Rear brake drums sizes

[dartfreak75]

I'm on rock auto getting ready to order some more brake parts I'm getting the spring kit and wheel cylinders for my rear drums they have two different sizes for drums 9 and 10 inch. Without the obvious me going outside and taking my wheels off and measuring ( it's dark and cold out there) how can I tell what size mine are did they use certain size for certain years that kinda thing? Mine is a 75 dart with large bolt pattern front disks. The rear is a 7 1/4 thanks

 

[72bluNblu]

I'm on rock auto getting ready to order some more brake parts I'm getting the spring kit and wheel cylinders for my rear drums they have two different sizes for drums 9 and 10 inch. Without the obvious me going outside and taking my wheels off and measuring ( it's dark and cold out there) how can I tell what size mine are did they use certain size for certain years that kinda thing? Mine is a 75 dart with large bolt pattern front disks. The rear is a 7 1/4 thanks

They should be 10x2.5" drums if they're the big bolt pattern

 

[dartfreak75]

Thank you very much.

 

[Alaskan_TA]

Prior owners can & have changed parts on many cars over the years.

It is better to check what you have.

 

[dartfreak75]

Prior owners can & have changed parts on many cars over the years.

It is better to check what you have.

I'm the 2nd owner the original owner was a 90yr old woman I'm pretty sure she didnt change anything lol its probably got the original shoes on it tho! The car has 77k miles and 25k of those are mine. I never did anything to the rear brakes I figure now is a good time.

 

[H22A4]

99.9% likely you have 10x2.5” drums.

 

[tonysrt]

I have a 74 Duster with a 318, 7 1/4 rear and have 10" brakes. The book lists 9" rear drums with the 6, optional 10" on the six. Depending on engine you're safest bet is to measure. Shipping is steep on the drums, so if you're wrong could be a costly mistake.

 

[Jimacuda]

no 9" large bolt A body drums.
10" only.
73 up with front disc is large bolt and 10" drums.

 

[tonysrt]

All I'm saying is that the 75 Service manual lists 9" drums with 6.

 

[72bluNblu]

All I'm saying is that the 75 Service manual lists 9" drums with 6.

If it was a SBP, 4 wheel drum car that might be possible. 4 wheel drums were still standard for a 73+ slant 6 car.

But plenty of /6 cars ended up with disk brakes on the 73+ cars, and if a 73+ car had front disks it was BBP regardless of its engine. And all the BBP cars had 10x2.5” rear drums. Doesn’t matter if the service manual says it could have come with 9” drums or not, if it’s BBP it doesn’t have 9” drums.

 

[dartfreak75]

If it was a SBP, 4 wheel drum car that might be possible. 4 wheel drums were still standard for a 73+ slant 6 car.

But plenty of /6 cars ended up with disk brakes on the 73+ cars, and if a 73+ car had front disks it was BBP regardless of its engine. And all the BBP cars had 10x2.5” rear drums. Doesn’t matter if the service manual says it could have come with 9” drums or not, if it’s BBP it doesn’t have 9” drums.

Thank you that is exactly the info I was looking for! Mine is BBP with front disks. Thanks guys