I thought I'd let you fellas know about I problem I've had with my exhaust brake.

I thought I had pump trouble because there was no poweroff the line untill I hit about 1800 - 2000 RPM. Then bingo, all kinds of jam.

I took it in for warranty and there was nothing wrong with the pump, but the mechanic thought I might have a bent exhaust push tube because of the sound in the intake. No bent tube found.

Turns out that the brake was staying on 'till the engine run time hit about 1800 RPM. This, of course, caused a bunch of back pressure which sounded like a bent tube and caused high crank case pressure.

The cause? Due to the cold weather ( -36C the last two days) and summer dust, the air line exhaust vent on the solinoid was plugged. Thus, the brake would not open when the throttle was pressed.

One more thing for routine maintenance, I guess.

Rick

 

Not sure if you have the room or want another guage, but install a brake pressure guage. It's really just a boost guage, but it will tell you loads about what is happening with your exhaust brake operation.
With mine, I now know when there is a problem, it needs adjustment, how much braking power I'm putting out, etc.

It's worth it.

Jeff

 

I've never seen or heard of a guage for exhaust brakes. Is it specific for the brake or did you just put a boost guage above the brake?

 

Your EGT's must have been going through the roof! Dont you have a pyrometer? My exhaust brake was sticking also (a whole new story, but resolved) and when it did for that few seconds at a time my EGT's would almost hit 1200*+. And it caused one heck of a jerking motion. You have to use it all the time to eliminate carbon build up or you will have trouble. I would think especially in the coolder months.

 

Ruadh- Whose Ebrake are you using?

This doesn't sound like a Cummins/Jacobs type with an "air line".....

 

I run a BD-Power brake and it has a port on the top side that you can install a pressure guage. It reqiures a hard line off the brake housing which then changes into a regular plastic boost line leading to a 60 psi boost guage. Simple as that.

During normal driving, the guage just sits there. When the brake is operating, it will read whatever PSI of retarding force the brake is applying to the motor. When my truck is warming up with the brake on, it shows 20PSI. This is also the setting that BD recommends to "set" the brake at idle. Normal operation will show anywhere from 30 to 45 PSI depending on how hard I'm using it. 24valve motors are rated for 60 PSI which equats to 190 braking HP at 3100 rpm. If your cruising down the road and your guage is showing any kind of reading and you are not using the brake, it is sticking.

It might be a little gimmicky, but it works.

Jeff

 

It's a Jakobs unit. On the 2002 they operate on air supplied by an air pump installed with the brake. There's a solinoid on the firewall to energize the brake with a signal from the ECM.

As far as exhaust temps go, it didn't stay on long enough to raise the temps noticably. It only stayed on long enough for the engine to go from 800 to 2000 RPM during 1st gear acceleration. During this brief time the air would bleed of through the valve and the brake would release.

Rick

 

I've got a Pac Brake, and I've had that problem twice, both times at start-up, when I started the truck with the e-brake switch on. I was able to back out of the driveway, because I don't have to use any pedal. I get out into the street, put it in drive, and give it the pedal. Then I get very little response, and a lot of grey smoke. I turn of the switch, and I still hear the brake engaged. I turn off the truck and restart a few times, the brake releases, and off I go. It's only happened twice, on very cold mornings, after I hadn't driven the truck for several days. I do use the brake nearly every time I drive to prevent buildup on the actuator shaft.

I'm glad that I'm not the only one having this problem, but unhappy for all of us having the problem.

 

I have had a problem with my PacBrake lately. It's been very cold. Mine, fortunately stuck in the open position. I think mine is caused by the rubber hoses being stiff. The PacBrake actuator has to flex the hoses when it engages. I don't have any problem when it warms up.

 

DPG, I will let you in on a secret that PAC doesnt want you to know. (I'm sure because they really dont want guys messing with the settings and then sending them back saying its broke!) I had a sticky brake situation. Called PAC, they sent me a new housing right away. Very good guys there! New brake worked great but stuck again after a few weeks. Called again and they said that this would be very rare so they tried find out other possible problems before sending another housing. Tried a new solenoid but that wasnt it. After checking EVERYTHING possible I gave up on PAC and started calling shops that sell PAC and asked them if they ever had this problem. Finally I get a hold of a smaller shop close to my home town that lets me in on the secret. They found out from PAC. Its so simple its stupid. When PAC puts the brakes together they use jigs with gauges to set how far the butterfly valve closes. These gauges wear and begin to read wrong, setting the valve incorrectly. What I found is that my valve was closing to far causing to much pressure behind the butterfly which made it to hard for the vacumm diaphragm to reopen the valve. So under higher RPM's the brake would stick. Now for the reason it didnt do it so soon was that it took a while for the carbon to build up enough to cause more of a seal around the valve. (Were talking 1000's of an inch) Now if your sticking problem is is erratic and has nothing to do with RPM's then try cleaning the solenoid and or checking the hoses for a vacumm leak. You clean the solenoid by removing the plate on the end of it and pulling out the valve. Clean and make sure valve slides in and out smoothly. Sorry for the lengthy responce but I thought it might help out some since I know what its like trying to find exhaust brake problems.

 

Here is the reply I got from PacBrake:

The problem you have is most likely your vacuum cylinder.The seals in the cylinder have probably hardened and so the vacuum is by passing. The fix is replace the cylinder.

Not the answer I wanted

 

How old is your PAC brake? Before I had to spend money on a new cylinder I would try taking off the hoses and spraying PB Blast in the old cylinder first. That stuff really does cool stuff and is supposed to bring rubber back to life. You might want to remove it so you can move it around getting it all over indside. Then you can check sealing abilities by hand. I was thinking of covering my cylinder with a heat shield too.