-
I want to add Jake Brakes
In another thread I mentioned I stopped at American Fleet in Springfield MO to talk about some work I’d like to have them do for me.
Danny from American Fleet said that I have the “tall Jake valve cover” which will obviously save me a few nickels. The big challenge will be wiring. He doesn’t know if Prevost might have pre-wired the shell for Jakes. I mentioned looking at the Prevost wiring diagram and he said (likely based on their experience) the online wiring diagram will typically be for a range of VIN#’s and might not be exactly what my coach has. So that is of concern.
Danny also said that Prevost provides a “soft Jake”, apparently not the most aggressive Jake available on a Series 60 DD. He said that entertainer coaches with aggressive Jakes when applied full on would cause “the star” on the rear bedroom to sit straight up out of a dead sleep; hence Prevost used a “soft Jake”.
Why a Jake? Two reasons. I love how they sound. I originally wanted a Peterbilt 379 truck conversion with a huge CAT motor, big open chrome pipes, lots and lots of lights all over, and a Jake brake. That didn’t happen … I’m really happy with our Prevost.
I’m looking for something more aggressive in holding the coach on a long, steep hill than the transmission retarder. Right now I’m not sure the retarder is working (temp doesn’t go up when invoked, doesn’t seem to hold back like it did five or six years ago). When it did work, on steep hills the temp got too high long before the bottom of the hill and haven’t been in the steep part of the Rockies yet.
Maybe I should add another cooler for the trans?
I’ve never driven a vehicle with a Jake. My expectation is that the Jake will hold the coach speed down longer than the retarder can (before the retarder heats up). Are there limitations as to how long a Jake can be invoked? My guess is not.
Danny from AF said that I can’t run the Jake and the trans retarder at the same time (which was a disappointment); one or the other.
I know there are Series 60 Prevost coaches with a Jake brake. I’d be interested in hearing from S-60 Prevost owners with a Jake. Does it get the job done on steep hills in the mountains? Are you happy with them?
Thanks!
-
6 Replies
-
My retarders are far more effective than my Jake was.
When I have run out west with 7% and 8% grades I was often able to descend hills without exceeding my self imposed limit of 230 easily, sometimes without ever touching the brakes.
-
I have never encountered a downhill that the Jake could not handle! If you gain speed down a hill, use the service brakes to lower the speed to where the transmissions downshifts, and you will have the braking effort you need.
-
Dick
My 95 Marathon has the 2 stage Jake, it was reprogrammed sometime in the 90,s to remain in 6th gear when Jake is applied.
I like the way it functions, i like the fact that it stays in 6th gear when i lift off the throttle, i keep it on in high at all times.
It holds my coach back very well when going through the mountains of western Canada, I dont think that there is a limit as to the extent of its use other than its own effectiveness, by that i mean as RPM decreases so does the effectiveness of the Jake requiring a downshift to raise RPM.
If i am in 3rd gear with 2nd stage Jake the only time i would apply service brakes is to maintain my max RPM of 2100.
I like the sound and the fact that it is serviceable by myself in the event of a problem.
In terms of Jake vs Retarder i think that a Retarder will prove to be more effective.
Gordon
-
Yes, my hearing is not the best for high frequencies, but for exhaust type noise it is pretty good.
I think “approved exhaust brakes” are routed through the muffler or muffled somehow. I really can’t hear my Jake (compression brake) when it engages. Probably in a tunnel I hear it…
The old style Jake brakes were un-muffled and loud. We have some dump trucks that deliver gravel to new construction in our development that are not muffled. After some discussion with the gravel company, the drivers no longer run with the Jake turned on in our fairly flat neighborhood (15 MPH).
Now if we could just get them to slow down.
-
Jon: My “Oil Temp” gauge (which I’ve come to learn is the transmission gear lube temp gauge) usually is around 195* to 200*F. Back when I think the retarder was really working, when invoked on a steep downhill at a fairly modest speed the temp would rapidly rise to over 250*F quite quickly, at which point I’d use the service brakes to bring the speed down and relax the retarder until it got to a more acceptable temp.
As I said earlier, I don’t think the retarder is working correctly now. I’ll look for a fuse, but other than that I suspect I’ll need to have an Allison service center look at it. If it more than a fuse or a wire, the quick temp increase and its apparent non-functioning might be related … or it might not be.
-
Dick this is gonna be kinda long but I’ll share my limited experience. A little history –
Out of HS went to work for UPS. Stayed thru college, then drove delivery truck and ended up in mgt, lastly automotive. Got exposed to lots of OTR tractors and equipment and loved it. Still have nothing but admiration for that company. Best run/managed oragnization I have ever been associated with bar none.
Left after 11 yrs for a simpler life (wife was tired of me never home) and was fortunate enough to be hired by a large metro Fire Dept. During my almost 25 year career there (now retired), spent probably 2/3 of that time behind the wheel of 2 (Dept had 4) E-One chassis, one with 135′ aerial and another 95′ platform. Same chassis, 8V92 T/A engines, Allison trans with retarder. These 4 rigs were the only ones in dept with trans retarders. They did make a noticeable difference – although maintenance shop heavily advised us not to use – due to trans heat. I always used them – had a left foot pedal left side of steering column. These rigs had an empty weight of 68,000 before any gear was added/loaded. And they carried ALOT. Hendrickson walking beam rear suspension. They had about ONE good hard stop on brakes – then that retarder was worth its weight in gold.
Side note – some of the lighter (relatively) pumpers and telebooms had TELMA retarders which were amazing. Huge electromagnet assy on trans output or driveline. Dept eventually got away from those claimed they ate alternators.
For the last 30 years did my fair share of part-time truck driving for various companies. Where I noticed a difference in Jake brakes was hauling fracking sand. These loaded were ALWAYS 80,000-80500. As much as I am a CAT fan, the Cummins ISX’s had really good jakes – better than anything else I’d experienced other than TELMA’s. These trucks were all 379’s (there’s a reason for that besides style. They are lighter than comparable KW, Intl etc). The C15 twin turbo Acerts, nor the Paccar MX pulled as hard as the ISX equipped trucks did – hard for a CAT fan to admit.
No Series 60’s in that mix, been in plenty of them in tractors doing contract mail runs (Plenty of FD rigs with them also – replaced the 8V and 6V engines). This was in the 90’s, mechanic there told me once the 60’s showed up he really didn’t do engine work just changed components (starters, alternators, wp’s, dryers etc). This terminal would run them 1 million miles then send them to larger terminal/bigger shop and run there. Prior to that was mechanical Cummins that he was inframing at 400-500K.
Also did some time pulling doubles for FEDEX GROUND for a now deceased friend that had contracts. Freightliner Cascadia with DD15. Very comfortable.
Before I retired I bought a Pete 379 ext hood with a CAT 3406E / 13 spd double over. Had it 5 yrs never pulled a thing but it is staying just because I like it – jake works well bobtailing!
Sorry for the lengthy reply – maybe there is a tidbit in there somewhere you may find useful.
Log in to reply.