Likes: 
Thanks: 
Stallion Front Caliper rebuild 101
Hello to all. Well my wife's front calipers need rebuilding. Noisy and they were dragging to the point it was hard to spin the tire while jacked up.
Removing the calipers is straight forward. You remove the front hemi joint that holds the caliper mounting plate from rotating. Remove the brake line from caliper. Then remove the 2 caliper mounting bolts. The caliper will swing down to the bottom and is easily removed leaving the pads in place. You might have to pry the pucks in a little to get it loose.
Take the calipers to your work area. You will need compressed air to blow the pucks out of the caliper housings. Mine were really stuck but they finally came out.
I took the parts to my buddy at NAPA and he advised that hardly anyone sold the parts for calipers any more just the rebuild kits. Now without knowing an application for the calipers you are kind of out of luck. The calipers I hear from TBMS were custom built.
So now the research started. There are 2 O-rings for each piston. The inner is to keep the fluid in and the outer to keep dirt out.
So I took my trusty micrometer and measured the piston diameter and the o-rings cross section.
The inner seal is a square o ring with a cross section of 1/8 and an inner diameter of 1 1/8. This is o-ring size 216. The outer is a regular o-ring 1/16 cross section and same inner diameter of 1 1/8. This is o-ring size 024.
So went on line to see about finding replacements. First thing I discovered is there are a lot of different rubbers used to make O-Rings. There is ONLY ONE recommended rubber for brake fluid (EPDM).
Next issue was they have phased out square o-rings. There are replaced with what they call Quad or X o-rings. Could not find any in the rubber (EPDM) and size needed.
After many more hours of research I found that a regular O ring of the right material (EPDM) should work. The only reason they use the Square o-ring is to help with the piston pull back when the brake pedal is released.
So I ordered the EPDM rings on line and re-built the calipers and they work great. By the way I had to order 4 sets of o-rings to meet a minimum order. So if anyone wants a set of o-rings you need 4 of each size I will sell you a set for $3.00 plus shipping priority mail envelope I think that's like 5 or 6 dollars not sure that's about what I paid for them. I am a moderator so you can "PM" me.
Originally Posted by Dragon
to Trike Talk and your first post