Front-end bearings
 

Hello, I am having an issue with a loud humming type nosie comming from the front end that gets louder as the speed increases. Seems like it's comming from the one side (drivers side) Is it possible that it is the wheel bearing? If so, how hard is it to fix myself, i am very handy but not a mechanic. I do my own brakes and rotors with no issues. Would a haynes repair manual help me out?

Thanks

Does this make sense?
 

I pulled these steps of the web, do they make sense to anyone?

First, you will be replacing the whole hub assembly. The wheel bearings cannot be serviced individually, you must replace the whole hub.

1. Remove the wheel

2. Remove the brake caliper, make sure you support the caliper so it is not hanging by the brake line.

3. Remove the caliper bracket.

4. Disconnect the ABS wires.

5. Loosen your axle nut until it is almost all the way off the shaft.

6. Remove the three bolts holding the hub to the strut.

7. Pull on the hub while hitting the axle nut with a hammer until the hub loosens. (An assistant is helpful at this point).

8. Remove the axle nut and hub.

9. Replace hub by reversing the above procedures.

Yeah those are the sets you need to take. Do you know for sure its the wheel bearing? I'm not saying its not because they are a known problem with the Alero, but I would sure before I dropped $100 on one.
The thing I would do before you even put a jack under the car is get that axle nut broke loose. If you have an impact gun it will help alot. This way you have the weight of the car on the ground and the tranny isn't taking the pressure as you try and turn the nut. Don't take the nut off the axle though, not till you get the car in the air and the tire off. Take the caliper off(2 15mm slide pin bolts) and use a bunge cord or zip tie to hold it from hanging. Then the caliper bracket, not sure what size they are. Probably 17 or 18mm. Then do steps 4, 6, 7 but don't hit it with a hammer, use a rubber mallet, 8, and 9.
When putting everything back together I would grease the caliper slide pin bolts, that is one of the major reasons calipers lock up. Most people don't thing those two bolts do anything but they take all the brake pressure from that wheel.
Hope this helps.

Thanks
 

Thanks, this helps. couple of questions. To get the axle nut loose, do i attempt this while the full weight ot the car is down? ( I do have an impact gun) How tight do i have to tighten the axle nut when i am done? Also the caliper slide pins, where are they, and what type of grease should i use?

Last will a haynes manual realy help me out on this?

Thanks, for all your help

Yeah with the full weight of the car on the ground. Just pop the lug nut cover off and toosen the axle nut then jack the car up and take the tire off. I will have to look around for the torque specs on the axle nut, GM has revised the specs a few times so I'm nut sure what the right torque spec is.

The caliper slide pins are on the back side of the caliper. They hold the caliper to the caliper braket and allow the caliper to slide when the brakes are pressed. You can't miss them when you are looking at the caliper. They look like normal bolts till you pull them out. I would think any high temp grease would work, any auto parts store should have something. I use Mystik JT-6 grease. I'm sure Napa carries it. The only reason I use the JT-6 is because I have a case in the garage that I got for free. If I had to buy something I would a lithium grease that is heat and moisture resistant.

perfect
 

In your first reply, If it is not the bearing by chance, what else would it be?

Well know that I reread your first post where you said the humming gets loader the faster you go, that sounds like a wheel bearing. Does it make a gringing noise when your turing one way or the other? I was thinking it could be the strut plate bearing or maybe a broken spring but they wouldn't make that type of sound when you speed up. Does your ABS, TRAC, and Service Engine Soon lights come on?

I gave you some wrong info. The slide pins aren't 15mm, they are 12mm on the front, 15mm on the rear. I took some pics so you can see.
http://i4.photobucket.com/albums/y13...9/DSCN1343.jpg
http://i4.photobucket.com/albums/y13...9/DSCN1346.jpg
http://i4.photobucket.com/albums/y13...9/DSCN1344.jpg
http://i4.photobucket.com/albums/y13...9/DSCN1345.jpg
http://i4.photobucket.com/albums/y13...9/DSCN1347.jpg

You can get a little packet of slide pin grease (SilGlide I think is the name) at any auto parts place. One packet is supposed to be enough for both sides. It's about a dollar.

Thanks for the pics
 

Rusty, thanks for the pics, that really helps out. Were you able to find the torque specs on the axle nut? Also i dont have a large enough socket for the axle nut, by chance do you know the size???

Thanks

No, for some reason the ABS,Trac and service engine lights have not come on. I am hoping the last time i took the car to a garage to replace one of the bearings, they didnt disconnect anything. Is that possible?

I got some info for you. Give me a minute to upload the pics.

I don't know if you have bought the new bearing or not, if not make sure its either a Timken or SKF. They may cost a little more but they are worth it. Advanced Auto only carries no named Chinese ones. Dont bother with them. O'Reily's/Murray's carries SKF bearings.
The new bearing should come with a new axle nut and the revised torque specs.
http://i4.photobucket.com/albums/y13...69/axlenut.jpg
http://i4.photobucket.com/albums/y13...xlenutinfo.jpg
Also GM used two different axle nuts. One looks like a regular axle lock nut and the other is a nut with a sleeve looking thing over the nut. I'm not sure what years had which nut but the nut with the sleeve is 35mm.
http://i4.photobucket.com/albums/y13...difference.jpg
Pictures courtesy of Ryan from Ohio from aleromod.com

It is possible. The bearing can still be bad even though the lights aren't on.

