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Author Topic: How hard on the brakes is hard braking?  (Read 2728 times)
belfert
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« on: May 15, 2007, 05:53:50 AM »

How bad is it for the brakes if I have to brake extremely hard?  I'm hoping I haven't wrecked my $6,000 brake job.

At least once since I had my brakes redone I've had to use so much brake that smoke was coming from the brakes all around.  This also happened once or twice before the brakes were redone.

These incidents all happened during rush hour.  I ALWAYS maintain a safety zone in front of me.  The problems all happened when traffic was slowing and a car changed lanes into my safety zone.  I had to really mash the brakes hard to avoid hitting the car.  In all of these cases I also activated the jake brake, but it didn't help much.  (I can turn on the jake without looking.)
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Brian Diehl
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« Reply #1 on: May 15, 2007, 06:14:15 AM »

I'm not sure about your brakes, but I have to wonder about you smoking them more than even once.  I've driven over 33,000 miles and never once let even a puff of smoke out of my brake linings.  I only got them hot once coming down out of the big horn mountains when one of my drive axle seals was leaking.  By hot, I mean hot enough to smell, but still no smoke.  I've driven rush hour several times in Washington DC and never had to mash the brakes hard enough to move anything.  Are you sure you are driving that thing defensively enough?

Another alternative to driver technique is the type of brake lining installed.  Maybe you have brake lining that is much more likely to gas than the lining installed on my bus?
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H3Jim
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« Reply #2 on: May 15, 2007, 06:26:37 AM »

How fast were you going when you smoked them?
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Jim Stewart
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« Reply #3 on: May 15, 2007, 06:30:58 AM »

Yeah, I agree with Brian. Nearly 50K miles on mine, and I've smoked them only once when I had a leaking seal I didn't know about and wanted to see if I really could stop if I needed to while coming down Rabbit Ears Pass. I was pretty new to driving the big beast in the mountains, and had been keeping it at 30 and under all the way down, but still wasn't really comfortable with the braking. They just didn't seem as effective as they should be. When I got to the last mile, which is a straight run down into the valley floor and into Steamboat, I had no traffic around me and stood on the brakes to see how it would react. Some oil had found it's way onto the pads, and the smoke really rolled out.

After that trip, I completely rebuild the drive and steer axle brakes. I'll be doing the tag axle in the next few weeks.

I've encountered many instances in heavy traffic where someone has cut me off only to be stopped
by the flow. I've been on the brakes hard in many of these situations, but never enough to smoke them.

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« Reply #4 on: May 15, 2007, 06:42:06 AM »

I have to agree with the others as I have been hard stopped in traffic seveal times and never seen them smoke. I have come off cabbage hill here and used braking and no smoke either. Jerry
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belfert
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« Reply #5 on: May 15, 2007, 08:26:52 AM »

I sure hope I have no leaking seals as C&J Bus Repair replaced all of the wheel bearings this past summer when the brakes were done.

The one issue I've noticed with my driving technique in heavy traffic is a tendency to look ahead a long ways and then not pay enough attention to the cars immediately ahead of myself.  The driving position in the bus is so much higher than a car that the driver gets a great view of traffic.  I make darn sure to leave lots of space in front of the bus in traffic as long as cars don't pull in front of me.

I never pull in front of trucks or buses in my car, especially after driving my bus.  I know they need that large buffer space.

Brian Elfert
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TomC
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« Reply #6 on: May 15, 2007, 08:40:03 AM »

Brian- it sounds to me like you should reconsider your braking techniques. The only time I've smoked brakes was in severe mountain driving, not ever in traffic (I live in L.A. and drove truck for 1.3 million miles).  Course now too I have a transit that has bigger brakes than highway buses, but still in traffic, you should be at a more constant movement than the stop and go around you.  You might also try having your Jake adjusted better.  You can usually tell if the brakes have been glazed by overheating-when they cool the brakes just don't feel the same-don't have the stopping power they used to have.  Also, with overheating, you have to watch cracking the drums.  If this overheating persists, maybe you should consider getting the steel/cast iron drums like Meritors Steelite, or Centrifuse drums that have the friction part of the drum steel and the rest cast iron, rather than just straight cast iron. Good Luck, TomC
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« Reply #7 on: May 15, 2007, 08:50:43 AM »

