| Author |
Message |
Geobus (4108gmc)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, November 09, 2004 - 11:14 pm: | |
Well I know there are alot of you guys out there that could install jake brakes in the pitch black. But is it something a guy who is willing to do-should do? I have a GMC 4108 1976 with a V730. I am thinking of spending some time out west and in the mountains (when the snow is gone). I read many of the old threads on the BB. It sounds like it isn't a bad idea to have jake breaks, possibly an overkill? Is it ok to put jake breaks on a 4108? Should I do this myself? If so where should I get the parts from? What is the general procedure?
Thanks and have a great day. |
Marc Bourget
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, November 09, 2004 - 11:35 pm: | |
Others will weigh in on this but I understand its not a job for the uninitiated, requires "re-running the rack" which is a technically difficult thing to do unless you're lucky or talented.
But lots have learned in the past and you can to. Go for it, but be careful!
Onward and Upward |
TWODOGS (Twodogs)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, November 09, 2004 - 11:51 pm: | |
no...have it done |
FAST FRED
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, November 10, 2004 - 5:38 am: | |
Jake will give you Da Book that covers instalation and normal service , maint & repair.
Read it and YOU decide ,if its within your abilities.
FAST FRED |
BrianMCI
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, November 10, 2004 - 8:37 am: | |
Unless you have the capabilities of a diesel mechanic, the shop to do it in, as well the proper tools and equipment...I'd have it done.
Remember that if installing a Jake is done improperly it could be disasterous.
But if a shop does it and it goes wrong, they have to then fix it, if you do it and it's done wrong... Oooops
Brian |
Rodger in WA
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, November 10, 2004 - 11:33 am: | |
In my opinion, for occasional use, installing a Jake Brake is not cost effective. Just drop to 3rd or 2nd gear and stab the brakes once in a while to keep the RPMs under control.
In my Prevost with 8V71 and Allison MT644, towing a Honda Accord, I've descended most of the long grades in NC, VA, WV, MT, WY, ID, OR, WA, NV and CA and never overheated my brakes.
You can find a lot of ways to benefit better from the $2K plus you'd spend on installing Jakes. |
Henry R. Bergman, Jr. (Henryofcj)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, November 10, 2004 - 6:30 pm: | |
Good idea getting your Jake installed. Might be best to just hire a QUALIFIED 2-stroke mechanic and let him do it. Perhaps you can help/watch and learn.
Not sure here but maybe some attention to the lock up clutch function on your auto trans may in order also. Believe you can hold lockup into and including 1st gear. Good luck. |
Stephen Fessenden (Sffess)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, November 10, 2004 - 10:38 pm: | |
I would not have wanted to travel the West Virginia Interstate route that I traveled last month without a Jake. The engine will overspeed even with a Jake on some of those long grades and the engine manual for the DD8V71 and DD8V71TA warns very strongly about exceeding the RPM limits of the engine, 2100 by the manual. There were some interesting runaway truck ramps with waves of sand to help stop you. I prefer the Jake and would pay what it costs to have it. I thought about the other systems on the newer more expensive conversions. Jake can brake forever. Hydraulic accumulator is limited by transmission temperature. The electric brake system must also eventually be limited by temp. |
Richard Bowyer (Drivingmisslazy)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, November 11, 2004 - 3:32 pm: | |
Steve, I currently live in WV and these hills here are just speed bumps! Wait till you get out west and you will really see some long steep grades and will appreciate the Jakes more than ever. LOL
Richard |
Busone
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, November 11, 2004 - 4:10 pm: | |
Since I will be visiting my family in CO often jakes are something that I will want to consider in the future. As a kid I always remembered coming down I70 and smelling burning truck brakes. It is several miles of a 6% downgrade. In fact a few years ago when my wife and I were dating we were going up to the mountains on WB I70 and on the 6% up grade a school bus was on the side of the road and on fire. I am glad it was only the driver because the bus was burned bad. It was a rear engine Internationl transit type. |
RJ Long (Rjlong)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, November 11, 2004 - 8:23 pm: | |
Steve - I agree with Richard! Everywhere I travel out of the Fresno area, except up the valley to Sacratomato, I've got 5 & 6 % grades to climb/descend.
