Jake Break Question???
 

Will excessive use of Jake Break wear your engine out prematurely or is that just a myth?

Thanks!!

Myth.........

I've heard it both ways. I don't see how it would wear a motor. The Jake brake holds the exhaust valves open, on the compression stroke. In other words, when the pistons are at Top Dead Center on the compression stroke, the exhaust valves are open, while the intake valves are still closed. I don't know where the excessive wear would be. If any, I would imagine it would be the valves, or rocker arms, maybe.

Jake brakes work better with straights. http://serve.mysmiley.net/evilgrin/evilgrin0010.gif

A bit less than accurate, but not critical...:)

The only damage I know of that comes from using the jake brake is if something goes wrong with a spring, and the jake remains in operation when you apply throttle. Then, you stand to brake the top ring of the piston.

I was told that the myth of engine wear comes from someone that did not like the noise generated by the brake in use. In order to try to get he drivers to reduce the use of the brake, "You'll wear out your engine prematurely". The fact is that you do not put any more "load" on the engine than normal use. As a matter of fact, you put MORE load on the engine when climbing a hill, because you have far more pressure in the combustion chamber when the fuel ignites than you do simply from bringing the piston up to the top of compression. This increases the load on the connecting rods and all crank journals.

I was hoping I was on the right track. I took a 'leap of faith' on this one. :lol: I remember someone telling me one time how they work.

I keep my Jake's on all the time unless I am in a truck stop parking lot. It saves my brakes and I have almost 1 million miles on one truck and have never had a problem with the engine from the Jake's. :cool:

The only time a Jake brake will hurt an engine is if the driver gets stupid and allows the weight of the truck going downhill to push the engine RPM's over the engine's maximum RPM limit.

Then again, letting the engine get pushed past maximum RPM will also cause damage without the Jake brake on.

.

the problem is they were talking about a Jake "Break" which would obviously break something, however, a Jake Brake should be fine
:moon:

I know I don't have to wory about you g but to others, even with the jakes, use the corect gear and have that foot ready to stomp that brake if you have to. I've had a few trucks where the jakes didn't engage. Once comming down cabage and once on fancy gap. That could have been interesting if I didn't have it in the right gear, lol

I was told that with my 1.4 mil miles, the reason my pistons looked good was because I have no jake & if I did, my pistons would be in worse shape if not needed replacement sooner.

Having been involved in rebuilding, I believe someone was pulling your leg.

A jake won't do you much good coming off a steep grade unless you are in a lower gear. Ideally, you should have it is a low gear which should require little or no need for your brakes. Some people don't have the patience to come off a mountain that slowly. Before jakes we were forced to come off mountains very slowly. If not then you could find yourself running off a cliff. :eek2:

I've had that happen too. I also have driven trucks that never had a Jake. One truck, the shifting linkage let go, and I didn't even have the engine on the way down. When going down a grade, make sure you have the right speed and the right gear before you start going down.

Jake not cutting out during gear shifts
 

Different question, but I am having problems with my Jake during gear shifts. I generally double clutch all my shifts cause I have never figure out how to float the gears with the Jake on(It messes up my timing and I miss or grind the gears). Anyhow, recently, after I have pushed in the clutch pedal, shift to neutral, and let up the pedal some to sync the engine speed to gears, the Jake kicks in. Of course, this screws up my shift!! I don't let up all the way on the clutch pedal; just enough to re-engage the clutch. I have a 13-speed transmission and this even happens when I am splitting gears(I don't use the clutch pedal between direct and overdrive).

I wrote this issue up the other day when the truck went into the company shop. The mechanic twice asked me to describe the problem. I got the impression from him that I didn't know what I was talking about or I didn't know how to operate the equipment(I have driven this truck for more than 2 years and 270,000 miles). He did adjust the free play in the clutch which wasn't needed, but it didn't change the current problem at all.

It is my understand that the Jake should NOT kick in at all if my foot is on the clutch pedal. I am thinking that there is microswitch in pedal that is out of adjust or failing(ed).

Any ideas to help me get the company to fix this problem?

Don't use the clutch at all, and instead just keep tension on the fuel pedal. There is a point where if you keep just enough pressure on the pedal, the throttle will be zero and the Jake will not engage either. It takes a little practice, but once you get the hang of it, it makes life a lot easier.

And for those who might be tempted to turn this discussion into a dissertation on how double clutching is vital and floating is bad (I KNOW it is coming because it has on other posts about shifting), my last truck had nearly a million miles on it when it was stolen and had never had ANY transmission or clutch repairs (save two clutch adjustments and two tranny fluid changes), and had never been double clutched.

I don't usually use the clutch for shifting, and I've never f'ed up a transmission yet. I'm gettin' on toward 40 years of doing this sh*t.

The first time I drive a particular truck, I'll use the clutch til I get the feel of the truck, then no more clutch once I'm comfortable with the truck.

Any of you guys with electronic Cat motors, they can be programmed so that the Jake doesn't come on until the foot brake is applied whenever the cruise on/off switch is in the on position. The cruise doesnt need to be engaged, just the on/off switch in the on position. The Cat motors where I work are set that way.

.

In truck driving school our instructors told us to use the same gear coming down a grade as we do coming up or maybe one gear lower. Is that the norm?

The standard has always been one gear lower than the gear you ascended the grade in. I think they even ask that question on the FL and IL CDL tests, if I remember correctly.

It depends on how big your motor is.
If you got the motor, you shouldn't have to touch the stick. :p

11 liter detroit 10 speed eaton, there's three pedals down there but that one on the left.....I don't know what it does!
Coming down a hill with the same gear I go up in and the jake on #3
The only pass I've had trouble was hwy 14 Lovell to I-90 79,900lbs and smoke signals all the way down.

That is the norm as long as the grades are the same or similar. I have been heavy and in a lot of mountains, lately. Some of the people who have been passing me apparently attended a different school. I am amazed how many people think that they can fly down a mountain passing everyone in sight. I just let them go without a word. They put a lot of faith in their brakes. I have seen quite a few who blow past me and all of a sudden they slam on the brakes and pull over into my lane. I guess they didn't see the sign about the 8% grade. :roll:

When I was driving I saw some of those turkeys doing the same thing Gman. One thing I never did was get in a hurry going up or down a grade. Going down I tried to use the correct formula of gear and jake brake.

If you start out down a steep grade in too high a gear with too much speed it can be next to impossible to gear down. You might be able to slow down enough to get in a lower gear, but if your brakes heat up too much you could be in serious trouble. It is better to get there a little slower than to not arrive at all.

Amen to that Gman!