Broken/snapped caliper bolt

[MStudt]

Maybe start with 1/8" which = 2/16" really equals .125", then 3/16" , 1/4"(4/16" or .25), 5/16"?
stepping up in size or am I missing something?
Either way good luck OP, really doesn't look that rusty.

Yes, you are correct about the 1/8" coming before 3/16", but not about the 1/4" statement. I skipped 1/4" on purpose since by moving to 5/16 you'll have a better chance of the bolt coming free. If you want to go with 1/4" before the 5/16" fine. I would then step up past 5/16" to maybe 3/8" (.375" or 6/16).

Mike

 

[alumarine]

To add to what [MENTION=142122]96RedRunner[/MENTION] said, if you have a drill bit the same size as the hole in the caliper you can use that to center the dimple for the pilot hole.

 

[96RedRunner]

use left hand drill bits. Mike

Turning the bolt lefty loosy is what started problem, they work don't think so in this case rust will never make it through knuckle.
You spot on with jumping from pilot hole to 5/16 or 3/8 for some meat of the bolt and heat.

 

[MStudt]

Turning the bolt lefty loosy is what started problem, they work don't think so in this case rust will never make it through knuckle.
You spot on with jumping from pilot hole to 5/16 or 3/8 for some meat of the bolt and heat.

No, turning it left with no heat is what caused this. You would have seen the same results if this were reverse threads.

Applying heat, and drilling with left hand bits "might" cause to the bolt to extract itself while drilling with the larger bit. If the left hand bit doesn't cause the bolt to come free a regular bit won't either.

If this were me I would drill the first pilot hole, and apply some heat to the knuckle. Drill the next hole, give some love taps with a hammer, apply more heat, hold a candle to exposed end, and a few more taps. Then start drilling the large hole while tapping on the spindle with the hammer. Chances are, it'll back out. I've been able to get several bolts out that way on my rustrunner.

 

[96RedRunner]

Chances are, it'll back out. I've been able to get several bolts out that way on my rustrunner.

More than one way to skin a cat, lol. Lefty's def have their uses have a small set to 1/2" Mapp gas on hand.
I feel for OP it's a PITA job.

 

[MStudt]

More than one way to skin a cat, lol. Lefty's def have their uses have a small set to 1/2" Mapp gas on hand.
I feel for OP it's a PITA job.

I agree, but it's doable.

 

[varol1]

n00b update: I've not even been able to make a noticeable dent in the bolt for the pilot hole. Using my Craftsman 19.2V cordless drill on the highest speed and torque setting with a 5/64" SureBilt left-handed bit, this is what I got after about 3-4 minutes of drilling:

(It's not obvious in the photo, but the bit has made next to no progress on top of the center punch I used.)

The drill bit clearly isn't the highest quality but my local Home Depot didn't have any left-handed bits and so I took what I could find at AutoZone. Do I need to get cobalt/titanium bits online or is my drill under-powered? I could continue though it feels like I'd need to drill for hours on end.

Edit: I checked about 10 times to make sure the drill is spinning counter-clockwise.

Edit 2: Decided to try a regular Cobalt bit and started cutting into it within 15-20 seconds. It will take time to go all the way through the bolt but at least it's progress. I figure it makes no difference whether I go CW or CCW. Will update more tomorrow.

 

[I_bRAD]

Using my Craftsman 19.2V cordless drill on the highest speed and torque setting with a 5/64"

Slow down! Not sure what your drill can do but probably you're going too fast.

Cutting speed should be 70-80 surface feet/minute for steel.

RPM=(cutting speed X 4)/ dia of bit. So with a 5/16 bit you're looking at ~900 rpm.

Throw the first bit out. You've probably burned it up. Start with a fresh bit, go slower and some coolant wouldn't hurt (if you don't have cutting fluid you can just use a bit of oil or transmission fluid)

If you're going the right speed you should see small chips forming and dropping off the drill as you go. Too slow and you'll bind. Too fast and it will just spin and dull your bit. Pressing harder won't solve that.

You might also consider starting with a pilot hole. Maybe 1/8" or so. That will be easier to drill and will help guide the larger bit.

When you get to tapping the hole, iron is difficult to tap! Take your time and back the cutter out as you go to clear chips. You don't need to break a tap off in there once you finally get the bolt out.

Good luck!

 

[varol1]

Gang - I gave it the old college try with various bits, MAP gas, candle wax, etc. but just can't get the bolt out. That said, it's clear the bolt is only seized to the knuckle as the caliper rotates freely around the broken bolt (until it hits the dust shield on the bottom).

Assuming I can remove the four bolts holding the caliper together and take off the pads, shims, etc., will the caliper separate into two if I smack it with a mallet? Just eyeballing, it looks like it would take serious force, so figured I should ask before going that route. Removing the caliper should allow a vise-grip to latch on to the end of the bolt.

 

[varol1]

The saga continues, albeit with progress. I was able to break free the four bolts holding the caliper together with virtually no effort and the caliper separated on its own. I now have much better access to the bolt:

I'm reaching out locally to see if anyone would be willing to come out with a welding machine and weld a nut on the end. Hopefully, hitting it with a torch some more and drawing candle wax in there will help break it free with a breaker bar. Wish me luck.

 

[4Runner4Leon]

That's progress. If I interpret your other photo correctly, you did manage to drill a good depth pilot hole in the bolt, right? Why not continue drilling through it with ever larger bits? I would stick with right handed bits, not left handed, because that will tend to force the bolt into the knuckle, instead of out, thus avoiding dealing with the rust collected on the back side.

