Reply
 
Thread Tools Search this Thread Display Modes
 
Old 12-19-2014, 01:19 PM   #1
Rivet Master
 
Al and Missy's Avatar

 
2002 30' Classic S/O
Melbourne Beach , Florida
Join Date: Nov 2013
Posts: 2,319
"Centering" Brake Backing Plate

I'm still struggling with my left rear trailer brake grabbing at slow speeds. I read on another forum that a potential cause is the brake backing plate being off center, and a centering procedure was identified.

My question is, is this a potential problem with the 2001 vintage dual axle trailers? If a PO hit a pothole, ran over a curb, etc. is it possible that the brake backing plate on the rear axle might have gotten knocked off center?

Another possibility I'm pursuing is I may have the boost set too high (B1). My trailer weighs around 6000# and the GVWR of the TV (which I'm probably close to) is 7200#. Per the P3 manual B1 is the maximum setting I should be using. I would have thought that if the boost was too high, more than one axle would be grabbing.

Thanks for any suggestions.

Al
__________________

__________________

"You cannot reason someone out of a position they have not been reasoned into"

Al, K5TAN and Missy, N4RGO
2002 Classic 30 Slideout
S/OS #004
2013 Dodge 2500 Laramie 4x4 Megacab Cummins
2001 Safari 25 RB Twin (Gone, but not forgotten)
WBCCI 1322, TAC FL-39, AIR 82265

Al and Missy is offline   Reply With Quote
Old 12-19-2014, 02:55 PM   #2
Moderator dude
 
Action's Avatar

 
1966 26' Overlander
Phoenix , Arizona
Join Date: Apr 2002
Posts: 6,067
Images: 13
As a ramdom thought related to cars. The brake shoes in most cars and light trucks are not the same length. The smaller shoe is towards the front of the backing plate and the larger one is placed on the rear. Mix it up and one issue is a grabbing brake.

I throw this out as a possibility and not necessarily as a diagonsis. Trailer shoes may be the same length.

>>>>>>>>>>>>>>>Action
__________________

__________________
1966 Mercury Park Lane 4 DR Breezeway 410 4V, C-6, 2.80 - Streamless.
1966 Lincoln 4 door Convertible 462 4V 1971 Ford LTD Convertible 429 4V Phoenix ~ Yeah it's hot however it's a dry heat!
Action is offline   Reply With Quote
Old 12-19-2014, 03:31 PM   #3
Rivet Master
 
HowieE's Avatar
 
1991 34' Excella
Princeton , New Jersey
Join Date: Aug 2003
Posts: 6,811
Images: 12
Yes the smaller shoe is the forward shoe.

As for centering. I have seen some backer plates with slightly larger holes than are necessary for the bolts. What I have done in that case is machine 2 bushings that fit over the blot and fill the holes in the backer plate. Position the plate using those 2 bolts and bolt down the other 3 before removing the bushings. If all 5 bolts are tight that should hold the plate on center.

Another thing that will cause grabbing is if the trailer is not parallel to the ground. The higher axle will have a tendency to grab because of reduced weight on it.

Most controllers suggest traveling at 25 mph on a gravel road and fully activating the manual control arm. If the brakes lock back off and repeat the test till the breaks just stop locking. That is max. braking.
__________________
WBCCI 12156 AIR 3144 WACHUNG TAC NJ6
2004 Excursion 4x4
1991 34 ft. Excella +220,000 miles, new laminated flooring, new upholstery, new 3200 lbs axles

HowieE is offline   Reply With Quote
Old 12-19-2014, 03:32 PM   #4
Rivet Master
 
Al and Missy's Avatar

 
2002 30' Classic S/O
Melbourne Beach , Florida
Join Date: Nov 2013
Posts: 2,319
Action: Thanks for the suggestion. As I recently re-packed the wheel bearings and cleaned, lubricated, and adjusted the brakes I am reasonably certain (but not 100%) that the shoes are in correctly. On the Airstream, the small shoe goes in front, if I remember correctly. Mine should all be the same, but only one brake is grabbing.

All: I was meticulous about cleaning the drums after repacking, so I doubt that grease contamination is the problem unless a grease seal failed.

I have owned the trailer for about a year, but didn't use it seriously until this summer. I had to add a brake controller to my truck. When I first towed the trailer I followed the instructions for setting up the controller and advanced the gain until I heard the brakes lock up when fully applied with the panic lever. I backed off on the controller gain and all appeared fine. About 1000 miles into a 1500 mile trip the grabbing at low speed started. It's possible that what I heard initially was only one wheel locking up.

