Bus Conversions dot Com Bulletin Board
September 02, 2014, 03:08:29 PM *
Welcome, Guest. Please login or register.

Login with username, password and session length
News: If you had an E-Mag Subscription: It can be read on any computer, iPad, smart phone, or compatible device.
   Home   Help Forum Rules Search Calendar Login Register BCM Home Page Contact BCM  
Pages: 1 2 [All]   Go Down
  Print  
Author Topic: How hard on the brakes is hard braking?  (Read 2687 times)
belfert
Guest

« 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.)
Logged
Brian Diehl
Hero Member
*****
Offline Offline

Posts: 982




Ignore
« 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?
Logged
H3Jim
Hero Member
*****
Offline Offline

Posts: 1398


1995 Prevost H3-41, series 60, B500 Allison




Ignore
« Reply #2 on: May 15, 2007, 06:26:37 AM »

How fast were you going when you smoked them?
Logged

Jim Stewart
El Cajon, Ca.  (San Diego area)

Travel is more than the seeing of sights, it is a change that goes on, deep  and permanent, in the ideas of living.
gumpy
Some Assembly Required
Hero Member
*****
Offline Offline

Posts: 3221


Slightly modified 1982 MC9


WWW

Ignore
« 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.

Logged

Craig Shepard
Located in Minnesquito

http://bus.gumpydog.com - "Some Assembly Required"
Jerry32
Hero Member
*****
Offline Offline

Posts: 726





Ignore
« 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
Logged

1988 MCI 102A3 8V92TA 740
belfert
Guest

« 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
Logged
TomC
Hero Member
*****
Offline Offline

Posts: 6751





Ignore
« 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
Logged

Tom & Donna Christman. '77 AMGeneral 10240B; 8V-71TATAIC V730.
Kristinsgrandpa
Sr. Member
****
Offline Offline

Posts: 426


1988 Neoplan AN 340, 6V-92 TA DDEC II, HT 748 ATEC




Ignore
« 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.
Logged

location: South central Ohio

I'm very conservative, " I started life with nothing and still have most of it left".
Lee Bradley
Hero Member
*****
Offline Offline

Posts: 706




Ignore
« 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.
Logged
Kristinsgrandpa
Sr. Member
****
Offline Offline

Posts: 426


1988 Neoplan AN 340, 6V-92 TA DDEC II, HT 748 ATEC




Ignore
« 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
Logged

location: South central Ohio

I'm very conservative, " I started life with nothing and still have most of it left".
tekebird
Hero Member
*****
Offline Offline

Posts: 2263





Ignore
« 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
Logged
JackConrad
Orange Blossom Special II
Global Moderator
Hero Member
*****
Offline Offline

Posts: 4447


73' MC-8 8V71/HT740 Southwest Florida


WWW
« 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
Logged

Growing Older Is Mandatory, Growing Up Is Optional
Arcadia, Florida, When we are home
http://s682.photobucket.com/albums/vv186/OBS-JC/
superpickle
Hero Member
*****
Offline Offline

Posts: 553





Ignore
« 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...
Logged

Support Global Warming:
Drive an SUV.
DrivingMissLazy
Hero Member
*****
Offline Offline

Posts: 2634




Ignore
« 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
Logged

Life should NOT be a journey to the grave with the intention of arriving safely in an attractive and well preserved body. But rather to skid in sideways, chocolate in one hand, a good Reisling in the other, body thoroughly used up, totally worn out and screaming:  WOO HOO, what a ride
bus05eagle
Guest

« 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
Logged
belfert
Guest

« Reply #15 on: May 15, 2007, 11:32:39 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

I tend to leave the Jake Brakes off in city driving because so many cities have ordinances against using them.  Heck, even on the open road a lot of counties and cities have rules against them.  Sometimes it almost seems like having Jake Brakes isn't worth it with so many places banning them.

The last thing I need is a ticket for using a Jake Brake in the wrong area.  I've never had a ticket and certainly don't want one for something this silly.
Logged
luvrbus
Guest

« Reply #16 on: May 15, 2007, 12:46:03 PM »

i drive with mine on all the time a bus is not like a truck with 7in pipes and no mufflers must buses have good mufflers and sound louder on the inside than the outside i have never heard but one real loud bus and it was and eagle with 6in  pipes if it came down to a ticket or running over someone it would be a ticket for me you can give a lots of space between you and another car and somebody will always pull between you and the next in line
Logged
Dreamscape
Guest

« Reply #17 on: May 15, 2007, 02:30:29 PM »

I agree with luvrbus. If we had Jakes on our Eagle and needed to stop fast in an area that banned the use of Jakes, I'd rather have the ticket and be able to stop faster. Good Point.

