Jake Brake Circuit Breaker Size?

[Geoff]

If you have a manual transmission, you are supposed to have a Jake disconnect switch on the clutch pedal.  Second, it is no problem running a three wire loom to the front of the bus for two stage brakes.  I got the wire from Home Depot.  Third, the reason Jake's are weak (on Detroit 2-strokes) is because the recommended clearance is too loose. Set the clearaces at .035-.040 and you will have strong Jakes and 1st and 2nd stage will make sense.

[sledhead]

I had the 2 stage jakes on the 6v92ta and used both stages at different times .
on the cat they work so good sometimes I never need to use the brakes

dave

[richard5933]

If you have a manual transmission, you are supposed to have a Jake disconnect switch on the clutch pedal.  Second, it is no problem running a three wire loom to the front of the bus for two stage brakes.  I got the wire from Home Depot.  Third, the reason Jake's are weak (on Detroit 2-strokes) is because the recommended clearance is too loose. Set the clearaces at .035-.040 and you will have strong Jakes and 1st and 2nd stage will make sense.

Three conductor? High/low and ground? Can it be done with two conductor and chassis ground? We ran a two-conductor cable front to back when we had things opened up for some other work. Would be difficult to run more cable right now.

[bevans6]

With two stage jakes you provide power to the buffer switch from the rear electrical panel, run that switched power (though a clutch switch if you need one) to the front dash panel jake switch  with two ON positions (one side and both sides) and run two wires back to the Jakes heads, one for each side.   With single stage jakes, you provide power to the dash switch from the front panel bus bar, and run one wire back to the Jake buffer switch, and from there to the Jakes heads on both sides.  with single stage switch you can run power to the clutch switch either before or after the jake on/off switch.  So need either three wires front to back, or one wire.  The only ground connection in both scenarios is via the Jake heads on the cylinder heads, so no, you cannot use chassis ground as a live feed control wire.

[chessie4905]

Study your wiring diagrams. There are spare wires going from drivers elect. panel to the one in engine compartment. No need to run new wire. Some wiring info is in the service manual under the relay, circuit breaker and electrical posts. Get a cable tracker from HF to verify. I have one and it works great. Cliff probably thinks they are junk.lol

[luvrbus]

Never saw Jakes on Trailways either,when Trailways went to Eagle in the 60's there was never enough clearance on the passengers side for Jakes remained like that till in the late 80's .Greyhound never had Jakes on the MCI even the MCI 9's 
A bus with low gearing like in the 4.25 + Jakes do work better, hiway gearing like 3.36:1 they are not much except in 1st or 2nd gear.
Sotra works like on the series 60 and Allison B500 with the hi gearing with my jakes the transmission automatically drops to 4th gear before the Jake's will engage,Richard with your gearing and a manual transmission I wouldn't waste the wire doing a 2 stage Jake on a 8v71. lol I had a guy that insisted on a 4 stage Jake on a 8v92 I told he was wasting wire so he ran the wire and I hooked those up for him in a week he told me yea it was a waste but I have a 4 stage brake and it makes for good conversation though           

[eagle19952]

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.

I think it's better to not get yourself into a situation where you'd have to rely on them.
If they don't do what you wished, (and they won't as often as they do in a 2 stroke) all that's left is prayer...

[Bill B /bus]

Used two stage Jake on the 4108/8V71. Example is east bound on I24. Approached the Monteagle down grade  in 3rd gear, Spicer 4 speed.  Reduced to one bank on the Jake. Speed held at 45-48 down the steeper parts.
Two stokes by design work great with  a Jake Brake. Every up stroke yields a  slow down. Try the Gaspe Peninsula without a Jake and tell me that they aren't worth the price.
Or north on the Alaska Highway with the 4108,  big Safari motorhome was behind me all day. He'd catch me on the uphill but wouldn't pass. Stopped in the same place that night, Toad River. Driver commented that we had brake light problem.  Really said I with surprise. He replied that usually I had no brake lights on the downhills when he was on the brakes. I had to explain Jake Brakes to him. I did add a wire from the Jake s on the first bank for the brake lights.

Bill

[eagle19952]

Spicer 4 speed. 

Bill

Makes a huge difference.
Many are hoping for the same result with an Allison.

[luvrbus]

The design of the 2 stroke with no intake valve makes it bad candidate for Jakes IMO ,Jakes and Detroit were around for years before Detroit ever used a Jake on that engine,I remember in the mid 60's when they first tried it was a big big problem on the 8v71 with the 4 valve head.Jakes on a 2 stroke are over rated compared to a 4 stroke engine.You want good oil pressure on a 2 stroke are they are worthless.You guys keep up the good work promoting Jakes I installed 6 sets so far this year with your help         

[Geoff]

I have a Suburban GMC RTS with highway gearing that ran commuters from Santa Rosa, CA to San Francisco.  They had the Allison V730's set up so they would not upshift when placed in any forward gear.  This was done because of the steep San Francisco hills, normally the Allison's would upshift at 2300 rpm's.  Great with Jakes.

[Geoff]

The design of the 2 stroke with no intake valve makes it bad candidate for Jakes IMO ,Jakes and Detroit were around for years before Detroit ever used a Jake on that engine,I remember in the mid 60's when they first tried it was a big big problem on the 8v71 with the 4 valve head.Jakes on a 2 stroke are over rated compared to a 4 stroke engine.You want good oil pressure on a 2 stroke are they are worthless.You guys keep up the good work promoting Jakes I installed 6 sets so far this year with your help       

It all in the Jake valve clearances.  Adjust them at .035 to .040 and they kick @$# downhill with no problem.

[luvrbus]

LOL go for it but I am not going to try that adjustment,? what is highway gearing on a RTS 4.10 or something like that 

[Geoff]

Highway gearing on the V-drive RTS is 4:56 and 4:10, with the slight overdrive of .875 in third gear giving you a highway speed of 70 or 80 mph at 2300 rpm's, respectively.

[Iceni John]

It all in the Jake valve clearances.  Adjust them at .035 to .040 and they kick @$# downhill with no problem.

Have you ever set a DDEC engine that tight?   I would like better Jaking, but not at the risk of catastrophic damage (or worse).

John