Humming noise and brake question
 

Hey all,

So after finding out the trans was good, the heater core is bad, I've had this issue where when i start up the jimmy, i get this loud annoying humming sound which goes away after about 10 seconds, and then will come back while driving for a second or two before going away again. Now i'm thinking at this point it may be the Vacuum brake booster that sits on the drivers side firewall? Its really annoying.

Then another issue ive been having is that my rear brakes sound like their in pieces. There is a ton of grinding when i hit the brakes, and then when going from 5mph to 0 it feels like someone is stopping the car with a lug-nut wrench, it just kinda jerks to a stop. Are rear brakes on these things that ****ty that i need to replace them already? Thanks!

:icon_nic: just wanted to use this.. :D

What do you mean replace them already? Have you looked at them?

Try narrowing down the source of the humming noise. It could be coming from a few places. Notice whether it only makes the noise upon cold starts or whenever it's already heated up etc. Try turning all nonessential systems off as it could something as unexpected as bad bearings in your A/C compressor and keep us posted.

As for the brakes, it sounds suspiciously like you need a new set of pads... and possibly rotors as they don't wear well when pitted against steel rivets.
Since there is significant cogging action in the brakes, I suspect that you have run out (out of round) that may be compounded by adjusters that leave something to be desired. I strongly suggest that you mic the rotors when you have them off and make sure that the caliper adjuster pins are clean and well lubed. It wouldn't be a bad idea to make sure that the pistons are operating smoothly while you're at it.
Good luck as you dive into this project.