Also, the wheel is locking up with only very light pressure on the pedal. I would think that if it were due to tilt or loading it wouldn;t happen so early in the pedal travel. I could understand one wheel locking up before the others, but this happens with the initial, very light, application of the brakes.

Al
__________________

"You cannot reason someone out of a position they have not been reasoned into"

Al, K5TAN and Missy, N4RGO
2002 Classic 30 Slideout
S/OS #004
2013 Dodge 2500 Laramie 4x4 Megacab Cummins
2001 Safari 25 RB Twin (Gone, but not forgotten)
WBCCI 1322, TAC FL-39, AIR 82265

Al and Missy is offline   Reply With Quote
Old 12-19-2014, 04:11 PM   #5
Rivet Master
 
1981 31' Excella II
New Market , Alabama
Join Date: Sep 2011
Posts: 5,648
Does it run hot when the brakes are not being used? My suspect is grease on the drum or some really bad mechanical issue. I had one wheel run hot and it blew the seal out and the grease caused it to lock easily. This is one that ran hot because it was adjusted too tight and/or it was not broken in yet. Make sure the magnet its properly attached to the lever and that the spring behind the magnet is working. A little drag on that magnet will cause it to stay on. Old worn out magnets can cause problems or using old magnets on a new drum.

Perry
__________________
perryg114 is offline   Reply With Quote
Old 12-19-2014, 04:34 PM   #6
Moderator dude
 
Action's Avatar

 
1966 26' Overlander
Phoenix , Arizona
Join Date: Apr 2002
Posts: 6,067
Images: 13
The other thought I have is brake adjustment. That wheel being different that the other wheels.

>>>>>>>>>Action
__________________
1966 Mercury Park Lane 4 DR Breezeway 410 4V, C-6, 2.80 - Streamless.
1966 Lincoln 4 door Convertible 462 4V 1971 Ford LTD Convertible 429 4V Phoenix ~ Yeah it's hot however it's a dry heat!
Action is offline   Reply With Quote
Old 12-19-2014, 04:44 PM   #7
4 Rivet Member
 
timmaah's Avatar
 
1999 25' Safari
On , the road
Join Date: Aug 2010
Posts: 296
I would back the adjustment screws off that wheel and see if it makes a difference.

I have the same situation in that if a wheel is to lock up it is always the same drivers rear wheel. This still happens even after a full brake job. New backing plates, drum, shoes, magnet.

The trailer seems to brake just fine otherwise, just after a good amount of driving and things are hot, that wheel gets touchy.
__________________
Our Adventure.. http://www.watsonswander.com/
timmaah is offline   Reply With Quote
Old 12-19-2014, 05:01 PM   #8
Rivet Master
 
Al and Missy's Avatar

 
2002 30' Classic S/O
Melbourne Beach , Florida
Join Date: Nov 2013
Posts: 2,319
Thanks Everyone!

The brake does not drag or lock. I check hub temps each time I stop and they are all always only slightly warm. A response to my original thread suggested adjustment so I readjusted all 4 brakes, being careful to get them with the same drag as best I could judge - no change.

In the interest of full disclosure, this wheel had a worn magnet and a scored magnet surface when I serviced the brakes in September. I replaced the magnets and turned the magnet surfaces on both rear axle drums. Prior to that service, I had not noticed a problem. Maybe the PO had the adjustment backed off on that drum. I know its usually conclusive that the last time it was touched is what created the problem, so I'm pulling the trailer from storage tomorrow to pull the drum and inspect again. If I find anything, I'll post it here.

Timmah: Enjoy your blog!

Al
__________________

"You cannot reason someone out of a position they have not been reasoned into"

Al, K5TAN and Missy, N4RGO
2002 Classic 30 Slideout
S/OS #004
2013 Dodge 2500 Laramie 4x4 Megacab Cummins
2001 Safari 25 RB Twin (Gone, but not forgotten)
WBCCI 1322, TAC FL-39, AIR 82265

Al and Missy is offline   Reply With Quote
Old 12-19-2014, 05:05 PM   #9
Moderator dude
 
Action's Avatar

 
1966 26' Overlander
Phoenix , Arizona
Join Date: Apr 2002
Posts: 6,067
Images: 13
Your quote .........
Quote:
Originally Posted by Al and Missy View Post
Thanks Everyone!

..... The brake does not drag or lock. .....
Al
You said above,
"I'm still struggling with my left rear trailer brake grabbing at slow speeds."
"Also, the wheel is locking up with only very light pressure on the pedal."

So now I am confused.

