Help! SBP to BBP and need help finding BBP Drums

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Wicked72ride

Wicked72ride

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I am converting from the small bolt pattern to the large bolt pattern (5 on 4.5) and am now stuck on finding the drums for the rear. Does anyone know where I can get a 5 on 4.5 drum which is 10" by 2" deep?

Thanks in advance

Jason
 
Wicked72ride said:
I am converting from the small bolt pattern to the large bolt pattern (5 on 4.5) and am now stuck on finding the drums for the rear. Does anyone know where I can get a 5 on 4.5 drum which is 10" by 2" deep?

Thanks in advance

Jason
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try rockauto

http://www.rockauto.com/catalog/raframecatalog.php

part number pdr0182 I think you will need to confirm this.
or bd60140

Are you sure it isn't 10 x 2.5"
 
You may need to swap out your backing plate and go to 2.5 rears.

I am not sure what you are asking exists, but I am not a brake expert.
 
Ahhhh, the fun in mixing and matching parts….

Later cars had wider drake drums, I believe 2 ½ “. You may have to swap later rear backing plate and shoes on to your axel. Or, and I’m not sure if this will work, have your existing rear drums re-drilled to larger bolt pattern by a machine shop.
 
drill them ..i went to 4.5 bolt and moser axles and drilled my old drums on my duster years ago..mike
 
The only ones that are narrower than the 10 X 2 1/2" common stuff is the 10 X 1 3/4" brakes that came on the '66-70 B-body 6 cylinder cars. Good luck finding them! Do yourself a favor and swap over to the 10 X 2 1/2" brakes.
 
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Those drums are the small bolt pattern 70 - 72 Bell drums. They are 10 X 1.75 Inch and there isn't a known replacement for bbp other than listed above. The ones above have been long obsolete.

Now tell us what you have done to go to bbp.
 
Oklacarcollecto said:
Those drums are the small bolt pattern 70 - 72 Bell drums. They are 10 X 1.75 Inch and there isn't a known replacement for bbp other than listed above. The ones above have been long obsolete.

Now tell us what you have done to go to bbp.
Click to expand...

I ordered some yukon axels from Randys ring and pinion and made the quick and easy install
 
Ditto wicked72ride's question. Why would it matter if the drum were flat across instead of the bell? Seems like he would just have a slightly wider shoe area that go unused, but that shouldn't matter. I doubt the bell is needed to clear the wheels.

Indeed, why couldn't he install wider shoes to match a wider drum? Seems worst case might be he has to also change the wheel cylinders if the fingers aren't in the right place for the shoes. Would the e-brake linkage be an issue with wider shoes? Sounds simple, but when you start swapping parts ...
 
Wicked72ride said:
whats the significance?
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Plenty. If the regular drum is flat and the Mopar drum is off set 3/4 of an inch the new drum will only be on 1 inch of the shoes and 3/4 will be sticking out behind the drum. A brake drum is designed with about 1/4 inch of play and any more than that the shoes are likely to shear the hardware and go everywhere.
 
BillGrissom said:
Ditto wicked72ride's question. Why would it matter if the drum were flat across instead of the bell? Seems like he would just have a slightly wider shoe area that go unused, but that shouldn't matter. I doubt the bell is needed to clear the wheels.

Indeed, why couldn't he install wider shoes to match a wider drum? Seems worst case might be he has to also change the wheel cylinders if the fingers aren't in the right place for the shoes. Would the e-brake linkage be an issue with wider shoes? Sounds simple, but when you start swapping parts ...
Click to expand...

As stated by others and myself the normal thing is to change the backing plates, all the hardware and the drums to a wider shoe such as a 2 1/2 inch.
 
Wicked72ride said:
I measured the inside diameter at a 10" and the friction area at 2", am I measuring the wrong parts?
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The width of the wear surface of a drum is a little wider than the shoes. this allows for some wiggle room so the edges of the shoes don't get hung up on the sides. Putting wider or narrower shoes on a given backing plate throws the geometry of everything out of whack. You need the shoes to sit square with the backing plate and drum. You also want the wheel cylinder push rods to push straight....not at an angle. The hardware has to be correct to provide the proper tension of the return springs on the shoes. The bell was added to the earlier A-body drum to add cooling capacity. The drums without the bell work just fine however.
 
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