8.3 liter exhaust break question

[bigdomino]

Ave a 2008 Monaco Knight with the 8.3 liter Cummins. Has been a great engine. Have 31,000 miles on it now.

I always drive with the exhaust break on. Works well enough for stopping. Certainly helps to reduce use of breaks. I noticed recently that when I turn it off, while driving, and then turn it back on it doesn't turn on right away. Anyone know why this would happen? Is there any adjustment or lubrication needed on the exhaust valve?

Thanks.

Steve

[Mr_D]

Exhaust brakes do need to be lubricated. They make a special high temp silicone lube for it. I bought a bottle of it at an FMCA rally years ago and am still using it. They only take a drop or so on each of the points. There should be a chart on the manufacturers website.

[GaryKD]

Hi bigdomino,
Consider not using the brake all the time. The coach brakes may be getting glazed over due to not being heated up enough. You may find (as I did) the coach will get more difficult to stop and required additional brake pedal pressure. I started using my brake based on the instructions (down hill grades or additional stopping power needed). I also got on my service brakes hard forward and backward several times. I was lucky. The glazing must have been light. For the last few years, the coach brakes like it did when it was new.

[bigdomino]

Yes the breaks seem to not stop as well. I have to use more pressure to stop. One reason I use the exhaust break. I am having the coach serviced in a month and want to have the breaks checked. Interesting comment concerning breaks not used hard enough.

Steve

[deandec]

If you use your exhaust brake frequently it does not need to be lubed. If your rig is parked for extended periods, the lube is necessary to avoid the flap from freezing in a position.

Your automatic slack adjusters need to be set up occasionally. You can do this easily by releasing the parking brake and pressing the service brake pedal several times until the air pressure is below 60 psi. I suspect you will then find the service brakes to be more responsive.

I do know the exhaust brake will not respond until you lift your foot off the throttle. You have probably already considered this delay.

The procedure I just described is actually part of the Air Brake System pre-trip test. Google those terms and you will get several hits on the test steps.

I have run with my exhaust brake active nearly continuously for 62,000 miles over 10 years and do the pretrip air brake test frequently on my drum style brakes. Both brake systems function fine.

[bigdomino]

When I push brakes to get air down to 60 pounds, is engine running? Also, what does this do when I go below 60? Does backing up and putting on the brakes do an adjustment like in a car?

Thanks

Steve

[deandec]

Engine off and park brake off. So be on level ground.

I do not have disk brakes so I do not know if the back procedure for air disk brakes is the same as a car.

Another part of the Air Brake pre-trip check, is measuring the time of recovery when the engine is started and the air pressure is below 60.

It would become clear if you look up the pre-trip test!

[Mr_D]

Quote:

Originally Posted by deandec If you use your exhaust brake frequently it does not need to be lubed. If your rig is parked for extended periods, the lube is necessary to avoid the flap from freezing in a position.

According to PacBrake:

If your vehicle is exposed to excess moisture, periodical or seasonal use, it is necessary that this simple preventative maintenance procedure be followed:

With the engine off, apply a sufficient amount of Pacbrake Exhaust Brake Synthetic Maintenance Lubricant (4 to 5 drops) to cylinder pivot ends, the brake shaft and the cylinder airport. (Some fitting removal required).

I use mine almost 100% of the time when out but it does sit for 4-5 months a year so I lube mine as per the instructions

[FormerBoater]

Quote:

Originally Posted by bigdomino Yes the breaks seem to not stop as well. I have to use more pressure to stop. One reason I use the exhaust break. I am having the coach serviced in a month and want to have the breaks checked. Interesting comment concerning breaks not used hard enough. Steve

Steve, it is very important to calibrate your automatic slack adjusters on a regular basis. This is accomplished with the coach running , parking brake off (on level ground obviously) and fully depressing the brake pedal for 30 seconds 4 to 6 times in a row.

If you have someone stand outside the coach or roll your window down you will hear a distinct clicking sound as the slacks re-calibrate.

After this procedure you should notice a distinct reduction in the effort to apply the brakes for a safe stop.

After you calibrate, go somewhere where you can make some hard braking stops to reduce the glazing which will enhance your braking performance.

Dave
1998 American Eagle 40EVS

[bigdomino]

Dave,

Thanks for the reply. Great advice. Question. When I do as you mentioned with the brakes, is the engine idling or do I raise the engine rpm?

When stopping hard, how is this getting rid of the glaze?

Thanks again.

Steve

[GaryKD]

Stopping hard raises the temp of the brake pads. If you get them to stink smell, your job is done.

It also makes sure the slack adjusters are adjusted as much as possible.

[Hooligan]

Steve; Here is the brake test procedures. Only takes a few minutes before each trip and checks the brake system.
Motorhome air brake system testing

hope this helps