WJ Knuckles / Brakes on JK44?

Brent T

New member
Like the title says. If I were to source a bare JK44 front axle, either secondhand or buy new from one of the aftermarket outfits, will the WJ stuff fit? Knuckles, Hubs, Rotors, etc.?
 

bajabronco

NAXJA Member
NAXJA Member
I know that both ball joints are the same between a JK and a WJ and the steering knuckles will bolt up. You still need to run a knuckle spacer, just like you would if you did it on a XJ. The outer axle spline count is different on the JK 44 vs. the WJ, so you would use the JK unit bearing. WJ knuckles and a 1/4" knuckle spacer, WJ brakes, WJ caliper and bracket, WJ rotor.
 

XJEEPER

NAXJA Member # 13
NAXJA Member
^^^^^This.
The JK comes with larger brakes and a dual arm Passenger knuckle. In general comparison, the JK knuckles/steering offer the same benefits as the WJ knuckles/steering. If you source a bare JK housing, then just add on the JK outer components to complete the axle.
 

bajabronco

NAXJA Member
NAXJA Member
Here is a thread over on Pirate that talks about it. https://www.pirate4x4.com/forum/general-4x4-discussion/2246754-jk-dana-44-wj-brakes.html . There is a slight advantage to using the WJ brakes over the JK brakes, since they are slightly bigger, but as others have said, it is probably easier to just get a whole JK setup, knuckles and all.

JK front caliper piston 2.6" (66mm) dia. or 5.31 in^2 (area)
WJ front caliper piston 1.889" (48mm) dia. or 2.805 in^2 (area) times two = 5.61 in^2 (area)

JK front rotor 302mm dia.
WJ front rotor 305mm dia.

JK front rotor swept area 220.6 in^2
WJ front rotor swept area 255 in^2


JK master cylinder bore diameter 1.0"
WJ master cylinder bore diameter 1.0"

So the magic is in the 15% larger swept area of the front rotors and a slight hydraulic leverage ratio increase. The WJ must have a taller brake pad that covers a wider section of the rotor radius since the diameters are almost identical.
 

Brent T

New member
^^^^^This.
The JK comes with larger brakes and a dual arm Passenger knuckle. In general comparison, the JK knuckles/steering offer the same benefits as the WJ knuckles/steering. If you source a bare JK housing, then just add on the JK outer components to complete the axle.
Main reason I'm asking is I already have all the WJ stuff. So I figured if I bought a bare JK front axle, I could use what I have. Maybe I'd be ahead to just sell what I have and go with all JK stuff . . .
 
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