Wanderlodge Owners Group  
BuyByeBlueBird.com
Donate

Go Back   Wanderlodge Owners Group > Mechanic's Corner > BMC (Bluebird Motor Coach Unique Issues)

BMC (Bluebird Motor Coach Unique Issues) If you have a unique issue with your BMC coach and it can't be answered in one of the other forums here, then this is where you can list it.....List your BMC Parts here too.

Site Search:
Reply
 
Thread Tools
  #1  
Old 1 Week Ago
Snowpig32's Avatar
Snowpig32 Snowpig32 is offline
Senior Member
 
Join Date: Mar 2018
Location: Mansfield
Posts: 117
Default Air Brake Anti Compounding Valve

Dose the BMC come equipped with a anti compounding valve to prevent spring / air overload?

I read once, one should not press the brake pedal if the parking brakes are on. This statement caused me confusion and concern. I had asked truck drivers about this and have yet to get an understandable response.

Having no previous knowledge of air brakes myself I did not know there was a spring break and service brake within the same air chamber. I have come to this conclusion on my own and it’s probably wrong, but if your parking brake is on and you apply service brake could this multiple x2 braking pressure cause damage to some air brake parts like chamber, chamber housing, adjuster, drums, etc..

I am seldom parked on a flat parking surface, mostly on an incline. I disengage the parking brake she is going to roll.

In a none air brake vehicle, I always have foot on the brake with pressure when moving the transmission from park into gear, seems silly to make this statement.

In an Air brake equipped vehicle with no Park only Neutral, should one anticipate the roll and keep their foot off the brake until after the parking brake is released? I cannot imagen everyone is doing this.
Please help get me back on track.

I have posting this in the BMC area because I believe it pertains to the Spartan chassis components more so than the Blue Bird.
__________________
Jim Howe
Mansfield, Ohio
1995 BMC 37
Reply With Quote
  #2  
Old 1 Week Ago
Rick's Avatar
Rick Rick is offline
Senior Member
 
Join Date: May 2009
Location: Bellefonte
Posts: 12,854
Default

Quote:
Originally Posted by Snowpig32 View Post
Dose the BMC come equipped with a anti compounding valve to prevent spring / air overload?

I read once, one should not press the brake pedal if the parking brakes are on. This statement caused me confusion and concern. I had asked truck drivers about this and have yet to get an understandable response.

Having no previous knowledge of air brakes myself I did not know there was a spring break and service brake within the same air chamber. I have come to this conclusion on my own and it’s probably wrong, but if your parking brake is on and you apply service brake could this multiple x2 braking pressure cause damage to some air brake parts like chamber, chamber housing, adjuster, drums, etc..

I am seldom parked on a flat parking surface, mostly on an incline. I disengage the parking brake she is going to roll.

In a none air brake vehicle, I always have foot on the brake with pressure when moving the transmission from park into gear, seems silly to make this statement.

In an Air brake equipped vehicle with no Park only Neutral, should one anticipate the roll and keep their foot off the brake until after the parking brake is released? I cannot imagen everyone is doing this.
Please help get me back on track.

I have posting this in the BMC area because I believe it pertains to the Spartan chassis components more so than the Blue Bird.
Just don't go over board with the foot pressure.
__________________
Rick Shawver
1SG Ret
2000 LX
Vise Grips
Bellefonte, AR
F127656
Reply With Quote
  #3  
Old 1 Week Ago
Randy Dupree's Avatar
Randy Dupree Randy Dupree is online now
Forum owner
 
Join Date: Dec 2007
Location: Archer,Fl
Posts: 34,006
Default

I have never heard you should not put pressure on the foot brake when the park brake is applied.
I don't think anybody that drives an air brake bus will release the park brake without having a foot on the brake pedal.
I could be wrong,ymmv
__________________
DO NOT SEND PM
email me at randy@randydupree.com only.

Randy Dupree
2000 LXI 43
Bainbridge,Ga.
Archer Fl.
www.buybyebluebird.com

randy@randydupree.com
Reply With Quote
  #4  
Old 1 Week Ago
Alever Alever is offline
Member
 
Join Date: Jul 2016
Location: Wapakoneta
Posts: 61
Default Breakdown of brake rear brake chamber cutaway picture.

Here is a good idea of how the service parking brake assembly works. The service brake works on one diaphram with air pressure when brakes are applied to stop. The parking brake will push against the back of the service brake diaphram when there is 60 psi or less air pressure in the parking brake allowing the spring to apply pressure to the back of the service brake. It takes 60 psi of air to release your parking brake. I have attached a cutaway picture. The picture showed a non servicable type of brake chamber that cannot be taken apart for safety as the spring is very dangerous. There is also a brake protection valve in the system to keep you from overloading the brake hardware when the parking brake is applied. It reduces the air pressure to compensate for the force of the spring.

Hope this helps.
Attached Thumbnails
Click image for larger version

Name:	Screenshot_20190514-082250_Chrome.jpg
Views:	18
Size:	103.9 KB
ID:	61931  
__________________
Allen and Sara Eversman
Wapakoneta, Ohio
93 WLWB
Had 81 FC35
937-407-0079
Reply With Quote
  #5  
Old 6 Days Ago
LDM680 LDM680 is online now
Senior Member
 
Join Date: Apr 2009
Location: Oakville
Posts: 166
Default

Jim:


Here is a video about the anti-compounding valve:


https://www.youtube.com/watch?v=LmrP_BxMfOI


Cheers
__________________
Len
1985 PT40
Oakville, Ontario

len.mcleod@gmail.com
Reply With Quote
Reply

Bookmarks

Thread Tools

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
FC Parking brake circuit air leak / Brake Relay Valve SR-1 Patrick LaBreck Tires, Wheels, Brakes, Steering and Suspensions 21 11-09-2017 07:38 PM
Spring Brake valve Rich Johnson Tires, Wheels, Brakes, Steering and Suspensions 9 10-12-2016 10:06 AM
Leak in Brake Valve Buckeye Bird Tires, Wheels, Brakes, Steering and Suspensions 14 04-26-2013 05:11 PM
Brake tredle valve access / air leak at valve JohnPav Tires, Wheels, Brakes, Steering and Suspensions 48 01-31-2012 10:36 AM
Anti-Siphoning Valve & Holding Tank Odor Rob Robinson 'Bird Projects & Modifications 9 02-07-2009 02:02 PM

Web Search:

All times are GMT -4. The time now is 09:02 AM.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2019, vBulletin Solutions Inc.