And More Brake Fun...

The two problems I can think of are: having the adjusters on backwards (so they tighten when braking in forward instead of reverse), or worn backing plates preventing the shoes from sliding freely across the "pads" on the face of the backing plate.

Another possibility is weak tensioning springs. The tensioning springs force the shoes away from the drum when you release the pedal, and they also resist slack in the self-adjust cable.

Rebuilt shoes are cheap, and I would replace them if they weren't near-new and I had the drums off. Drum brake linings don't last as long as disk pads anyway, so it's good to take any opportunity to freshen them up.

As well as the backing plates being worn, you can have trouble with the adjusters if your drums are way oversize.

 

There will be a left and right adjuster, so that the adjuster lengthens when the adjuster lever climbs the star wheel. When you brake in reverse, if there's any slack, the adjuster cable will pull on the adjuster lever and make the climb up to the next notch. The cable goes on the rear shoe.

If you have the adjusters reversed, the shoes will loosen instead of tighten. If you put the cable on the front shoe (ie left assy on the right and vice versa), they should tighten going forward.

 

Not sure what your frame of reference is re CW & CCW. To loosen the adjusters, you have to force them to turn against the adjuster lever. To tighten them, you go with the lever, so it click-clicks over the star wheel. To loosen, you need to make a bang-bang, as you're pulling against the lever and the springs - actually forcing the lever in reverse till it gives. With the drums off, you lift the lever off the star wheel to loosen.

 

Ok, tighten: CW from the front on the left, CCW from the front on the right.

 

Yeah, the driver's left (driver's side), not your left.

If the adjusters are functioning, it should not be easy to loosen them with the drums on. If you could turn them easily to loosen, either something's backwards or the adjuster is not contacting the star wheel.

 

I'm lost. Could the system actually hold pressure against the switch if the shoes were adjusted too tightly? Seems like the farther away the shoes go, the less pressure there would be. Any chance the switch itself is intermittently functional? And all sure we don't have a problem with that tow circuit and the diode situation?

 

Hey Boyink,

I know I've seen similar issues before on WT, so I did a quick bit of research, and pasted what I hope is pertinent info for you here. Don't know why the lights stay on, but this may explain the one brake sticking. Hopefully, you find one, you've found the other. Good luck!

Cut'n'pasted from WillysTech.........

Its trash. Gotta be trash. I had the same problem with my '46 2A
shortly after I got it. In my case when the brakes wouldn't let go
the brake lights would stay on. Turned out to be a small piece of trash
in the master cylinder that was blocking fluid return into the MC
reservoir, but not blocking the flow *from* the reservoir. When the
fluid would eventually bleed past the blockage (small piece of what
looked like silicone) the lights would go off and I'd have normal
brakes again... for a pump or two anyway.

Merl, Tejas


Bill, I had a similar problem on my truck last year except that it was only one wheel and it would lock up hard. I had put the small brake pad on the front instead of the back. Once I reversed it my problem went away.
Have you blown your break lines out both directions with compressed air to verify that they are clear of obstructions?

Rick S (TX) (MS)



Bill, back when I first got my 2A and it was still in mostly one piece, I had
the same problem. I wanted safe brakes so I decided to go through the whole system at once. Rebuilt the master cylinder & all four wheel cylinders, cleaned everything, new shoes blew out all the lines and put it all back together. Still had the problem. Got to inspecting the rubber lines that connected the hard lines to the front brakes. On a hunch, I took my lineman pliers and cut one right in the middle. The hose had collapsed down and was acting like a check valve. It would pass brake fluid only when strong pressure was applied. Cut the other one and had the same problem. I replaced them and that solved the problem. Then I had a new problem, I realized this was as good as the brakes would ever be. It only took a few trips into traffic to convince me to start collecting parts for the four wheel disc conversion.

Jack Starcher
Lewis Center, Ohio



Now, the moment you've all been waiting for, my personal experience with the subject. I once had a car where the rear brakes would apply all by themselves sometimes while I was driving. They didn't suddenly lock up, but slowly increased their braking effort until driving was almost
impossible. If I jabbed the brakes, I could sometimes get them to release but not always. This problem drove me nuts, although this was before I knew everything, a long time ago indeed.

My initial thoughts were the rear calipers were sticking (4-wheel disc brakes, but the concept is the same) so I rebuild them to no avail. I was
able to stop the dragging by cracking open either bleeder on the rear axle so I knew the problem was hydraulic in nature. (A single flex line was
T'd to both rear calipers) I replaced the brake compensator, which cut off rear brake pressure to prevent skidding as the rear of the vehicle
lifted during heavy braking. Again, no help. Through my amazing powers of deduction, I figured the master cylinder was at fault and purchased a
new one. Much to my surprise, I noticed no fluid pressure trapped in the lines when I loosened the fitting at the master cylinder. Hmm, fluid
pressure trapped at the rear calipers but not at the master cylinder? What was happening?

That is when I discovered residual pressure trapped downstream of the flex line, but not at the upstream end. Replacing the flex line cured
the self-applying brake problem 100%. This wasn't one of those situations where I changed a bunch of parts and the problem finally went away. After wasting my time and money on the calipers and compensator, I had the fault fully isolated to the flex line. I only wish I had known to look there first. And I most definately, with no
ifs, ands or buts, had the brakes self-apply while driving until I changed the flex line. The calipers didn't fix it, the compensator didn't
fix it, and the master cylinder wouldn't have fixed it either.

=====
Regards,

Dr. Vern in Vancouver, WA http://vernco.com/

 

Heat makes things expand....

You may want to hit the WT knowledge base and do a search. Heat was brought up, but I didn't include a quote about it.