Failed Brakes

The rule of use the gear you climbed the hill in to go down never made any sence to me as what if there was no hill to climb or if it was just a hill and a rated incline going down.

I use the gear that meets the speed limit for the hill I'm on! That and a good jake brake works wonders!

Tip: If you don't like crawling under a trailer during a PTI please QUIT DRIVING! OR go buy a creeper. They make a fold up one that takes up little room.

 

Still ain't nothing scary. If you miss, go back to the one you had and try again. I've had that tanker slap push me past the gear I want to shift to but I've still always managed to get the gear I want. Not that I advocate doing it, but sometimes you go around a bend and theres one of those "two gears lower than you climbed it" types #### near stopped in the road and you got to react. I came up on one of those guys the other night on donner. I could not tell he was moving untill I rolled passed him.

 

Reading some of these posts ("nothing scary about shifting on a downgrade") I think about the all of the folks who have ended up dead doing just that. You guys are rolling the dice - and you don't want to loose the bet.

 

Yeah, that's the scary part. What might happen. It made me pretty nervous when I first started out. Now I just don't miss. And if I do, like TD said, I just put it back where it was without really thinking about it and set up to try it again.

I have a couple rules for it. One is to slow down to the low end of the gear I'm in first. Never try to downshift when the engine is already revved up, you'll miss. Second is brake, let off, brake, let off, brake, downshift while still on the brake, let off. Third is, you only get one rev to hit it. Like if you miss the gear normally while revving up, you let the engine wind back down and maybe you have to rev up again, etc. Not on a downgrade. One rev up, hit it. If you can't hit it on the first rev, go straight back to the gear it was in, immediately. No coasting down the hill allowed.

 

Better to get set up too low, and upshift further down!

Back in the late 60's it was very common... now maybe every year or two - some guy thinks he's gonna run 80k down I70 in Mt. Vernon Canyon at 70 mph on a hot day. Works great until the grade and the curves really wind up at the bottom - while the brakes have already faded, and there's no way to slow down enough to catch that gear.

The drivers usually end up being burned to death.

 

I came down Grapevine northbound I-5 the other night. Signs say 35. So I put it in 6th (8 speed) and engaged the 3 stage Jakes to the 3rd stage. The Jakes kept dogging it down below 35 so I flipped it to 2nd stage and let it get back up to about 37 miles per hour then back to 3rd stage. Rinse and repeat all the way down never touched the brakes. My question, is that an OK strategy?

 

That's a little rough on the engine actually. Remember that a Jake works by holding back on the valves so that you're using compression to slow the engine. By switching back and forth you're loading/unloading those 2 cylinders in a different pattern than the other 4. That "shock wave" travels down through the piston, rod,bearings and the thin film of oil to the crank. You're actually "twisting" 1/3 of the crankshaft.... not good.

 

I know it. You are rolling the dice everytime you put that thing in gear and alot of things are out of your control. I had a motor explode coming down a grade in the middle of the night at 80,000lbs. Wasn't doing nothing wrong. Had it at 1500 rpm with the jake and it went like the 4th of July with the left lane full of passing cars. Instead of paniking, I moved it to the shoulder and got it stopped and waited for a wrecker. Thats another thing - If you can't stop it with only the service brakes then you comming down too fast. I've known drivers that would have freaked out and done something drastic if put into that situation.

What I'm saying is, you got to be ready to miss a gear or have something else go wrong. That way, you can control the situation if at all possible. When you panic, you stop thinking. Thats when you end up flying down a hill in nuetral with the brakes on fire or jerking the wheel into oncomming traffic or doing a whole list of things you know not to do. When you get through it, then you can freak out. Thats not to say anyone whos died driving a truck died because he didn't think, but I think its safe to say that a few of them did.

 

my top speed down a hill 94mph