10" brake backing plate problem

[jims440]

 I purchased 2 1/2" brake shoes for my 10 X 2 1/2 " drums and new axles, but the 10" backing plates don't seem to won't to accept the 2 1/2" shoes.  Is there a different backing plate that I need especially for the wider 2 1/2" shoes?

Thanks,

Jim

[jamesdart]

some backing plates take 2" shoes.

[Jim_Lusk]

What did the backing plates come off of?

[jims440]

Thanks for responding.  I don't know what the backing plates came off of, but they are 10" and fit with my 10 X 2 1/2 drums.  The problem is that the top shoe mounting stud doesn't seem to be long enough for the wide 2 1/2" shoes.  When I put the shoes on, they stick out further than the stud mounting place.  Can I run 2" shoes on the 10 X 2 1/2" drums or must I try to find different backing plates?......   Any suggestins are welcome.  I never dreamed switching to larger bolt pattern and larger  brakes would be such a challenge!

Thanks,

Jim

[robgoudy]

Brakes are too important to start mix matching. 2" shoes will walk around inside 2.5" drums causing a lot of chattering ( I know) not to mention the added vibration and side load that walking shoes will put on the wheel cylinders. That's not even considering how fast the master cylinder will empty out if the shoe walks far enough to cause the wheel cylinder to unseat and explode. If you change backing plates, make sure that the wheel cylinders are correct. They like to change up cylinder bore sizes a lot....and they will look very similiar. And if the wheel cylinders are a different bores then you may have to change the proportioning valve. The best bet is to get ahold of a complete set and start from there. It should even be cheap, 10"x2.5" are very common.

[Jim_Lusk]

You don't have the correct backing plates for those drums. They need to be a matched set.

[jamesdart]

you will have to check for yourself. i had a set of 11x2" brakes, the drums were bad and they are almost imposible to find new 11x2" drums. i tried one of my drums from my 11x2.5" setup, it fit fine, those drums actually had 3" of contact surface, it all depends where the shoe rides. if the shoe contacts the drum all the way inside the drum, it should be fine, if it contacts near the edge of the drum, i dont think i would use it. measure from the axle flange face to the edge of the shoe, see how far the axle sticks out past the shoes, then measure the axle contact flange on the drum and see where the shoe will contact. how much does your axle stickout from the backing plate where they attach to the housing? i actually had 2 sets of the 11x2" drums, one from a mid 70's valiant the other from a 66 polara. they both used the same axle offset as the 2.5" brakes.

[jayrock440]

I ran into the same problem on my 72 Duster and I found that the  guy I bought the rear end from put B body backing plates on it so I had to use B body drums. It's got something to do with the backspacing.

[jims440]

Thanks to all for responding.  I have found the correct backing plates and all is well!

Jim