| Author | Message | ||
| kyle pesely (Kylexisxrad)
Rating: N/A |
as a somewhat newbie preparing to take my bus on the first long trip, I'm getting ready to tackle some pretty gnarly grades(including socal's famous grapevine) and would love some input on how to properly use my jake brake. the bus is an Eagle 10 with a 6v92TA, allison HT-740 and the factory mechanical throttle w/out cruise control. any help is appreciated. thanks! kyle in norcal | ||
| John MC9 Rating: N/A |
I never drove a bus with them, only trucks. There will be a lot to follow, but....... 1. Never, ever, use it while on ice, snow, or slippery surfaces. | ||
| Gary Stadler (Boogiethecat)
Rating: N/A |
It's pretty darned simple... go down the grade as if you didn't have them (ie in a lower gear than high), and then turn them on. You should be in a range that the engine is near it's maximum governed RPM, that's where the Jakes are most effective. If you find that the jakes are so good that they are now slowing you down to a standstill, shift up a gear and you'll go faster... and if you have Jake selector switches (ie bank 1-2-3) play with them until you strike a balance going down the grade at what you consider to be a safe speed, without having to use your service brakes, and not gaining speed. My experience on the grapevine for example is that prior to having jakes I could come down it at about 45 with my exhaust brake on, in 7th gear (out of 9) and maintain that speed without using the service brakes. With the jakes I can now take that same grade at 65 in 8th, under full control. They are amazing!! Many may shout: Oh you can't do that (go that fast), what if the Jakes FAIL !!!) Well, in that case your service brakes are nice and cold because up to the jake failure (rare) they havn't been used, and they will be plenty able to slow you down to 35 or so at which point you can come down the rest of the way with just the engine holding you back as you would have with no jakes in the first place. You'll love em.... and as John said, never use em on ice, snow, or slippery surfaces because you have not got enough control of them to be safe in those conditions. They are kinda on or off, not much inbetween.... | ||
| Dale Fleener (Dale_mc8)
Rating: N/A |
Check out the Jake Brake website (Google for it.) There is an operators manual available for print out there. | ||
| Richard Bowyer (Drivingmisslazy)
Rating: N/A |
I think I have travelled most of the major grades throughout the US and parts of Canada. My experience is that the majority of downgrades can be travelled with use of the Jake Brake and proper selection of gears. Service brakes are typically never required to properly control speed. The only exception to this that I found was when the downgrade was so steep and the road so narrow and crooked that I had to reduce speed below about 15 mph. At that speed the transmission lockup of the 740 tranny would drop out and I then had to use service brakes. Of course if you have a manual tranny, then this would not be a problem either. I tried to maintain engine rpm at 2000 or above to get maximum Jake action. I only had a Hi and Low selection. Gary's recommendation for a Hi, Medium and Low selection is a great idea and one I would incorporate if I still had a bus. Richard | ||
| R.C.Bishop
Rating: N/A |
Like anything else....practice! Great tool if one doesn't expect the ridiculous out of them...wouldnt' trade mine.  FWIW RCB '64 Crown Supercoach (HWC) | ||
| Jim Stewart (H3jim)
Rating: N/A |
I consider them a basic piece of safety equipment and would not be without them. Gary is right on the money. | ||
| Henry Bergman
Rating: N/A |
Used to drive the North half of the grapevine every school day hauling kids to Bakersfield and back. Ride was a 1963 Crown 10-wheeler with a 743 220 Cummins, a Spicer 5-speed---and a Jake Brake. Old #21 with the Kern High School District. Could come down the grade going North at 35 mph in 4th gear WITHOUT TOUCHING THE SERVICE BRAKES!! Usually about 50 to 60 kids on board too. Would pull off the freeway with the brakes still COLD SQUELLING!! (hugh?) Long ago and far away. | ||
| Buswarrior (Buswarrior)
Rating: N/A |
Hello Kyle. Think of the jake brake as something that drags to keep your speed down. The goal is to NOT use the brakes to control your downhill speed. A bus/truck wants to speed up down hill in ways a car will never do! The brakes will not do it alone. If you use the brakes too much to control the downhill trip, they will start smoking, become ineffective due to heat and the vehicle will run away. Choose the road speed and a gear in the transmission that lets the jake brake drag enough to keep the road speed under control without using the brake pedal. And there is no shame in being passed by other vehicles. The goal is to reach bottom and be able to continue the journey. If you find the jakes drag too much, use the lighter setting or try a higher gear, if they drag too little, slow down with the brakes and shift to a lower gear and try the jakes some more. It is, as noted earlier, a practiced experience, where the road speed, the slope of the hill, the choice of gears and the choice of jake setting all create more than one combination that works. For instance, I can get down Fancy Gap in West Virginia without a jake by running about 40 mph in third gear. 6% steepest, maybe one or two brake applications in 5 miles to drag it down from above 45. 8V71, HT740, 3.7 diff in an MC8. With a Jake, I suspect that I'd be able to run in 3rd with a light setting up just below 50 mph, or in 4th and a touch faster at lower revs in the higher setting and keep it in balance. Yes, not the Rockies, but a theoretical example. happy coaching! buswarrior |