Wheel hub mounting bolts STUCK. Need some ideas.

[jacobarber]

Vehicle is a '93 Blazer Cheyenne.

I'm replacing my front hub assemblies. All bolts on the driver's side unit came out of the knuckle just fine. I've been fighting tooth and nail to get the passenger's side bolts out though. I did manage to get one out after soaking in PB Blaster overnight. The other 2 are not budging though. I've let my Makita impact wrench crank on it a lot, and am using a good 6-point impact socket to get really solid purchase.

I have replacement Dorman class 10.9 bolts waiting to go in with the new units, but don't know what class or grade the original bolts are. I'm hesitant to sit on a breaker bar for fear that I'm going to snap these suckers off in the knuckle then have to suffer new extraction problems.

Any ideas how much muscle the original hub mounting bolts can handle?

 

[Schurkey]

6-lug hubs, or 8-lug hubs? The three 6-lug bolts come out from the front-side, the four 8-lug bolts come out from the back side.

When I did my 8-lug, I had a 3/4" air-impact wrench adapted down to a 1/2"-drive swivel socket. I had more issue with the bolt hex rounding-off than with any fear of the bolts breaking.

Photos from the second (right-side) hub; the left side was worse in part because I didn't own the swivel-socket when I did the left side.

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Bolt head from left side. Had to remove knuckle from vehicle to get these out.

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The 6-lug hubs don't use the same bolts as the 8-lug hubs, and I've never pulled those apart. However, I don't think an electric/battery impact has enough snort to do any damage to the bolts OTHER than MAYBE rounding-off the hex if the socket doesn't fit well.

The problem with breaker-bars and cheater-pipes is that it's hard to keep the socket properly placed on the hex-head of the bolt, and you're also adding force that's not in-line with the bolt. OTOH, I'm sure you could apply more torque than a battery impact.

When it was me, I grabbed a bigger impact wrench and turned-up the air pressure.

The hub bolts went back in with anti-seize, and the torque reduced by 20%.

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[jacobarber]

This is the 6-lug unit, and yes the bolts go in through the front. The sockets I have fit very snug and bottom out very well on the heads, so this is one of the few times I am not concerned about rounding anything off.

Looks like I just need a bigger impact wrench.

 

[xXxPARAGONxXx]

Apply some heat from a torch, even a small propane torch from the local auto or home store.

 

[jacobarber]

I took the risk. Put the whole knuckle & hub assembly back on the truck and cranked on it with a breaker bar. Took some real weight, but the bolts came out. Brand new Mevotech TTX ball joints + Timken wheel hubs are hopefully gonna give me some great reliability for another 30 years.