New front drums not fitting correctly

[CFrance729]

I know I started talking about this in another thread, but I cannot for the life of me figure out whats going on. Maybe its something similar I am overlooking, I don't know.

A couple months ago I started redoing all four of my drum brakes on my 73 Coupe. After waiting for parts, starting a new job, dealing with rusty (understatement) brake lines, and a couple other things not going as planned, I was finally ready to finish up and take her on her first test drive last weekend. Or so I thought.

I have the rear brakes completely finished, rear drums fit perfect. But when I went to put the front drums on, they didn't fit like they should. The old hub is in the new drums (had a shop press them out). They slide over the shoes just fine, thats not the problem. Both the new shoes and drums are 2.5", measured to be sure. I can put the hub on by itself and it fits fine, with the placement of the washer, castle nut, and the hole for the retaining pin sitting just where it should. But when I add the drum into the mix, it'll slide on with everything...but the studs aren't sticking out enough. They only come out maybe 60% of the length they should, but they aren't sitting where they were previously held in with the swedges.

So I took all of that back off, put the hub in the drum and got it to where it should be, where the studs were previously swedged in. Put the assembly back on, but then the nut won't go far enough past the hole that the retaining pin goes into.

I just don't know what else it could be. I can't find anything related online, I guess being that front drums aren't very common.

I really appreciate any help you guys can provide, thanks for your time.

 

[Don C]

Leave the hubs off and see how far you can get the drums on. Try to determine what is

 

[Don C]

Leave the hubs off and see how far you can get the drums on. Try to determine what is preventing them from going on all the way.

Look up the part numbers online to make sure they are for your application.

 

[CFrance729]

So I've been messing with this on and off now since I have started it, its been a couple months due to weather and work.

Its looking like the only possible thing it could be now is that the drums/shoes are the wrong size. They are both 2.5", which is what I need according (I believe) to the manual and to NAPA.

It's possible I could be reading the manual wrong though.

(302)

 

[rocket366]

try it with shoes off.

shoes may be adjusted out too far for assembly.

Paul

BTW tall shoe goes to the rear

 

[CFrance729]

It fits over the shoes fine, it just doesn't go far enough back. Both the drums and shoes are the same size specified in the manual though.

 

[piper62j]

If the wheel bearing races re not pressed all the way down to the shoulder inside the hub, the bearing cone will sit higher on the race and prevent the hub from seating in far enough on the spindle.. Also, I have not come across a front brake drum that was not securely pressed onto the front hub. The hub, drum and lug nuts should all be one piece. .

 

[CFrance729]

They are new drums, so I have to put the old hub in the new drum with new studs.

 

[CFrance729]

So I've done some figure outting today, as one does. With the shoes off, the spindle extends about 1 3/4" past the face of the drum. Shoes on, its about 1 1/2". Well there is the 1/4" I need. But I'm still not understanding how its not working, being that both parts are the size specified in the manual, same size as the old. Now, I have also seen that the shoes are actually about 1/16" bigger than the drums, but that should have nothing to do with my missing 1/4"?

So I at least know its not the hub/bearings I suppose.

 

[Bentworker]

Post some pictures, that might help.

 

[Don C]

The brake shoes should not be wider than the drum, but should be a little narrower. I suspect that you have 2 1/2" wide shoes but 2 1/4" drums. Earlier Mustangs had 2 1/4" shoes and drums for 302 equipped Mustangs.

Remove the shoes and then see if the drum goes on all of the way. Also, when you have the drums on, the flange should slightly cover the edge of the backing plate. If there is a gap, the shoes are keeping the drums from going on far enough.

 

[CFrance729]

With shoes:

Without:

Not sure what else I might take pictures of that would be helpful, I believe the last two show the problem pretty well.

 

[CFrance729]

The brake shoes should not be wider than the drum, but should be a little narrower. I suspect that you have 2 1/2" wide shoes but 2 1/4" drums. Earlier Mustangs had 2 1/4" shoes and drums for 302 equipped Mustangs.

Remove the shoes and then see if the drum goes on all of the way. Also, when you have the drums on, the flange should slightly cover the edge of the backing plate. If there is a gap, the shoes are keeping the drums from going on far enough.

Yep I have tested without shoes and the drums go back further without the shoes. What gets me though is the old shoes are 2 1/2" for the front and that is what the 1973 Service manual specifies. The shoes are only wider than the drums by maybe 1/8" at most, otherwise they are both 2 1/2". Could this be a manufacturing error with the drums?

 

[CFrance729]

Do the forums not auto resize pictures anymore?

 

[Don C]

Most likely whoever looked up the parts number erred and ordered the 2 1/4" drums for the front. The shoes are 1/8" wider than the drums, but should be about 1/8" narrower. There's your 1/4" difference.

 

[CFrance729]

Ahhh OK that makes sense. Never figured that 1/8" in the other direction too. Good to know these past months were most likely because the wrong drums were ordered. Wonder if NAPA will change them out still haha

 

[CFrance729]

Nobody seems to sell 2.5" front drums for the 73 though, even though its what the manual specifies. Might I have to get 2 1/4 shoes and drums?

 

[Bentworker]

Do you look at Rock Auto?  Seems like they list a few different brands of 10" front drums.  They are vague about width though.

This is the pic from Rock Auto.  

Raybestos 1634R

 

[CFrance729]

Yeah, according to other websites with the Raybestos 1634R, they are 2 1/4.