West Coast

I have a 84 Peterbuilt Water Truck with a CAT motor. The exhaust brake does not work. How can I trouble shoot the issue? Where do I start looking? Right now I have no power to dash switch for the brake. I purchased the truck last year and the brake did not work when I bought it. So I am trying to get all the bugs worked out this winter...... Thanks.....

Dave

LUKE-MM-PULLER

try tracing the wire back it could just be broke or shorting out somewhere. I was taught to start with the simple stuff.

West Coast

Luke thanks for the reply. I am going to tackle this issue this weekend. And will definately cross out the obvious and easiest stuff first. I am just hoping that someone with CAT experience might know of a common issue with the exhaust brake. I now they have solenoids and that sometimes they go out. I tried jumping the solenoid with a hot wire but could not get the brake to come on. But that is not to say that their is not more involved with getting the brake to function properly.

Dave

LUKE-MM-PULLER

With an older engine like that it should be something fairly simple. I also drive truck and some jake's wont turn on if the is not moving. also check the clutch pedal sometimes there's a switch wired to it so if your foot is on it it wont let the jake's work.

dodgeguy71

It's been awhile, but I'm sure someone with more memory than I have will chime in. But from what I remember you'll have your on/off switch and then another switch for either 2/4/6 cylinders. I would assume( not a good idea) that there is a relay involved somewhere going to your switch(on/off) and possibly a fuse(?). I'd check wires from the power source to the switch, or put a test light on the back of the switch(on/off) and see if you actually have voltage at the switch, if so turn it on and see if you have voltage at the other switch(2/4/6). You could also check down on the engine where the harness goes into the valve cover for the jakes. Most of the trouble I saw on Jakes was the wires sometimes would just get so hard and break, or little things like that and would only kill the Jake for those two cylinders.

Good luck, if I was closer I'd come help, I like problems like these.....especially when it's someone else's money!!

GTX2500

I haven't had to work on that old of a truck in awhile, but if memory serves me correct there is a switch on the clutch pedal and one on the injection pump. Like the other guys say check your fuses first and get power to that switch, then go down the line. I'll see if I got a wiring diagram at work , I'll send to you if I do. If applying power to everything doesn't work, you're going to have to pull the valve cover and activate each brake manually and see if the plungers are working.

West Coast

Thanks to all of you........I will check all of the suggested items when I look at the truck.

Dave

Hvytrkmech

There are 4 switch's in the system, 1- main power switch, 2- hi low switch, 3- clutch pedal swith (usually the culprit) 4- throttle switch (usually mounted by the pump).

Check fuse or the little round circuit breaker on the dash, then confirm power to the main stitch, then to the hi-low switch, if all is good, then with key on engine off and all power switch's on full, go to the clutch pedal switch with a meter or test light and make sure you have power to one side of switch if you do, then move the switch armature and test for power to the other side of the switch, do the same for the throttle switch. If all is good and it still does'nt work then trace the wires to the passenger side of the heads and test for continuity. Also inspect where the wires mate with the bullet style connector on the heads,(also a problem area).

The clutch switch is the place that they have most of the failures, but not always, just be sure to check all the electrical connection really well and post what you find.
Good luck.

West Coast

Thanks Heavy....... I will post back my findings.....

Dave