The Grapevine (I-5) into LA. . .
The Altamont Pass (I-580) into the City (SF). . .
NB I-5 out of Redding into Oregon. . .
US 50 into Lake Tahoe. . .
I-80 EB/WB, Sacratomato to Reno. . . This one, WB, is probably the worst, more than you've probably ever seen on the right coast - you've got 70 miles of 4, 5 & 6% downhill grades!!
For me, I'll disagree with Rodger, and say that IMHO, it's well worth the investment: after all, what price SAFETY?
FWIW,
RJ
PD4106-2784
Fresno CA |
TWODOGS (Twodogs)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, November 11, 2004 - 8:40 pm: | |
R.J.
don't forget Indio......
and...the worst one I ever went down....CABBAGE |
Mike (Busone)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, November 11, 2004 - 8:58 pm: | |
Cabbage sucks when the weather is nice and it really sucks when it is snowing, 25F and dark out. I will never do that again in the winter months again. Ok if my Grandma is sick and asks me to, she never will though. She thinks we should ride a train everywhere we go because cars are too dangerous. |
Stephen Fessenden (Sffess)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, November 11, 2004 - 9:31 pm: | |
We had one 9% grade of reasonable length in WV. Most were 6% or 7%. |
Buswarrior (Buswarrior)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, November 13, 2004 - 3:59 am: | |
Hello my friends.
So that the less informed have some other input, and because some don't have a lot of cash...
This guy will make the argument, that you don't "need" a jake brake, if finances are tight.
If you are concerned about spending the money on a jake brake, and really want to not spend that money, you don't have to.
Running down hill in a bus is not running down hill on your bicycle: faster is NOT good.
Whatever hill, mountain or cliff you find yourself descending, you want to go slowly enough that you are NOT using the brakes all the time to keep your speed under control.
In a perfect world, you want to be going slowly enough that the engine and transmission keep the vehicle under control (meaning that the speed doesn't increase).
In the real world, you want to be coasting far longer than you are using the brakes to slow down.
Use your brakes to slow down 5 mph slower than your target speed on the hill. It should take much longer to coast back up to your target speed than you used the brakes to slow down. If you speed up right away, you are going too fast for that slope. Pick a lower target speed. And your target speed is not the speed limit, or the speed of cars. It is whatever speed the bus is only gently speeding up from, not running away dangerously!
In Virginia/West Virginia on I77, the grades are signed for vehicles exceeding 26000 pounds GVW, 45 mph for them, 55 for the light stuff. My MC8, stock 8V71, automatic tranny, needs only a few brake applications, dropping the speed to 40 mph and then coasting back up, to keep it under control for a 4-5 mile 6% downgrade, using the 45mph as a target speed, and using 3rd gear, out of 4.
To the crew, please correct my details, if I've messed something up.
Out west, or off the beaten path, here in the east, you will need to go a lot slower to keep your bus from losing control due to overheated brakes on those steeper slopes.
Slower you go, less stress on the brakes, less heat in the brakes, less cash spent...
If you are going any significant speed less than the rest of the population, please be courteous and safe and show some 4 way flashers!
If only we could get a bit of government money and shoot some video, it would be so much better...
happy coaching!
buswarrior |
Stan
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, November 13, 2004 - 10:17 am: | |
Back in the middle ages when I was taught how to drive a truck, I was told to go down a hill in the same gear needed to go up the hill. At that time a 180 or 220 HP Cummins was a big engine and the rule made sense. With engines in the 500 HP range trucks climb hills at the same speed as the cars but still still face the need for control on the down grade. Engine brakes (Jakes) were the answer to incompetent drivers and faster trips.