Paul

Dreamscape
Logged
belfert
Guest

« Reply #18 on: May 15, 2007, 02:39:13 PM »

I think most cities have exemptions for emergency use of Jake brakes.  I wouldn't worry about a ticket for emergency use of Jake brakes, but I would worry about a ticket for routine use.  It would be better to have them on all the time than to to try to turn them on in an emergency.
Logged
NJT 5573
Hero Member
*****
Offline Offline

Posts: 808




Ignore
« Reply #19 on: May 15, 2007, 08:30:48 PM »

Belfert, I think Jack is right. It is tire smoke.The only other possibility is a bad diaphram on the emergency side of a spring brake can. If that diaphram is blown it will cause that wheel position to drag the brakes to the point of burning your coach to the ground. If its the diaphram, it will leak only with the parking brakes released, so it's not anyone's favorite to check out. A truck has enough air flow to usually not burn. A bus does not. If that diaphram blows and you drive with the brake dragging it will get hot and blow out the tires. Then with you sitting still and no airflow, the tires will start on fire. Then its up to a Fire Dept. to see what you salvage. I have broken in many new 7 inch truck brake shoes and my preference is to run them off the hill and smoke the hell out of them. Run to the next hill and adjust them and smoke the hell out of them again. Most truck shops don't surface drums and unlike buses don't have oversize shoes that I'm aware of. As a driver you won't have good shoe to drum contact patches until you as a driver make them fit. I guess if you glaze a shoe, you can unglaze it next time you use it. I don't think you can tell a difference between a glazed shoe and an unglazed shoe however.... As the new shoe wears to fit the old drum you will notice a difference in stopping power because the slack (distance) between the drum and shoe are increasing and that is why you will have to do frequent brake adjustments or you will soon have no brakes. If you run a Jake on your play bus that runs 10,000 miles a year, you may never seat the shoes to the drums. Since smoking the brakes on a passenger bus to seat the shoes (make the curvature of the shoe the same as the curvature of the drum), may not look good to the public, commercial bus brakes usually get a different approach than trucks do. The drums are heavier, the drums are designed to be turned oversize in 1/8 in increments, ( I think its 1/8), and shoes are available in oversize to give full contact with each size drum hole at rebuild time. If your drums have been turned and had say 3/8 inch of drum removed over the years and your shop replaced your linings with stock shoes for your coach, then you may have a very small contact patch of the shoes touching the drum. If you are really smoking the brakes and not the tires, then this is why. Your first few times down the mountain just might be real exciting!
Logged

"Ammo Warrior" Keepers Of The Peace, Creators Of Destruction.
Gold is the money of Kings, Silver is the money of Gentlemen, Barter is the money of Peasants, Debt is the money of Slaves.

$1M in $1000 bills = 8 inches high.
$1B in $1000 bills = 800 feet high.
$1T in $1000 bills = 142 miles high
belfert
Guest

« Reply #20 on: May 15, 2007, 08:45:49 PM »

It may have been tire smoke for all I know.  I just know I braked so hard that smoke was coming out of the wheel wells and the bus smelled bad for a while.

My dina has Q brakes and I was told the drums cannot be resurfaced.  The drums and pads were all replaced.  I have automatic slack adjusters so the brakes should go a while between adjustments.  The brakes were already rechecked once since being replaced.

I guess I won't worry about it since the bus seems to brake fine.  I'll try to leave more room when I do have to drive in rush hour, but too much room just invites cars to pull in front of the bus.
Logged
buswarrior
Hero Member
*****
Offline Offline

Posts: 3571


'75 MC8 8V71 HT740




Ignore
« Reply #21 on: May 16, 2007, 07:53:17 PM »

Hello.

What might be the differences in stopping distance between Jakes on, and Jakes off?

Not as big as you guys believe, me thinks!

happy coaching!
buswarrior
Logged

Frozen North, Greater Toronto Area
bus05eagle
Guest

« Reply #22 on: May 16, 2007, 08:27:11 PM »

when the jakes are adjusted and maintained right jake brakes make a big difference on my Eagle
Logged
Stan
Hero Member
*****
Offline Offline

Posts: 973




Ignore
« Reply #23 on: May 17, 2007, 06:38:10 AM »

If you are locking up the wheels with the brakes, Jakes will not lock them up any tighter.
Logged
DrivingMissLazy
Hero Member
*****
Offline Offline

Posts: 2634




Ignore
« Reply #24 on: May 17, 2007, 07:31:26 AM »

My experience is that with Jakes adjusted properly they will not come even close to locking up the drive axle, whereas the main brakes will immediately lock up all axles, steer, drive and bogie (tag).

After I installed a good muffler I did leave my Jakes on most of the time while driving in city traffic. They did a good job of regulating the speed somewhat in normal city traffic, but in my opinion were worthless as a means of providing emergency (panic) stopping power. I also do not believe they were ever meant to be used for this requirement.
Richard
Logged

Life should NOT be a journey to the grave with the intention of arriving safely in an attractive and well preserved body. But rather to skid in sideways, chocolate in one hand, a good Reisling in the other, body thoroughly used up, totally worn out and screaming:  WOO HOO, what a ride
niles500
Niles500
Hero Member
*****
Offline Offline

Posts: 1188


ROSIE




Ignore
« Reply #25 on: May 17, 2007, 10:06:25 AM »

I can't have any fun   Cry       I have ABS brakes   Cry
Logged

(\__/)
(='.'=)
(")_(")  

- Niles
Pages: 1 2 [All]   Go Up
  Print  
 
Jump to:  

Powered by MySQL Powered by PHP Powered by SMF 1.1.18 | SMF © 2013, Simple Machines Valid XHTML 1.0! Valid CSS!