Gregg K

Ouch. That's something I hadn't considered. Thanks for mentioning it. But I don't think the impact goes beyond the bearings of the wrench itself. I could be wrong.

dr bob

I think I ended up with the H-F 3/4-drive deep impact socket set, FWIW. The one that fits the crank bolt is exactly the right length for the drive end at the end of the front pulley. In my collection I also have an adapter that has a hole that allows me to insert the end of a 5' demolition bar. I think the bar comes from Home Depot or similar, tapered round one end, chisel/wedge the other end. Those two bolts are just north of one-handed pulls with the long bar for leverage. OK, the rear nut needs a little more than one hand, but really not that much. The long lever really makes the difference.

I have a 3/4" impact gun too, but can't get enough air to it fast enough to take full advantage. The biggest port on my home compressor is only 3/8" NPT, and it really wants 1/2" and a large-diameter hose that's not very long. I'm sure it will make the rated 500+ lbs/ft, but not with the relatively wimpy air supplied from my 5HP 30gal home compressor and 3/8" supply hose.

Lizard928

An impact gun will not damage the bearing when properly held. I do this with the tire off the ground. I dont even leave the e-brake on, or have someone standing on the pedal.
Though I have had to do that with the breaker bar method.

Dave928S

I agree and would worry I could hammer something in the drive train if it wasn't held properly (like CV joint ball bearings).

I use a five foot piece of steel with two holes drilled at the end so that it will go over two of the wheel studs, without covering up the centre nut. With the rear on stands, and that bar on the studs at one end and on the ground at the other, it makes a perfect counterhold and you can put all the pressure you want on it, including an impact gun.

I tried the jpitman2 jacking up method and couldn't get the nuts to budge ... and bent a breaker bar.

blown 87

How exactly do you know this? That it will not damage a bearing?

I have no prof that it will, but I know using a big enough ratchet wont hurt them.

Landseer

This tends to work

Phil 9xx

Timely information -- this is next on my project list!

Lizard928

Greg,

You will do a heck of a lot more damage by running over rumble strips, washboard, potholes and the likes than a minute with an unloaded wheelbearing getting a tiny shake put into it.

Additionally, every wheelbearing that I have seen fail in the rear has been due to a lack of grease, or dried up grease in other words. I have yet to see one rear wheel bearing fail from taking a pounding.

blown 87

I can tell you that it is verboten to use a impact on a retaining nut on most aircraft, I just wonder other than you have never had one fail where you are getting this prof?

It is not a shake, it is a impact that I have been told will put very small flat spots on the bearings and shorten the life of them, I learned that during prep for my A&P ticket.

Again, got any thing other than you have never had one fail in a few miles to back that up?

Or were the old time mechanics that taught me all wrong?
I also am pretty sure it is in AC-43- something not to do this.

I am not trying to be a ***, just trying to find a source that proves it is ok.

I also doubt that running over a rough road is anything like the forces imparted by a 500 FT/LB impact.

I have seen front wheel bearings in FWD cars fail due to impact use.

Gregg K

Greg, thanks for sharing that. I like learning stuff like this. Another live and learn thing.

It wouldn't have an affect on roller bearings. But ***** are a different subject. Hammering the tiny contact point of the ball against the races doesn't take much if it's an impact. The area under the impact curve amounts to a very high force.

blown 87

It is no less of a impact on a roller bearing, it is just spread out more.

Bottom line is that I see no upside other than it is easy to use a impact as to doing it the way the WSM says to.
Same goes for cutting holes in cars, using RTV and other stuff that has no place on a German car.

Bill Ball

With that extension you should be able to do it with one pinky.

Dave928S

Chris ... I used exactly that equipment and bent the handle like a pretzel. After trying every way possible without using an impact gun ... but that's what I eventually had to resort to.

I agree with those overall principles, but sometimes nothing works, and you have to use a last resort when it comes to freeing bolts/nuts.

Surely if the hub is stopped from rotating at all by a wheel on the ground, or a bar to take its place, such as I use, I would have thought that the wheel or bar would absorb the rotational impact from a gun. Although its less torque .. the same sort of rotational impact is applied to car hubs all the time in tyre outlets and on race cars during pit stops.

Gregg K

On a roller bearing the impact is parallel to the line of contact. But I agree with the principal of not using one at all on a bearing location.

IcemanG17

I think the torque spec on that nut is around 340ftlbs.... What worked for us was getting a 170lb person (Bill) standing on a 2 foot breaker bar.....I can't remember how we got it off though?