What makes a clutch brake go bad?

A clutch brake will be destroyed when some steering wheel holding cowboy decides to depress the clutch fully to the floor when making one of those "certified gear jammer" shifts, like I saw this jack@ss doing on American Trucker.

The teeth get sheared off when the brake is engaged during a shift. Shifting without the clutch never hurt a clutch brake.

 

I have a Mack and I have heard the same thing from the shop, you can cut the one piece out and put a two piece in there. I think mine is a little slow getting it in gear sometimes from a stop light, but for now its working out.

 

I blame idiot drivers.

My trainer was a "20 year veteren". Just because you've been doing it for 20 years, doesn't mean you've been doing it right.

The doofus had no clue what a clutch brake is. Even after I described it, then showed him how not to grind gears, he still didn't believe me

 

That's exactly what the mechanic at my previous employer did when one would go bad.

 

There are several different styles of 2-piece clutch brakes. Some you put on, then have to push the clutch to the floor to press the pins into place. Others have the allen screws (those are a real pain in the rear to install), and the ones I prefer have a hinged joint on one side, and there are a pair of rods you insert into holes in the other to have enough leverage to snap the thing together once you have it positioned around the input shaft.

1 piece (do not use if you can avoid it)



Hinged clutch brake w/ press in pins:


PITA bolt-on clutch brake:




Hinged clip-on style (my preferred style):

 

When a driver depresses the clutch pedal all the way down into the clutch brake while the truck is still rolling, the clutch brake will attempt to stop the truck and eventually destroy it. The one piece clutch brake has a built in slipper clutch to prevent damage from a driver doing this.

 

If the drive tangs aren't sheared off or linings missing from the clutch brake, then you can make an internal clutch adjustment to regain 1/2" measurement between the release bearing and the clutch brake disc, then you adjust your clutch linkage for proper free travel and all should work.

 

I like the type of clutch brake, 2 piece, with the two spring pins to hold it together, I do nor remember the name the ones with the set screws, in the aluminum are Junk.
The clutch brake is made to work in grease, if it runs dry it will eat the bearing cover on the transmission. Adjustment is very important, but training the driver is the best way. I have had drivers I had to adjust the clutch pedal so the pedal had to be fully to the floor to get any life from the brake.

 

It's supposed to be on the floor anyway. The only time you ever put the clutch on the floor is when you're completely stopped and putting it into gear.