Technical Ford 9" Brake Drum FIt Problems

I've rebuilt a set of 10 x 2 1/2" rear brakes on a FOrd 9" for the deuce. New shoes, cylinders, everything looks correct. I go to put on the brand new Raybestos drums and they're too tight to go on. I've backed off the adjusters to the minimum- still no go. Looks like the new drums are @ .125 " smaller diameter than the worn originals. ANy suggestions for this mopar guy workin on a Ford on how to find clearance so I can use these new $$$ drums? thanks

 

Take the old drum to the parts store have it match up to one

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You may have to do that. I'd at least take them to a shop that had a brake gau(inside mike for brake drums) and measure the id of the drums to make sure that they were actually 10.5 inches id and not noticeably smaller.


A few things first though:

Are the adjusters turned all the way in? I've gone out and looked at more than one set of brakes a guy was having trouble getting back together and he didn't back the adjusters off when he put the new shoes on.

Also are the notches on the ends of the adjusters setting down over the shoes right? Sometimes that brown stuff (usually brown) that they put on brake shoes when they reline them gets so thick right where the adjuster slips over the shoe it won't slide down all the way. that works for the top where the pins that the wheel cylinders push the shoes out with slip over the shoes too.

Are the shoes centered on the backing plates? Sometimes they get cocked off to one side a bit and the drum won't go on.

are there grooves worn in the pads on the backing plates that the shoes ride on. There are several little raised pads on each backing plate for the shoes to ride against and they can become worn to the point where the new shoes with sharp edges on the sides catch on the grooves. You can buff them smooth with a flap wheel on an angle grinder or with a grinding disk and put a little bit of lube on them .

Are the springs all on correctly so that they pull the shoes in correctly?

Those are just some things I have run into on brake jobs that I did or found on brakes I ended up straightening out for someone doing their own brakes.

 

Thx for the pointers. I'll be heading out to the shop to go these tips after supper.

 

More than once I've had to manually push a wheel cylinder in (retract the pistons) after installing new shoes.

 

I had one pair that drove me bonkers.
The slide pads on the backing plate were worn down so bad that the shoes were cocked as if bent down the center .The square drum wouldn't slide over the cocked shoes because the drum was seeing the edges and they were spread out.

5 mins with the welder and 5 mins with a roll rock fixed the problem.

 

Might sound silly but the Emergency brake cable needs to be slack.

 

Not silly..good point..

 

Very good point. The equalizer bar between the shoes should have a little clearance between the shoes when everything is installed.

 

Just a long shot, but check the drums for roundness.I did brake and front end work for many years and every once in a while I would find a drum that would not fit and it was due to some gorilla dropping the drum on it's edge somewhere form manufacturer to parts house. More than once I have had to "clean up" a new drum on a brake lathe before installing it.

 

Yep, good point there too. And some times they don't get put on right and hold the shoes off a bit.

 

I had that happen and the shoes I purchased were oversized so make sure they are standard.

 

Any OTC shoes these days will be pre-arced to fit any drum within wear limits.

I'd suspect a shoe hanging up as described in some of the replies above. And it doesn't hurt to get the drum measured up.

Bob