Hi everyone. This is a very confusing problem, but here it goes. Before replying, PLEASE read the whole posting. Thank you.

A few months ago, I was getting an intermittent card-in-bicycle spoke scraping noise whenever I was driving in the mountains (I posted a couple times on this) and the brakes were hot from driving down steep hills miles long that went away after letting it sit for a while. It would only happen in the mountains, not on the highways stopping from high speeds. Now, I am getting a faint wheel squeak/whine noise that is intemittant and I can only hear it at slow speeds. I decided to jack up the wheel and I was getting a whine when I rotated the wheel and there is some resistance. The wheel only rotates about 180-270 degrees if I give it a spin. I think it is dragging on something. I did the same to the passenger side and there was barely any noise and it would go almost a full 360 degrees when I gave it a spin. Now here are additional facts that are relevant to this:

-Both CV axles are only a couple years old

-WHEEL BEARINGS ARE 2 MONTHS OLD

-ALL RUBBER LINES, PADS, CALIPERS AND ROTORS REPLACED LAST SUMMER

-Brakes were bled several times since May 2010, the most recent a few months ago.

-Differential seal on that side was replaced in March. Fluid is always full. There is still a leak (quarter size spot on the ground every night, not that much) from near the cable housing, but I am trying to put epoxy putty around it to see if that stops it (I don't know exactly where it is leaking from) and keep it topped off.

-Both me and a mechanic checked it and cannot find any issues, but that was before it started making the faint noise all the time (I took it in for the earlier loud issue that only occurs in the mountains). Both pads on that wheel are still very thick and nowhere near the squealers.

-Stopping distance is variable depending on if the brakes are hot, the grade, speed and related factors. They don't "grab" unless they are wet or I am just starting it in the morning

-Pedal feel is normal and stops about a 1/2" above the gas pedal. Sometimes it goes down another 1/4", but never goes lower than the top of the gas pedal. Mechanics say the travel is normal.

Now is there a chance that the rotor on the left front is warped and is hitting the caliper even with the brakes released? Would having the front rotors cut/turned/resurfaced fix the problem?

Is there anything else I am missing? Could something else be contacting the rotor that was not touched? I am confident it was coming from the wheel when I rotated it. I had my ear close to there. That same wheel also squeals sometimes when I hit the brakes, but as I said, the mechanics cannot find problems with it.

I don't know if this matters, but I just had the upper right and lower left ball joints replaced and the rest were replaced a couple years ago, but it was making the noises before the repair and then it started doing the later noise just recently.

 

if it were me i would take the brakes apart on that wheel and look at the rotor to see if it has any discoloration from the heat and look at the pads to so you can verify that they arent glazed over from the extreme heat or warped. hope this gets you going in the right direction. if you do alot of heavy braking all the time, drilled and slotted rotors and ceramic pads may be a good investment. IMO.

 

Well here is the problem: The rotors themselves look fine to the naked eye. They are silver and not discolored. I can't really take the brakes apart where I am. They are Napa Premium rotors. Maybe I should ask the shop about having them turned? Could something else be touching the rotor that only happens when the brakes are hot? Something that can be bent away from the rotor?

 

Check the tin gravel shields on the front hubs. They are pretty easy to bend and if the rub even a little bit, the noise can be pretty annoying. I have seen it before on my 2wd s10 and other vehicles as well.

 

On the hubs? Are you talking about the plate that covers the back of the rotor? Could that have been caused by either the wheel bearing or ball joint repairs? How would I bend it? Is there a photo someplace on this?

 

It is definitely dragging on something. But not the backing plate for 2 reasons: 1. It isn't touching the rotor 2. It isn't a metallic sound.

When I rotate the wheel, it barely turns 90 degrees if I give it a spin and makes a rubbing whining noise when I rotate it either by hand or at crawl speed.

The brake isn't that hot when I stop the car. It is just hot enough for me to touch and not get burned and it is the same way on both front wheels. The back ones are slightly cooler.

Something is dragging, but not in the way that it would cause the brake to get so hot that it almost catches fire like last summer when I had that hose fail and cause the caliper to start smoking. That caliper was replaced 3 times in 2 days before the shop did the hose and solved the problem.

EDIT: Could sticky slider pins cause this problem? I really do hope this isn't a caliper. Could the winter we just had in NY cause slider pins to stick? If it isn't the pins, what else could it be?

 

I had a similar problem with my 2000 Blazer. When I engaged the 4WD, the problem would go away. MY HVAC was also kind of screwy and my gas mileage was bad also. My mom works at a GM dealership and I was telling one of the mechanics what my car was doing, he gave me a Transfer Case Vacuum Switch to replace. Ever since doing that, the problem has gone away, gas mileage is back up and HVAC works just fine.

I suggest this because my problem was that the front axle was partially engaged, causing the noise you described.

The part is like 20 bucks and pretty simple to replace, just my two cents and another angle to think about

 

That is an excellent theory and it is one I thought of myself, but however there are only two flaws with it: 1. The car has a Posi-Lok system, so there is no way the axle can be partially engaged. 2. It does it in 2 and 4 wheel drive. I took it into a parking lot and did an experiment. The axle also locks and unlocks (always was difficult to do, but it works) properly and the noise is there no matter what.

Is there a way to bypass the vac switch? I am also having the other problems you described with the A/C (the airflow decreases with RPMs once I get to higher RPMs) and gas mileage (10-14 in town, 18-20 highway)

If it was the switch, it would be less than $20. I found it in Autozone for around 14-16.

 

Well let me pull my foot out of my mouth Even with the Posi-Lok system, there could still be something going on in the axle, what exactly, I'm not sure, but it is possible; maybe shift fork, engagement collar, etc.

It could be the hub bearing going out. Does the noise get louder with speed? I see that the bearings were replaced recently, but it is always possible you got a defective bearing.

 

All that was replaced in November 2007. Shift fork was broken when we bought the truck and a dealership took the whole thing apart. 4WD wasn't working, it is now. I only use the 4WD for snow and I don't abuse it, so the chances of a repeat break are slim.

The truck is silent, even at high speeds. The bearings aren't making their "replace front wheel bearings soon" groan that the old ones were making or the ABS light. It doesn't get louder with speed. The dragging noise I am talking about is only audible under 5mph and after that you can't hear it over the road noise. You can also feel and hear it if the front left wheel is off the ground and rotated manually.