Very odd rear brake problem

1945 - 196*, Willys CJ series, questions, discussions, regarding anything related to the post war jeep.®
Joe Gopan
Jeep Heaven
Posts: 49841
Joined: Sun Mar 02, 2008 12:37 pm
Location: Proving Ground

Re: Very odd rear brake problem

Post by Joe Gopan » Tue Nov 07, 2017 4:28 am

If it is glazed, you can lightly wire brush the linings or replace them.
2011 MVPA PIONEER AWARD - MVPA #1064
HONOR GRAD-WHEELED VEHICLE MECHANIC SCHOOL 1960 - US ARMY ORDNANCE SCHOOL(MACHINIST) ABERDEEN PG 1962 - O-1 BIRD DOG CREWCHIEF - 300,000+TROUBLE FREE M-38A1 MILES
LIFE MEMBER AM LEGION-40/8-DAV
7 MIL SPEC MAINTAINED MV'S
COL. BRUNO BROOKS (ARMY MOTORS) IS MY HERO


Bob Bell
G-Command Sergeant Major
G-Command Sergeant Major
Posts: 204
Joined: Tue Oct 21, 2003 5:01 pm
Location: Oakland, CA

Re: Very odd rear brake problem

Post by Bob Bell » Tue Nov 07, 2017 6:36 am

I wired brushed the shoes REALLY thoroughly, so I am confident that the problem does not lie there.
Bob Bell

1946 CJ2A 36116
Have owned dozens of flat fenders over the years including 1945 CJ2A 10011 which I sold in 2002.
First 4WD was an Austin Champ in 1965, and then a GPW UK license number HRO 443, sold in 1974.

Rus Curtis
G-Second Lieutenant
G-Second Lieutenant
Posts: 503
Joined: Wed Apr 05, 2006 3:51 am
Location: Alabama

Re: Very odd rear brake problem

Post by Rus Curtis » Tue Nov 07, 2017 7:09 am

I've never used a wire brush on shoes/pads before so I'm not sure how effective that would be. I've always had success using a very coarse sandpaper, i.e. 40 or 60 grit. Light would not be the way I'd go about sanding shoes that are glazed. I would want to remove the top layer and expose un-glazed material underneath - before it affects the drum.

Perhaps this can be achieved with a wire brush - I just don't have any experience with doing this.
Rus Curtis
'54 CJ-3B
T3-C

Joe Gopan
Jeep Heaven
Posts: 49841
Joined: Sun Mar 02, 2008 12:37 pm
Location: Proving Ground

Re: Very odd rear brake problem

Post by Joe Gopan » Tue Nov 07, 2017 7:10 am

It could if there is imbedded rust or grease.
2011 MVPA PIONEER AWARD - MVPA #1064
HONOR GRAD-WHEELED VEHICLE MECHANIC SCHOOL 1960 - US ARMY ORDNANCE SCHOOL(MACHINIST) ABERDEEN PG 1962 - O-1 BIRD DOG CREWCHIEF - 300,000+TROUBLE FREE M-38A1 MILES
LIFE MEMBER AM LEGION-40/8-DAV
7 MIL SPEC MAINTAINED MV'S
COL. BRUNO BROOKS (ARMY MOTORS) IS MY HERO

Bob Bell
G-Command Sergeant Major
G-Command Sergeant Major
Posts: 204
Joined: Tue Oct 21, 2003 5:01 pm
Location: Oakland, CA

Re: Very odd rear brake problem

Post by Bob Bell » Tue Nov 07, 2017 8:36 am

That is true. I sprayed the linings liberally with brake cleaner, and really scrubbed them. There was no, or very little visible grease there to start with. I replaced the bearing seal while I was in there, as it was showing signs of beginning to fail, but the entire set up was pretty darn clean to begin with.
Bob Bell

1946 CJ2A 36116
Have owned dozens of flat fenders over the years including 1945 CJ2A 10011 which I sold in 2002.
First 4WD was an Austin Champ in 1965, and then a GPW UK license number HRO 443, sold in 1974.