Perfect, thanks again, i have not purchased the bearing yet. i will try and find a timken or skf, problem is, i am in Ontario Canada. I guess i can try Napa auto parts, that might be my best bet! I checked at our local Canadian tire store. They had 2 options for me and the premium bearing was on sale for $129.99 not sure the name brand though, they just said "premium".

Thats a huge difference from 173 ft lbs to the 248ft lbs. How long should this take to change the bearing?

I would say around 3 hours. Thats taking your time and cleaning everything up. Make sure all the threads on bolts and the threads on the axle are clean. I would also get a medium thread locker. Don't forget to get the little grease packs for the slide pins like Iflylow mentioned. If you need all the torque specs for the rest of the bolts let me know.

I picked up the hub bearing assembly and it is an SKF. i will grab some medium thread locker, is that just for the axle nut? as far as the grease packs for the slider pins, will any bearing grease thats water and heat resistant work?

what happens if i remove the old bearing and hub assembly and it seems fine, can i put it back on?
still not sure how to test it to see if it needs replacement. the only thing i know how to do it wiggle the rim back and forth to see if there is any play, other than that????
Thanks Rusty

I don't think you need the thread lock on the axle nut because it is a lock nut, its kinda oval shaped. I would use the thread lock on the caliper bracket bolts and the bolts that hold the caliper, and you don't need much, I put enough on the bolt so it goes around the bolt on two or three threads. I would clean all the bolt threads with a wire brush first though.
For the grease for the slide pins I would use the little packs of grease, they are really cheap and its made for the caliper slide pins. Not that you couldn't use another grease, but if you use the stuff that was made for the job it will probably last longer.
This is the stuff I picked up today:
http://i4.photobucket.com/albums/y13...9/DSCN1349.jpg

I would say give the wheel bearing a real good look over after you take it off. The back side has a seal that holds the grease in, if that seal looks damaged its pretty much junk. Hold the bearing from the part that sits in the steering knuckle and spin the hub part. If you feel anything other than it turning smoothly its on its way out.

I changed my front rotors and pads today and took a few pictures.
New rotors:
http://i4.photobucket.com/albums/y13...9/DSCN1348.jpg
New pads:
http://i4.photobucket.com/albums/y13...9/DSCN1350.jpg
Cleaned up bolts and caliper bracket: By the way the caliper bracket bolts are 13mm.
http://i4.photobucket.com/albums/y13...9/DSCN1351.jpg
This is where the slide pin slides in the caliper bracket. I cleaned the old grease out with brake cleaner and Q-tips.
http://i4.photobucket.com/albums/y13...9/DSCN1352.jpg
The hub with no brake hardware:
http://i4.photobucket.com/albums/y13...9/DSCN1353.jpg
Top view of the hub:
http://i4.photobucket.com/albums/y13...9/DSCN1354.jpg
I quit taking pictures because it was starting to get dark and I still had the driver side to do.

Thanks those pictures were great. So if i take off both of the hub assembly's, to test them and give them a spin. is it ok to put the ok one back on?


No lock tight on the axle nut, but what about the 3 bolts that hold the hub?? by chance, what is the torque specs on those three bolts that hold the hub? i will check the paperwork

One more thing, that stuff in a can to clean brakes called brake kleen, its a brake cleaner but how do you use it and what can and cant you spray it on?

I don't see why you couldn't put the old hub back on if you find nothing wrong with them. I would use lock tight on the three bolts that hold the hub to the steering knuckle. My book says those three bolts are 70 ft-lbs.

You can spary the brake cleaner on all of the parts pretty much. Maybe not any of the rubber seals, I have without any problem but I'm not sure if it reduces the life of them. I just spray it all over the caliper, caliper bracket, and rotor. Brake cleaner evaporates pretty quick so I don't think it will hurt anything. Just don't get it on the paint, it will eat the clear coat.

Any idea on how to get at the three bolts with a socket set? That other part of the hub assembly is in the way.

The new hub assembly, does anything have to be greased? or is it ready to go?

I'm not sure on that. You could probably turn your wheels in whatever direction you need to get better access to the bolts.
The new hub will have grease inside it already, its a sealed bearing so there is no way to grease it.
One more thing I should mention, when your taking the hub off make sure you don't pull the axle with it. That could cause the axle to seperate from the half shaft, then you get pissed off and have to fix something else.

Ok, hopefuly the Axle doesn,t seperate. All i will do is pull on the hub while i hammer the axle with a rubber mallet to loosen the hub off. Firstly i have the joy of trying to figure out what bearing is bad. Everytime i drive its like the sound chooses to switch sides on me. I will make sure i take pics while i am replacing these bearings. Thanks for all your help Rusty , you have been a great help!

