Wanderlodge Owners Group  
BuyByeBlueBird.com
WOG Gear

Go Back   Wanderlodge Owners Group > Mechanic's Corner > Engine

Engine Discussion of preventative/corrective maintenance and other technical issues regarding your coach's engine.

Site Search:
Reply
 
Thread Tools
  #11  
Old 12-14-2010
bwinter1946's Avatar
bwinter1946 bwinter1946 is offline
Senior Member
 
Join Date: Mar 2009
Location: Madera
Posts: 3,902
Default

Quote:
Originally Posted by Randy Dupree View Post
Ian.
Just like your foot brake,the Jake brake can get you into trouble on ICE/SNOW!

Chances are that on I-15 the roads will be fine,get on your CB and ask the other drivers what the road looks like,and take it slow.
X2 on that. The thought of "drifting" a 40+ foot bus weighing 50,000 lbs would scare me to death. Going slow costs you nothing but time.
__________________
Brad Winter
Madera, California
1997, 37' BMC
1999, Jeep Cherokee, Toad
1970, VW Baja Bug, Alternate Toad
Reply With Quote
  #12  
Old 12-14-2010
Itchintogo
Guest
 
Posts: n/a
Default

Exactly! Randy's advice is good. You will get to know your rig and what setting you need for what % grade to hold you. The secret is to always keep your brakes fairly cool so if you need them they are there for emergency situations or an unexpected slow corner. Until you know your rig start off slow and try things out. It also helps if you know what is ahead of you. You should be fine on I 15.

For example: on Field hill at the BC/AB border I start down there at not much more than 60KPH because I KNOW there is a 60KPH or 40MPH zone for tourists to stop and look look at the train tunnel half way down the mountain. I go down with my jake doing most all the work to hold me back. So my brakes will slow me slightly with out alot of wear or getting them hot. They will stop me no problem if someone pulls out in front of me.

All it takes is a bad wire for your jake to quit. This is why no one should ever depend on full jake/retarder and a medium to heavy brake application to hold them. If your jake quits your toast in that situation if it is a long hill. A number of years ago a friend of mind was going down Field hill depending a bit too much on the jake. His jake failed about 1/3 the way down. This is a road we all drove many many times. He was a full loaded semi truck. Lots of experience.

He used his brakes until he felt fade start to happen. Remember we all knew the road and every corner and how fast we could take each corner, an advantage most RV's don't have. He decided to save what was left of the brakes should something else happen. He was going 140 KPH or 85MPH and took all four lanes and the shoulders to make the curve at the bottom. Good thing no one was coming the other way. He also had put the truck in neutral so as to not blow the engine with too many RPM's. In neutral your vehicle handling changes dramatically and not for the better with that heavy trailer pushing you in every corner. All of this just because a simple solenoid wire broke.

It takes years of daily practice to manage all of this and you must do it in seconds. I will start another thread just to see what people would do if their bus quit on a long steep grade. It would be a good education for everyone to share.

Think of your retarders, and jake or pac brakes as brake savers. Then you won't get into too much trouble.

Last edited by Itchintogo; 12-14-2010 at 11:28 AM.
Reply With Quote
  #13  
Old 12-14-2010
cmillsap
Guest
 
Posts: n/a
Default

Quote:
Originally Posted by Who Moved my Stuff ? View Post
I have a three speed Jake brake, but I'm not absolutely sure how to properly use it.

Currently when I see a knuckle whitener downgrade, I switch the Jake on Low and brake to slow.

Consider that I'm a newbie, and negatiating dry, wet and snow combinations, and I'm looking at a 6900 ft pass tomorrow.

Occasionally there's a red warning light comes on, about excees RPM's.

Any help would be appreciated.

Thanks
Ian,

My 3 stage Jake will not engage if I am traveling at a speed high enough to over rev the Detroit. I think this is programmed in the computer. I have never seen a red light indicating over revs of the engine. If I’m traveling over 63 mph with the Jake on, I must use the chassis brakes to slow the coach to that speed where the Jake will then engage.

