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imadriver2
Active Member
19 Posts |
 Posted - 08/24/2011 : 10:33:23 AM
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Correct me if I am wrong. But I'm just guessing here that you should not be able to drive with your parking brake engaged?
The reason for the Emerg. Brake is to ensure the bus does not move AT ALL if the bus should happen to be in Drive. Or am I wrong about that?
The Parking Brake on my bus does not prevent the bus from moving if gas is applied. Was told by our mechanic that its OK? and there is no way to prevent the bus from moving if the gas is applied heavily?
Someone PLEASE tell me this is NOT OK!
Is he correct? |
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slippert
Top Member
USA
630 Posts |
Posted - 08/24/2011 : 11:42:20 AM
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You are correct! you should not being able to drive with park brake engaged no matter what system is on vehicle. What park brake do you have? hand or air operated drive-line brake or air brakes w/ spring brake, or the Lucas-girling setup? There are a few things on each, that can cause your problem.
Your vehicle wouldn't pass MI inspection, as it must hold with a slight acceleration of throttle in drive or second gear. If you can drive it down the road with park brake applied it cannot be working correctly.
I have a mixture of all listed above in my fleet and if bus/vehicle moves with park brake applied, It's coming into shop for repair, replace or adjustment.
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Edited by - slippert on 08/24/2011 12:12:21 PM |
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Fastback
Top Member
1500 Posts |
Posted - 08/24/2011 : 12:19:14 PM
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quote:
Originally posted by imadriver2
Correct me if I am wrong. But I'm just guessing here that you should not be able to drive with your parking brake engaged?
The reason for the Emerg. Brake is to ensure the bus does not move AT ALL if the bus should happen to be in Drive. Or am I wrong about that?
The Parking Brake on my bus does not prevent the bus from moving if gas is applied. Was told by our mechanic that its OK? and there is no way to prevent the bus from moving if the gas is applied heavily?
Someone PLEASE tell me this is NOT OK!
Is he correct?
I would have to say that if your bus has hydraulic brakes, the parking brake is a drum on the back of the transmission and the parking brake is applied with a hand operated over center lever, that with enough pressure on the accelerator pedal the bus will move.
"The reason for the Emerg. Brake is to ensure the bus does not move AT ALL if the bus should happen to be in Drive. Or am I wrong about that?"
Its not an emergency brake, its a parking brake.
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Why yes, the ORIGinal CHARGER is a Fastback |
Edited by - Fastback on 08/24/2011 12:31:42 PM |
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bwest
Administrator
United States
3820 Posts |
Posted - 08/24/2011 : 2:09:53 PM
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| I concur ^^ If you adjusted the drive line park brake enough where it will hold with pressure applied from the engine/ trans. you would not be able to operate it with out a cheater pipe (leverage). Even then the cable would give way after a few applications. |
Bryan |
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IBTMech
Top Member
USA
973 Posts |
Posted - 08/24/2011 : 2:10:22 PM
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Fastback is correct.
If you have air brakes, the applied spring brake has the same effect as applying the footbrake with 55 lbs of pressure........ not enough for driving purposes.
You can take a brand new truck or bus, put it in gear and floor it with just the parking brake set and it will move. However, if it moves while standing on the service brake with full air pressure, you have a problem. |
If it doesn't fit, FORCE it.
If it breaks, well, it needed replacing anyway.
Pullin' wrenches for 45 years. |
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slippert
Top Member
USA
630 Posts |
Posted - 08/24/2011 : 2:55:27 PM
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I agree the driveline brake is more prone to slip and the bus will/may lurch forward if you hold throttle long enough, but why would ya do that anyway? but you should not be able to drive with it on.
I don't know about you guys but mine don't move with driveline brake on or set with a mild accel. and nobody here has ever been able to drive down the road with one that's working good on! it's amazing how easy the hand operated ones work and how good they hold with new parts once in awile.
As for an air brake vehicle/bus moving with the park brake set, if it moves, it's got a problem. if you can't hold it with spring pressure, say it's like 55lbs on the foot brake, your not going to stop at the corners, We use to run brake application gauges in the road trucks and unless you were in a panic stop mode or your one of those people that has to fly up to every corner and cram on the brakes, it only took 10-20 psi on foot brake to stop. IBT try setting the PB on a air brake vehicle at highway speeds and see what happens if ya don't beleive me, the wheels will stop turning and begin skiding.
I had a SP Inspector here a few years ago, that would hold throttle at 1500 for it seemed like 60 seconds and expect them to hold, he didn't care if it was air or hydraulic on the air brakes he told me that was how he found broken springs. |
Edited by - slippert on 08/24/2011 3:43:06 PM |
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bwest
Administrator
United States
3820 Posts |
Posted - 08/24/2011 : 3:18:52 PM
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| Cool test ^^ I'll have to try that sometime! |
Bryan |
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slippert
Top Member
USA
630 Posts |
Posted - 08/24/2011 : 3:25:36 PM
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| Just make sure your life ins is paid up first, if your going to try the road test, I had a driver (training) accidently do it once. scares the H out of ya if you know what i mean |
Edited by - slippert on 08/24/2011 3:39:38 PM |
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Bus Tech II
Senior Member
121 Posts |
Posted - 08/24/2011 : 4:01:40 PM
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| Are you sure your light Park brake light is on but the brake is functioning properly? Is this bus a Thomas C2? Possible AMU problem |
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Emergency Brake
