Jake Brake Circuit Breaker Size?

[richard5933]

I'm putting together the last details on our Jake Brake install for this winter/early spring. Right now I'm working through the wiring plan. I've found the wiring diagram in the GM book for the optional Jake Brakes. It indicates the addition of a circuit breaker to an unused spot. Problem is, it doesn't indicate what size breaker.

Running a 24v system. Anyone know what size breaker is needed to run the Jakes on an 8V71?

[bevans6]

MCI's have a 6 amp auto-reset breaker for the jake brakes.

[luvrbus]

I use a 5 amp fuse not a breaker,are going to waste wire and wire your Jakes for a 2 stage ? with a manual transmission a clutch switch will make like easier for you shifting

[richard5933]

I use a 5 amp fuse not a breaker,are going to waste wire and wire your Jakes for a 2 stage ? with a manual transmission a clutch switch will make like easier for you shifting

Going with single stage - all or nothing. Didn't seem like the two stage made any sense on the 2-stroke engine.

Clutch switch is in the plan.

[luvrbus]

Going with single stage - all or nothing. Didn't seem like the two stage made any sense on the 2-stroke engine.

Clutch switch is in the plan.

That will work the clutch switch is a good idea when hunting for gears some people can master it without one but most have a tough time

[Lin]

There it is again, that "2 strokes need a single stage Jake" myth. Mine is two stage and I use it on first stage more than on second stage.  Must be the placebo affect.

[richard5933]

There it is again, that "2 strokes need a single stage Jake" myth. Mine is two stage and I use it on first stage more than on second stage.  Must be the placebo affect.

Maybe you can explain. You sound like you're advocating adding the extra wiring to have two-stage Jakes, but the more popular opinion is that the first stage doesn't do enough to make it worth the effort. Aside from your personal experience, why is this a 'myth'?

We had single stage on our 4106 with an Allison V730. They certainly were helpful when driving, but I never considered them too strong or wished we could cut the stopping in half.

now we're installing Jakes on a 4108 with a 4-speed manual. At times the Jakes provide too much help, I figure that the engine/tranny will do the job just fine and the Jakes can be turned off.

[eagle19952]

There it is again, that "2 strokes need a single stage Jake" myth. Mine is two stage and I use it on first stage more than on second stage.  Must be the placebo affect.

Standard transmission ?

[luvrbus]

If you are in the mountains or steep grades the 2 stage are not much good,Lin has spent a fortune adding valves to make his transmission lock up to use the Jakes so he has to be in 1st or 2nd gear using his Jakes.The 2 stage Jakes on the Detroit will not hold you back on the descend from Flagstaff to Phoenix unless you are in 1st or 2nd gear at 15mph with people fliping you off .4 strokes have real Jake brakes 2 strokes make noise   

[chessie4905]

I'll bet they work fine in an MC-6 with a 12V-71.

[luvrbus]

I'll bet they work fine in an MC-6 with a 12V-71.

could be the trucks worked ok with the manual transmission but Greyhound never used Jakes brakes on their older buses,Jakes are a personal preference on a 2 stroke to me anyways it just makes the oil consumption increase on those old engine also     

[richard5933]

At least by 1975 the Jakes were an option from GMC. There are wiring diagrams showing the install for all the various configurations (auto, 4-speed, with/without other options). The only thing not there was the size of the circuit breaker.

When I talked to Luke about this bus before we bought it, he mentioned that Jakes were rare to find on east coast buses, but that they were more common on the west coast.

[luvrbus]

At least by 1975 the Jakes were an option from GMC. There are wiring diagrams showing the install for all the various configurations (auto, 4-speed, with/without other options). The only thing not there was the size of the circuit breaker.

When I talked to Luke about this bus before we bought it, he mentioned that Jakes were rare to find on east coast buses, but that they were more common on the west coast.

I never saw Jakes on the old dogs here in the West,the GM transit buses I see those were factory

[eagle19952]

I always thought Jakes on a two stroke
and prayer were for when there was no option left.
Not a first line of defense.

[richard5933]

I never saw Jakes on the old dogs here in the West,the GM transit buses I see those were factory

If my understanding is correct, by the time GM was offering Jakes as a factory option, Greyhound was getting all their buses from MCI. Only charter companies or maybe Trailways would have ordered the optional Jakes. From what I've seen online, Greyhound bought their last GM coach in the late 60s, before the Jakes were available from the factory.

I always thought Jakes on a two stroke
and prayer were for when there was no option left.
Not a first line of defense.

First line of defense or last hope, I still think it's better to have the option to flip the switch and have whatever help Jakes provide rather than just having the prayer option.