HI ,Napa online can be a problem child ,Here is a trick for the Napa to find parts for your truck .
1 - put in search box master cylinder
2 - do not put any info to what kind of vehicle your looking for click search .
3- now it will be a new page showing master cylinders now look for medium to heavy duty trucks in the menu on the left ,then the make ,and then the year .
Now you should see the master cylinder listed for your truck it should say one and a quarter inch bore same as my 48 2 ton Part Number: UP 33 $20.70 /ea rebuild kit only available
wheel cyl. front Part Number: UP 3406 31.95 /ea
kit Part Number: UP 8 $14.85 /ea
Wheel Cylinder - Rear Part Number: UP 3677 102.60 /ea
kit Part Number: UP 37 $15.75 /ea
RAYBESTOS Part # MC9220 master cyl rockauto.com $44 and change plus shipping
DORMAN Part # M9220 master cyl. rockauto.com $80.79
rockauto.com has the the wheel cyl's much cheaper
Just call me I can give you more info .865 274 3793 EST Florida .,I'm up late paul
I changed mine to a one and a quarter inch bore dual circuit master cyl. a 7" dual diaphragm booster ,great brakes but it needs a vacuum holding tank and check valve put into the system .
Hope this helps
Paul N.
