TR2/3/3A 56 TR3 Rear Drums Not Fitting

[mgedit]

The rear drums on my car do not fit the axles. I could likely force one on but the other is not fitting. The issue is that that hole in the drum is smaller than than the flange on the axle (see pic). When I took this apart the rear drum were very hard to get off and one was cracked (they were both sticking on the flange). The edge of the flange was damaged a bit (likely when the drums were last forced on) and I've carefully cleaned that up with a file and some emery paper, but the hole is still about 15-20 thou smaller than the flange as best I can tell. My first impulse was to grind gently on the drum with my small air-driven angle grinder. But, now I wonder if I should take the drums in somewhere and have to hole enlarged a bit. I'm thinking that the "roundness" of the hole in the drum is not critical and careful grinding should work. Advice and suggestions welcome. Cheers, Mike

 

[sp53]

Are you sure it is hitting there? I have found with the 10inch drums that new brake shoe material is too thick. Try fitting the drum without the shoes on, but if it hits just a little on the drum I would grind it out a little.
Steve

 

[mgedit]

Hi Steve. Thanks for the note. My micrometer says the hole is too small and given the earlier removal problems I think clearance is the issue. However, I'll try removing the shoes to double check before grinding. Cheers, Mike

 

[TR3driver]

A little careful work with your grinder should be fine, IMO. You're not taking off very much, so the hole should still be reasonably concentric to the braking surface, even if it doesn't come out perfectly round. And I believe the studs and bolts are mostly what hold the drum concentric anyway.

 

[TR4nut]

Hi Steve. Thanks for the note. My micrometer says the hole is too small and given the earlier removal problems I think clearance is the issue. However, I'll try removing the shoes to double check before grinding. Cheers, Mike

I think if you just flip the drum you can check clearance, no need to take the shoes off.

 

[Twosheds]

I think if you just flip the drum you can check clearance, no need to take the shoes off.

I was going to post that, but at second glance, it looks like the shoes might hit the outside edge of the drum before it's seated on the flange.

 

[TR4nut]

I think if you just flip the drum you can check clearance, no need to take the shoes off.

I was going to post that, but at second glance, it looks like the shoes might hit the outside edge of the drum before it's seated on the flange.

Yep, nevermind!

edit: just thought about that, but how can that be? The shoes need to end before there is interference with the drum, otherwise it definitely wouldn't seat on the flange, would it?

 

[Twosheds]

edit: just thought about that, but how can that be? The shoes need to end before there is interference with the drum, otherwise it definitely wouldn't seat on the flange, would it?

You're right!

Optical illusion? Old eyes?

 

[TR3driver]

You're assuming that the face of the drum is flat. I don't know about the Lockheed drums used on early TR3, but the Lockheed drums used on Stags have a 'dish' to them so the edge of the shoes is actually out farther than the face of the hub. Turn them around, and the drum hits the shoes before it reaches the hub.

Just a WAG, but I'm guessing that was so they could use wider shoes for the heavier, more powerful car; without having to redo the hubs and/or trailing arms.

 

[mgedit]

First thing I tried was to flip the drum and see if it cleared the hub. Outer edge of drum does hit the shoes first. That's when I resorted to measuring. Thanks for the input. Cheers, Mike