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06-25-2007, 23:34

Randy,

Yes, I have a Detroit Series 60 Diesel with Allison World 6 speed transmission
with the Engine Retarder, which I guess is what you call the Jake Brake. I
assumed that it closes the valves and turns the cylinders into a compressor
thereby holding the coach back. I can see where that would be an effective
process.

Thanks Randy for clearing that up. Jake Brake was a new term to me and I wasn't
sure that what I had was a Jake Brake. It is all switch controlled though.

Thanks for the input.

Regards,
Ron Thompson
Waller, Texas (near Houston)

martingregg598 wrote:
Ron, if you have a Allison HT-755 five speed with a retarder, I have
know advice, if you have a 1995-42' you should have a Allison HD-4060
and a DD series 60 with a 3 position Jacobs engine brake. Jacobs's
brakes close the valves and turn the cylinder into a compressor
creating braking horsepower, each position adds more cylinders. I
haven't driven a 95 in the mountains but I have driven over a lot of
the passes in the Cascades, Montana, Idaho and so on, but I can't
imagine that if your in the right gear at the right RPM that the
engine brake won't hold it back. For me with a less effective Pac
Brake, it is 4th gear at 50 mph at about 2400 rpm's on a 6% or so, on
a steeper grade it's 3 gear at 35-40 mph and I almost never have to
use my air brakes. If I am in 4th and it starts to run away, faster
that I like, I use the brakes to get the coach down to the speed that
I can select the next lower gear. If the Jacobs brake doesn't hold
you back, maybe there is something wrong with the Jacobs brake?
As for the "Drum type" air brakes, if you have been on the road for a
time and the ambient temp. is hot, and If you ride the brakes for a
long period of time the drum can expand away from the shoe and you
lose your brakes. With some real bad luck you could heat the wheel up
so hot that it heats the tire up and blowout.
Marty
95 BMC 37
Kennewick Wa

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