Joe Gopan
Jeep Heaven
Posts: 49841
Joined: Sun Mar 02, 2008 12:37 pm
Location: Proving Ground

Re: Very odd rear brake problem

Post by Joe Gopan » Tue Nov 07, 2017 9:18 am

Possible contamination (Grease/Brake Fluid) is still a reasonable consideration.
2011 MVPA PIONEER AWARD - MVPA #1064
HONOR GRAD-WHEELED VEHICLE MECHANIC SCHOOL 1960 - US ARMY ORDNANCE SCHOOL(MACHINIST) ABERDEEN PG 1962 - O-1 BIRD DOG CREWCHIEF - 300,000+TROUBLE FREE M-38A1 MILES
LIFE MEMBER AM LEGION-40/8-DAV
7 MIL SPEC MAINTAINED MV'S
COL. BRUNO BROOKS (ARMY MOTORS) IS MY HERO

Bob Bell
G-Command Sergeant Major
G-Command Sergeant Major
Posts: 204
Joined: Tue Oct 21, 2003 5:01 pm
Location: Oakland, CA

Re: Very odd rear brake problem

Post by Bob Bell » Fri Nov 10, 2017 12:09 pm

I would agree with Ben Dover's comment regarding grease contamination being the likely culprit if I was reading this post too. However I put in brand new linings a couple of years ago, and have had the drum off several times since then. The linings have appeared to remain 100 % grease free the entire period.
One brake shop I discussed this with said perhaps the drum is out of round. Possible, but I have tried two other drums (also possibly out of round) and there has been no change in the squeal volume. One of those drums is on the other side, and that side doesn't squeal.Another brake shop opined that the edges of the shoes were NOT lubricated where 'they rub against the backing plate'. When I said they don't rub against the plate he looked at me like I was a cretin. Indeed, he had me wondering so much that I had to take a look. And of course they don't rub against the plate - the only points of contact are the anchor pins and the female ends of the pistons in the wheel cylinders.
Bob Bell

1946 CJ2A 36116
Have owned dozens of flat fenders over the years including 1945 CJ2A 10011 which I sold in 2002.
First 4WD was an Austin Champ in 1965, and then a GPW UK license number HRO 443, sold in 1974.

Joe Gopan
Jeep Heaven
Posts: 49841
Joined: Sun Mar 02, 2008 12:37 pm
Location: Proving Ground

Re: Very odd rear brake problem

Post by Joe Gopan » Fri Nov 10, 2017 2:00 pm

Look again at your backing plate, they have short 1" raised pads either side of the wheel cylinders that the shoes rub against. Professional brake shops used a smear of LUBRIPLATE 630AA at these locations.
They allow free movement of the shoes, won't help squeal.
Surface rust sometimes builds up on drums of Jeeps that sit a lot and can imbed into the linings creating a hard glaze that will squeak when the brakes are applied.
2011 MVPA PIONEER AWARD - MVPA #1064
HONOR GRAD-WHEELED VEHICLE MECHANIC SCHOOL 1960 - US ARMY ORDNANCE SCHOOL(MACHINIST) ABERDEEN PG 1962 - O-1 BIRD DOG CREWCHIEF - 300,000+TROUBLE FREE M-38A1 MILES
LIFE MEMBER AM LEGION-40/8-DAV
7 MIL SPEC MAINTAINED MV'S
COL. BRUNO BROOKS (ARMY MOTORS) IS MY HERO

Bruce W
G-Colonel
G-Colonel
Posts: 1684
Joined: Thu Mar 13, 2003 4:45 pm
Location: Northeast Colorado

Re: Very odd rear brake problem

Post by Bruce W » Fri Nov 10, 2017 4:09 pm

Check the six bolts that hold the backing plate onto the axle housing. Loose backing plate bolts can cause a chatter or squeal. BW
G Trp 2nd Sqdrn 3d Armored Cavalry Ft. Lewis 1970-71. 43GPW(Sarge?) 47CJ2A(Teddy) 47CJ2A(Rusty) 47CJ2A(Zak) 48CJ2A(Lefty) 48CJ2A(Uncle Linden) 53CJ3B(Bulldog) 88XJ(Pluto) NE CO

Joe Gopan
Jeep Heaven
Posts: 49841
Joined: Sun Mar 02, 2008 12:37 pm
Location: Proving Ground

Re: Very odd rear brake problem

Post by Joe Gopan » Sat Nov 11, 2017 1:10 pm

Anyone notice the flat spots on the backing plates where the shoes contact the backing plates?
2011 MVPA PIONEER AWARD - MVPA #1064
HONOR GRAD-WHEELED VEHICLE MECHANIC SCHOOL 1960 - US ARMY ORDNANCE SCHOOL(MACHINIST) ABERDEEN PG 1962 - O-1 BIRD DOG CREWCHIEF - 300,000+TROUBLE FREE M-38A1 MILES
LIFE MEMBER AM LEGION-40/8-DAV
7 MIL SPEC MAINTAINED MV'S
COL. BRUNO BROOKS (ARMY MOTORS) IS MY HERO

fiveftsix
G-Second Lieutenant
G-Second Lieutenant
Posts: 575
Joined: Thu Dec 27, 2012 5:37 pm
Location: Kissimmee FL