Your welcome, thats what I'm here for.

I have heard of people putting the front of the car on jack stands and putting it in drive, let it idle and go listen to each of the wheels to find the bad one. I would say thats not very safe but to each their own.
Another way would be a GM dealership. The Tec 2 that they use can tell you which wheel bearing bad. The only problem with that is they charge close to $100 just to hook the damn thing up.
I think that if you pull one bearing and everthing seems fine, put it back in and go to the other side. If anything else its a learning experience and your saving yourself money.
Let me know how it goes.

Chances are pulling the bearing will ruin it and youll be stuck with an extra job and wasted money since it cant be put back together, the jacking up the front of the car and blocking the back tires sounds like it would work fine, ive never done it because i have the liberty of using a lift when i need to but it would make life easier. What ive been taught and what ive used always to check wheel bearings is get the car running around 30m/h or 50km/h and use a listening device, im pretty sure there is one meant to check car noises, i just call it a stethoscope cuz its 2 ear pieces and a long piece of metal that you put on the back of the hub assembly with the tire spinning and you can tell plain as day which bearing is noisey.

1.Get the front jacked up on stands and block the back tires (if you dont have a lift)

2.Get a buddy

3.get them to press the brake and hold it

4.Clamp off the flex hose (rubber brake line) on the opposite side you wanna check with vise grips(dont clamp too tight, it doesnt have to squish it flat to stop the flow of brake fluid and you dont wanna tear the hose cuz theyre expensive, just enough pressure that your not straining a lot to lock it.)

5.Get them to start the vehicle and give it a bit of gas to see if the vise-gripped tire spins and if it does, repeat step 3 with a bit more pressure on the vise grips. If only one tire spins your good.

6. Put your stethoscope thingy listening device on the back of the hub where the bearing would be. Now do all steps for the other wheel and whatever side is loudest, thats the bad bearing.

Note!!!!!

I know this should be obvious but this is only for FRONT WHEEL DRIVE VEHICLES and TESTING THOSE FRONT WHEELS IF YOU DO NOT HAVE A LIFT!

Even though this is an Alero forum some people may think hey ill do this with my truck. haha no. truck will go vroom and you will go squish sitting under it trying to check a bad front bearing.

Hey your way may work better, I don't know. Taking the bearing out wouldn't ruin it though. Its a sealed unit, all your doing is unbolting it. The only thing that I could see messing it up would be the torque that GM used on the axle nut, then the torque that gets reapplied when putting it back on. I maybe wrong, I haven't had the pleasure of doing the wheel bearings on my car yet.

If your gonna clamp off the brake hose I wouldn't use vise grips. I would be afraid of the teeth doing damage to the hose. They make a tool to pinch off rubber fuel line that would work great though.

Im not sure i am comfortable with the whole pinching of the brake line. I will just jack the car up on stands and give a little gas and try and listen for the noisey side.

by the way, what is the torque spec for the GM axle nut?

i am going to attempt this on the weekend?

Im a registered apprentice learning from a 20+ year red seal journeyperson and ive done many wheel bearings and hes used this way for years and teaches everyone and it works fine, it's reasonable that you might think youll tear the line with the vise grips though, its always in the back of my mind but ive yet to tear one.

I also forgot about the Alero having bearings similar to cavaliers, my bad.

The old torque spec was 284 lb ft/385 N.m
The new torque spec is 173 lb ft/235 N m

Is it normal for bad bearing noise to increase while braking as well? I get the usual humming noise while driving , but it gets louder with braking, and its not my pads and rotors because they are all brand new.

That I'm not sure about. Maybe someone else will chime in and let you know.

You are probably just hearing the regular braking sound or abs sound. Bearing wouldnt get louder because its getting slower, other than that i dont know for sure.

The new torque spec you gave me at 173, is that an SKF by chance? the SKF bearing that i have came with a instruction sheet like the one you have posted, but it says nothing about torque specs.

Also, you posted that pic for me with the two spots for me to place my two jack stands, ive looked everywhere and cannot find it?
just wanted to have one more look before i get out there

Found the pictures, they were in the "this is not my week " post.

Ok, Axle nut is off, 3 bolts that mount the hub to the strut are off, i am having a hell of a time pulling the hub off the axle? there are two of us, one pulling and the other hitting the center axle with a rubber mallet. It wont come loose, keep going? or try something else?

You may have to get a puller. Its a tool that will pull the hub out but will push on the axle, much like a pulley puller. You can soak the area with something like WD40, PB Buster, any good penatrating oil. Let that set for a while and try again but you may need the puller. Sorry I didn't answer you sooner, me weekend has been long, I had my 25th birthday on the 4th, had my youngests sons B day party on the 5th(Birthday is the 6th), and started my new job on the 5th. I have been busy.

No problem Rusty, eventualy i got it off, but it cam off in two peices. The actuall bearing cover came off and got stuck inside. With a little help from a air chisel, it popped out. I replaced the new hub with ease! Slight problem though. The same sound is still there, it didnt correct a thing. Ive almost given up at this point.

Damn, all that work and the noise is still there.