I'm with Charlie, I think that when you get the bolt drilled out enough, you'll be able to drive it out. And if the bolt threads are so rusted to the knuckle that this won't work, then no welding of nuts to the bolt will help anyway, you'll be in the same boat as I was above with the O2 sensor picture, you'll just have to drill it all out and retap either for the same bolt or a heli coil.

BTW, I don't see all that much rust on other components, so I don't think you'll have that much trouble, but I could be wrong.

 

[00Spork]

I'm in Evergreen, but I'm about to head out of town. If you are still having trouble when I get back next week, once I have time I'd be happy to come help you out.

I have a MIG welder, so might not be as easy to weld as somebody that has TIG, but we could give it a go.

Keep at it and use a lot of heat!

 

[96RedRunner]

I'm reaching out locally to see if anyone would be willing to come out with a welding machine and weld a nut on the end..

My $.02 on the welding of nut, not just any ol'weld will work in this case.
You already broke a bolt that's torqued past 90 ft/lb's You need a high tensile strength weld 70k+ PSI.
Mig, Tig won't do that with the wire most welders use, Stick will.
70/18, 100/18, 120/18 1st # is tensile strength in K psi, 2nd # filler rod dia I would use 12018.
No need to tell welder these numbers or about wire, make it clear what he will be dealing with during call.
He'll have a torch set on truck also could be needed.
Your also going to pay more welder coming to you.
Lol, sorry $.04 worth.

GOOD LUCK !

 

[Seven Bar S Ranch]

Just finished this upgrade myself on my 98. Several posts said the factory 16 inch wheels will fit. WRONG. I had to buy hubcentric wheel spacers in order to keep my factory wheels. I actually like the stance better with the wheels set out just a little farther, only issue is when I put brand new tires on the wheels there is a touch in the front fender corners when backing up and turning sharp at the same time. I don't think this will be an issue for long as I intend to add a small lift when the weather warms. Keep us posted on your progress and any additional issues.

 

[lpsoldia311]

Soaked it down?

I may have missed it but didn't see it specifically called out in the thread, just to be clear have you absolutely drenched and soaked what's left of that bolt in PB blaster/Kroil/etc? Hard to tell from pics if the light sheen is from spray residue or just working on/around it. Those sprays, if left overnight, and especially right after heating up the bolt can really penetrate into the threads and work some miracles. If you end up with time waiting for someone to weld the nut on, I'd second going the heat/soak/punch route like the others mentioned.

Heating up both slightly expands both objects, I've heard (but almost no one has had the patience for it in the industrial field) that if it was a big enough bolt they'd heat up the surrounding area and the stuck bolt together. Then right after that spray cool water or literally the upside down cans of keyboard dusting cleaner right onto the bolt to immediately shrink it every so slightly to help break any rust adhesion within the threads. Also had a coworker who used to work for Boeing way back in the day and said they'd do something similar with main wing (dowel/clevis?) pins during assembly to the fuselage and were so close of a tolerance they'd stick the rod in a super cold freezer for several days and heat the thru-hole up. Team of guys would have less than 5 minutes to to seat the rod with a sledgehammer and if they didn't get it started within that time they'd have to start all over.

 

[varol1]

Thanks for all the continued suggestions, gang. Given the feedback, I'm going to hold off on the welding approach for now.

I had stopped drilling before as it seemed I wasn't making any further progress. I decided to make a mad dash to Home Depot in the snow and picked up another set of cobalt bits. They started cutting immediately, so I definitely must have spun the last set of bits too fast and dulled them out (I read cobalt bits can be sharpened but I'll save that for another time).

I've now got a 3/16" hole going all the way through the bolt and drenched it in PB Blaster last night. I plan to reapply a couple more times throughout the day. I'll also draw in some more candle wax after heat.

I may also take a dremel with a cutting disc to the seized end of the bolt and even it out with the knuckle. I figure it can't hurt and may even help when I go in with the final 5/16" bit to try and turn it out. The photo makes it look like the bolt is not seized on but it definitely is; it could be the lighting. I'm also thinking it may have been cross-threaded the way the end is angled. I'll let you guys know how it turns out tonight.

 

[Wedgy]

You could also try freezing it with liquid nitrogen, some of that wart remover spray, might shrink the bolt a bit and heat(MAP) on the spindle.
Good work on the drilling...slow and steady. If you try a punch be sure to put an anvil on the backside of the spindle.

 

[phattyduck]

You could also try freezing it with liquid nitrogen, some of that wart remover spray, might shrink the bolt a bit and heat(MAP) on the spindle.

Canned air (for keyboard cleaning, etc.) turned upside down will work as a freeze spray too.

-Charlie

 

[4Runner4Leon]

Speaking from my O2 sensor experience I mentioned above, I'd minimize the time spent screwing around with all these techniques. If you tried heat and penetrant with no luck, just get out the drill set, try to drill it as large as you can to see if the remaining threads come out, and if not, have a heli-coil set on hand and just drill, tap, and heli-coil that sucker.

It's a very accessible bolt/hole, so you can have it done in an hour.

I spent several weekends screwing around with the O2 sensor, as I said earlier, all time down the drain. Once I committed to drilling and tapping, I had it heli-coiled in an hour, and that's including the time to remove the steering rack to get access, and doing the whole thing on my back. That was for an M18 thread - your job will be much easier and faster.

 

[johnbyebye]

I had the same thing happen with an LBJ bolt. I ended up replacing the whole spindle. Hopefully you have better luck than I getting that out.