Hi guys,

I posted before about a vibration in my '01 Blazer 4x4.

I've had two new problems in the last 1500 miles or so (1 week :-P).

(1) I have a "hum" when my wheel is straight. The hum is at all speeds, but it's kind of a periodic hum -- sounds like it could be in sync with tire rotation or something -- and the period of the hum is shorter as you increase speed.

When my wheel is turned to the right, the "hum" goes away. (To the left, hum still present.)

I think I can hear it louder on the driver's side (but I could be insane), and I definitely feel a floor vibration more in the driver's side.

(2) My ABS & Parking brake lights are on. I mention this only in case it could be related to (1). I've searched the forum and have come up with a variety of causes for this, and the only one that seems plausibly related to (1) would be if my wheel bearings were going. I have not yet scanned the ABS codes, because I'm on a road-trip, but I will soon if people think this could be causing (1).

Thanks in advance for your thoughts.

-BKW

 

From the sounds of it, it could be a bad passenger side wheel bearing given that it goes away when turning right (passenger side suspension unloads when turning right), but is still present when going straight or turning left (driver side suspension unloads when turning left).

You can test the WSS (wheel speed sensor) with a multimeter and a jack. Jack up the suspect side, locate the WSS wiring connection at the frame, disconnect it, connect your multimeter to the lead that runs to the wheel hub, set it to the mV-AC scale, and spin the tire. The value should be >250mV-AC.

Aside from that, you need to have your ABS system scanned. This isn't typically available through the free scans most autoparts stores offer though...

 

Thanks. I was hoping someone would say wheel bearing, since that connected these two symptoms (which started about the same time).

I'm far away from home (in Montana) and on a tight-ish schedule for a couple days. What are the consequences of not addressing this immediately? I'm supposed to drive up to Glacier NP and out to Seattle by the weekend. This something I *must* take care of before then?

Thanks.

-bkw

 

Nevermind.

Google is my friend.

I'll update when I have it checked out. Thanks again.

 

Went in this morning. Mechanic said it was rear pads and rotors (I knew they were low, but not this low), and the front DRIVER'S wheel bearing.

This made my head explode, but he said the front passenger bearing was quiet and the front driver's was worn. He tried to explain that you load the right side of the car when you turn right and that it's usually the opposite wheel bearing. (??) Even if that's phooey, I've read cases of the "wrong" bearing causing the problem, so I don't doubt their diagnosis.

And ABS code was a power problem to the ABS unit. I'll see if I can get the actual code when I pick the car up.

If it drives right when i pick it up, i'll be a happy camper.

Hub assembly (the higher end of the two at napa): $295.00
2 rear rotors @ 47.90: $95.80
good pads: $131.58 (could have saved $50 here by getting the lesser pads)

Total parts: 523.22

Labor
110.88 for the hub
102.35 for the rotors and pads
85.29 for ABS diagnosis (code scan + checking the fuses and power to the ABS module)
Total: 298.52

 

My wife's blazer sounds very similar to this. Did the mechanics end up fixing the problem?

 

Yep. I ended up having to replace both wheel bearings, but now it sounds as good as new.

 

Geeze both of them huh? Our problem is similar... the low vibration/hum starts about 30mph and gets to its loudest at about 40-45. If your driving over 30, and do a left turn, it gets worse. (Weight of vehicle is on right wheels) however on a right turn it goes away. (Weight on left wheels)

So I ordered a wheel hub and I'm assuming it will be the right side that needs replacing since when the vehicle is leaning to the left and the wheels on the right have minimal weight on them, stress is relieved and vibration goes away.

 

I wouldn't bet on it being the right side; in fact, I'd guess it's the left.

Don't ask me why, but every (good) mechanic I've talked to has said that it's always the opposite wheel bearing than you'd expect. One gave sort of an explanation for why, but I am drawing a blank at the moment.

In my case, my noise went away when I turned right, and my driver's side was the one that needed replacement. (We replaced the passenger side first, and the symptoms remained. The passenger side bearing was on its way out, though.)

GL and keep us posted.

 

I'm going to go for the drivers side then. If its not I'm gonna find you and look agrily in your direction. haha.