braking on big mountains...

Trucks use lower gears = use the lower side of transmission. not come out of 10th gear and go to 9th gear.
Pressure causes heat.On a 6% grade 10 speed transmission no jake 4th gear heavy loaded and 5th gear light to med loaded Braking with 5-7and no more than 10lbs light steady psi all the way down a grade will cause less heat, than fanning your brakes, its like fanning a barley lit camp fire. air will make it flame up becoming hotter.You can rub your hands together lightly with little heat,but rub than together and apply more pressure and they get hotter plus your creating heat faster than you can get rid of it.
I remember 1st week out with my trainer Grapevine north bound. I done my brake check and started going down.no jake he said just keep it in 6th gear, and i said im suppose to be in 4th he said, awe youll be alright just keep light steady pressure all the way down. we got about half way i was checking my mirrors i had smoked em.so he reaches over and turns on the jake brake to finish the grade.then he said yes u should have been in 4th gear. i just wanted to show you, if you are not in the proper gear this is how you smoke your brakes.you did the braking part just fine, but gear selection is also important.I said lesson well learned.

 

I ran with no jake for a while, if you have a brake pressure application gauge keep a steady 5 to 7 lbs of pressure on your brakes, if you dont you have to get a feel for it. Most important is start off in a low gear, put your 4 ways on so chicken trucker on crank doesn't run you over. watch for smoke( you can still see it at night if you watch your mirrors when people pass).
And keep your speed down in case you gotta hit the shoulder

 

A very important step is to be in the correct gear before starting your descent. That's why you will see the slower speed limits for mountain grades before starting downhill. I used to run north down the Grapevine every other day without a jake at about 72 to 74,000 LBS. Many times I would see drivers pass me as I hit the 35 MPH zone only to see them slow to my speed after starting down the hill. The result was usually a smelly cloud of white smoke from the brakes all the way down.

I was taught to use the RPM's to help slow the truck and steady even pressure all the way down. I never smoked them but I know they were hot when I got to the bottom.

GasHauler said it best when he typed something to the affect of not letting other drivers influence how you come down the hills. I was once heading dowhill on HWY 163 into Mexican Hat, Utah. I think that was a 9% grade (someone please correct me if I'm wrong). I didn't pay much attention to the angry line or 4 wheelers behind me. My only concern was getting to the bottom safe.

 

Three different styles are being refered to here, the first is called a panic stop, which if you have functioning anti-locks you never use. Apply till the point of lock out, then release till all are rolling and repeat, all the time looking for somewhere else to go, you can change directions easier than a panic stop can stop you.

Paying attention and allowing the correct following distance will keep you from needing this most of the time.

Your right thats how I was taught was apply and drop 5 mph, then release reapply as necessary. This will work if executed properly.

The steady light pressure approach started getting taught in the mid 80's at the schools I believe, and also works maybe better for unexperienced drivers or easier to use without over heating your brakes.

And of course its better to have engine brakes to work with your friction brakes.

Oh yea the question about Cajon, when traveling south on I15 down the hill I go over the top at 45 mph in 8th gear if all is going well I may grab 9th if conditions warrant. If you were traveling west it would be a short but interesting ride.

Also if your brakes get warm and you stop to cool them you maybe alright, but if they are hot you do not want to stop, you want a light steady pressure just enough to keep the lining against the drum, you actually do not want air between the lining and the drum it can cause it to flare or flame burning the grease and seals, then eventually the trailer. Ask a Hay trucker...

Best to stop and check the adjustment before you go over the edge, then always go over the edge with caution, like your life depends on it, by the way it does. You can go down a hill to slow a lot of times, but you can only go down it to fast once.

 

I'd come to a complete stop, pull out the yellow button on the dash, and go find a truck with a jake.

 

a jake can fail driver as soon as u turn it on at the top the hill or anywhere.so you should always know how to descend without one.

 

Yeah, what primeexample said...

The jake is just another tool that you use. You had best know how to deal with the situation if that tool is suddenly "lost."

 

Shift down atleast two gears before you start to go down. Hit the jake as you go start to go down. But reality is you will need to use your brakes when your going down because the jake can;t hold back all 80k or how ever heavy your loaded.

 

Back in 1992, the method I was taught was the "light, steady pressure method" all the way down the hill...used it a lot since the truck didn't have a Jake. I'd say I was mostly successful with that method, although, there were a few puckering exceptions to that. I remember heading east towards Green River, UT running a full 80k in a leased trailer. Did the usual brake check on top of the long grade out of the hills and started off, about halfway down, lost the trailer brakes (no action whatsoever). Got everything stopped safely in a cloud of smoke and shaking knees, lol. Turns out the trailer brakes were warm, but not hot...everything was in proper adjustment. Waited for the tractor brakes to cool down and then managed to limp into Green River. The shop found that the valve assembly on the trailer had an internal seal fail and block the airflow...thus preventing the trailer brakes from fully engaging. Fun times.

Spent years running local out of LA, running up to Bakersfield at night "Jake-less" and used the snub method most of the time. The northbound Grapevine always provides an interesting ride when you have no Jake and are at max weight. Good thing with the night running and no traffic, should you start to lose braking action near the bottom, you can generally run out the bottom without getting into too much trouble (speed or otherwise) since it drops dead straight out into the valley (the hill speed restriction stops as you come around the final bend) and starts an ever so slight rise all the way to the TA up there.

 

Exactly how I brake on my decents. The technique is called snub braking (not to be confused with stab braking), and is very effective. In my case, with a straight 10spd, I'll let the rpm's rise to 1700 and then scrub off 400rpm (which translates to apx. 5mph) in 5 seconds of steady braking, release and repeat as necessary. I've never overheated the brakes using this method.

This technique works ok, but on lengthy or 8%+ grades it can cook the brakes. I prefer snub braking.

Agreed. 8th gear on my 10spd, progressive engine braking and I can ride down there at 45mph all day long.