Tap out broken bolts? - alternator bracket

[ant.xlt.96]

Hi all,

I've got two snapped bolts out of the three that hold the alternator bracket. They're flush, so nothing to grab on to.

(This is a 96 4.0L xlt 2wd for reference. )

I've been able to drill out enough to try an ez-out screw removal tool, but the first one broke. I've taken this engine apart to the heads a few times already, so I'm not scared of getting in there, but i'm working on the street.

I don't have access to a welder and it doesn't seem like theres enough of the bolt to weld a nut on anyway.

Long story short: should I attempt to drill out the bolts and just retap the holes or is this something I should have it towed to an engine shop for them to repair.

Every thing else is running strong before the bolts snapped. Just need to reassemble and go.

Thanks!

 

[adsm08]

I want to tell you to drill and heli-coil, but I think there is a water jacket near the hole in the head. You need to be careful with that one.

 

[Andy D]

If you need to remove a snapped off EZ out, forget it. figue out a jury rig for that one. If it is a 8mm bolt,, start with a sharp 1/8 b it then move up to 3/16 , then a 1/4, 9/32. You let the drill hog out the bolt material. When you start seeing threads, stop. Then use a pick and a small screwdriver to clean the threads. It takes time.

 

[black_demon69]

Hi all,

I've got two snapped bolts out of the three that hold the alternator bracket. They're flush, so nothing to grab on to.

(This is a 96 4.0L xlt 2wd for reference. )

I've been able to drill out enough to try an ez-out screw removal tool, but the first one broke. I've taken this engine apart to the heads a few times already, so I'm not scared of getting in there, but i'm working on the street.

I don't have access to a welder and it doesn't seem like theres enough of the bolt to weld a nut on anyway.

Long story short: should I attempt to drill out the bolts and just retap the holes or is this something I should have it towed to an engine shop for them to repair.

Every thing else is running strong before the bolts snapped. Just need to reassemble and go.

Thanks!

can you post a pic?
are they the bolts that hold alternator?
are the bolts threaded into aluminum? (if so you could be dealing with electrolysis due to the different metals) coat new bolts with antiseize

have you tried heat?
have you tried a good solid wack or 2 with a hammer?

 

[Spott]

If there's an EZ-out broken off in there, it's going to be tough.

If it's aluminum, and you had a welder, you could do it (if you have a bit of skill); if you can reach it you can weld to it. The filler metal won't stick to the aluminum.

Definitely apply plenty of penetrating oil, preferably before it breaks off, but it will still help the removal process at this point.

On of my favorite tricks is to use left-handed drill bits. They're not common, but they're awesome for broken bolts. Punch a good center mark, and drill straight in. Start small, and increase bit sizes until either the bit grabs and spins the piece out, or you reach the minor diameter of the screw and there's only threads left.

 

[Mark_88]

Definitely apply plenty of penetrating oil, preferably before it breaks off, but it will still help the removal process at this point.

On of my favorite tricks is to use left-handed drill bits. They're not common, but they're awesome for broken bolts. Punch a good center mark, and drill straight in.

Start small, and increase bit sizes until either the bit grabs and spins the piece out, or you reach the minor diameter of the screw and there's only threads left.

Yep...yep...yep...

I had a few break off on my last alternator bracket. Soaking them in penetrating fluid (PB Blaster worked unbelievably fast) and reverse the drilling...

When you put the bolt in it is a clockwise rotation...taking it out works better when you are drilling in reverse because it spins the same direction as removal...chances are it will free up the remainder better.

Most broken bolts of that kind are short...so also think short and not much more to go to remove it...be positive...it works better on bolts...

 

[Andy D]

After yrs of using the method I described, I splurged 8 bucks or so on a Harbor Freight set of left handed bits. I have yet to use them, mostly because now I anticipate trouble removing parts from the Rat. Much oil and percussion is used before I even set a wrench to a bolt head. After all the prep. pull down and tighten it just a skosh . Movement is important to get oil into the threads. Rock the bolt back and forth in an increasing arc. You guys know the routine

 

[black_demon69]

just make sure there is an oil leak for 1 year prior to removing bolts

 

[adsm08]

just make sure there is an oil leak for 1 year prior to removing bolts

Yup, leaking seals and gaskets aren't a "failure", it's just the automatic corrosion inhibitor doing it's thing.

 

[Andy D]

Yah there is that. When I had a Jeep that didn't leak. I would get nervous figuring that it was empty

 

[enjr44]

This is the fault of the engineers that have made all the attached parts so good that by the time you have to take it apart, the bolts are frozen!!!! LOL

Back in the old days nothing stayed together for twenty years.

 

[ant.xlt.96]

Thanks for all the replies, guys. I'll try to post a pic later on today if I can. I'm thinking I may be SOL on this one; I've been contacting some auto shops nearby, but no one want to take this job on.

I don't want to mess up anything on this engine, but it's looking like I'm going to have to drill these out myself. Of course, I drilled the center of the first bolt too close to the edge (I'm assuming), but maybe I'll be able to chisel it out without too much damage to the threads.

Also, to clarify these are cast iron heads. Not sure if that would change anyone's advice.

Does any one know the drill bit size / tap size I'll need for this?

 

[ant.xlt.96]

This is the OHV engine.

Can anyone confirm/ deny that there is a water jacket behind one of the bolts?

Facing the truck, the two snapped bolts (attaching the alternator bracket to the engine) are the two on the passenger side and the single on the drivers side is intact.

 

[Andy D]

Ok, I don't know about the water jacket particulars. More on that later. As for the off center pilot hole drill the next size up, 3/16. Angle it toward the center of the bolt. once this is reached, straighten out the bit
Use oil and sharp bits. If you used a 13 or 14mm wrench then it is probably an 8mm bolt. (5/16). You want to stop shy of 5/16. so that you have something to make threads into. Iron head I think, I'm ashamed that I dont know more about the 4.0. That is the Rat's engine too. In the 4 yrs of ownership. I have just replaced the starter. The Rat is one of the best starting vehicles I have ever owned. I had both rear plugs out and they were burning fine. The fuel injection is practically the same system as my old BMWs and so far just as good running.

Should you hit water stop drilling and unplug the drill. Make sure the new bolts don't block the passage. Coat the bolt threads with Permatex Aviation Forma gasket. On the Jeep 360 V8s, there were bolts tapped into water jackets by design.

 

[ant.xlt.96]

Thanks for the tip Andy D. I'm going to give this a shot over the weekend.

It seems like this is the last resort unless I take the head into a machine shop. No one local will touch it with the engine in.