I broke two bolts putting my oil pan on my freshly rebuilt engine that is outside of my car right now. Yes, two. Had the torque wrench at its lowest setting - 10 ft-lbs, which I know is more than what the haynes says but of course I was stupidly like "AHhh, what's a couple of foot pounds??" - and managed to snap off two. And one of these is in the front row, which I think can't be gotten to directly (as with a drill) if I put the engine in.

So I'm faced with either extracting these, which I SUCK at (especially with the engine hanging from a chain and moving around and ****) and with trying to jury rig the thing with more RTV and hoping for the best when I put the engine in.

I guess my question is how you guys would go about extracting these. I don't know much about extracting broken bolts in general so any details would be great. And whether or not you think I could get away with having two bolts (on opposing sides of the pan) missing and still have the pan do its job well, assuming I RTV it up well enough?

Constructive advice only would be appreciated, as I can almost smell all the perfect people out there waiting to pounce on a mistake like this. Thanks.

 

If the entire head snapped off, it's going to be a delicate operation to drill & easy-out the bolt body with the oil pan on...

If you laid down a good bead of RTV in the right places while putting the pan on, it may work yet, only if the broken bolts are not near each other...

 

Far as I know my RTVing was good. Inside all the holes and whatnot. I hate to take that chance though.

 

How far apart are the bad bolts?

 

Try this- let the RTV cure, then add a couple of quarts of oil (maybe some MMO if you want a light oil), tilt the engine on the lift so the front of the oil pan is lower, & leave it overnight like that. If any seeps out, you'll know it definetly won't work. If none seeps out, you'll know it MIGHT work...

 

Just take the oil pan back off, there should be enough of the shaft of the snapped bolts sticking out for you to get a pair of vise-grips onto, and unscrew them.

 

The bolts are basically on opposite sides of the pan. I will take the pan off tonight and see how much of the screws are sticking out. I don't think they're sticking out enough though.

 

I'm missing one bolt off of my oil pan, due to the same reason.. 3000 miles on my rebuild and so far no oil leak!

 

i second this suggestion.. vise grips can solve alot of problems .. but if you have the engine on a a hoist then taking of the pan will only be a minor pita.. do it right since you went through the whole game of rebuilding your engine .. so why take a chance?

 

I took a look and there's definitely nothing protruding to grab onto with vice grips or anything. So I guess that leaves me with extracting.

I got one of those reverse thread screw extractors from home depot. It was like 2.50 or so, and the second size up from the bottom... I had tried the smallest size on a totally separate project and managed to snap it off, at which point that bolt was then totally undrillabe.

Time to put my surgeon's hat on. Sighhh

 

Well I got em out and I don't think I hurt the RTV either. Guess there's something to be said for not freaking out immediately. And something to be said for not worrying about bolt that's stuck in by all of 10 foot pounds.

 

When I broke a bolt on my oil pan, I just had my step-dad drill a slightly larger hole and tap it for the next size up. Worked like a charm, except for the fact that I have a odd looking bolt, but you can't see it so I guess it doesn't matter.

 

too easy. i did the same thing when i had a shitty seal on my oil pan. its called welding. you can weld a nut on the original to make it a bolt and then just unscrew it. i had a buddy do it for me. u cant over torque those screws or they break. id feel safer with all screws in, maybe its just me though.

 

Yes. Happened to me. Last time I did the oil pan on my car, I broke two bolts. Oddly enough, both were in the rear rotor housing.

Since my engine is in pieces, it was a simple matter to extract both bolts. I was prepared to drill and retap, but as I started to drill the first the bolt began to rotate. I then simply used a Craftsman damaged screw remover to extract. The 2nd bolt appeared very stuck, so I carefully drilled a hole straight through it. I was about to enlarge the hole so that I could tap, but on a whim I tried an EZ Out. I normally hate those things, but this time it worked perfectly. This will be more difficult to do on an engine hoist, and a MAJOR pain in the *** to do in the car.

The reason the bolts break off is because RTV and other gunk gets pushed into the top of the hole, so you are actually tightening your bolt against that mess. For this reason, I give all the bolt holes a blast of carb cleaner and air to clean them. I also use only stainless hardware. If you chose to use stainless hardware, you ABSOLUTELY MUST use plenty of anit-seize. If you don't, the stanless and the aluminium form a battery, with the aluminium being reduced. BAD THING. Either the bolt will weld itself in, or in several years it will simply fall out due to the aluminium around it disappearing.

 

Good point on the dissimilar metal contacts, Aaron, not something a lot of people think about

Easy-outing is an art, once you get the hang of it, it's a snap, but the learning curve makes you swear them off for life. I've probably extracted at least 1000 screws this way on aircraft, but none that I can remember on our cars.

10 ft/lbs (120 in/lbs) is too much for those 3/8" or so bolt shanks. Normally that size is in the 40 to 80 in/lb range, depending on application. A mechanic that's been at it for years knows by "feel" how much "oomph" to put on a particular fastener size, it all boils down to the "live & learn" philosophy when you break one...

 

THE WINNING ANSWER ABOVE

 

What I always did to get screw like that out was get a drillbit that was broken off severely and another that was sharp and a little smaller and would pilot drill the bolt in question about 1/8 inch and would put the broken bit (the gnarlier the break, the better) and put the drill in reverse, then when you start to drill, take it easy, and use plenty of force pushing down, and it will usually snag, and back the bit out slowly. Keep a firm grip on the drill, being that it will whip out of your hands when it catches. I use a high torque drill, or even my mill with a drill chuck in the bottom (YOU NEVER USE A DRILL BIT IN ONE OF THE GROMMETS DIRECTLY INTO THE MILL, YOU EXPLODE WORKHEADS THAT WAY). Works for me, maybe will for you, too. Just have your biggest friend, or youself, hold the drill when you do it.

 

I would back them out, the RTV will not hold over time.

 

First of all, stock spec max is 96 in-lbs.
96 in-lbs. is 8 ft-lbs.
So, you're 10% higher at 10 ft-lbs.

Second, don't use the extreme bottom and top scales of the torque wrench.
Torque wrenches are calibrated for the middle ranges, and they are wildly inaccurate at the extreme ends.

You were probably pumping close to 20 ft-lbs. to that tiny little bolt.

If you wanna use a torque wrench on those oil pan bolts, get a torque wrench which uses 96 in-lbs. in the middle of it's range...

BTW, I have never broke an oil pan bolt in my life.


-Ted

 

The guy that said to remove the pan and see IF there is any bolt left to grab is right. If you are lucky sometimes there is. If there isn't, before going to the drill bits and ez out I grab a very sharp scratch awl. I put the punch way out to the edge and start to tap it. As it starts to dimple the stub I start to angle the scratch awl so it is at a 45% with the broken bolt and try to tap it counter clockwise to spin it out. The vibration can break the threads loose like the torch and the dimple helps hold the scratch awl in place when you start spinning the broken bolt out.

It doesn't work on really rusted big bolts but I gotten a number of these small bolts out that were broken off flush in areas I couldn't work with a torch.