My set up may be different than others but I like it as it is a good way to help prevent over revving of the Detroit. As someone just mentioned, over revving the engine can be a dangerous and costly practice.

I forgot to mention also that my Jake will automatically disengage when my slowing speed reaches 15 mph.


Chuck

Last edited by cmillsap; 12-14-2010 at 01:09 PM.
Reply With Quote
  #14  
Old 12-14-2010
wranglergs
Guest
 
Posts: n/a
Default

What is the relationship between the jake brake and the tach? If you lose your tach will you lose your jake?
Reply With Quote
  #15  
Old 12-14-2010
MIKE MARTINKUS MIKE MARTINKUS is offline
Junior Member
 
Join Date: Sep 2010
Location: DOUGLASVILLE GA.
Posts: 18
Default

when I used to give owner instructions at delivery I always referred to the Jake as a brake ASSIST. That is, it decreases the amount of service brake you need to use. In going down a steep grade, it allows your brakes to remain COOLER so that you would always have a maximum brake function in an emergency.
The object should be to slow the vehicle enough that service brake is unneeded. That however is a rarity because the grade is seldom the same all the way down. So the secondary objective is to increase the distance or period of time between service brake application. This is accomplished as a result of jake application and by lowering the maximum speed that you allow the vehicle to reach before application of service brakes.
Say you start down a grade that you feel comfortable going 55 MPH. You start at 50MPH in first stage [2 cylinders retarding] but quickly go to 60. Slow back down to 50 and go to stage 2 retard. If speed still gathers too quickly go to stage 3. If you still gain speed too quickly, start reducing your initial speed. Slow down to 45. If that still is too quick, downshift to a lower gear. You may need to slow the coach down considerably in order to get it into a lower gear. Heed the above warnings about ice and slippery surfaces.
Just remember the object...stay off the service brakes as much as you can. You can descend just about any hill you are likely to encounter by staying slow. Speed heats and kills brakes . Retarders save brakes and lives.
__________________
Mike Martinkus
Motorhomes Of Texas
Nacogdoches Texas
Reply With Quote
  #16  
Old 12-15-2010
peteaeonix's Avatar
peteaeonix peteaeonix is offline
Former Bird Owner
 
Join Date: Jan 2008
Location: Ridgefield
Posts: 2,010
Default

For those with a Series 60, the redline under power is 2100 RPM. With no power, (i.e. with the jake brake enabled), the red line is 2250 RPM. You should manage your speed to not exceed 2250 RPM.

The DDEC measures the RPM and controls the Jake, so if the rpm sender is not working, then the Jake may or may not work properly (I'm not sure where the DDEC takes its readings). If the tach 'head' is not operating, then the DDEC and Jake would not be affected. However, a tach is a primary instrument in managing a diesel engine, so I'd see a broken tach as a must-fix component before traveling any distance.

The low, med, and high settings refer to the amount of resistance the Jake provides. If you're gaining speed with a setting, try the next higher setting. On many grades down mountains the medium or high setting is required to maintain a steady, safe speed.

The transmission control has 2 modes (Mode on, mode off). Usually you travel in mode off, but turning mode on will affect both the speeds where the transmission chooses to shift and when the jake kicks in. If you run into a situation where the shifting/jake operation is not acceptable, try switching mode to on. (I found rolling terrain in certain places on CA US 101 would have too frequent down/up shifts -- and I'd turn off the Jake.) There are remarks in some threads where some individuals had an Allison dealer reprogram the "mode on" shift points to give better drivability with the jake and under certain other conditions. This struck me as an excellent idea which I would have implemented had I not sold my coach.

Specific to the 1995 (and some 1996) 42/43' coaches: There was (apparently) a recall on the Jake brake due to an error in the DDEC. the "medium" setting was wired out, essentially giving the switch a low, high, high setting. If you look at the main electrical panel (behind the plate on the front of the coach) and examine the relays at the upper right of the panel, you'll see the wiring changes, if it was done on your coach. (Do not "mess" with that!).

