Clutch Repair

This is an overview of what happens during a clutch repair at Art’s Automotive.

This is a picture of the transmission in the car before the work was started. The yellow arrow points to the top of the transmission. The transmission must come out to replace the clutch. As you can see, there is a lot of stuff blocking access to the transmission.

Transmission hidden by other car parts

This next picture is the transmission viewed from under the car after the splash shield was removed. The yellow arrow is pointing to the lower control mount on the sub-frame. The transmission will not come out past this mount, so the sub-frame will need to be removed.

toyota manual transmission

Below is the sub-frame removed from the car. It spans the front of the car, going all the way from the left wheel to the right wheel.

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What gets replaced?

What’s done during a clutch job varies from shop to shop, but here at Art’s we always perform a complete job. To us, complete means a new disc, pressure plate, clutch release bearing (AKA “throw out bearing”), and pilot bearing. We also re-machine the flywheel every time we do a clutch repair, which isn’t the practice at most shops, at least here in the East Bay. It probably goes without saying (but I’ll say it anyway) we replace the manual transmission oil whenever we replace a clutch.

 

Clutch disc
This is the clutch disc. It rides on the transmission input shaft. The clutch disc is squeezed between the pressure plate and flywheel to transfer power to the transmission.

 

clutch pressure plate
This is the pressure plate. It bolts to the flywheel, which bolts to the engine. It provides the pressure to squeeze the clutch disc and a friction surface.

 

clutch release bearing
This is the clutch release bearing. Since the pressure plate is always spinning and the clutch release fork is stationary, the bearing is necessary absorb the spinning motion.

 

Below is the flywheel grinder. The flywheel is quite expensive, so we won’t replace it unless it’s absolutely necessary. The flywheel friction surface is every bit as important as the pressure plate surface, so it does not make sense to reinstall a worn part without repairing the surface. Most shops either do nothing to the flywheel or send it to a machine shop to be resurfaced. Art wisely realized that even though a flywheel grinder is an expensive piece of shop equipment, it will pay for itself fairly quickly. The cone is made from an abrasive material and spins very quickly. The flywheel is bolted to the table, which turns slowly, just like a turn table on a record player.

flywheel grinder stone and table

Here’s the flywheel grinder in action.

flywheel being machined

This is the flywheel after grinding. The friction surface has been ground perfectly flat and the “step” (the area the pressure plate bolts to has also been ground to maintain the original flywheel dimensions.

machined flywheel

First the flywheel is installed on the car, then the clutch disc, then the pressure plate. Since it’s hard to take pictures of this with these parts on the car, I took the pictures on the bench.

 

The release bearing is next in line. The release bearing is actually installed on the transmission, but I thought this picture helped to illustrate where it connects with the pressure plate.

clutch disc sitting on top of a flywheel
The clutch disc fits between the flywheel and pressure plate after bolting the flywheel to the crankshaft. Some mechanics feel this is the only part that should be replaced during a clutch repair unless other parts are obviously worn out. Not us. Since the bulk of the repair cost for a clutch job is labor, all of the parts should be replaced every time, even if they seem OK.

clutch pressure plate on top of a clutch disc on top of a flywheel
The pressure plate installed and bolted to the flywheel.

clutch release bearing on top of a pressure plate on top of a disc on top of a flywheel
Finally, here’s a picture of the release bearing riding on the pressure plate levers. The pressure plate spins with the engine and the release bearing fork is stationary. One half of the release bearing is stationary and the other spins with the pressure plate.

This is a picture of the inside of the transmission bell housing The yellow arrow is pointing to a pivot point for the release bearing fork. The release bearing fork is like a teeter totter. On one side the lever is a hydraulic slave cylinder or clutch cable that will move when you step on the clutch cable. On the other side is the release bearing that presses against the pressure plate release levers to disengage the clutch. The red arrow is pointing to the release bearing sleeve. This is where the release bearing rides. The blue arrow is pointing to the input shaft splines. We lubricate all of these points with Honda Super Urea grease to prevent noise or stiffness in the clutch.

inside manual transmission bell housing with arrows pointing to input shaft, clutch fork pivot, and release bearing sleeve

This is the inside of the transmission bell housing after the release bearing and fork have been installed.

inside bell housing with clutch release bearing

After installing the new clutch, we put the transmission back into the car. When I asked Erick why he didn’t use one of the $1000 transmission jacks we own, he said he could have the transmission installed in the time it would take to pull the jack out and mount the transmission to it, and he was right. It took 20 seconds from the bench to the car.

two men lifting transmission into position