We just changed the driver side rear break cylinder after it was leaking and we go to bleed the breaks and it's leaking again. Has this happened to anybody before? The passesnger side is fine and wasn't leaking before but we decided to change it anyways so the brakes wear evenly.

 

Welcome to the forum

"new" used to mean "tested and working"
"new" now means "YOU test it WE will replace it if it doesn't work"

So either the new cylinder/slave is bad, or the brake line is what was leaking not the cylinder/slave

 

I have found the definition of NEW is "Never Ever Works" especially when it comes to cheap aftermarket parts shipped in from China.

My question to the OP is what wheel cylinders did you buy?

What brand were they and where did you buy them?

Did you replace the brake shoes and machine or replace the drums?

Is it possible while installing the wheel cylinders and brakes that you could have pushed the piston out of the bore and had to re install it?

Did the box it came in look like it was previously opened?

Personally I have never ever had a rebuilt by me wheel cylinder or new wheel cylinder installed by me or anyone I know leak while bleeding it.

Did you remove the leaking wheel cylinder and inspect it?

Before I proceeded further I would want to know the cause of the leak.

This would let me know if I would just exchange the defective one for another new one or return both and buy wheel cylinders from a better name brand company.