[NGEE]

I currently have my underbelly pan off the car. When I backed my car out of the garage this morning, I found this on the garage floor right below where the oil pan would be with the car parked. It is a bolt for the rear of the oil pan where it meets up with the bell housing (I believe?). It literally fell out of the oil pan while the car was parked. Oil pan has never been touched. All other bolts in good shape. Never seen a self-shearing bolt before.

Since I have plans to replace the oil pan gasket this fall, this should make the job a bit more interesting.

[krhodes1]

Probably over-torqued when installed at the factory. These are torque to yield bolts, and sometimes they yield a bit too much. Shouldn't be a big deal, the remains usually spin right out. Not like a bolt that broke because it was rusted in place...


Germans are really good at an awful lot of things, but perfect quality control really isn't one of them. :

[mweisdorfer]

Originally Posted by krhodes1

Probably over-torqued when installed at the factory. These are torque to yield bolts, and sometimes they yield a bit too much. Shouldn't be a big deal, the remains usually spin right out. Not like a bolt that broke because it was rusted in place...


Germans are really good at an awful lot of things, but perfect quality control really isn't one of them. :

You are gonna need a spline kit and a good drill set

https://www.amazon.com/IRWIN-HANSON-.../dp/B0002SRG66

[NGEE]

Originally Posted by mweisdorfer

You are gonna need a spline kit and a good drill set

https://www.amazon.com/IRWIN-HANSON-.../dp/B0002SRG66

Thanks for the link. What drill type would you use? It seems to me the difficult part of this is to get "grab" in the center right away so there is no drift.

[mweisdorfer]

Originally Posted by NGEE

Thanks for the link. What drill type would you use? It seems to me the difficult part of this is to get "grab" in the center right away so there is no drift.

I'd use a cobalt bit & a small amount of drill oil. The spline kit will tell you exactly what size bit to use for each spline. Use a socket on the spline, after you twist it in by hand.

[Barrique_Red]

This happened to me on the Valve Cover. One of the bolts broke off, caused an oil leak. I prepared for some hardship in getting the piece out from the block, but it turned out to be quite simple. I used the end of an awl to reach into the hole and unscrew the broken piece. Granted, the bolt for the valve cover wasn't as long as the one you show, but for some reason the broken piece of the bolt unscrewed using little or no force. Good Luck!

[desertman123]

Originally Posted by Barrique_Red

This happened to me on the Valve Cover. One of the bolts broke off, caused an oil leak. I prepared for some hardship in getting the piece out from the block, but it turned out to be quite simple. I used the end of an awl to reach into the hole and unscrew the broken piece. Granted, the bolt for the valve cover wasn't as long as the one you show, but for some reason the broken piece of the bolt unscrewed using little or no force. Good Luck!

Can confirm this works.

Also I've used a small drill bit to drill a hole into the bolt, then rubber-mallet a disposible flathead into it and turn it out.

[Welcome to NBA Jam]

Left-handed drill bits are your friend here. They'll let you drill a hole in the middle of them to get an easy-out in there, and there's a possibility that the drill ends up removing the bolt while it's drilling the hole.

[nsjames]

Originally Posted by Welcome to NBA Jam

Left-handed drill bits are your friend here. They'll let you drill a hole in the middle of them to get an easy-out in there, and there's a possibility that the drill ends up removing the bolt while it's drilling the hole.

this.

once the bolt has broken there's usually no tension on the threads.

lefty bit will bring it right out.

Do not break off an easy out. They're hardened and it becomes a massive PITA.

[NGEE]

I'm asking more about how to get the drill bit to bite in the center of the sheared bolt - it can be a disaster if it starts to "drift". Seems like it would be easy if the sheared fragment of bolt was concave or even "square". Which it never is. So if the fragment that's stuck in the block is convex or pointed (as pictured here), how can you get the drill bit to bite in the center without drifting?

Looking for advice from experience, not conjecture.

[nsjames]

find a bushing that fits in the hole. Or make one. They do sell them specifically for this reason. That's the proper way to do it.

The get it done method is to center punch the middle of the bolt and just use a small left hand bit. It will come out because it's not corroded in place. It's just a remnant that isn't really mechanially held in there by anything other than the friction of metal against metal.

[PhaseP]

Originally Posted by NGEE

I'm asking more about how to get the drill bit to bite in the center of the sheared bolt - it can be a disaster if it starts to "drift". Seems like it would be easy if the sheared fragment of bolt was concave or even "square". Which it never is. So if the fragment that's stuck in the block is convex or pointed (as pictured here), how can you get the drill bit to bite in the center without drifting?

Looking for advice from experience, not conjecture.

