You need to work out which accessory or pulley is stuck, and remedy that issue. This should be very easy to check with the belt removed. Once everything is able to turn freely, replace the serpentine belt.
Just because a used water pump was installed doesn't mean that's where the problem is.

 

Mine is an 02 at 189200 miles....when I took it on the interstate a week after I got it, it had a hum to it over 70-75mph. That was a month ago. Since then, I can reach 70 and no extra hum. I have been noticing, though, in the mornings, my brakes seem like I have to go a little closer to the floor for braking. After I've driven a while or it 'warms up', its normal braking. However, in stop and go traffic, I can hear a little 'clunk' or 'thunk' when I brake without slowing down, that seems to come from the rear....any thoughts? Also, on expressway yesterday, reaching speed a little above 70, trying to pass a semi, I felt a lot of swaying and slowed because I thought it would flip.... Hmmmmmm

 

Also, I don't have a record of last tuneup or spark plug/wire change but I'm due an oil change....is the service engine soon light the same as a check engine light? Service engine soon illuminates on my dash after interstate driving and isn't present once truck has sat overnight....hmmm?!?!

 

So, you have two Discos. Both with issues?

You might want to take stock of where you are at with them, plan high mileage services on them both. Get a code scanner so you can check what the Check Engine Light is telling you. Start searching and reading up on what the issues are.

Seems like you are asking a lot of questions about some fundamental stuff. Those two cars of yours are going to have to be looked after... by you. With the help here, sure.

If you plan on keeping them both, get a list of servicing things together. follow the thread at the top of this page about High Mileage Service. Start reading and ordering bits.

Cant own one disco without getting dirty and knowing what is what. Two, would be insane/expensive.

 

So. The service engine soon light IS the 'check engine light'? And all I ever get as a printout is something regarding my o2 sensors which in VA and in this here 'valley' of Roanoke is allegedly common...

 

Mind you, the first rover was bought 3 yrs ago and the owner has NOT appreciated it! Has taken it for granted. Me being in nursing and having to go whether rain sleet or snow was impressed by how it goes and handles in snow....that was how I was won over. I am eager to Lear ANYTHING and knew that getting one meant work. However, I'm willing to do several repairs myself, or be taught how to. The RAVE manual I find to be quite complicated. So far, I've done simple stuff ...expansion tank, rewired radio, brake light switch, going for spark plugs and wires next