Problem with Jake Brake

[g_man1146]

I have a series 60 Detroit with a three position Jake brake. Originally it was
wired to either be "Off" or come "On" with throttle lift. Blue Bird added a wire
to the brake light relay and changed the switch so it has a center "Off". One
way it works as before with throttle lift and in the other position the Jake
comes "On" when the brakes are activated.

Occasionally it stops working altogether and when this happens I pull the relays
in the compartment under the drivers window, spray the sockets with cleaner and
all is well for another year or so. (Bennie showed me this "fix")

The last time this happened only the "throttle lift" mode started working again.
The relays, wiring and switch check OK. The green LED next to the switch lights
when the service brakes are applied so I know the trigger voltage is there. Any
ideas on what to try. The Jake works normally in the "Throttle Lift" position
just not in the "On with Service Brake" position.

Thanks for your help!

Rich D. '99LXi43' CT

[Gregory OConnor]

This is a good example of how dangerous it is to risk depending on a jake to
slow you to a stop. One big fear I have with these electric actuated systems is
the bus shifts to n if there is a power failure then you are freewheeling and
without the assumed hp stopping of the supplemental system. (The driveline
retarder does not need the tranny in gear)

My rule is "go down hill slow enough to piss off the cars behind me".
(the trucker rule is "go as slow down hill as you can go up").

a jake on a manual tranmission rig has a more dependable operation but still
rely on all the prompts to be working. many on road truckers modify the if-then
prompts to run the jake at driver demand. I use the jake to slow the engine on
my dump truck while trying to upshift going up hill. it allows me to reduce the
lag time waiting for the rpm to reduce to 1200 from 2100 to make the nonclutch
shift. often waiting for the natural lag the truck slows to a stop or out of
range for the next gear.

Greg of'Tim&Greg
94ptca



--- In WanderlodgeForum@yahoogroups.com, "g_man1146" wrote:
>
> I have a series 60 Detroit with a three position Jake brake. Originally it was
wired to either be "Off" or come "On" with throttle lift. Blue Bird added a wire
to the brake light relay and changed the switch so it has a center "Off". One
way it works as before with throttle lift and in the other position the Jake
comes "On" when the brakes are activated.
>
> Occasionally it stops working altogether and when this happens I pull the
relays in the compartment under the drivers window, spray the sockets with
cleaner and all is well for another year or so. (Bennie showed me this "fix")
>
> The last time this happened only the "throttle lift" mode started working
again. The relays, wiring and switch check OK. The green LED next to the switch
lights when the service brakes are applied so I know the trigger voltage is
there. Any ideas on what to try. The Jake works normally in the "Throttle Lift"
position just not in the "On with Service Brake" position.
>
> Thanks for your help!
>
> Rich D. '99LXi43' CT
>

[Pete Masterson]

The operation of the Jake brake is not a simple electro-mechanical device -- it uses the engine computer module to actually engage or disengage the brake. So, if you're sure that the electrical system (including the cannon plugs) are all up to snuff, then it's time to get a DD technician to plug in and check the ECM with a reader device.

Pete Masterson

'95 Blue Bird Wanderlodge WBDA 42

El Sobrante CA

"aeonix1@mac.com"

On Jul 14, 2009, at 6:45 AM, g_man1146 wrote:

I have a series 60 Detroit with a three position Jake brake. Originally it was wired to either be "Off" or come "On" with throttle lift. Blue Bird added a wire to the brake light relay and changed the switch so it has a center "Off". One way it works as before with throttle lift and in the other position the Jake comes "On" when the brakes are activated.

Occasionally it stops working altogether and when this happens I pull the relays in the compartment under the drivers window, spray the sockets with cleaner and all is well for another year or so. (Bennie showed me this "fix")

The last time this happened only the "throttle lift" mode started working again. The relays, wiring and switch check OK. The green LED next to the switch lights when the service brakes are applied so I know the trigger voltage is there. Any ideas on what to try. The Jake works normally in the "Throttle Lift" position just not in the "On with Service Brake" position.

Thanks for your help!

Rich D. '99LXi43' CT