9" or 10" drums?

[User Name missing]

Went to autozone to pick up parts to do complete rear drums. Got thru the make, model and engine size, then the guy asked me if the drums(?) where 9" or 10".............I have no freakn clue!? Didnt know there was different sizes! So anyhow, '96 ranger, 2.3, std cab long bed, what size do I need or is there an easier way to find out besides removing the wheel?

 

[jrboatin]

From what I was told years ago is that if you measure the backing plate that will tell you what size they are..... plate being 9 or 10 inches Dia...

 

[09ajmaros]

I thought it was the outside of the drum is where you measure, but yea I had no idea that there were different sizes.

 

[Nhaz]

I could be off base but I think the 4x4 has the 10 and the 2wd has the 9.

I measured my back plate when I didn't know and it was slightly more then 10. I bought 10's and they fit.

 

[User Name missing]

^^^if that was the case, then wouldnt the auto store computer be smart enough to know the difference since 2wd was put in the options? was hoping to not have to take the tires off until I do the brakes..........

 

[Jason]

I think it's based on your rear axle size. Or course, it's easier for most consumers to measure the drum than ID an axle.

 

[Roadkill]

I think it is a 4x4 thing. My B3000 had a 7.5" rear axle with 10" drums. Where Red85's 2.3 (both '94 year) has 9" and is a 4x2 with a 7.5" rear axle.

Some Sport or special models may have upgraded drums and still be a 4x2 though.

 

[04 EDGE]

simple, take the drum off and measure the inside diameter.

my guess is you have 9" brakes

 

[Toms01PSD]

It has to do with towing package...etc. Take the drum off, and measure the inside diameter across. it may be slightly larger as they will be worn.

 

[User Name missing]

actually I called the last place I had it serviced and brakes checked out. 9"

 

[Toms01PSD]

Did they replace the drums for you? If not, then how would they know?

 

[np24]

If they are the correct drums on the truck, 9" is a finned drum, 10" is a plain drum (not finned).
However, the aerostars use a finned 10" drum which some of the guys like to swap on because they run cooler.

 

[cocoasranger]

Did they replace the drums for you? If not, then how would they know?[/QUOTE

When rear brakes are checked, it's standard procedure to measure the inside diameter of the drums and compare it with the figure cast into the drum. The difference is how worn the drum is (and/or how much it was turned). There is a max. limit for this which if exceeded makes the drum unusable.

Many shops keep a record of these figures, especially in areas which have state inspection programs.

 

[Toms01PSD]

Did they replace the drums for you? If not, then how would they know?[/QUOTE

When rear brakes are checked, it's standard procedure to measure the inside diameter of the drums and compare it with the figure cast into the drum. The difference is how worn the drum is (and/or how much it was turned). There is a max. limit for this which if exceeded makes the drum unusable.

Many shops keep a record of these figures, especially in areas which have state inspection programs.

Ya I understand they have a max diameter on them. I had to replace mine last year because they had rust holes through them. The previous owner was not truck-friendly.

Edit: I also understand that you check them, so that you know whether you can turn the drums or not.