General Suspension: how to change your front wheel bearing
05-06-2010, 02:48 PM
#1
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how to change your front wheel bearing
The front wheel bearings on a cobalt are like most modern front drive cars, that is, they are an assembly and must be replaced as such.
It's not hard to do, and can be done with hand tools, although an impact gun does make life a little easier.
what you'll need:
The correct bearing for your car. that may seem obvious, but i had a hard time getting one, kept getting four lug hubs.
15mm shallow wall socket
6" socket extension
3" socket extension
thread locker
30mm deep wall socket
axle grease
6" bearing puller. you may need this, sometimes they just slide out. i wasn't so lucky.
roller jack
2 jack stands
STEP one: to determine which bearing is bad, a quick test is to jack up both front wheels, spin the wheel hard by hand, then grab the spring, if you can feel it vibrating roughly, it's a bad bearing. you can usually hear it grinding as well.
STEP TWO: remove the break caliper and rotor. both bolts needed to be removed are 15mm.
STEP THREE: there is a large nut in the centre of the hub, it's a 30mm and you'll likely need a deep wall socket to get there. Use a box wrench as a holder to keep the wheel from spinning as you remove the nut. an impact wrench makes this a lot easier, because you won't need to hold the hub in place.
STEP FOUR: on the back side of the knuckle, you can see three 15mm bolts. remove them.
STEP FIVE: un plug the wheel speed sensor.
STEP SIX: if the hub just slides out in your hand, consider yourself lucky. more often than not, if the bearing failed, it's somewhat stuck on the spline of the axle.
STEP SEVEN: using a six inch three arm bearing puller, the hub should come free. also, you will again have to use a box wrench on the lug studs to keep the hub from rotating.
STEP EIGHT: apply a light coat of axle grease to the spline of the axle, and to the inside of the knuckle.
STEP NINE: be sure to apply thread locker to all the bolts before reassembly.
STEP TEN: reassemble, first slide the new bearing in, making sure that wheel speed sensor is routed correctly. tighten the three hub bolts, then the centre nut. install your brakes and wheel.
fin
It's not hard to do, and can be done with hand tools, although an impact gun does make life a little easier.
what you'll need:
The correct bearing for your car. that may seem obvious, but i had a hard time getting one, kept getting four lug hubs.
15mm shallow wall socket
6" socket extension
3" socket extension
thread locker
30mm deep wall socket
axle grease
6" bearing puller. you may need this, sometimes they just slide out. i wasn't so lucky.
roller jack
2 jack stands
STEP one: to determine which bearing is bad, a quick test is to jack up both front wheels, spin the wheel hard by hand, then grab the spring, if you can feel it vibrating roughly, it's a bad bearing. you can usually hear it grinding as well.
STEP TWO: remove the break caliper and rotor. both bolts needed to be removed are 15mm.
STEP THREE: there is a large nut in the centre of the hub, it's a 30mm and you'll likely need a deep wall socket to get there. Use a box wrench as a holder to keep the wheel from spinning as you remove the nut. an impact wrench makes this a lot easier, because you won't need to hold the hub in place.
STEP FOUR: on the back side of the knuckle, you can see three 15mm bolts. remove them.
STEP FIVE: un plug the wheel speed sensor.
STEP SIX: if the hub just slides out in your hand, consider yourself lucky. more often than not, if the bearing failed, it's somewhat stuck on the spline of the axle.
STEP SEVEN: using a six inch three arm bearing puller, the hub should come free. also, you will again have to use a box wrench on the lug studs to keep the hub from rotating.
STEP EIGHT: apply a light coat of axle grease to the spline of the axle, and to the inside of the knuckle.
STEP NINE: be sure to apply thread locker to all the bolts before reassembly.
STEP TEN: reassemble, first slide the new bearing in, making sure that wheel speed sensor is routed correctly. tighten the three hub bolts, then the centre nut. install your brakes and wheel.
fin
05-16-2010, 08:32 PM
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Awesome write-up. Need to order mine (Front-left I believe). That means a week of Jeep 4X4ing til it arrives. Where can I get a bearing puller and how much is that going to run me?
Mine made noise after 30mph, and I couldn't drown it out with the radio. Think I busted it while Dyno-tuning. O well. Worth it imo.
Mine made noise after 30mph, and I couldn't drown it out with the radio. Think I busted it while Dyno-tuning. O well. Worth it imo.