Another "bug" in the Jake system (I don't know which years this may have affected) was that switching the jake "off" while it was activated would cause it to fail to switch back on until the engine was shut down and restarted.

I normally operated my coach with the Jake enabled on low to give a mild assist to the brakes while operating in normal traffic. While traveling through Texas, I noted that many cities had local ordinances prohibiting use of the Jake while in town. (Usually announced by signs as you enter a lower speed zone near the town limits.) I discovered that I needed to manipulate the throttle to disengage the Jake before switching it off, so that it would be available when I next switched it on -- while slowing down during the entry to towns with the Jake brake restriction.
__________________

Pete Masterson
(former) 95 WBDA 42'
(now) 2011 Roadtrek RS-Adventerous
Ridgefield, WA
aeonix1@me.com
Reply With Quote
  #17  
Old 12-15-2010
jwasnewski jwasnewski is offline
Senior Member
 
Join Date: Jan 2008
Location: Dahlonega, GA
Posts: 1,110
Default

This is how I was formally trained in Jake use. This applies to S60, ISX 450, and C-15 or any other large inline 6 cylinder diesel. Typically, the normal operating range is between 1300 and 1700 give or take 100 rpm.
I run a 10 speed but use the same rule with my 8v92 and Allison 5 speed.
General rule. Use position three if multi-stage. Go down any grade one gear lower than the gear it took to get up the hill. The optimum rpm pulling the hill is 1400 to 1500 rpm full throttle or not. Get in the proper gear and the speed will take care of itself. If the rpm builds to 1800 apply service brakes until rpm is 1300. Don't ride them, get on them.
I routinely come down grades of 6-7% and never touch the service brakes using this procedure.
One thing I have not read about haulin down a 6% grade at 55 or more on the Jake is-- what you gonna so when a steer tire goes boom? I will tell you what your gonna do. If I am beside you you're
gonna take me and everyone else around out with you.
Getting in the right gear before you go down will automatically reduce your speed.
I would not consider engaging the Jake at any rpm above 1800.
__________________
Leroy Eckert
Dahlonega, GA

Former "Smoke N Mirrors" caretaker
Reply With Quote
  #18  
Old 12-16-2010
peteaeonix's Avatar
peteaeonix peteaeonix is offline
Former Bird Owner
 
Join Date: Jan 2008
Location: Ridgefield
Posts: 2,010
Default

Quote:
Originally Posted by jwasnewski View Post
This is how I was formally trained in Jake use. This applies to S60, ISX 450, and C-15 or any other large inline 6 cylinder diesel. Typically, the normal operating range is between 1300 and 1700 give or take 100 rpm.
I run a 10 speed but use the same rule with my 8v92 and Allison 5 speed.
General rule. Use position three if multi-stage. Go down any grade one gear lower than the gear it took to get up the hill. The optimum rpm pulling the hill is 1400 to 1500 rpm full throttle or not. Get in the proper gear and the speed will take care of itself. If the rpm builds to 1800 apply service brakes until rpm is 1300. Don't ride them, get on them.
<snip>
I would not consider engaging the Jake at any rpm above 1800.
Leroy,

I agree completely. The S-60 produces full rated HP and full rated torque over a wide RPM range. So I generally climbed hills at 1600 to 1800 RPM. (As I recall, max power/torque kicked in at about 1600 RPM, but my memory could be wrong.) Coming down the grade, I'd also keep the RPM in the same range.

