So the duel master cylinder I ordered was the wrong one, and the correct one is on back order. I was thinking of just getting a rebuild kit and fixing the old one. It is leaking at the engine side firewall. Will this work or am I just putting a brand aid on a bullet wound?

 

I would go with a new unit if I had the choice. That said if you take the old one apart and all the seal surfaces look alright then a rebuild kit should do the trick.

 

Depends. If it's just a leaking seal then a rebuild will work fine. If the metal is cracked or scored to the point a seal can't "seal" then you will be wasting moolah

 

We used to always rebuild them as long as they weren't pitted. But be sure to lightly hone it before you throw in the new seals.