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Stripped Valve cover bolt

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Old 06-09-2018, 02:49 PM
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Default Stripped Valve cover bolt

Okay, I'm pretty angry at this car at the moment, been spending a small fortune on tools and odds and ends and a stupid amount of time getting part way into it before having to stop for an unanticipated tool or part I need. Right now, the bottom back valve cover bolt on the passenger side has been stripped. I ended up cutting a small hole in the heat shield to access it and had the bit on there perfectly straight, all the way in, and it just stripped immediately. I think it may have been already damaged, but I can't be entirely sure. After trying to drill so an extractor could get in there, it ended up that the extractor tapered, and you can't drill deep enough without going all the way through the head of the bolt to get it to catch, and the next size up won't catch either, being too large to go in the hole. So I got a hold of a dremel and a full kit to go with it, and there seems to be no way to get a cutting wheel in there to make a slot, a slot which would be too wide for a flathead, by the way, but I figured I could find something that could work, like a chisel or something. Do I cry uncle and leave it for a shop to do? My wallet is screaming at me at this point, between that and other things, and I really am getting sick and tired of this thing being apart in the garage. It's doubly aggravating to think I will get it back together after repairing the oil cooler, rebooting the CV joint, doing the upper and lower control arms, and the transmission filter seal only to have to be unable to do a valve cover gasket. At this point, it's hot and I'm exasperated and need ideas from calmer minds.
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Old 06-09-2018, 05:10 PM
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Feeling the hurt. I had something like this on W12 when I had one of those "why the hell did they use that type of oddball [super fine and shallow tri-square fastener there" experience. It was on the water pump to block mounting where I had little clearance in front of motor, it was deep down reach wise, and there was no way it was an "optional" fastener.

See this 90 degree drill attachment in pic. My objective was to cleanly drill a hole for the extractor. Like $20 on Amazon IIRC. I wondered it if it was more for toys when I bought it--like you, I did day over day of tool ordering to try to find something. This one cracked it. It accepts any standard hex mounted bit or tool, and you can get very short bits too--ignore one in pic except to understand tool. On back either just attach cordless drill or yet another extension like I did to get the reach. If the firewall is your most important tight clearance, you need less than an inch of clearance around that head to fit it. Usually a lot less than dealing with some big drill chuck and body. Depending on the bit, probably 3" of clearance in line with the fastener you are going after.
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Old 06-09-2018, 05:36 PM
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I appreciate it! I actually got a fairly clean hole, the problem seems to be that the set I borrowed from my brother has a problem. The smallest size that might work is too narrow at the tip, it is too far up the bit by the time it is wide enough to be useful. The next size up is too wide at the tip, I'd end up sawing the head of the bolt off if I tried to drill for it.
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Old 06-09-2018, 05:39 PM
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Default Maybe drill the head off

how about drilling it out so the valve cover will be able to come off, then extract with a pair of vise grips? Those bolts are only supposed to be at 9ftlbs or 9nm or some super light torque, so once you get the head out of the way, you’d should be able to get the rest of the bolt out after the valve cover is out of the way.
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Old 06-09-2018, 06:33 PM
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Originally Posted by tsuter View Post
how about drilling it out so the valve cover will be able to come off, then extract with a pair of vise grips? Those bolts are only supposed to be at 9ftlbs or 9nm or some super light torque, so once you get the head out of the way, you’d should be able to get the rest of the bolt out after the valve cover is out of the way.
They are supposed to be on light, but they aren't, they are all pretty stiff, at least 25ftlbs, I think the last person, either Misha or my brother, noticed the valve cover gasket leaking and tried to tighten them a bit to stop the leak. I also suspect the bolt was damaged already, because it stripped immediately with little resistance. Here is what it looks like now.
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Old 06-09-2018, 08:09 PM
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Idea 1: Trying to drill in with a much smaller hole than what you have going so far --whatever is needed for smallest extractor. Maybe 7/64". Maybe with that tool I pictured. Or,

Idea 2: a variant of what has been suggested: go the other way and drill off the head with like a 3/8" bit. As you get near the end of what you want to drill, drill should just dig into that washer that covers over the rubber spacer/gasket underneath. Once you drill off head (only), then remove valve cover. Now go in with some pliers with decent teeth and just turn the threaded remnant out. Get a new screw and maybe washer from dealer and good to go with a new gasket set.

Idea 1 was my W12 water pump stripped screw. I did virtually exactly idea 2 with some trailer brakes in recent days where the pad was held in by a screw in a recessed hole on pad face side--sort of like a recessed rivet on a brake shoe conceptually. The screw head I had to get undone to change pads got ground down when the pads wore too much and at an angle. I could put the piece on a drill press, but screw was also stainless (hardened effectively) so it took a masonry bit to drill through the head area. And one I had head drilled off (actually mostly chewed through given hardening), the pliers did get the threaded part out.

Plan to buy a tap to clean up these and other threads. I try to do that in anything around intake or valve cover area, and then locktite when done. A tiny bit of grease on tap fluted side cuts if you want to improve capture of any minor particles that come out,

Last edited by MP4.2+6.0; 06-09-2018 at 08:11 PM.
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Old 06-11-2018, 07:40 AM
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OH, i feel you pain...went through this last year by stripping out a few bolts. Here is another option, I had a cousin who knows welding....he welded a new bolt on top of the stripped one. We then put a socket on it to remove and reinstall. I actually left the welded bolt on for any future use. Obviously, the welded on bolt has a nice standard head on it for the socket to fit.

I can take a pic if you need it....however, it wasn't the rear bolt, it was the 3rd one from the front on driver's side. He welded it from the top of the motor.
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Old 06-11-2018, 09:27 AM
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Originally Posted by Aceler8 View Post
OH, i feel you pain...went through this last year by stripping out a few bolts. Here is another option, I had a cousin who knows welding....he welded a new bolt on top of the stripped one. We then put a socket on it to remove and reinstall. I actually left the welded bolt on for any future use. Obviously, the welded on bolt has a nice standard head on it for the socket to fit.

I can take a pic if you need it....however, it wasn't the rear bolt, it was the 3rd one from the front on driver's side. He welded it from the top of the motor.
Yeah, me and my brother discussed this, he is a welder, but no longer has access to one. It would have to be bought.
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Old 06-11-2018, 09:52 AM
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Originally Posted by Jack88 View Post
Yeah, me and my brother discussed this, he is a welder, but no longer has access to one. It would have to be bought.
You can't drill a hole because lacking of space? I got mine done with $3 bit but mine was in the open. It's the best way IMO.




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Old 06-11-2018, 10:39 AM
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Originally Posted by ltooz_a6_a8_q7 View Post
You can't drill a hole because lacking of space? I got mine done with $3 bit but mine was in the open. It's the best way IMO.




Cheers,
Louis
Stop the press! It looks like Louis is doing a timing belt job!

Why the change of heart?
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