 6,500 miles a year to train station, parked inside, runs great. Last week parked out in hot sun, '90s, for 8 hours. At first, no problem. When did errand and returned to car, pushed clutch pedal and it would not return or allow gear to engage. “Jammed” into 1st, then could not shift, shifted slightly by pulling up on clutch pedal with my foot. Parked overnight, cool, next morning seemed to be fine and crept to mechanic. Mechanic road tested and found no problem and now seems to be working okay. Would parking in sun, high heat cause “clutch cylinder” to “seize” or “freeze”? Is there a “fix”? Also, increasingly hard to get parts for this car. Suggestions?
When did you last change the clutch fluid? DOT 3 brake fluid, also used ny the clutch, is hydrophilic. It will absorb moisture from the air. This moisture will cause corrosion the master and slave cylinders. A combination of corrosion and contaminated fluid could be the problem.
It is most likely that you need to replace the clutch master cylinder. It appears that as the aluminum housing of the clutch master cylinder expands with high heat, the rubber cups shrink allowing the trapped fluid to bypass the piston back to the reservoir.
If the master cylinder is original, you have gotten great service out of the hydraulic components.
I got this one! Happened to my '89 Accord 5 speed 4 cylinder. Similar cars I believe. Follow the clutch cable to the shifting fork at the front of the car. Mine stuck and if yours is similar I can help you fix it. Post back. Rocketman
To check for clutch master cylinder leaking internally when it gets hot, carry a bottle of water in the vehicle. The next time the clutch pedal doesn’t function properly, open the hood and pour the bottle of water over the clutch master cylinder. If the clutch pedal now functions normally, the clutch master cylinder is being effected by heat.
Tester
In researching the clutch system on this Acura, I found some interesting points. The flywheel is a dual mass unit with torsion springs coupling the two masses. The clutch disc uses elastomer cushions instead of torsion springs between the disc proper and the hub. The pressure plate uses a diaphragm spring but it works in reverse. Instead of the fingers coming away from the flywheel on application, the fingers move inward. The cone presses the clamping plate agsinst the disc. As a result the throw out bearing pulls on the fingers to disengage the clutch. That puts the slave cylinder on the transmission side of the throwout fork with the fork pivioting in the center of the fork.
Also in the hydraulic system there is a damper. I did not see a call out for the part. Does anyone know how this damper works? Has anyone taken one apart to see how it works?
I have always wondered why the clutch pedal can stick to the floor when the master cylinder fails. Common sense says it should dangle part way up. I see that this Acura has a clutch assist spring which is of an overcenter design. When the pedal is up the spring holds the pedal against the up stop and allowing the master cylinder piston cup to clear the compensation port. When the pedal is down, the spring will hold it there unless the pressure plate reaction rebounds the clutch master cylinder and pushes the clutch pedal past the springs center position. That explains a lot.
Just curious
Guess the OP found a solution. My sticky pedal was also due to temp but COLD made mine stick. I followed the clutch cable from the firewall to the clutch fork and used a spray lube (via the sprayer tube thing) to soak the moving parts that I could get to. I re-sprayed it every month or so. Worked about 99% of the time, for the other 1% I kept a small piece of wood in the trunk which I could use to unstick the fork with a gentle tap, easy fix. I had to park the '89 in January (585,000 miles on the original clutch) due to underbody rust. Rocketman)