What makes a clutch brake go bad?

38 years and I have only had problems with a clutch brake once it had nothing to do with it being worn out, the rear seal went on the engine, resulted in oil on the brake.

 

My seal does leak. I found a guy with my same problem at work. I think the brakes are junk.

 

Thanks for the education.

I drive a 9400 day cab in the PA area with trips to NYC regularly and the clutch brake is on it's last legs. Unit has 190k miles on it.

So there are a few things I could do better. But I'm going to chalk it up to this unit being the company b#$%-truck and having been driven by just about everyone, including all the guys we've fired for incompetence since I've been here.

Question is, is 200k about right for a clutch break to go on a slip-seated urban tractor that doubles as a yard dog?

 

These hold up the best for a two piece replacement, just about bulletproof.

 

It's hard to say, clearance to clutch release bearing needs to be checked and condition of tangs to input shaft, the lining condition and if it's been way overgreased the brake won't work well.

 

This is the second thread that I have read recently about the clutch brake, and I still haven't read a post about what the clutch brake really is, and what it is for, so here is a short history lesson. They did not used to put clutch brakes on trucks, I started seeing them in the early to mid seventies. The clutch brakes were being installed and the manufacturers were advertising them for one purpose, and that was to eliminate double clutching. The object was, that you could go to neutral, tap the clutch brake, then go immediately, in to the next gear and go, thereby eliminating the need to double clutch. This is the ONLY purpose for the clutch brake. The clutch brake is NOT for use anytime that the transmission is in gear, they are NOT for use while you are setting at a traffic light and trying to keep the truck from rolling. The ONLY time you should engage the clutch brake is when the transmission is in NEUTRAL.

Now, having said that, they have never been a comfortable item to use for the intended purpose, it was quite simply easier to double clutch. One other time they MIGHT be a "convenience" is when you have just started up on a winter day, after your pretrip, the truck is not up to temperature, and sometimes the clutch will not fully release, in this case the clutch brake can be used to get the transmission in gear. Anytime the truck components are up to normal operating temerature, you should never have to use the clutch brake to get the transmission in gear, if you do, you need a clutch adjustment. Just remember, when you use the clutch brake, the transmission should ALWAYS be in NEUTRAL. The OEM Manufacturers could stop putting clutch brakes in trucks and a good driver would never miss it.

 

A clutch break has tabs that connect it to the shaft. If you put full force into the break at say 1500rpm, you will shear off the tabs and thus the break will now spin with the clutch and not slow it down. I have never heard or seen where a clutch break is intended to be used to replace double clutching. mechanincally, this is how you destroy the break, not how it is to be used.

 

No offense, but you are completely off base on what a clutch brake is and what it does. It serves one purpose and one purpose only, and that is to stop the transmission's input shaft so that you can get the truck in gear while the truck is stopped. It should NEVER be used while the truck is rolling, because it would be counterproductive to stop the input shaft from rotating while the wheels are still driving the output shaft.

Without a clutch brake, you've got to press the clutch and sit there waiting for everything on the input shaft side of the transmission to stop spinning so that you can get it into gear without grinding the hell out of the gears....or if you're on a hill you can let the truck roll a bit....or you can shut the truck off, put it in gear, press the clutch in, and refire the truck.

 

I just gave you a history lesson and explained exactly what the clutch brake is and what it is for, that is all I can do. Just like I said earlier, if you need to use the clutch brake to get the transmission in gear when the vehicle components are up to temperature, then you need a clutch adjustment. And, if you use the clutch brake while the transmission is in gear, then you will tear the tabs off as well as wear it out prematurely. Read the post for the use of the clutch brake, you shift the transmission in to neutral, tap the clutch brake to slow the input shaft down, then shift to the next gear, without the double clutching. I have worked for more than one company that didn't even put the clutch brake back in, when they replace the clutch, and I have done this myself on my own trucks as well. As I stated it was easier just to not use the clutch brake, because when you double clutch, you are just using the top two inches of the pedal. All I can do is give you the information, there it is, if you still want to do it the way that you think is correct, by all means go right ahead, but if you step in to a room where there are several old timers and start talking all that, you will only embarrass yourself.

 

This is exactly why you can't always believe that everything you read on here is correct. Use of the clutch brake with the truck in motion,any motion at all, will destroy it. Do not do what this crackerhead is telling you. Unless you are mad at the company and would like to tear up the equipment.