Very odd rear brake problem

1945 - 196*, Willys CJ series, questions, discussions, regarding anything related to the post war jeep.®
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Bob Bell
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Very odd rear brake problem

Post by Bob Bell » Wed Jun 15, 2016 9:36 am

Here is an odd problem. I have a 1946 2A. I overhauled the brakes last year. New shoes, wheel cylinders etc. I did not machine the drums. Fairly recently, i.e., about three months ago, 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, and the vehicle stopped pulling to the left. I removed the drum. No obvious problem. The shoes are wearing in very evenly - indeed, there is no noticeable wear at all. No grease anywhere, both springs intact. I re-adjusted all the wheels but the problem persists. Once the vehicle has been driven for a few minutes and the brakes applied three or four times, the squeal disappears and the jeep stops without pulling to one side. The squeal sounds like metal on metal, but it ain't so! If the jeep is parked for more than an hour or so, the problem returns until it is driven again for a few minutes. The jeep is a daily driver, if it makes any difference.

I thought it might be a weak return spring, but figure that can't be so as the wheel locks up while I am still applying pressure. Any ideas, anyone?

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.


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Re: Very odd rear brake problem

Post by Joe Gopan » Wed Jun 15, 2016 12:10 pm

First impression is a sticky wheel cylinder.
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Re: Very odd rear brake problem

Post by Bob Bell » Wed Jun 15, 2016 12:17 pm

That was my first thought, but would not the wheel still be locked AFTER I took my foot off the brake in that case? The wheel locks up when I hit the brake, unlocks immediately I ease off. And why the squeal?

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.

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Re: Very odd rear brake problem

Post by Joe Gopan » Wed Jun 15, 2016 1:24 pm

There may be brake fluid or grease, residue or rust imbedded in the linings It still commands inspection of the wheel cylinder.
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Re: Very odd rear brake problem

Post by artificer » Wed Jun 15, 2016 1:29 pm

Joel wrote:First impression is a sticky wheel cylinder.
I agree.
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TO DIAGNOSE, TROUBLESHOOT OR FAULT FIND ANY AUTO SYSTEM....
Understand how system parts interact with one another. GOOD parts can then be established & the NOT GOOD problem/s part/s isolated for repair or replacement.

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Re: Very odd rear brake problem

Post by Joe Gopan » Wed Jun 15, 2016 1:39 pm

I always dip the pistons on new cylinders in Castor Oil when doing Jeep Brakes. I learned this from a Bendix Factory Brake expert who advised me that some Jeeps set a lot between use, hunting, fishing, fire dept., etc., and the Castor Oil which is a component o DOT 3 will delay sticking of the brake cylinders from age and sitting.
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Re: Very odd rear brake problem

Post by artificer » Wed Jun 15, 2016 2:20 pm

Castor oil is hygroscopic [i.e. it attracts & absorbs water] just like DOT brake fluids [except DOT5]. I would not recommend using Castor oil no matter what anyone was shown or taught in the 1930's when hydraulic brakes were introduced & castor oil was commonly used as brake fluid.
None of this stuff is current in 2016. Castor oil [& brake fluid external to the closed system] will oxidize & contribute to sticky wheel cylinders.

Red rubber grease is what is recommended & practicing mechanics use when inside brake hydraulic systems in the 21st century.
A very, very light smear in wheel cylinders is enough when assembling.
This is a comprehensive list of red rubber grease properties:
....Fully compatible with natural & synthetic rubbers
....Compatible with brake fluids & some hydraulic oils.
....Rust inhibitor [protects from oxidation & rust].
....Red rubber grease is water resistant.
....High temperature. The grease can be used in applications with temperatures up to 210-230F. It will not melt & will not contaminate brake linings.
....Gasoline resistant. Although it will get contaminated in contact with gasoline, but still it will protect rubber parts from it.
....High chemical & structural(mechanical) stability.
....High resistance against water washing [will stay on after a rain, or car wash].
....Has high wear protecting quality.
John GIBBINS Member Institute of Automotive Mechanical Engineers [Ret], ASE Master Medium/Heavy Truck & Auto Technician USA -2002 Licensed Motor Mech NSW MVIC 49593 Current 2015
TO DIAGNOSE, TROUBLESHOOT OR FAULT FIND ANY AUTO SYSTEM....
Understand how system parts interact with one another. GOOD parts can then be established & the NOT GOOD problem/s part/s isolated for repair or replacement.

