I have a 2001 F-350 4x4, apx 67,000 miles. There is a grinding noise in the left front. A metal on metal sound, it comes and goes, and is more noticeable at low speeds. I feel it more than i hear it i think. It goes away when the breaks are applied. It sounds like something is rubbing in the same place as it goes around. Both front brake rotors are within clearances according to the shop. Any other ideas? a hub maybe? Thanks

 

I would think there would be something hung up with the brake pad, or something wrong with the pad all together. I would pull those off and have a look see. Then if nothing wrong there, then pull the hub off and have a llok see at the bearings. Just beforew you do all that though, make sure the metal back flashing plate has not been mashed a little and its been rubbing on the back side of the wheel. You should be able to see signs of that on the wheel without removing it

 

OK so i am told that it is the front hub. I am also being told that i have to replace both left and right hubs. Can these be rebuilt, or do i have to buy brand new ones

 

Before you pull the hubs, take the front tire off and look on the inside of the hub just below the brake caliper. There's a space in there where gravel/rocks can lodge against the inside of the brake caliper and rub. I have had the same symptoms on my 2000 twice from small rocks being lodged in there.

The factory hubs are not serviceable/repairable.

 

I had a very similiar problem in my 2000 Excursion 4x4 LTD 7.3. Grinding metal-to-metal noise that would come and go. Mine also would go away when brakes were applied, and would return whenever I hit a bump or the freeway turtles. I found that when I manually locked the hubs the noise would never happen, so this way I kindof narrowed it down to the hubs. Hubs are pretty easy to pull put by just removing the snap spring and pulling the assembly out. You may need to coax it a little with a rubber mallet to free it all up. Once you have the hub assembly out you can disassemble it with a pair of snap ring pliers. I found that the spring in my left hub was not seated correctly and was not putting enough pressure on the ring gears to force them apart in the "free" mode. The grinding I was hearing was the ring gears rubbing together. I manipulated the spring a little so that it would seat properly, cleaned out the hub and parts with WD40 and reassembled. No problems now whatsoever.

On a side note... I would not suggest using grease inside the hub. These hubs don't seal that great and you will find alot of dirt in there. I think it you added any grease you would just end up making "gunk" that might effect the operation of the hub.