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Topic: P:arking brake (Read 1023 times) previous topic - next topic

P:arking brake

I need to work on mine - but I can't fix something that I know not how it works. Will someone point me where to start learning, please. It seems to activate most times but not have much holding power. My '78 travco has an adjustment knob on the top end of the actuator. When it is set, the coach won't move. The operators manual for the Grand Villa tells me how to operate the brake but not how it works. The manual tels me on front cover, it's for a VC-RD, V-line coach rear diesel...(for a 1991 model year & my title says it's a '92?  Someone has penned on the cover "VC 22 RD.
'92 Grand Villa 36' w/8.3Cummins mechanical
ORED
Build#4062

Re: P:arking brake

Reply #1 –
Anyone know if it's a drive shaft brake OR a drive wheel  brake?

Jim
'92 Grand Villa 36' w/8.3Cummins mechanical
ORED
Build#4062

Re: P:arking brake

Reply #2 –
Holy shit ... I can't wait to find out... my parking brake light is always on. Travco.. hmmm
Paul
'92 U300 SBID 40'  #3968 "Large Marge"
Detroit Diesel 6v92TA & Allison HT746
'09 Mini Clubman w/ manual 6spd @ 39 mpg

Re: P:arking brake

Reply #3 –
The parking brake is applied to the rear wheel brakes only, by springs in the air chambers.  When you pull out the knob to set the parking brakes air pressure is released allowing the springs to apply pressure to the brake disk pads through the automatic slack adjuster arm.  When air pressure drops below a certain level the parking brake will come on.  See the articles here for more detail. Technical Help - Air Brakes The transmission does not have a park detent as in most cars.  The parking brake does not have the ability to hold the coach on a steep slope.  The automatic slack adjusters need to be properly adjusted for both proper operation of the brakes and parking brake.  Too much slack results in poor braking and too little slack in dragging brakes.  With the coach stopped and with 100+ air pressure, full brake pedal applications should remove excess slack.  With parking brakes on, my coach will move in 1st gear on level ground at about 1000 rpm.  It is possible to drive with the parking brakes on, resulting in damaged rotors and pads.  If air pressure is available the parking brake knob can easily be bumped to the off position by pets and humans. A safety hazard in my opinion.
Jerry Whiteaker former owner 96 U270  36' #4831 Austin,TX-Owner Mods LCD TV w/front cabinet rebuild - LCD TV bedroom - Dual Central AC, either can cool coach w 30 amp - Skylights at roof AC openings - Drop ceiling for ducting of AC - Shower skylight white gelcoat/wood/epoxy frame - Air Springs/Shocks replaced - 2014 CRV - 8K Home Solar - Chevy Volt

Re: P:arking brake

Reply #4 –
Thank Jerry - my coach is old and doesn't have air brakes and the Travco has a cable to the brake around the drive shaft. I think my Foretravel has a drum around the shaft somewhere. I just had my 83rd birthday last month so I haven't spent much time under it. I looked yesterday and there is a bunch of stuff in the area of the driver's chair, in front of the brake pedal, with an electric motor. I hear the motor when I set the brake if the engine is not running and feel pulsing thru the pedal.

Jim
'92 Grand Villa 36' w/8.3Cummins mechanical
ORED
Build#4062

Re: P:arking brake

Reply #5 –
Look for a drum at the end of the transmission.  On the P30 Chevy there is a hydro pump  that releases the very large spring tension. The default  is no go. Loss of pump pressure or electrics and you dont move.  Very common problem with Chevy  Motorhomes. 
  Look up data for your transmission and check for park options. 

Re: P:arking brake

Reply #7 –
found info at a place called mechanics tips on the MT643 and it talks about adjusting so it holds when on and does not drag when off - so there must be adj. points. Some of us will look when NATE gets outta here.

Jim
'92 Grand Villa 36' w/8.3Cummins mechanical
ORED
Build#4062

Re: P:arking brake

Reply #8 –
The linings on the brake shoes on the park brake drum on the driveshaft nay be worn. There is an adjustment for the shoes. if I remember right it has a star wheel at the bottom of the shoes so you can expand the shoes. and also there is an adjusting nut on the arm that comes from the hydraulic servo that releases the park brake.
previous 1984 35 ft ORED 250 HP 3208 Cat       
previous 1998 40 ft U295 CAI 325 hp Cummins
previous 2003 40 Ft u320 build #6140 450 Cummins M11.                                                         
1999 Mazda Miata
Ron, Nancy, Tipper the cat, Max The dog
1997 U 270 36 ft build number 5174 8.3 Cummins

Re: P:arking brake

Reply #9 –
Looked at the brochure.  The tire sizes go as large as 38.56 in. The 9 R is about the same. All on the narrow rims?