clutch adjustment

Hello Cummins ISB: I believe credit goes to Mr. H. for this information.

The Eaton/Spicer Solo clutches are a pain in the arse. They require a special clutch fork also. The clutch can be changed to a standard Spicer Easy Pedal if he changes the clutch fork, but then he'll have to do regular clutch adjustments.

Over the years I've learned a lot about clutches and how to properly adjust them. I'm willing to bet that 90% of the trucks with more than 500,000 miles on them have the clutch improperly adjusted.

There is only one way to adjust a clutch

The only way to adjust a clutch is to measure the spacing between the throw out bearing and the clutch brake. With the clutch brake against the front bearing cover..........you must have an air gap of 1/2" to no more than 9/16" between the brake and the throw out bearing. The clutch manufacturers like it to be at the 1/2" measurement.

Now there is a second measurement........for toe play in the linkage.......but you do not use the toe play as your measurement. Each truck will be different depending on the truck builder and model of the truck........ do not adjust the linkage for a 2" toe play at the pedal

Do not adjust the linkage for the clutch brake to work

What do you adjust and measure then???????????

You adjust the linkage to move the clutch fork to or from the throw out bearing. When you look up at the clutch fork there are two fingers that push the throw out bearing away from the engine towards the transmission..........you measure the air gap between these two pieces when the clutch is engaged

The measurement is 1/8" between the clutch fork and throw out bearing.

Now if the clutch brake doesn't work properly after the adjustment has been done in this manner..........you have a problem.

The clutch fork and cross shafts can be worn. The flywheel could have been machined to thin at some point. The clutch linkage is worn and has too much play in it. The bushings in the bellhousing are worn.

You can compensate for the flywheel being machined too much with thicker clutch brakes. The company's name that makes them is Illinois Auto Truck Company. They also make tools to measure the clutch adjustments, so you know that you set it properly without guessing at the measurements. Part numbers M-1748 and M-1749, you can buy both tools in a kit M-1750


http://www.iatcoinc.com/eng/home.asp


Once the clutch is set in this manner..........the toe play in the cab is what it is. You should never have to make an adjustment to the clutch linkage ever again. At each adjustment you will only adjust the distance between the throw out bearing and the clutch brake. When you replace a clutch at a later date............you will only have to adjust the distance between the bearing and clutch brake. If you need to use a thicker clutch brake, because of machining the flywheel to thin........then you use a thicker clutch brake, you don't adjust the linkage. If the linkage is worn.........you replace it, you don't adjust for worn linkage.

If you follow these instructions in adjustment and don't abuse the clutch, you maybe surprised how long it lasts