I put in a new walker exhaust system in my car but am getting leaks at the joints of the muffler and exhaust spout, as well as the rear cat converter (comes in 2 pieces). I was given exhaust clamps (U-bolts) in the kit, but they aren't doing a good job keeping the fuel off the the ground... any suggestions for dealing with this issue? And how tight should the clamps be?

but they aren't doing a good job keeping the fuel off the the ground...

 

You aren't supposed to have fuel in the exhaust system at all.  Something else is very wrong and you need to find out why fuel is there in the first place.  I suggest not running the vehicle until that is resolved.

Sorry I think it might just be water. Looked a bit yellowish but it doesn't smell stongly of fuel. I'm still concerned as to why it's leaking where the u bolts are.

Also, should I be worried that my new system smells much more heavily of gasoline than my old one. I rechecked the liquid and it is indeed water.

I was given exhaust clamps (U-bolts) in the kit,

 

I would contact the supplier of the kit and ask how to resolve the joint problem.  Make sure you got all the right parts and get information about how tight to torque down the connections without crushing the pipe.

 

The crude way would be to just tighten them down until things start to crinkle, then you know it's time to stop.  I don't recommend that approach.