1999 Beaver Marquis - Air Brake & E-Brake Adjustment Problems

[Devin Ginther]

Any air brake pros specific to a 1999 Marquis?   We r trying to prep for a 7500 mile trip thru the Rockies and our local diesel shop is struggling with the brake system.  Our parking brake does not work whatsoever when applied. That's was the primary purpose of dropping it off, outside of fluid & filters. 

They went through the adjustment procedure provided by Meritor.  Apparently this is a Meritor brake system installed on Beavers for 3 years or that's what he is telling me.  He says it is a stange, antiquated setup even for 1999.  I'm not familiar with Meritor or really know much about the brake system in these coaches as this point.   I was told it appears that they entire brake system lines are new and were completely replaced at a painstaking effort or that's what he believes.  The original owner of this rig, was great at maintaining and storing this thing.

 Also, I will say that is a VERY good diesel shop that is well respected and does a ton of big rig and diesel pusher RV related work.  The owner of the shop is troubleshooting this thing personally for me and is certified across various air brake systems.   This is NOT his 1st rodeo but certainly his 1st Beaver rodeo!  Lol.   

What's strange to me is that I had noticed there is a large diameter rotor mounted on the driveshaft when I installed the Air Force One system. I'm familiar with that system as a very good e-brake setup on big trucks.  However, there is no caliper installed against the rotor.  Almost as if when they made this Marquis they used a driveshaft from "old" inventory.   Wondering if maybe it was removed at some point but not sure why anyone would do that.   

Any suggestions or insights you might would be appreciated.  I'm a bit fearful we won't be able to resolve this without tribal knowledge.   

[Eric Maclean Co-Admin]

Devin
The parking brake on that motorhome was used by beaver for a very short time they where problematic and the parts are very hard to come by
It would most likely have had a mechanical caliper made by Hayes corporation as a part number LM 100  mounted to that brake disc on the drive shaft which would have had a cable operated by a remote spring brake ( Maxi chamber)

If you go to the coach assist section library you will find a section ( brake) there which has an original brochure with a picture of the caliper.

As for the Maxi brake it was a haidex/ Midland part.with a cable that ran from the Maxi mounted up on the frame rail down to the caliper to operate the caliper.
If yours is missing you could try Visone RV salvage at (606) 843-9889
As a side note the earlier model year patriots used the same system but had an more common drum brake mounted to the rear of the transmission housing at the drive shaft.

https://www.haldex.com/en/na/actuators/maxibrake-spring-brakes/maxibrake-r-series-spring-brake/

https://www.hayesperformance.com/heavy-equipment-brakes/m100lm


Hope this helps
Eric

[Devin Ginther]

Eric,

Thanks for your response. 

"It would most likely have had a mechanical caliper made by Hayes corporation as a part number LM 100  mounted to that brake disc on the drive shaft which would have had a cable operated by a remote spring brake ( Maxi chamber)"

So my Marquis has a caliper mounted on the driveshaft but that's it??

#1) So the one thing I'm trying to figure out is if my "years" of the Marquis (1999 for me), originally ALL had these driveshaft mounted brakes.  Maybe my unit was modified as my diesel mechanic mentioned that all the air hoses looked to be replaced.  I would be quite surprised if this was the case but you never know.  I've assumed it was simply leftover inventory from the prior brake setup.  I do have the Magnum "D" series Blue Diamond chassis with 8 air bags. 

How does the driver apply the e-brake within this setup if it is cable actuated?   My Marquis has a standard big rig yellow push/pull style that is air actuated.   

#2) Per previous forum posts on this subject, I have found that the mid-1998 to 2002 Marquis had the Meritor ADB 1560 brake system.   What I don't know is how the air actuated e-brake functions within the ADB system as I've honestly never taken off a wheel.  I typically don't work on big truck air brakes but seems I need to be more familiar with this entire setup.   

[Devin Ginther]

Wanted to let others know that I've confirmed with at least one additional owner of a 2000 Marquis Amethyst that it was a stand-alone driveshaft rotor with no additional parts.   They e-brake system is based on the Meritor ADB 1560 brake system so it actuates at the wheels. 

I'm still trying to determine root cause of not having the e-brake system.  My diesel shop is struggling to adjust it properly, following Meritor documentation. 

However, I did just speak with my mechanic and he confirmed that a conventional modern grease was in the system, not the Meritor clay based lube. 

Meritor manual states: "Only use Meritor specification O-616-A or O-645 grease inside the disc brake caliper. Do not use lithium-base grease, which can melt from high temperatures inside the caliper.  Damage to components can result."

So unfortunately, the last shop that performed brake service work on my Marquis used standard "red" based grease.   We are going to purge the system and install a O-616-A or O-645 grease and see if we get better results. 

If anyone happens to know what type of "damage" to components is typically, PLEASE let me know as I may end up ordering the replacement parts.   

 

[Eric Maclean Co-Admin]

Devin
I believe your right your coach may have been built during the change over to the ADB brakes both the earlier system with the drive shaft mounted P brake and the ADB system utilize the yellow P brake control knob to operate the Parking brake the only difference is the drive shaft brake was a stand alone system where as the ADB uses the brake service brake calipers to accomplish the parking brake function .
On the ADB calipers you should find a regular slack adjuster which is operated by an air chamber this air chamber has two separate diaphragms the one closest to the slack adjuster is the service chamber which operates the brakes during normal driving,the second chamber the one furthest from the slack adjuster is the parking brake chamber commonly referred to as the spring brake chamber.
When you push on the yellow Parking brake knob at the driver's station the yellow valve applies air pressure to the spring brake chamber where the pressure in that section of the brake chamber pushes on a diaphragm which compresses the large spring inside the chamber this release the brake .
However if the air system pressure drops below 45 psi the yellow Parking brake valve knob will pop up and dump the air off the spring brake chambers causing the Parking brakes to activate.

If your problem is that the Parking brake won't hold the vehicle there are several things to check.
1) check the mechanical operation of the service brakes.
2) check the slack adjuster for proper adjustment
3) check the chamber push rod stroke when parking brake activated ( your looking for a broken spring brake spring)
4) check the caliper guide pins for free operation ( these are a common fault with the ADB the guide pins get rusty and won't slide properly which causes the brake to not center properly wearing one pad more than the other and making proper adjustment of the brake almost impossible.
5) the use of the wrong grease can cause several problems as the caliper heats up the wrong grease can expand causing the brake to drag and over heat.
    It can also effect the operation of the caliper itself.

https://youtu.be/7N-St4Px8cs?si=YXvbSMFLSmiHIZ_G

https://graphicvillage.org/meritor/mm4m.pdf

Hope this helps
Eric

[Frank Bergamo]

Brake pads and rotors.

[Eric Maclean Co-Admin]

Devin
If your parking brakes don't activate at all. Or are very weak you are looking around one of two things
1) the air is not being removed or exhausted from the spring brake chambers (possible internal leak in the yellow valve or a bad relay valve)
2) broken or weak  springs in the spring brake chambers.(Common problem)


Eric

[Eric Maclean Co-Admin]

Devin
here is a video of the drive shaft parking brake system as installed on a Beaver motorhomes.

https://youtu.be/pdgyNiK2PCk?si=O2k7O0WuGSOvHZuu

Eric