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Drum sizes

AIDANMELAD

NAXJA Forum User
Location
NYC
Hi guys, my 2001 XJ Limited,had some rotted brake lines. Replaced them, then found out the wheel cylinder's are shit. My Jeep is upstate, I'm in the City, How can I tell what size drums my Jeep has...TIA!
 
Every XJ I have worked on had 9" drums but Rock Auto shows a 10" drum, used in police cars.
Measure the outside diameter of the drum. If it is almost 11", it's a 9" drum. if it measures 12-1/2" in diameter, it's a 10" drum.
Specs taken from Rock Auto's site.
 
Chances are it is a 9" drum.
Ways to tell.
9" drums are not finned. 10" are.
To further confirm.
The wheel cylinders.
With a 9" set up the wheel cylinders for each side are the same. The brake line goes straight in.
With a 10" set up the wheel cylinders are different for right and left. The brake line comes in at an angle to each.
 
9" drums are smooth, 10" drums are finned.

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9" drums have 2-1/2" wide shoes, 10" shoes are 1-3/4" wide.
Good to know that 10" drums have fins.
 
I had the "big" (10 x 2-1/2") brake package on my D44.
FH000024_zpsr2unwojy.jpg
 
I think the Dana's had the 10" diameter drums and narrow/er shoes while the 8.25 have 9" drums and the wide shoes.

https://www.naxja.org/forum/showthread.php?t=1053079

I just went back in the archives. I remember this being discussed years ago.

1. If my 2000 XJ limited has the 9" drums, can they be replaced by the 10" drums?
2. Is it worth the swap? Has anyone done it? Would you do it again?

I just picked up an 8.25 off craigslist for $100 and I need to go through the drums. Wondering if an upgrade is worth doing. I've read mixed reviews about rear discs. Sorry, I didn't mean to hijack the thread. Just providing background as to why I am asking about the drum swap.

TYIA
 
answer is to measure the inside diameter of the existing drum, or if you don't have those to measure the diameter of the backing plate

almost all XJs had 9" so it is the safe default assumption. you will know right away if its not right
 
.... 9" drums, can they be replaced by the 10" drums?

Most likely, yes.

IMO, if you are going to change anything, go with disk brakes. KJ Liberty disk brakes are about as close to bolt on as you can get.
 
Most likely, yes.

IMO, if you are going to change anything, go with disk brakes. KJ Liberty disk brakes are about as close to bolt on as you can get.

Amen to that, if you change drums you have to change the backing plates and wheel cylinders also.
 
Most likely, yes.

IMO, if you are going to change anything, go with disk brakes. KJ Liberty disk brakes are about as close to bolt on as you can get.

I am totally with these guys'. If you are ion through all that work, go with disks.

I do not know wat you heard but,... I did not set any breaking improvement going from a good working drum brakes to discs. However, other benefits include maintenance free over the years and better break pedal feel which adds to the comfort feeling when a panic break application is needed.
 
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