Rounded off nut, suggestions?
 

Well, I finally did it... I was out in the sleet today trying to get one final job done on the W201/190D before heading out for time with the family down south. The goal was to get the fuel injectors out to send to C Sean Watts for a rebuild. I might have been able to do it by just loosening the hard lines and pushing them aside, but I've heard bad things about how fragile they are in the later motors. I also need to replace the delivery valve o-rings badly, they're leaking all over the place. So, it made sense to remove the input manifold to get at everything: with that off I can remove the hard lines from both the injector pump and the injectors, and also get at the delivery valves cleanly.

The inboard side of the air filter box is held in place by four nuts, two fore and two aft. They were tight on the front, but I got them out OK. On the back I nearly stripped the top one but bore down on it and it loosened. The last one is down low, and the stud for it comes out from the oil filter canister body; I started out with a 12 point 10mm socket, and I couldn't budge it. I felt the socket give a little, the tell-tale sign of buggering it up. I quickly switched to a six point socket, and tried to budge it. No go, though it rounded some more despite all the force I could put on it. Gave up, went to the store; came back with Liquid Wrench lubricant, freeze spray, a micro butane torch, and a Sears Bolt-Out Plus set. I lubed it, tapped it, froze, heated it, froze it, heated it, and then finally completed the rounding process with the Bolt-Out Plus. The bolt out plus has flutes on it that are supposed to grip the head tighter as you turn it, but in this case the nut is cheap and it just shaved the remaining corners off quite neatly.

So, now that damn rounded nut sits there laughing at me, and I got nothin. I can't get a nut splitter on it, no room. I could buy an extra long chisel, and maybe drive it around. I could buy a grinder and maybe jam it in there to grind one side off. Got any ideas, besides waiting for Spring?

Kurt

How about using a dremmel with a cut off wheel? I have used it a few times in some tight places

Charlie

Any chance of getting some vice grips or locking pliers on that sucker? Sometimes if you can get a real good bite on the bolt head and then some sort of cheater bar and slowly apply pressure . . .

The nut that has been rounded attaches a bracket and that bracket attaches to the oil filter housing if I'm not mistaken. Perhaps you can disconnect the bracket from the oil filter housing, you might also sacrifice the bracket and then get a replacement bracket, that would allow you to get the filter housing off and you might be better able to work on it on the bench.

I thought all nuts were round??


oh.. you have a pm

There is a heap of threads about "stuck nuts" maybe even the ones jt20 speaks of !!:D
The absolute worst I ever had to do was to cut one off (yea we do that to bull calves all the time jt) using a hacksaw blade in a pull type handle.
If you can get a hammer there, you may be able to drive a slightly smaller socket on to the nut.

Good Luck.

I would say, Vice Grips or one of those tools like a socket with a cam in it that grips rounded nuts or possibly a nut splitter.

Nothing works better on round or rounded than a pipe wrench. I have a 6" I put a pipe extension on for extra leverage.

Go to Autozone, NAPA, or your favorite auto-parts store and buy a set of IRWIN internal-helix sockets. They have a sharp reverse-helix that bites into the bolt head, I removed a couple of head bolts with them (the head bolts other than being very tight, are in internal-hex and round on the outside). About $15 for a set.

Don't forget to spray your favorite penetrating oil on it.

Also wouldn't hurt to use some heat on the sucker. Propane or the always trusty MAPP gas. :cool:

X2, I go right for the pipe wrench on a rounded off nut or bolt if it will fit. Never have I had good luck with vise grips, I just use vice grips for clamps.

The trick to vice grips is getting them on there nice and tight, which sometimes requires using another tool to squeeze the handles together - channel locks or something of that nature. But if you can get them on there tight enough they can do the job - then you have to undo them, but at least you have solved your first problem. Never tried the pipe wrench, sounds like a good one though.

Dremel and diamond bit
 

With virtually no access I would go in with a dremel straight diamond bit and cut through the side of the nut. Once you are through the nut should spread and come off. This is a nice controllable process compared to chiseling heating and beating. It will be slow but should ultimately work. Cheers Dan

Thanks, everyone, for your cheering responses. Dan, what shape bit do you recommend for the job of drilling off one side? I see rounded ball tips with diamond grit on them are available; are these a good choice?

Thanks,

Kurt