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Brakes do not hold when break pedal released
#1

I am a proud owner of a 2007 Newell .

My coach has a ZF transmission that is essentially an automatic manual transmission. When stopped the transmission has the clutch in so the vehicle can roll.

There is suppose to be a break hold to keep the coach from rolling after stopping until the accelerator is depressed.

Mine does not hold.

Any suggestions on how to trouble shoot this, where the components are and how it connects with the breaks and the accelerator?

Thanks

Steve & Debbie Rose
2007 Newell
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#2

According to ZF's website http://www.trw.com/braking_systems/elect..._brake/epb

"Automatic Hold: The Auto Hold function holds the vehicle automatically if standstill is detected. The functionality is divided between the Stability Control System (SCS) and the EPB. As soon as the SCS sends a lock command, the EPB will apply mechanical clamp force. If the SCS sends a release command, the EPB system will unlock."

Note: EPB is Electronic Parking Brake

Don't know if that is the same procedure they used 10 years ago.

Michael Day
1992 Newell 43.5' #281
NewellOwner.com
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#3

From the old site from John Clark the old Service Manager.
==============
As for that rolling back at stop signs on a ZF, that's a driver controlled option. If they push hard on the brakes at the stop and then let up slowly and completely, the front brakes lock "on" and will remain on until you accelerate, which takes them "off" -- but if you don't push hard, they won't lock.
==============

Bill Johnson
Birmingham, Alabama
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#4

(11-28-2016, 11:33 AM)Fulltiming Wrote:  According to ZF's website http://www.trw.com/braking_systems/elect..._brake/epb

"Automatic Hold: The Auto Hold function holds the vehicle automatically if standstill is detected. The functionality is divided between the Stability Control System (SCS) and the EPB. As soon as the SCS sends a lock command, the EPB will apply mechanical clamp force. If the SCS sends a release command, the EPB system will unlock."

Note: EPB is Electronic Parking Brake

Don't know if that is the same procedure they used 10 years ago.

Thanks for the reply, I will see if I can find these systems and check for a voltage that responds to the break being held.

Steve

(11-28-2016, 11:35 AM)bikestuff Wrote:  From the old site from John Clark the old Service Manager.
==============
As for that rolling back at stop signs on a ZF, that's a driver controlled option. If they push hard on the brakes at the stop and then let up slowly and completely, the front brakes lock "on" and will remain on until you accelerate, which takes them "off" -- but if you don't push hard, they won't lock.
==============

John,

I will try the hard push and slow release to see if that does the trick.

Thanks for the reply, 

Steve

Steve & Debbie Rose
2007 Newell
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#5

I have tried pushing hard and slowly releasing the breaks.

The breaks seem to hold for about 30 seconds and then I can hear the air release the breaks at which time the coach starts to roll.

Any suggestions?

Thanks

Steve & Debbie Rose
2007 Newell
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#6

Keep your foot on the brake pedal while stopped!!!
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