Air brakes on Class A diesel pusher

[flyboykuao]

Hello, we recently purchased a Fleetwood diesel pusher. We have been on 3 short trips with it. It is equipped with air brakes - when switched on the RV will slow when my foot is off the pedal. I read up, and now understand, how they work. What I am not clear on is WHEN to use them. I assume one scenario is when on a steep downgrade. What about using them during normal travel as a way to save the brakes?

I am interested in your recommendations. Thanks in advance.

[Trumpet_Player]

An exhaust break has absolutely nothing to do with the vehicle's brake function. An exhaust break system simply closes down the engine exhaust and stops the exhaust gases from going through the exhaust pipe. The result is backpressure is built up in the manifold and in the cylinders slowing the vehicle down.

[Mondooker]

Well stated Exexutive and it can be confusing no doubt about that. Many excellent videos on the subject as well.

[Executive45]

If the OP was confused when he wrote this post, he sure should be more confused now. 🙂 IMO, Canada has it right...no one can drive a vehicle with air brakes unless they understand them. That being said, the OP needs to familiarize himself with what he has and then how they work. Obviously he's NOT describing his braking system but rather an engine retarder, an exhaust brake or an engine brake. All do the same thing, more or less, but are separate from the system that stops your coach.

To the OP. While all three are retarders, they differ in how they work. First thing you need to do is determine what type of braking assistance YOUR coach has. It will be one of the above listed three. They all work to slow your coach, hence they are brake ASSISTANTS, not brake systems. Your air brakes stop your coach, these simply help slow it down. An exhaust brake closes the exhaust temporarily causing back pressure in your system which will slow the coach. It is a valve assembly attached in your exhaust system. You should be able to see it. An engine brake is an assembly INSIDE your engine. You won't be able to see it. When operated, it aligns your engine's exhaust valves making the engine a power absorbing air compressor. Low aligns three exhaust valves and high aligns all six. Below is a link to how it works. An engine brake will provide the most efficient retardation of your coach. The third operates in conjunction with your transmission. It's important to know which one is on your particular coach. Finally, be sure to check out the information provided by Greg above. I've provided a clicky for you. Good luck...Dennis

Engine Brake clicky

Canada's Air Brake Manual

[Mondooker]

Hi RH,

A tag adds stability while underway and allows the coach to carry morre weight. And yes the tag wheels have air brakes to help in braking. You can also lift the tag axle to put more weight on the drive wheels for better tracking to get out of mud etc. The tag can also be lifted to allow for tighter turns.

You will find some parks having a sign saying “lift tax axle”. These is to stop the dragging/skidding effect a tag can have, especially on blacktop.

Hope that helps.

[rhagfo]

et2 wrote:

Mondooker wrote:
You guys are correct, air brakes do not turn on and off, they are constantly on with the engine start. Most diesel pushers have a gauge or trouble lights on the dash showing that brakes and airbags are fully aired up.

As for the slowdown you've noticed its your exhaust break or Jake brake that is slowing you down. You should see a three position switch on the dash allowing you to set it to High (maximum of breaking), Low and off.

Most folks leave the exhaust brake on at all times EXCEPT in icy or wet conditions. Especially true if your coach has a tag axle.

Not sure what a tag axle benefit the exhaust brake gives vs no tag. The brakes on a tag axle are way more capable of slowing down vs no tag. Actually the exhaust brake on our tag is not as effective as the non tag we had. Probably because it's a lot more weight. I find I use the brakes more.

Getting a little confused here, typicality TAG axles are not driven, so not affected by an exhaust brake function, it only works on driven wheels. Now yes a tag axle will have air brakes on it and will help with braking.

[Mondooker]

My reference to tag axle had to do with turning the Jake/exhaust brake off during inclement weather.

[azdryheat]

Mondooker wrote:
You guys are correct, air brakes do not turn on and off, they are constantly on with the engine start. Most diesel pushers have a gauge or trouble lights on the dash showing that brakes and airbags are fully aired up.

As for the slowdown you've noticed its your exhaust break or Jake brake that is slowing you down. You should see a three position switch on the dash allowing you to set it to High (maximum of breaking), Low and off.

Most folks leave the exhaust brake on at all times EXCEPT in icy or wet conditions. Especially true if your coach has a tag axle.

