I wanted to do the mod but cant find anything in the size that was listed.Does anyone have any ideas on doing this as to what all will work and size? I live in california and cant find no 7/16 copper anywhere tehy all tell me there isnt any that size.Please help.

i used 10mm compression fittings/olives. as u are in the US they are probably available, but listed with an imperial size, something around 3/8" perhaps?

thanks i finally found some copper tubing that was 3/8 and that worked great.

Just broke my first diff cup this weekend doing WOT donuts on sandy dirt at the local park. I have a pack of 3/8" compression fittings and will be doing the diff cup mod immediately. Seems the diff cup came completely out of the diff housing. Is this normal when they break? Anything I should look for when installing the new diff cup?

Has anyone done this mod with 3/8" compression fittings? They are really hard to slide onto the diff cup and appear to be the exact same size.

ive done it with 10mm fittings, i would expect the 3/8 to be the same size to be honest, as their dimensions arent particularly critical in their intended use. have u tried to get the fittings on from both ends of the cup? mine wouldnt go on from the open end, but fit snugly when pushed on from the other end, i also scuffed both the inside of the fittings, and the outside of the cup with sand paper and then ca glued them on. perhaps they need a little "encouragement" to go on..?

I think a little encouragement may be in order. The 3/8" is right between a 9 and 10 mm. The next sized up for me is 7/16" which is just a little bit larger than 11mm. I will try sanding it tonight.

Stick the cup in a drill so you can spin it, then hold some sandpaper against it, do this till it fits, if its taking to long then use a file, but dont go too far!!

I was able to do this mod with the 3/8" compression fittings, but the dogbone end of the swing shaft that fits into the diff cup binds up. The 3/8" compression fitting is too snug around the tip of the swing shaft to allow it to move freely in the diff cup. This creates a jerky movement as the swing shaft struggles to move in the diff cup. The 3/8" compression fitting is getting pretty thin where I have been sanding it to fit the diff cup and I do not want to remove any more metal. I am going to step up to the 7/16" compression fitting and use the aluminum foil wrap. The ends of the swing shaft easily fit inside the 7/16" fitting and should not bind when I am finished.

Also, the trick with the drill works great and saves a lot of time.

I finally did the diff cup mod on the front diff cups. I ended up using 3/8" compression sleeves and you have to take quite a lot of material from the inside of the fitting but they do fit. Do you guys do the rear diff cups also? I was not sure if they were as prone to breaking as the front.

All i have ever broken was the rear diff cups by the diff it'self, never had a problem in the front or by the wheels. But i just traded my CEN away :-(

Just in case anyone has any doubts whether or not the diff cup mod works, let me show you it does. I just hit a curb hard enough to do all the damage you see below and the diff cup did not break. It actually pulled out of the differential and flew about 8 feet away from the car. Take a look at the damage and you will see what happened. The bottom suspension arm came out of the wheel hub, the shock came loose, the tie rod popped loose and the cv shaft pulled the diff cup clean out of the differential. I was able to put everything back together with the same parts, but will take it easier till my replacements arrive.