Broken/snapped caliper bolt

[96RedRunner]

"I spent several weekends screwing around", we've all learned the hard way at sometime.

Setup in a mill 10-15 min, drill it, chase threads with bottom tap 15 min, done. $100.00, my hourly rate on this.

 

[4Runner4Leon]

"I spent several weekends screwing around", we've all learned the hard way at sometime.

Just to clarify, my estimate for a shop doing this work was $900.

Setup in a mill 10-15 min, drill it, chase threads with bottom tap 15 min, done. $100.00, my hourly rate on this.

Agree - and with the bolt being so accessible, he can easily drill it out, tap and drill for the heli-coil, install the heli-coil, and be done in an hour. No need to pull the knuckle or take it to a shop. Heli coil kits in that size are not outrageously expensive like my $180 M18 heli-coil kit was.

 

[96RedRunner]

[MENTION=198376]4Runner4Leon[/MENTION] " Once I committed to drilling and tapping, I had it heli-coiled in an hour"

Wasn't knocking you and the job, was good example of time for different tactic.
OP has gone the route, my post just another tactic.
To me this is no place for a heli-coil, could get different spindle tricky work with bearings.
Pick your poison.

 

[varol1]

Alright gang, after what seemed like an endless amount of time, I was able to finally drill most of the bolt out with a 5/16" bit. Unfortunately, the combination of PB Blaster, heat, wax, etc. just didn't let me get it out - it's totally seized to the spindle. I did find a video of a guy who ended up heating a caliper for 25+ minutes and going at it with a nut and breaker bar repetitively until it gave way - his reaction is priceless (I was longing to get the same outcome but alas, no luck).

So how do I determine which particular heli-coil set is needed to finish the job? The bolt head requires a 17mm socket although I don't know if 17mm is the head size or the bolt diameter. I don't think I can go up in size at all since the bolt barely fits through the caliper hole as is. Here's a link to the various Heli-Coil kits/sets, appreciate any help: https://www.mutualscrew.com/media/refguides/helicoil chart.pdf

 

[Bad Luck]

Alright gang, after what seemed like an endless amount of time, I was able to finally drill most of the bolt out with a 5/16" bit. Unfortunately, the combination of PB Blaster, heat, wax, etc. just didn't let me get it out - it's totally seized to the spindle. I did find a video of a guy who ended up heating a caliper for 25+ minutes and going at it with a nut and breaker bar repetitively until it gave way - his reaction is priceless (I was longing to get the same outcome but alas, no luck).

So how do I determine which particular heli-coil set is needed to finish the job? The bolt head requires a 17mm socket although I don't know if 17mm is the head size or the bolt diameter. I don't think I can go up in size at all since the bolt barely fits through the caliper hole as is. Here's a link to the various Heli-Coil kits/sets, appreciate any help: https://www.mutualscrew.com/media/refguides/helicoil chart.pdf

17MM is the bolt head size. You'll need to figure out the thread pitch and pattern and then order the corresponding helicoil kit. You'll need the helicoil, helicoil install tool, drill bit, and tap. I'm not sure what thread pitch and pattern that bolt is, but hopefully a more intelligent member than I can chime in.

 

[Bad Luck]

Here's a good video on the helicoil process:
YouTube

Try Amazon or Ebay for the helicoil kit. I got mine from Amazon when I had to repair a snapped/seized exhaust bolt a couple years ago.

 

[I_bRAD]

It was only one bolt that was stuck right? Measure the one that wasn't damaged.

My guess is M12 but measure the diameter and then you'll also need the pitch which will be specified by the distance between each peak (or valley) A thread gauge tool is useful but you can just measure the distance across 10 threads, and then divide by 10

Edit: pay attention to the markings on the head too. A brake caliper bolt will be a specific grade. This isn't the place for whatever they have at the hardware store (unless they happen to have the correct grade!) Best bet is just to buy the toyota bolt.

 

[96RedRunner]

I was able to finally drill most of the bolt out with a 5/16" bit.

Oh so close, good deal.
Something you could try with small chisel and hammer.
Strike whats left of bolt nub toward center of hole you drilled.
You should be able to get whats left broke loose enough to get it out no damage to threads.