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Re: Very odd rear brake problem

Post by Bob Bell » Wed Jun 15, 2016 4:19 pm

I very much appreciate the input from Ben and Artificer. I will most certainly take the hub off once more and inspect for foreign material, BUT I did do this about a month ago and both shoes looked as new as when I had installed them. Very clean. No signs of grease nor brake fluid anywhere, whether upon the shoes or the backing plate or the drum. And It still doesn't explain the fact that the wheel locks up the moment I first hit the brakes. Certainly the wheel cylinder expands immediately. And as the wheel unlocks immediately pressure is released surely indicates the cylinder has retracted. Nor does it really explain the squeal ...

I guess I'll order a new cylinder and just replace it when I next take the wheel and hub off, and see if it makes a difference. I have to say that in view of what I laid out in the first paragraph I really don't think it is the problem, but what else could it be? I'll replace the springs while I'm at it.

Anyway, thanks again folks.

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.

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Re: Very odd rear brake problem

Post by Joe Gopan » Wed Jun 15, 2016 5:21 pm

Deteriorated brake hose can restrict, but there is only one hose for both rear cylinders. Pinched brake tubing may be a source.
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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

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Re: Very odd rear brake problem

Post by Bob Bell » Wed Jun 15, 2016 5:52 pm

As I live in California, where one has to - unfortunately - go a long way to take one's jeep off road, the possibility of having damaged or pinched a line is a non starter. I'm under the rig very often, tightening things, servicing it and generally checking things out. The steel lines are fine, and the rubber hoses are all fairly recent. And as you imply, if it was an old swollen hose, it would be both wheels. Also, the swollen hose scenario usually results in the cylinder not returning or returning slowly. Mine returns immediately pressure is taken off the pedal.

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.

Joe Gopan
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Re: Very odd rear brake problem

Post by Joe Gopan » Wed Jun 15, 2016 6:54 pm

Have you checked the Anchor Pin Cams (those eccentric brass washers at the bottom)? Sometimes during brake shoe installation they do not get installed in the holes on the bottom of the shoes and pinch the shoe), rare but possible. It is also good practice to use 630AA Lubriplate when assembling the eccentrics.
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

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Re: Very odd rear brake problem

Post by artificer » Wed Jun 15, 2016 7:42 pm

Something some folk miss is to always chamfer new brake shoe linings about 1/8" @ 45* on each end. This stops grabbing.
Do it, as it will not hurt anything & your problem may disappear
Bob wrote:I will most certainly take the hub off once more and inspect for foreign material, BUT I did do this about a month ago and both shoes looked as new as when I had installed them. You are looking under the dust boot to see if there is evidence of oxidization in the wheel cylinder proper outside of the piston

Very clean. No signs of grease nor brake fluid anywhere, whether upon the shoes or the backing plate or the drum. that won't cause squealing And It still doesn't explain the fact that the wheel locks up the moment I first hit the brakes. You didn't replace or have brake drums skimmed & there are often hard spots develop in brake drums. One can usually see the material difference on close inspection it really explain the squeal ...

I guess I'll order a new cylinder and just replace it when I next take the wheel and hub off, and see if it makes a difference. Why? You have not established that is the problem I have to say that in view of what I laid out in the first paragraph I really don't think it is the problem, but what else could it be? I'll replace the springs while I'm at it. That won't achieve anything if the springs are identical with other springs....if you are in the mood, change bits from side to side until your noise is gone.
John GIBBINS Member Institute of Automotive Mechanical Engineers [Ret], ASE Master Medium/Heavy Truck & Auto Technician USA -2002 Licensed Motor Mech NSW MVIC 49593 Current 2015
TO DIAGNOSE, TROUBLESHOOT OR FAULT FIND ANY AUTO SYSTEM....
Understand how system parts interact with one another. GOOD parts can then be established & the NOT GOOD problem/s part/s isolated for repair or replacement.

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Re: Very odd rear brake problem

Post by Fortyeight2A » Wed Jun 15, 2016 8:44 pm

Is it possible that the driver side brake is grabbing because the passenger side brake cylinder is seizing and not operating? Sometimes with brakes, the problem is on the other side from what you think.
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Re: Very odd rear brake problem

Post by Rus Curtis » Thu Jun 16, 2016 5:14 am

I have experienced grabbing and squealing when doing a partial brake job that didn't include turning the drums/rotors. I would also inspect all brakes (both sides) as suggested. If new cylinders have been installed, there may be internal issues that a tear down/reassembly inspection may find.
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Re: Very odd rear brake problem

Post by Bob Bell » Thu Jun 16, 2016 8:03 am

Thanks again for the input gentlemen. I too have been contemplating that the problem may indeed lie on the opposite side, and will check both sides as soon as I get a spare couple of hours.
I'll report back with my findings.
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.


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