HELP!?! I rounded off the rear upper caliper carrier bolt head.

[Blwalker105]

Yes, I have done the unthinkable with my '02 Outback. Since you have to access it through a hole in the upright, there is no way to cut the head off. Yes, I have tried to hammer on a smaller socket, but that failed also. I need to separate the backing plate from the upright. If I remove those four bolts from around the circumference of the CV joint boot and remove the axle nut, will everything from the backing plate outward come off as an assembly?

[NetWRX]

You have to press out the inner wheel bearing race that has the wheel studs on it to get that plate off. The whole knuckle has to be removed and disassembled. The wheel bearings and seals are not likely to survive the inner race being pulled so you might as well replace them while you're in there.

After removing the inner race I wound up using an air chisel to separate it from the knuckle, hammers had no effect.

I have used these to remove rounded bolts with about an 80% success rate. The key is to get it on there straight before you start torquing on it.

https://www.lowes.com/pl/Bolt-extrac...ols/4294425058

[Blwalker105]

I think I’d rather go get a salvage spindle/hub assembly, as I am attempting to sell the car. After I cut the carrier off to get the rotor off, disasssemble the parking brakes and remove the parking brake cable, I am going to try a last ditch measure: place the whole assembly hub-side down and weld another bolt onto the rounded-off head of the existing bolt. If that doesn’t work, it’s off to the salvage yard.

[phil1734]

Can you drill through it with a small 90-degree air drill? Or fit a small dremel cut-off wheel back there?

If you have to go so far as to remove the knuckle, then you definitely should be able to drill it out then.

[Dave Howard]

Those "extractors" that NetWRX referenced are the answer. Plain and simple. THEY WORK, and will grab onto the rounded fastener in question.

[Blwalker105]

OK, after 6.5 hours, I am finally ready to start the rear brake job! More than a few of those rusty 16 yr old nuts and bolts needed persuading to come apart! Had to slice off the caliper carrier and remove the entire spindle/hub/trailing arm assembly. After that it was a piece of cake to drill out the bolt head. Even then I had to keep drilling down past the thickness of the backing plate as the caliper carrier is meant to slide in and out of place. There is a secondary plate that interferes with it’s coming straight off.

BTW, the Irwin bolt extractor did not work. After I did the initial damage, than tried to hammer on the next size smaller socket, the result was a size that was exactly wrong for any of the extractors.

[Blwalker105]

Can you drill through it with a small 90-degree air drill? Or fit a small dremel cut-off wheel back there?

If you have to go so far as to remove the knuckle, then you definitely should be able to drill it out then.

Not to make an excuse for my mistake, but the design of that spindle assembly is HORRIBLE!!! The carrier bolt heads are not flush with the rear surface of the spindle like every other car I’ve ever seen, but are flush to the backing plate and accessible only through holes cast into the spindle. To make matters worse, the edges of the 1/4” thick backing plate are “tuliped” inward, completely enveloping the bolt head. To make matters really worse, the upper transverse link interferes with socket extension geometry, which is how my whole situation started. In hindsight, I should have used no extension...lesson learned.

[NetWRX]

If you take the strut and trailing arm bolts out where they connect to the knuckle it will lean outward and you may be able to slip the axle out and get a straight shot at the bolt.

[Blwalker105]

If you take the strut and trailing arm bolts out where they connect to the knuckle it will lean outward and you may be able to slip the axle out and get a straight shot at the bolt.

I didn’t think of that, but that axle is about 6” long, so that means the trailing arm would have to move outward about 18”. Might be tough. Good thought though.

[Blwalker105]

If you take the strut and trailing arm bolts out where they connect to the knuckle it will lean outward and you may be able to slip the axle out and get a straight shot at the bolt.

I didn’t think of that, but that axle is about 6” long, so that means the trailing arm would have to move outward about 18”. Might be tough. Good thought though.