« previous next »
Pages: [1]   Go Down

Author Topic: Park Brake Not Holding  (Read 3111 times)

Frank Bergamo

  • BAC Member
  • *
  • Posts: 283
  • Thanked: 73 times
Park Brake Not Holding
« on: November 01, 2018, 03:42:46 AM »
       
       Am having issue with park brake engaged, not holding on slight incline/decline, with trailer attached. With coach in gear or reverse it will hold, but with coach in neutral it wants to roll. All brakes recently serviced with new pads, rotors and helper springs. Merritor ADB system. Am wondering if this is normal. Don't like leaving coach in gear when not in drivers seat. Any thoughts appreciated.
Logged
Frank & Paulette Bergamo
2019-       : 2007 Marquis Topaz IV  C-15 600 HP Allison 4000
2014-2019: 2002 Marquis Emerald C-12 505 HP Allison 4000
2004-2014: 1986 Executive Diplomat 3208 250 HP Allison MT-643
Grand Junction, CO.

Pat Long

  • Guest
Re: Park Brake Not Holding
« Reply #1 on: November 01, 2018, 02:59:38 PM »
Sounds like you will need to adjust the brakes at the slack adjuster so they are applying more pressure to the pads themselves.  Do this at the driver for the parking brakes, maxi cans, or spring brake cans.  I had the same thing happen and just needed to tighten them a full turn each side.  I also upgraded to a different brake can since my cans were 18 years old have having trouble returning to neutral, sure enough took them off and it was time to change.  This is the can I changed to in case you are wondering, and also provided is how to adjust the brakes according to Rockwell Meritor video.   Be sure to Only use Clay base grease in the brake calipers, and after you grease them make sure to purge the air out of them and readjust the brakes.  Watch the video it shows all the need info for the ADB 1560 system

http://graphicvillage.org/meritor/PB1461.pdf


https://www.ebay.com/itm/MGM-BRAKES-MJS3030ET051-Brake-Chamber-Series-Mjs3030et-Model-Mjs3030et-3-00/302411607967?hash=item466922ef9f:g:pDwAAOSwugha9mVe
Logged

Frank Bergamo

  • BAC Member
  • *
  • Posts: 283
  • Thanked: 73 times
Re: Park Brake Not Holding
« Reply #2 on: November 01, 2018, 05:01:48 PM »
   Cans have been replaced. Brakes have been greased, purged, and adjusted. Wondering if spring in cans that activate parking brake are not adequate to hold coach with trailer attached. Beginning to believe it is more of a design flaw with the Merritor system than something that can be adjusted or replaced in the system.
Logged
Frank & Paulette Bergamo
2019-       : 2007 Marquis Topaz IV  C-15 600 HP Allison 4000
2014-2019: 2002 Marquis Emerald C-12 505 HP Allison 4000
2004-2014: 1986 Executive Diplomat 3208 250 HP Allison MT-643
Grand Junction, CO.

Gerald Farris

  • Guest
Re: Park Brake Not Holding
« Reply #3 on: November 01, 2018, 06:29:32 PM »
Frank,
The normal test that most mechanics use to test parking brake effectiveness on a coach is to put the coach on a level surface with the coach in drive and the engine running to see a what RPM level the coach starts to move as you slowly accelerate. I believe that most RV chassis mechanics consider that if the parking brake will hold the coach still up to 1200 RPMs, it is OK although I think that some use 1100 RPMs. If your coach parking brake will not pass this test, you need to revisit your mechanic.

Gerald     
Logged

Frank Bergamo

  • BAC Member
  • *
  • Posts: 283
  • Thanked: 73 times
Re: Park Brake Not Holding
« Reply #4 on: November 01, 2018, 08:36:26 PM »
Gerald,
I have done the test that you describe and the coach starts to move @ 800 RPM'S from an idle of 700 RPM'S. Have done all adjustments per Meritor specs. All other aspects of brake function are great. Would be interested to know what results other coach owners have with same brake system, performing test you describe. Any results appreciated. Thanks, Frank
Logged
Frank & Paulette Bergamo
2019-       : 2007 Marquis Topaz IV  C-15 600 HP Allison 4000
2014-2019: 2002 Marquis Emerald C-12 505 HP Allison 4000
2004-2014: 1986 Executive Diplomat 3208 250 HP Allison MT-643
Grand Junction, CO.

Pat Long

  • Guest
Re: Park Brake Not Holding
« Reply #5 on: November 02, 2018, 02:06:25 AM »
Frank,     If your cans are original and are adjusted as per Meritor specs then its time to change them out thee is no doubt damage to the inner workings of the spring brake.  I gave you an example of what I used as the replacement it worked in my confined space and travel.   While caging the old brakes I could use a 3/8" drive ratchet.   Caging the New cans I had to use my 1/2" drive ratchet, much stronger spring
Logged
Pages: [1]   Go Up
« previous next »