Re: Very odd rear brake problem

Post by fiveftsix » Sat Nov 11, 2017 3:59 pm

Anyone thought about the axle shaft an bearing with this problem ??
"the driver's side rear drum started to squeal and seize up when I first drove the vehicle. After a few stops the squeal went away, "
Geoff Bull

Joe Gopan
Jeep Heaven
Posts: 49841
Joined: Sun Mar 02, 2008 12:37 pm
Location: Proving Ground

Re: Very odd rear brake problem

Post by Joe Gopan » Sun Nov 12, 2017 7:49 am

Same first impression, sticky wheel cylinder.
2011 MVPA PIONEER AWARD - MVPA #1064
HONOR GRAD-WHEELED VEHICLE MECHANIC SCHOOL 1960 - US ARMY ORDNANCE SCHOOL(MACHINIST) ABERDEEN PG 1962 - O-1 BIRD DOG CREWCHIEF - 300,000+TROUBLE FREE M-38A1 MILES
LIFE MEMBER AM LEGION-40/8-DAV
7 MIL SPEC MAINTAINED MV'S
COL. BRUNO BROOKS (ARMY MOTORS) IS MY HERO

fiveftsix
G-Second Lieutenant
G-Second Lieutenant
Posts: 575
Joined: Thu Dec 27, 2012 5:37 pm
Location: Kissimmee FL

Re: Very odd rear brake problem

Post by fiveftsix » Sun Nov 12, 2017 8:32 am

I`m not doubting that for one moment Joel.
But it`s not unknown for the bearing to be running dry first off
Until some Diff oil is getting past an old inner seal to partially lub the bearing.
With all the inspections the OP is doing , cleaning etc it appears to be getting worse ???
If the hubs off to check out the shoes an cylinder not a big task to just check the bearing at the same time is it ?
Geoff Bull

Bob Bell
G-Command Sergeant Major
G-Command Sergeant Major
Posts: 204
Joined: Tue Oct 21, 2003 5:01 pm
Location: Oakland, CA

Re: Very odd rear brake problem

Post by Bob Bell » Mon Nov 13, 2017 11:00 am

Well, lots of suggestions since I last looked !Thanks everyone!

I'll go over some of the points.
1. When I wire brushed the linings, I did it very vigorously indeed, and I did sand them. Ditto the drums.
2. This jeep is a daily driver - so there is no opportunity for the drums to rust. I live in California - not much rain out here anyway!
3. The little 1" bumps on the backing plate. I was told by a brake guy here in town that that was my problem - that I should put a little lube on those high spots to avoid squeal. I was surprised because I had never heard about that before, but went home to check. There is a gap between my backing plates and the shoes - the shoes do NOT rub on my vehicle. If they did, the paint would have rubbed off at those points.
4. The bearings are well greased.
5. I have NOT checked the backing plate for tightness, and will do so.

I'll report back soon.
Thanks everyone,
Bob
Bob Bell

1946 CJ2A 36116
Have owned dozens of flat fenders over the years including 1945 CJ2A 10011 which I sold in 2002.
First 4WD was an Austin Champ in 1965, and then a GPW UK license number HRO 443, sold in 1974.

Bob Bell
G-Command Sergeant Major
G-Command Sergeant Major
Posts: 204
Joined: Tue Oct 21, 2003 5:01 pm
Location: Oakland, CA

Re: Very odd rear brake problem

Post by Bob Bell » Mon Nov 13, 2017 12:23 pm

Took off the brake drum once again.
The backing plate was fully tight. Sanded the linings and the drum once more.
The only places where the shoes make contact with the backing plate are mid way on each shoe, where they are kept in position by by pressed steel 'forks' that are attached to the raised plates on the backing plate. I am assuming this is what Ben Dover was referring to. I had already applied Lubriplate to these two points.
The wheel bearing is well lubricated.
Put it all back together and went for a test drive. It squealed the first time I applied the brakes, and pulled to the side (wheel I just worked on braked first). One more application and the squeal has disappeared and the vehicle stops in a straight line.
So it appears that the wheel cylinder on the other side is sticking again. Before I tear that down for the second time, I am going to drive it for a few days and see what happens. I hate to be a pessimist, but I will bet the squeal returns. I'll post again after a few trips. And thanks again for all the suggestions.

Bob
Bob Bell

1946 CJ2A 36116
Have owned dozens of flat fenders over the years including 1945 CJ2A 10011 which I sold in 2002.
First 4WD was an Austin Champ in 1965, and then a GPW UK license number HRO 443, sold in 1974.


Post Reply

Return to “CJ Technical Knowledge Base”

Who is online

Users browsing this forum: No registered users and 46 guests