i have a 91 toyota 4runner and it needs a bottom half rebuild can someone give me advice as how to do it the crank is welded to the bottom belt pulley's so i need a new crank. can someone tell me how to replace it.

 

You need a puller... a crank puller.

 

You'll need to do a lot of searching in regards to this job... for it sounds like it's going to be a big one.

This link will help:
http://personal.utulsa.edu/~nathan-buchanan/93fsm/

Look under your motor for tear down procedures.

 

Search for "3.4 swap"

You're gonna have to pull the motor, may as well put something worth half a damn back in...

 

I've actually gotta go with TC on this one.

 

I'm rebuilding mine right now, with help from the FSM, other posts here, and.... ehhhh. that's about it. Learning as I go. I have my engine out now and will be taking the heads off shortly.