>>>>>>>>>>>>Action
__________________
1966 Mercury Park Lane 4 DR Breezeway 410 4V, C-6, 2.80 - Streamless.
1966 Lincoln 4 door Convertible 462 4V 1971 Ford LTD Convertible 429 4V Phoenix ~ Yeah it's hot however it's a dry heat!
Action is offline   Reply With Quote
Old 12-19-2014, 05:15 PM   #10
4 Rivet Member
 
Gregsch's Avatar

 
1979 24' Airstream Excella 24
Tipp City , Ohio
Join Date: Feb 2012
Posts: 495
I had this problem on my 27' Overlander. After exhausting all other possibilities I had the drum turned. Problem solved, It looked just fine but the drum must not have been perfectly round.
__________________
Gregsch is offline   Reply With Quote
Old 12-19-2014, 09:34 PM   #11
Rivet Master
 
Al and Missy's Avatar

 
2002 30' Classic S/O
Melbourne Beach , Florida
Join Date: Nov 2013
Posts: 2,319
Action:
Sorry for the mixed terminology. Instead of "Also, the wheel is locking up with only very light pressure on the pedal.", I should have said "Also, the wheel is grabbing with only very light pressure on the pedal."

What I meant was the brake was not dragging or locking without pedal pressure, but when even slight pedal pressure is applied the brake goes to full on and the wheel locks up.

Sorry for the imprecision.

Al
__________________

"You cannot reason someone out of a position they have not been reasoned into"

Al, K5TAN and Missy, N4RGO
2002 Classic 30 Slideout
S/OS #004
2013 Dodge 2500 Laramie 4x4 Megacab Cummins
2001 Safari 25 RB Twin (Gone, but not forgotten)
WBCCI 1322, TAC FL-39, AIR 82265

Al and Missy is offline   Reply With Quote
Old 12-19-2014, 10:08 PM   #12
4 Rivet Member
 
timmaah's Avatar
 
1999 25' Safari
On , the road
Join Date: Aug 2010
Posts: 296
Quote:
Originally Posted by Al and Missy View Post
What I meant was the brake was not dragging or locking without pedal pressure, but when even slight pedal pressure is applied the brake goes to full on and the wheel locks up.
Pretty certain that is how we all understood it from the beginning.

Why not try adjusting that single wheel back off more than the others?

Thanks for the kudos on the blog. I can't take much credit as it is mostly the wife.
__________________
Our Adventure.. http://www.watsonswander.com/
timmaah is offline   Reply With Quote
Old 12-19-2014, 10:14 PM   #13
Moderator dude
 
Action's Avatar

 
1966 26' Overlander
Phoenix , Arizona
Join Date: Apr 2002
Posts: 6,067
Images: 13
Throwing out another thought ...... is it possible the brake magnet on that one wheel is different than the others?

Newer versus older
Round verus oval
Brake wiring different than the other 3 wheel such that the current or voltage is different?

Just grasping at anything.

>>>>>>>>>>Action
__________________
1966 Mercury Park Lane 4 DR Breezeway 410 4V, C-6, 2.80 - Streamless.
1966 Lincoln 4 door Convertible 462 4V 1971 Ford LTD Convertible 429 4V Phoenix ~ Yeah it's hot however it's a dry heat!
Action is offline   Reply With Quote
Old 12-19-2014, 10:14 PM   #14
4 Rivet Member
 
timmaah's Avatar
 
1999 25' Safari
On , the road
Join Date: Aug 2010
Posts: 296
Also per your boost on your P3 thought:

Quote:
Another possibility I'm pursuing is I may have the boost set too high (B1)
I'd say you are good using B1. I leave mine on B1 80% of the time and up it to B2 on interstates or when descending mountains.

The boost is just how fast the braking power is applied, not the max level of power. You might want to try and tweak the power level voltage (forget what it is called) and see what that does. (Assuming you haven't messed with it much) I know for me there is a certain perfect sweet spot. Few tenths too high the trailer gets really grabby and a few tenths lower and I feel I want more trailer braking.
__________________

__________________
Our Adventure.. http://www.watsonswander.com/
timmaah is offline   Reply With Quote
Reply


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

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
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
brake backing plate to fit a 60? badger Brakes & Brake Controllers 3 06-27-2010 08:35 AM
Brake Backing Plate Question Kris. Brakes & Brake Controllers 2 11-30-2009 05:03 PM
Backing Plate position... HansenClan Brakes & Brake Controllers 5 07-12-2008 09:44 PM
New Backing Plate Installation Raptorrider2001 Brakes & Brake Controllers 3 06-12-2007 12:11 PM


Virginia Campgrounds

Reviews provided by




Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -6. The time now is 03:58 AM.


Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, Jelsoft Enterprises Ltd.

Airstream is a registered trademark of Airstream Inc. All rights reserved. Airstream trademark used under license to Social Knowledge LLC.