Originally Posted by NGEE

I'm asking more about how to get the drill bit to bite in the center of the sheared bolt - it can be a disaster if it starts to "drift". Seems like it would be easy if the sheared fragment of bolt was concave or even "square". Which it never is. So if the fragment that's stuck in the block is convex or pointed (as pictured here), how can you get the drill bit to bite in the center without drifting?

Left hand drill bits are great (Harbor Freight has surprisingly good quality set for small amount of money), but you will most likely won't need to use them in your case. As others already noted, you can take it out with a long thin flat screw driver or similar (an awl was mentioned above). Need something to turn the remainder left to get it out of the threads. If had corroded in place then you do need the left handed drill bits.

Is the bolt aluminum? (you can test with a magnet)

Do you have XI (your signature says otherwise)? XI oil pan uses such long bolts, I don't think the RWS oil pan has such long bolts (from what I can deduce the picture you posted) [Edit if Auto transmission, oil pan could have long bolts even with RWD)

If it is aluminum, and long and you have RWD, it could be one of your starter bolts.

[NGEE]

Originally Posted by nsjames

find a bushing that fits in the hole. Or make one. They do sell them specifically for this reason. That's the proper way to do it.

The get it done method is to center punch the middle of the bolt and just use a small left hand bit. It will come out because it's not corroded in place. It's just a remnant that isn't really mechanially held in there by anything other than the friction of metal against metal.

Ah, bushing. Makes sense, thanks.

[NGEE]

Originally Posted by PhaseP

Do you have XI...

RWD, auto trans. Definitely an oil-pan bolt.

[NGEE]

Well, mystery solved. I finally pulled the sub-frame to change out the oil pan gasket. Yep - oil pan bolt sheered from factory torque and fell out on its own accord. Planning to extract it tomorrow.

It's the corner bolt near the passenger-side rear of the oil pan, next to the inspection hole cover. Given the slant of the engine, that explains the oil dripping onto the down-pipe and smoking so much.

Super freaked about torquing the new bolts. Bought a digital torque wrench that goes all the way down to 1.5 Foot Pounds.

Replacing the water pump (again) since I have so much access right now. And control arms. And radiator. And... the list goes on. So tempted to do the turbos, engine mounts, etc., but I hate fixing what ain't broke.

[NGEE]

Sheared oil pan bolt extraction update - I got the bolt extracted with no problem. It took me a lot of research and hunting for tools - I was kind of freaked out about trying it but in the end it was pretty easy.

My internet searches left me more confused than when I started - everyone seems to have a different method. So I'm just posting what worked for me.

The biggest problem is access - unless you're on the shallow passenger side of the pan, a regular drill bit will not work because your drill will most likely rub against the pan and send your bit in at an angle. So you will need extensions.

Here are the tools I used:



First, very important to make a divot in the center using an awl or punch. This will get your drill bit started without running off-center.

Next, I used a 5/32 Irwin metal drill bit with hex base. Hex base allowed me to use a regular hex extension, which come in any length you might need.

With the right extension, I could line the bit up at a perfect perpendicular angle and run it straight in. I set my drill on low speed and went slow. TBH I did not go deep at all, because the right-hand bit started to run the bolt even further in. Given that the bolt was obviously easily moved, I stopped with a very shallow (approx 1/8) hole and went ahead to try the extraction.

The tapered spline I used wasn't Irwin, but it was labeled #3 and called for a 5/32 drill bit. The square base fit snug into a spade bit extender, which has set screws for really getting it snug and tight. I used an Irwin T-handle to turn it slowly. It came right out.

YMMV, but my advice is go slow, use the right tools (get the extensions) and make sure to get your drill bit centered.

[nsjames]

well done.

[antonmn]

8 of the bolts were broken when I did my pan. All but one came out easy. That last one had the ends to TWO steel bolts jammed up there. It was a nightmare.

Glad you came out better!

[clegg]

Great job on the broken bolt. Harbor freight has an automatic center punch that works well. You don't have to hit it with a hammer.

[NGEE]

Originally Posted by clegg

Harbor freight has an automatic center punch that works well. You don't have to hit it with a hammer.

Saw that spring-loaded punch in a video - cool tool, but I have sooooo many tools.

Originally Posted by antonmn

That last one had the ends to TWO steel bolts jammed up there.

Jesus. Oil pan porn.

The torque specs for the oil pan bolts are 8nm+90 degrees for the short bolts, and 8nm+180 degrees for the long ones. Those stretch bolts scare the shit out of me - I went more like 8nm+45/60.

Curious if anyone knows why BMW uses the stretch aluminum bolts - most other cars I've worked on just use steel bolts on the oil pan.

[marvinstockman]

Depending how much thread the new bolt has to grip, you can probably leave the broken section where it is, and either shorten the new bolt or make up the space with flat washer.