  Belfert,  it seem that almost everyone wants to relate to personal driving experiences and question your driving ability/technique rather than help with the question so I would like to offer a suggestion:
  The next time you drive your Dina pay close attention to your braking capability to see if it differs from the way it has been doing.  If you have extended stopping distances, brake squeal, needs more pedal pressure, (harder to stop) you may have damaged your linings.
  If everything seems to be normal then you probably didn't hurt anything.

I have only limited experience with braking heavy vehicles (my dump truck is under 26,000GVW) but that is some experiences I've had with cars and light trucks.

HTH Ed.
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« Reply #8 on: May 15, 2007, 08:56:26 AM »

Well, now that we have beat you up for your bad driving habits.  Roll Eyes

Generally hard braking is not bad for the brakes; just wears them out faster.  However when you get them hot enough to smoke the brakes, not just accumulated oil and grease, the linings become glazed (hard crystalline structure) and will wear the drums about as fast as the linings. Over all the brakes will last longer but the drums and linings will both have to be replaced next brake job. This can also cause nosey brakes and shuddering. The linings can be sanded to remove the glaze.
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Kristinsgrandpa
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« Reply #9 on: May 15, 2007, 08:58:31 AM »

Oh... and the next time someone cuts in front of you and slams on the brakes just use light pedal pressure, sure you'll hit him  in the @$# and be cited for it and your insurance will be raised but you won't damage your brake linings.

Ed
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« Reply #10 on: May 15, 2007, 09:05:33 AM »

I would have to agree that most likely it is driver error.

perhaps  you need to not accelerate  so fast or maintain a lower speed in such traffic conditions.......I can't see any need to smoke your brakes on 'flat" ground.

where your brakes already hot prior to the smoking?

I have never even smoked brakes when doing simulated emrgency braking   during training scenerios.

Concerns?  Probably not much to   worry about in this case but it is not hard to glaze your friction surfaces by heating them up.......this will leave you with severly limitied stopping capacity  due to the reduced friction surface.

Suggestion:  put 4 quarters stacked on your dash.......and learn to drive without them falling over........I drove a 6 moth political lease last year with 4 quarters stacked on the dash the entire time.  One short stop caused   top quarter  to shift forward maybe 20%

Forget what company it was but they used to have new driver's do all thier training with a bowling pin on the front step.....it was allowed to fall 3 times during training......more than that NO JOB FOR YOU
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JackConrad
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« Reply #11 on: May 15, 2007, 09:32:11 AM »

Are you sure it is the brakes smoking and not the tires? I have never seen brakes smoke from a quick rapid brake application, although this type application can certainly lock up the wheels and cause the tires to smoke. The only time I have seen brakes smoking was at the bottom of long grades where trucks had a long constant brake application.  Jack
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« Reply #12 on: May 15, 2007, 09:46:18 AM »

How can you Smoke brakes in ONE quick stop HuhHuh?

It takes me a LONGGGG  down grade to even get a brake Hot..

You must have somethin else going on.. and I dont think you are puting enough space between you and the other cars..

Paul...
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« Reply #13 on: May 15, 2007, 10:01:55 AM »

Are you positive it is the brakes and not the tires smoking?
I had a problem where the tension was not proper on my bogie axle and it was very easy to smoke the tires. Since you just had all new brakes, maybe you are just applying them too hard and smoking the tires. I smoked all the tires on my Eagle a couple of times during panic stops.
Also, I really do not think the Jakes are quick responding enough to be of any benefit during a panic stop. That is really not their purpose.
Richard
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bus05eagle
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« Reply #14 on: May 15, 2007, 10:40:11 AM »

i leave my jakes hot all the time except when on a long open highway doesn't hurt them and i don't need to look for the switch when trying to slow down
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