Damaged Bolt Extraction

I'm in the process of pulling the drive plate off a vehicle to replace the rear main seal. In the process of loosening the 10 bolts, I managed to bugger up the heads on two of them. The socket I was using slipped off and rounded off a couple of shoulders on the bold head.

When this happened, I stopped screwing with them in order to minimize further damage. There are several methods for removing such bolts. Prior to drilling and seriously messing around, I seem to recall some special damaged bolt sockets (with helical teeth in them). What are these called? Are they any good (the bolts are 14 mm, torque to 75 ft-lbs). Who would carry them in the Seattle area? Any tips when using these? Or other advice?

Reply to
Paul Hovnanian P.E.
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Sears has them. As do many of the better parts stores. I have a set from Irwin and they do a good job. I have used them with a LOT more than 75 ft-lbs on the drive.

Reply to
Steve W.

"Paul Hovnanian P.E." wrote

If the special sockets don't work, be happy that the bolts are so exposed...

Grind a bit of a slot on the faces of the old bolts, near the edge, and just deep enough to give a chisel something to grab, then tap-tap-tap with a hammer to get them turning. Or, if you like the grinder's spark show, just keep going until the heads are completely gone. The plate will fall off, and the "stubs" will come out easily. Then get some new bolts, and a better socket.

Reply to
MasterBlaster

Your idea should work--for an idea of the torque, lots of lug bolts are more than 75 ft-lbs.--80, 90, 95 are a few common ones. If you have an acetylene outfit and the surrounding metal/oil can accept it, the bolts when heated red will screw out with vice grips. Just another way to accomplish the same thing. When stranded, sometimes a metric sized socket which is a tad too small can be driven onto the stripped bolt head and remove it. Six-point sockets may also help. s

Reply to
sdlomi2

"sdlomi2" wrote in news:IUBTj.49648$% snipped-for-privacy@bignews7.bellsouth.net:

I've had good success with using a Dremel to grind a new hex on the stripped bolt, then hammering a smaller socket onto the new hex.

I've also used this method on bolts whose heads are so badly rusted that they're both rounded and smaller than the original socket.

And in my personal opinion, nobody should ever be using 12-point sockets on any automotive fastener unless it's very small.

Reply to
Tegger

ws7.bellsouth.net:

Even then, I don't like them. I actually had to go buy a set of 12- point sockets when I bought some ARB rod bolts and realized that they took 12 point nuts.

nate

Reply to
N8N

With luck, you can take a 6 point socket and grind the opening down to remove all the 'relief' at the opening, then that may grip the unmarred part of the bolt head right next to the flex plate.

Or, you can find a local buddy with a mig welder and buy him a 6-pack, just weld a nut right on.

Dave

Reply to
spamTHISbrp

Or any old piece of scrap iron can be welded on. The heat also helps loosen things. In a former life I was a shop foreman in a remanufacturing shop, and we used the weld-and-wait-15-seconds-and- then-twist-it-out method almost exclusively with stuck stuff. The 15 seconds gives the heat time to penetrate and break loose any corrosion. If it was in a zinc/aluminum alloy part, it was weld-and- instantly-loosen, or risk melting the alloy.

But the welding heat and sparks can set fire to oil and other crud under there. Have an extinguisher handy. Stay clear of fuel lines.

Dan

Reply to
Dan_Thomas_nospam

I've found that a surprising number of bolts I would expect to have problems with come out easily if I try to TIGHTEN them first. Apparently breaks something loose...

Pete

Reply to
ratatouillerat

I have seen the same...Liberal dose of penetrating oil and cyclically tighten and loosen.

This is particularly true if the threads are fouled.

If you are not heavy handed, and use the right tools, most bolts will give up whether you use a 12 point or 6 point socket. But for those really tough cases, a 6 point, before you destroy the shoulders, is preferable.

Reply to
HLS

Wack the bolts straight on with a big steel drift and a good size hammer before you try to loosen them again.

Reply to
Steve Austin

I picked up a set at Sears. They worked quite nicely.

The tip (which I figured out) to using these is to tap them on to the bolt head gently with a plastic mallet to get all the teeth to bite evenly. When I tried starting the socket by turning it, the asymmetrical damage caused it to bite unevenly and slip off. The mallet trick fixed that.

I'm not certain what the thinking was, but these bolts have very short heads. Any misalignment with a socket (mine are 6-point) and it doesn't have enough bolt head to bite on anymore.

Reply to
Paul Hovnanian P.E.

I've ruled out using any dangerous (flammable) or large equipment on this project. My truck is in my garage and is too tall to be jacked up enough to get the transmission out from underneath it. I just dropped it on the ground and slid it back far enough to squeeze in and finish the job. If I or anyone else started a fire under there, there would be no getting out alive.

Reply to
Paul Hovnanian P.E.

In that case if the 6 point sockets don't work I second the recommendation for the "bolt outs." They worked for me on some Allen head bolts with stripped heads, so I expect they would work on a regular hex head just fine.

nate

Reply to
N8N

I've had some luck with this method in other situations. I hesitate to try this on an installed crankshaft (wheel bearing, etc.) die to the damage it might do to internal components like bearings.

The thing I did which may have helped (other than using a damaged bolt socket) was to re-torque the surrounding good bolts back to spec. The idea being that, as each was originally loosened, the remaining load was transferred to nearby bolts, making them harder to extract (and easier to damage).

Reply to
Paul Hovnanian P.E.

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