Bus Warriors advice is very true. The major bus lines ran all the mountain grades without Jakes for more than fifty years. Until they went to Series 60 engines they didn't use them. |
Tom Caffrey (Pvcces)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, November 13, 2004 - 9:46 pm: | |
Buswarrior, I would add, for those who don't already know it, that double the speed does not mean that there is double the energy stored that must be gotten rid of in a full stop.
Instead, the energy is proportional to the square of the speed, so that slowing from 30 to 20 means a lot less brake heat than slowing from 60 to 50.
This is why high speed stops are so hard on brakes and why high speed descents from altitude cause runaways. In cars, we hardly notice the effect, and there are too few reminders to the driving public about it.
The effect can be easily seen by observing how long it takes to speed up from 20 to 30 and from 50 to 60. It's the same weight, and the power is limited to what you can get out of the engine.
For what it's worth.
Tom Caffrey PD4106-2576
Suncatcher |
Marc Bourget
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, November 14, 2004 - 3:44 pm: | |
Simply put, you have to convert 4 times as much kinetic* energy to heat energy slowing from 60-0 as from 30-0.
60-30 requires shedding 3 times as much energy as stopping from 30-0.
Onward and Upward
Marc Bourget
[* I think kinetic is the proper term] |
Mike Eades (Mike4905)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, November 14, 2004 - 9:23 pm: | |
I ahve jakes on 8v71 and I found that the first mechanic to adjust the rack tightened one valve too tight and I dropped a valve and cost me a cylinder kit. The next mechanic was Bill at U.S. Coach. No more problems. If you decide to do it yourself, Becarefull. Needs to be done right or big dollar repairs.Graduate of Hardknock U. Mike4905 |
TWODOGS (Twodogs)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, November 15, 2004 - 12:36 pm: | |
there are some tall valve covers for jake brakes on the E**Y place.... |
Geobus (4108gmc)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, November 15, 2004 - 1:51 pm: | |
Thanks everyone for all the great feedback.
Thanks for the lead on the new covers. I went ahead and bought them. They looked pretty clean. I guess I am committed to the Jake Breaks. If you have any more good leads on the rest of the parts, which I don't have a clue what I need, I would likely follow up on them. Also, the project sounds like something I would try, if it was something else other than my coach, like a lawn mower. I decided to have a prof. do it.
Thanks again and have a great day. |
TWODOGS (Twodogs)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, November 15, 2004 - 3:28 pm: | |
be prepared to spend some money...think before it's all over with it's going to be close to 3000 |
TWODOGS (Twodogs)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, November 15, 2004 - 3:35 pm: | |
everybody that has a two stroke needs to find a two stroke mechanic in his town,or the next town over..the four stroke guys don't like to work on them...after you find him...he will know everything that needs to be done...& where to get the jake.. |
TWODOGS (Twodogs)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, November 15, 2004 - 3:37 pm: | |
try LUKE...he might have a jake for a 8v71 |
Larry Baird (Airhog)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, November 15, 2004 - 6:31 pm: | |
I had mine put on at the local college for the price of a few pizza's, would not be without them. |
Geobus (4108gmc)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, November 16, 2004 - 6:58 pm: | |
I think I found someone to put the Jakes in, but I would like to have a good idea of how many hours it should take, a good man vs a slow man.
Thanks and have a great day. |
Geobus (4108gmc)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, December 23, 2004 - 7:26 pm: | |
Just a follow up.
I made it back for the holidays. The coach ran great. It was a real pleasure having the jake breaks. Ya, I could have made the trip without them but it was great having them. They are sort of like having 4wd on your truck (or car) or having a really fast internet connection instead of slow dial up.
It was great going through the mountains in GA, SC, NC, and KY and not having to break. The coach responded very well. I think one of the nicest things about having the breaks is the rapid deceleration in city driving. I don't remember any one discussing this benefit. Ya, one should drive so they don't need the jakes. But when you are trying to get 15 tons through stop and hurry up and go traffic, the breaks are nice. My wife liked them too, because the coach slows down faster, which she is use to in a smaller vehicle. Yes, after all is said and done it is nice having both high and low jakes, instead of just high as talked about above.
Have a great holiday. |