Just to be more accurate, it depends on the coach as to the 3 position switch. Some have Off/ON, others have LOW/HIGH, while others have LOW/MED/HIGH.

[et2]

Mondooker wrote:
You guys are correct, air brakes do not turn on and off, they are constantly on with the engine start. Most diesel pushers have a gauge or trouble lights on the dash showing that brakes and airbags are fully aired up.

As for the slowdown you've noticed its your exhaust break or Jake brake that is slowing you down. You should see a three position switch on the dash allowing you to set it to High (maximum of breaking), Low and off.

Most folks leave the exhaust brake on at all times EXCEPT in icy or wet conditions. Especially true if your coach has a tag axle.

Not sure what a tag axle benefit the exhaust brake gives vs no tag. The brakes on a tag axle are way more capable of slowing down vs no tag. Actually the exhaust brake on our tag is not as effective as the non tag we had. Probably because it's a lot more weight. I find I use the brakes more.

[GREGORYJ]

In much of or maybe all of Canada we need to pass a test to get an air brake
endorsement to legally drive a motorhome with air brakes. Here it the download address of the Air Brake Manual we use that may be helpful.

https://digitalcollection.gov.mb.ca/awweb/pdfopener?smd=1&did=20528&md=1

[Big_Katuna]

tropical36 wrote:

Mondooker wrote:
You guys are correct, air brakes do not turn on and off, they are constantly on with the engine start. Most diesel pushers have a gauge or trouble lights on the dash showing that brakes and airbags are fully aired up.

As for the slowdown you've noticed its your exhaust break or Jake brake that is slowing you down. You should see a three position switch on the dash allowing you to set it to High (maximum of breaking), Low and off.

Most folks leave the exhaust brake on at all times EXCEPT in icy or wet conditions. Especially true if your coach has a tag axle.

Just to be clear, both Pac and Jacobs make both exhaust and engine brakes, with only the engine brake having a switch selection of braking strengths. These are only found on the higher end coaches and are superior in braking performance. Granted that Jake has the market on engine brakes and seems that Pac has the market on the exhaust type.

And lets not forget transmission retarders. Many Foretravels don’t have exhaust brakes but have transmission retarders.

[tropical36]

Mondooker wrote:
You guys are correct, air brakes do not turn on and off, they are constantly on with the engine start. Most diesel pushers have a gauge or trouble lights on the dash showing that brakes and airbags are fully aired up.

As for the slowdown you've noticed its your exhaust break or Jake brake that is slowing you down. You should see a three position switch on the dash allowing you to set it to High (maximum of breaking), Low and off.

Most folks leave the exhaust brake on at all times EXCEPT in icy or wet conditions. Especially true if your coach has a tag axle.

Just to be clear, both Pac and Jacobs make both exhaust and engine brakes, with only the engine brake having a switch selection of braking strengths. These are only found on the higher end coaches and are superior in braking performance. Granted that Jake has the market on engine brakes and seems that Pac has the market on the exhaust type.

[tropical36]

flyboykuao wrote:
Hello, we recently purchased a Fleetwood diesel pusher. We have been on 3 short trips with it. It is equipped with air brakes - when switched on the RV will slow when my foot is off the pedal. I read up, and now understand, how they work. What I am not clear on is WHEN to use them. I assume one scenario is when on a steep downgrade. What about using them during normal travel as a way to save the brakes?

I am interested in your recommendations. Thanks in advance.

Given that your brakes are air operated and there is no shutoff.
What you're speaking of, is the aux. and most likely an exhaust brake, by Pac, rather than an engine brake. I have the same and never shut if off. I would though, if I was driving on snow or ice.

[Mondooker]

You guys are correct, air brakes do not turn on and off, they are constantly on with the engine start. Most diesel pushers have a gauge or trouble lights on the dash showing that brakes and airbags are fully aired up.

As for the slowdown you've noticed its your exhaust break or Jake brake that is slowing you down. You should see a three position switch on the dash allowing you to set it to High (maximum of breaking), Low and off.

Most folks leave the exhaust brake on at all times EXCEPT in icy or wet conditions. Especially true if your coach has a tag axle.

[Terryallan]

You can use the exhaust brake all the time. However, doing so will hurt your fuel mileage as the coach will not coast nearly as well. The only time you really need it is in the mountains on a downgrade. Then it is priceless.