Just bought myself my first car 1991 Chevy Blazer S10..

Ontopic:
The 4-wheel drive takes some time to connect.. It seems like i have to rev it abit and drive up to 300ft. sometimes.. But when it connect, it runs perfectly.. It's the old manual shifter, not the push-button.. Any ideas?

 

So no answers for me?
Maybe it's the wrong category to ask?

 

could be the front axle vaccum actuator(cable runs from axle to actuator)which is located under the battery might have a vaccum line leak

 

I think that might be normal, i have a 91' S10 and it takes a few seconds for the 4WD to actually engage.