Jake Brake and effectiveness

[kwood]

I have the Jake manual and read it but must admit that I am not getting a bit confused on how to use them effectively.  I have an MC9 with 8v71, Allison automatic, Jakes, and a manual foot switch to activate the Jakes when I want (there is also a dash switch with off/low/hi). 

Any recommendations on how to best use these and not hurt the transmission/brakes/engine?

Thanks,

[buswarrior]

The engine brake can be thought of as increasing the effect of regular engine compression.
It is another variable, or tool, that you can choose to throw into the mix of slowing down.

So, to slow down, sometimes, you just lift your foot off the throttle.

Sometimes you gear down, to increase the effect of engine compression.

Turning the Jake on will increase the effect of engine compression choices.

So, you use it when you want these effects to be stronger, with the added choice of low or high on the Jake controls. With some practice, you will be able to manipulate all these variables to get the desired slowing, or holding speed on a downhill.

HTH
happy coaching!
buswarrior

[PP]

My Jake manual says I can leave the jake on all the time, especially for in-town driving to reduce the need for use of the service brakes, the only thing it recommends against is leaving the jake on after shutting down the engine. When I first brought mine home, the toggle was broken off in the high position and made for some hard starting. Didn't know enough until reading the advice here about wiring the jake to correctly repair it. (Thanks BW for that). Will

[DaveG]

Jim, that is not true in all case some of these older buses need all the help you can get to whoa it up even here in AZ and TX on flat ground. 
A lot of folks with the early 01 and 05 Eagles with crappy brakes from Eagle use the Jake's for assist in stopping on level ground. 
I for one before upgrading my brakes would have bought several cars without my Jake's in Houston or Phoenix


good luck

What are some of the differences between the different brake designs?  (chamber size, drum width, etc)

[luvrbus]

Dave, it was the width on older Eagles with the std 4 inch on the front and tag or boggie, and with 6 inch on the drivers not enough shoes or drum I now have 6 inch on the front and boggie with 9 1/2 inch on the drivers big difference in stopping now.  



good luck

[buswarrior]

Drums and linings smaller than modern sensibilities consider adequate.

Increasing chamber size isn't very effective, it's the surface area of your brake friction materials that make the difference.

Small surface area heats up sooner and has less "traction" than larger surface area.

happy coaching!
buswarrior

[DaveG]

Drums and linings smaller than modern sensibilities consider adequate.

Increasing chamber size isn't very effective, it's the surface area of your brake friction materials that make the difference.

Small surface area heats up sooner and has less "traction" than larger surface area.

happy coaching!
buswarrior

Thanks, I wasn't suggesting that chamber sizes would fix things, just fishing for what the differences were. Clifford answered that, makes all the sense in the world.

[buswarrior]

I was typing while you were, I was cutting that concept off at the pass, not commenting on your good stuff!

Some folks mistakenly think larger chambers will be their salvation.

happy coaching!
buswarrior