Rear Drum/Axel Question

[Cole]

Need some tech help. When I tighten the lug nuts on both drums the drum freezes up and wont rotate. I think I may have gotten the wrong drums but they fit great and go on with ease until I tighten. I can inset some washers on top of the studs then install the brake drum and the problem goes away. I took some measurements and marked up the photo. Total width of the drum is 3.71" thats from outside where lug nut goes to top of the lip on the inside. It seems like the .47" lip on the drum is hitting the back plate.

Any ideas?

 

[72HCODE]

got your PM.

i didn't have any metal gasket on mine.

I'm trying to remember it was axle flange, cork, then the brake backing plate.

they made 3 different widths of brake shoes for the rear and also 3 different drum widths.

there was 1.5" and 1.75" and 2" inch if i remember. then there was a 2.5" conversion i remember i saw as well.

sometimes people got them confused with the front drum shoes. the front was 2.25" and 2.5"

i can't imagine a thin metal gasket causing the binding. i'm thinking maybe incorrect drum cover to shoe width?

i would have to pull out my shop manual and take another look.

was going through my order records,, i used 10"x2" drums with 10X2 shoes.

on my rear.

there was a note that some cars used 1-3/4 due to a different type of brake backing plate.

 

[shgrrttn]

Need some tech help. When I tighten the lug nuts on both drums the drum freezes up and wont rotate. I think I may have gotten the wrong drums but they fit great and go on with ease until I tighten. I can inset some washers on top of the studs then install the brake drum and the problem goes away. I took some measurements and marked up the photo. Total width of the drum is 3.71" thats from outside where lug nut goes to top of the lip on the inside. It seems like the .47" lip on the drum is hitting the back plate.

Any ideas?

The drums and backing plates are specific to the width of shoes you are running. What do you have on the front? Disc or drum?

 

[Cole]

I have disk on the front Ritchie.

I slapped a little axle grease on the lip of the drum and froze it up. No transfer so that wasnt it. Put some on the edge of the shoes and did the same. Found some grease on the inside lip of the drum. Just had my guy shave that lip off so now the surface goes all the way to the back wall.

I'll let yall know if that works. Think its just aftermarket chinese stuff that caused the trouble. I don't think that back lip should have been there.

Here's a pic of the metal flange when she came out 72H. I'll post a pic of the new ones I got from NPD after I try the new drum later tonight.

 

[Cole]

No, nada, negative, nope.....

Still binds up. I'm convinced its the drum. Didn't feel as heavy as the originally ones that came off. If the steel where the holes are drilled was 1/16 of inch thicker it would spin free and clear. Got the cheapest ones from Parts Geek. At least its not a costly mistake. I'll put a washer on each stud and roll it around that way. Too many other issues. Already junked the old drums or I'd be out there with that digital caliber thingy proving it.

72H I'm gonna start my front suspension rebuild pretty soon. Saw the pics of your rebuild. Nice work! May hit ya up with a PM or two on that if you don't mind.

Again thanks yall.

 

[72HCODE]

Oh the metal flange holds the axle to the housing, I thought it was some extra gasket or something. You have it correct.

I'm thinking the drum is hitting the brake backing plate and binding up.

If you tighten the lug nuts slow maybe you can hear the drum binding and figure out what is hitting.

Sure hit me up if I can remember it has been over 6 years now time flies heehee

No, nada, negative, nope.....

Still binds up. I'm convinced its the drum. Didn't feel as heavy as the originally ones that came off. If the steel where the holes are drilled was 1/16 of inch thicker it would spin free and clear. Got the cheapest ones from Parts Geek. At least its not a costly mistake. I'll put a washer on each stud and roll it around that way. Too many other issues. Already junked the old drums or I'd be out there with that digital caliber thingy proving it.

72H I'm gonna start my front suspension rebuild pretty soon. Saw the pics of your rebuild. Nice work! May hit ya up with a PM or two on that if you don't mind.

Again thanks yall.

 

[Don65Stang]

Mark, I'm learning a lot from every one of your post so if you don't mind ask the Q's in the forum instead of PMs. The more I read posts from Dan and other exerts, the more I see how much mechanical stuff I don't know.

Keep up the good work on the build. You're doing great.

 

[Cole]

There's the problem. With a brake surface of 2.11" I obviously got drums for a 1 3/4" shoe.

Give em away if anyone can use them.

 

[Jeff73Mach1]

why not just buy some 1 3/4 shoes? Unless you are driving like an ******, even smaller rear brakes will be all you need. The rear of the car at the axle is about 1400 pounds or the same as a Honda Accord

 

[72HCODE]

just remember its more then the drum, the backing plate had 2 different offsets i forgot there was a bendics style plate and then something else that was deeper.

somebody once told me that the wider rear shoes was a 1972 addition, the 71 was suppose to use a narrower rear shoe and for 72s they beefed up the rears to a wider set so the braking was a little more powerful.

i don't know if that is actually true I've heard it more then once from different people that it was a another difference between 71 and 72 but everybody has fuzzy memories on stuff like that and you have no idea what was replaced on the car unless your an original owner.

for me i remember i took the measurements off my 72 original parts and then reordered new parts with the same dimensions.

i did keep the original parts for a long time to make sure. that is why people always tell you never throw anything out first always later when it is replaced.

thing is i would just make sure it isn't a problem with the machining on the drum, you don't want to waste money on shoes again only to find out it is still binding. it is possible the drum cover is incorrect for the application.

oh i forgot another thing was 71 used a rear wheel cylinder with a smaller bore. and 72-73 was a slightly wider bore for the wheel cylinder.

i didn't know that either when i ordered parts and i actaully put the smaller wheel cylinders on and later i went and got the wider ones but i never installed them. So far i haven't had any issues. knock on wood.