more brake problems

[Matt167]

I was driving my Rambler American on sunday, trying to time the most power out of the engine. I stepped on the brakes hard 1 time, like I have b4 w/o issue and somthing went clunk and then sounded like a flat tire when turning on the drivers front.. now when I step hard on the brakes under movement, the secondary shoe seems to push out and grind against the drum. I pulled the drum off and inspected everything and it all looks ok except where it's pushing out on the bottom of the secondary shoe, can see a contact point.. Drums are brand new but could a warped drum pull out on the shoe? it uses an inferior ( I think anyway ) spring hold down design, where there is no solid nail.. Maby a streached out hold down spring could do it?

[Dave Severson]

How are the shoes???? Did you size the shoes to the drum before you put it all together...

[Matt167]

The shoes are decent but there not new, I did not replace the shoes when I replaced the drums, so they were broke in on old shoes.. how do I size the shoes to the drums? I'v heard of doing that, but I never understood how..

[Dave Severson]

Measure the OD of the shoes, ID of the drum, see how far they have to travel to contact the drum. They do make a tool for measuring it, but just a good ruler will get you ballpark on it.

Could be the arc is off on the shoes, don't know if anyone has the machine anymore to re-arc shoes, but they were the answer to getting drum brakes to work half ways decent...

[R Pope]

Something broke or stretched or unhooked when you hit the brakes hard. Take it apart and inspect everything closely.

[Matt167]

cool thanks.. gonna measure it up... think I'm going to replace the hold down springs too. seems if there weak they could let the shoe pull outward, I didn't replace them so there a likely cause for streaching.. it's the only car I'v worked on that uses that type of hold down. there Ford Bendix drum brakes, 9"x2" same as my Falcon but it uses the more conventional type of hold down.



the more and more I think about it, the drums arc has to be off, the drums I removed were original ( 1 was bad so I replaced both because the new 1's are a little diffrent ). most likely they were machined at least once, so when I put the new drum on, it had a smaller diamater and a more promonant arc per inch.. so the shoes could have been catchy on the drums, and slammed them into energized position quick enough to really streach the hold downs and cause a problem

[Dave Severson]

Matt, they're just old drum brakes... They weren't much more then acceptable when they were built, doubt they are any better now.... If you're going to keep the thing, consider an update to discs.....

[Matt167]

Matt, they're just old drum brakes... They weren't much more then acceptable when they were built, doubt they are any better now.... If you're going to keep the thing, consider an update to discs.....

I don't know how long I'm going to keep the car but an update to discs is pretty easy and cheap, as Scarebird sells a caliper bracket and adaptors that will fit it ( even tho there made for a Javelin, they'll fit any drum brake AMC spindle )... but for now, I'll fix the small problem with the driver side drum brake, as I just put on 2 new front drums, 2 new wheel cylinders, master cylinder and rebuilt the rear wheel cylinders.

[Matt167]

Well after an in depth inspection today, altho I did not take anything apart yet.. I noticed the adjuster pawl is out of wack and the point that comes down on the adjuster is pushed right into the brake shoe and in no way can I correct it, I took it apart, put it back still the same.. the part that grips in the hole in the shoe looks a little bent, I think the problem inlies with the adjuster pawl