05-16-2010, 08:56 PM
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can you not break that axle nut loose with the brakes on and someone standing on the brakes? instead of having to hold the rotor from spinning with a wrench? I cant remember if you can get to it or not with the breaks and rotors still on.
05-16-2010, 09:14 PM
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You can get to the nut with the brakes still on...I've had someone standing on the peddle while I took off and put on the nut...although I'm not sure if that's an ok way do do things.
05-21-2010, 09:36 PM
#7
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Thread Starter
Awesome write-up. Need to order mine (Front-left I believe). That means a week of Jeep 4X4ing til it arrives. Where can I get a bearing puller and how much is that going to run me?
Mine made noise after 30mph, and I couldn't drown it out with the radio. Think I busted it while Dyno-tuning. O well. Worth it imo.
Mine made noise after 30mph, and I couldn't drown it out with the radio. Think I busted it while Dyno-tuning. O well. Worth it imo.
i got a puller from harbor freight for like, $15 for a set of three. not the best pullers in the world, but, i needed them for only this.
i guess you could. i just used an impact gun.
Last edited by joeworkstoohard; 05-21-2010 at 09:36 PM. Reason: Automerged Doublepost
05-21-2010, 11:20 PM
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This was a total bitch. I had to pry the old hub from the axle, and put the gasket on the wrong way, which added 30 minutes into the time. I cut the tip of my finger off too. Lots of blood and sweat and language later, its fine. All fixed.
05-22-2010, 09:26 AM
#9
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On mine I had to remove the steering knuckle and press the bearing out of it. Here in the salt belt the bearings tend to seize into the aluminum knuckles. I used a good amount of anti-seize on the new one.
05-22-2010, 11:08 AM
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Its probably easier to break the nut loose while before raising the car, IE, while the tire is still on the ground. You'll need to install the spare tire (or winter steelie) first so the nut is reachable.
On mine I had to remove the steering knuckle and press the bearing out of it. Here in the salt belt the bearings tend to seize into the aluminum knuckles. I used a good amount of anti-seize on the new one.
On mine I had to remove the steering knuckle and press the bearing out of it. Here in the salt belt the bearings tend to seize into the aluminum knuckles. I used a good amount of anti-seize on the new one.
11-14-2012, 09:26 PM
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LNF revisions
Exact same procedures for LNF cobalts save for the following details
*Axle nut is 35mm
*Brembo caliper bolt heads are 13mm, same for wheel bearing hub bolts
*Axle nut is 35mm
*Brembo caliper bolt heads are 13mm, same for wheel bearing hub bolts
11-14-2012, 10:47 PM
#20
Done a bunch of these, cobalts and other cars/trucks.
One tip for the axle:
Spray it down with some penetrating oil before you try to remove it. You can also strike it carefully with a hammer, there is usually an indent in the end of the axle, use a punch there to avoid damaging the threads (or put the nut back on if you really don't trust yourself
)
Usually you can break the axle loose fairly easily and just slide the hub out, barring any major corrosion issues.
One tip for the axle:
Spray it down with some penetrating oil before you try to remove it. You can also strike it carefully with a hammer, there is usually an indent in the end of the axle, use a punch there to avoid damaging the threads (or put the nut back on if you really don't trust yourself
)Usually you can break the axle loose fairly easily and just slide the hub out, barring any major corrosion issues.
11-15-2012, 05:32 AM
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I was a little miffed when i realized the tell-tale signs of a failed wheel bearing was upon me @76k miles but for the ease of that change out, i'll gladly service them @ 75k. It was literally 20minutes from breaking of the wheel lugs to retorquing them with a beer and a cigarette somewhere in between.
This is the first time i have seen a sealed wheel bearing assembly detachable from the transaxle drive hub, is this design pretty common now days? What model year did it start being pretty standard? A coworker of mine who was a Ford technician for a decade before coming on board at the kite factory said he was totally unfamiliar with the design so also i am wondering if this is a GM thing or if i failed to adequately describe the mechanical layout (i am bringing him my worn bearing assembly to answer my own, last question)
This is the first time i have seen a sealed wheel bearing assembly detachable from the transaxle drive hub, is this design pretty common now days? What model year did it start being pretty standard? A coworker of mine who was a Ford technician for a decade before coming on board at the kite factory said he was totally unfamiliar with the design so also i am wondering if this is a GM thing or if i failed to adequately describe the mechanical layout (i am bringing him my worn bearing assembly to answer my own, last question)