My only "complaint" is that the automation on some long (relatively straight) grades on I-80 across southern Wyoming and eastern Nevada would drop the transmission into a lower gear more quickly than I'd prefer. I could hold a controllable speed at 1800 RPM in (say) 5th ... (55-60 mph) but the system would jump into 4th (and spin up the engine to 2200 RPM) if the speed would bleed off a little too much. (The Allison "World" transmission has 6 speeds with the top to "overdrive" gears.) On more curvy roads, (such as I-80 crossing the Sierras) then I'd hold down the speed to 45 or so to ensure good control in the curves. In that case, 4th at 1800 RPM was not a bad place to be. (That is the basis of the programming modification I was considering for the "mode on" situation.)
__________________

Pete Masterson
(former) 95 WBDA 42'
(now) 2011 Roadtrek RS-Adventerous
Ridgefield, WA
aeonix1@me.com
Reply With Quote
  #19  
Old 12-16-2010
cmillsap
Guest
 
Posts: n/a
Default

I have a home in Bullhead City, AZ, where one must negotiate a long 12 or 13 mile 6% to 7 % grade on three of the four main roads into the city which sets down in the Colorado River valley. So depending on which direction I’m coming from or going, odds are that I will have to travel up or down one of the grades. The grades headed north and east are curvy and dangerous. The one headed west on I-40 is not bad. I’ve had many years of practice over the last 14 years of driving a large diesel pusher up and down those grades. So has Tela, by the way, as she can drive the coach up and down those grades and any other grade for that matter as good as anyone can. So it doesn’t take a pro trucker to negotiate them safely. All it takes is being sensible and use a little common sense.

First and foremost, check that your Jake or retarder is working properly before you crest the grade starting down. You’re probably in a lower gear climbing the upside, so button the coach in that gear, if not gear down one gear and slow the coach about 10 mph. Start down the grade and watch your speedometer (forget about the tach). If the coach starts to pick up speed, do not let it increase more than 10 mph and use your chassis brakes to lower your speed back to where it was before. If you have a 2 or 3 stage Jake, lower the setting one notch. If the coach still picks up speed, slow the coach with the chassis brakes and lower the Jake setting again or drop the transmission into the next lower gear. The whole idea here is to keep the coach at a maintained safe speed so that you can use either the Jake or the chassis brakes to stop in case one or the other fails.

Arizona closed the road over Boulder Dam after 9/11/01 which required east and west bound truckers to detour through Laughlin, NV and Bullhead City. This is the shortest route to get to/from Las Vegas to/from I-40 east. This went on until a new bridge was built away from the dam which was just completed and opened last month. So, for several years, these truckers had to negotiate both of those bad grades in and out of our city. After the first few runaway trucks ended up in the Colorado River or caused an accident, they installed a runaway truck ramp on each grade near half way down the grade. After more runaway truck accidents, they installed another ramp about 70 % down the grade. Still, trucks managed to end up in the river. Most of these runaway truck accidents were blamed on driver error and was mainly caused by the trucker allowing the truck speed to get too high for his Jake to work causing the chassis brakes to fail from overheating. This seemed to happen most often after the truck had passed the last runaway ramp. This indicated that the chassis brakes finally malfunctioned when the truck was more than three quarters down the grade and with no more runaway ramps to save them, they ended up in the river or ditched the truck to get it stopped. We’ve had everything from beer trucks to car haulers dumping their load in or along the river.

So, after this long dissertation, the moral of the story to anyone that has anxiety about negotiating downgrades is just make sure your equipment is working properly and go down the hill at a slow safe speed.

Chuck
Reply With Quote
Reply

Bookmarks

Thread Tools

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Retarder vs Jake Brake Joatha PT & WB (Twin Axle Pusher Unique Issues) 69 07-31-2017 10:51 AM
Jake brake nfun2 Engine 13 07-13-2010 07:06 PM
Jake Brake rrueckwald Engine 0 02-10-2010 09:20 PM
Lost the Jake brake rrueckwald Engine 16 10-28-2009 10:49 PM
Jake Brake Robmk2 General 1 06-05-2008 10:20 PM

Web Search:

All times are GMT -4. The time now is 03:26 AM.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2019, vBulletin Solutions Inc.