CUCV front end noise

[thedeliverator]

Hi all,
Been searching around for info on what might be wrong with my M1009 front end - there's a lot of noise coming from something down there. It's intermittent, but noticeable.

My mechanic swears it was the passenger's side wheel bearing - which he replaced, and that seemed to help for a few days. I'm wondering if the driver's is having the same problem (seal on the hub locker failed, letting some dirty water in).

I've raised the front end and rotated the wheels by hand - they both make a little noise when rolling, but the passenger's seems to slow much more quickly.

How do I check the wheel bearings, to see if the driver's is full of crud, and to see if the repair on the passenger's side was successful? What do I do to see if it's in the front differential? Should I prepare to open up the diff and check it, or is it more likely something in the bearings/hubs?

 

[Recovry4x4]

If its a wheel bearing it will be consistant with speed. The faster you go the higher pitch the sound is. Whether you are mechanically inclined or not, repacking front bearings is within your ability. Repack them both and be certain.

 

[steelsoldiers]

Pick up the Hayne's manual for your Blazer.

Checking the wheel bearings is pretty easy. Jack it up. Take off the wheel. Unbolt the caliper, remove, and hang with wire from inner-fender. Remove 6 allen head bolts from hub. Whack hub lightly with rubber mallet until it pops out enough to remove. Lay parts out in order on clean rag or cardboard. Take one apart at a time so you always have the other to look at if you forget where something goes. Remove snap ring from inside of hub body and remove c-clip from axle shaft end. Slide rest of hub off of axleshaft. Remove square key from axle nut using a small screw threaded in to key and pliers to pull out. Back off nut using hub socket or large screwdriver. Once axle nut is off, the hub/rotor will slide right off of the spindle. Check the inner and outer bearings/races for rust, pitting, blueing, galling, etc... Replace parts as needed. Pack bearings with a high-quality water-proof high-temp grease and re-assemble.

Setting the bearing preload with the axle nut is something you just kinda get the feel for. After having my M1009 for 10 years I could tear down a hub, pack bearings, and re-assemble in about 30 minutes.

I always tightened my axle nut until resistance was felt when turning the hub and then backed it off just a touch. You want the hub to spin freely, but you want enough pre-load so that there is no side-to-side play. I always did it like that and never had a hub fail. I usually repacked everything several times a year, especially after playing in the water and muck.

Differential? You shouldn't get any noise out of it unless one of the hubs is engaged or the transfercase is engaged. Do either of the hubs get hot?

 

[thedeliverator]

Thanks for the suggestions!

Both of the hubs do get hot to the touch after ~20 miles of driving. I'll be taking it all apart tomorrow.