 

[varol1]

I picked up a new bolt from Toyota yesterday. She's either an M10 or M12 x 1.25mm (fine thread). My guess is M10 but going to order one of each Heli-Coil just in case.

Coolest website ever: Bolt Depot - Printable Fastener Tools

Oh so close, good deal.
Something you could try with small chisel and hammer.
Strike whats left of bolt nub toward center of hole you drilled.
You should be able to get whats left broke loose enough to get it out no damage to threads.

Thanks, will also give this a shot.

 

[MStudt]

Edit: pay attention to the markings on the head too. A brake caliper bolt will be a specific grade. This isn't the place for whatever they have at the hardware store (unless they happen to have the correct grade!) Best bet is just to buy the toyota bolt.

It's a metric bolt so the markings on the head won't really matter. The crappiest metric bolt will be an 8.8, and that comparable in strength to a Grade 8 bolt. Which should be more than enough for mounting calipers.

When talking about imperial bolts then yes. Make sure count the dashes on the head, add two additional, and that'll give you the grade of bolt.

Mike

 

[4Runner4Leon]

Definitely try to use a chisel to pound the remnants of the bolt inward, that might work.

If not, then go with the insert. I think it's either an M10 or M12 (I'm guessing M10 based on your pictures). Like others said, measure the diameter of the good bolt (at the threads) to get the "M" number - e.g. 10 mm is M10. To measure the pitch, measure the length of 5 or 10 threads, then divide by the number of threads. So if you measured 12.5 mm for 10 threads, you get 1.25, so it's a 1.25 pitch. So in our example you'd have an M10-1.25 bolt.

BTW, Heli-coil is just one brand, I often use Perma-coil, which are made in USA, I get them on Amazon. For instance, here is the M10-1.25 set - https://smile.amazon.com/Perma-Coil...=permacoil+m10&qid=1549640832&sr=8-3-fkmrnull.

 

[MStudt]

No need to measure the bolt diameter, length, and thread count. There's room for error on the thread count when you go that route.

You need a 12-1.25 x 35mm for the caliper. You can also go OEM for the bolt, and that part number is 90105-12175.

Mike

 

[4Runner4Leon]

In that case I'd grab this one, about $20 cheaper than the same kit on Amazon, or the heli-coil version - Perma Coil 3221-M12F Metric Thread Repair Insert Kit M12x1.25, 5543-12, loc A7 | eBay

 

[phattyduck]

If you can go up one more drill size without hitting the threads, you got this.

If you can deform/break the bolt now, go for it. Otherwise, go up one more drill size.

If you are careful, a quick clean up with a tap and you will be all good.

-Charlie

 

[varol1]

If you can go up one more drill size without hitting the threads, you got this.

If you can deform/break the bolt now, go for it. Otherwise, go up one more drill size.

If you are careful, a quick clean up with a tap and you will be all good.

-Charlie

I'll give it a whirl.

Taking the safer assumption the OEM bolt is M10, the Time-Sert kit comes with a 13/32" drill bit (0.40625" diameter). I've clunkily drilled with a 5/16" bit (0.3125"), so I figure I can go up to a 3/8" (0.375") safely without impacting the ability to put in a Time-Sert. FWIW, I haven't read any horror stories with Heli-Coils, but the general sentiment is Time-Sert is made from more durable components, and given the bolt is holding the freaking brake caliper in place, I'm not taking any chances. The additional ~$60 is worth my life .

 

[AntleredRuin]

I'm confirming that the stock bolt size is M12x1.25 x 35mm.

I lost a caliper bolt after doing my TBU (my fault, I didn't torque). Long story short, no one in my area carries that pitch of bolt besides Ace Hardware. Not Home Depot, Lowes, etc. I've been using the same bolt I got from them for over a year now, no issue.

 

[MStudt]

I'll give it a whirl.

Taking the safer assumption the OEM bolt is M10, the Time-Sert kit comes with a 13/32" drill bit (0.40625" diameter). I've clunkily drilled with a 5/16" bit (0.3125"), so I figure I can go up to a 3/8" (0.375") safely without impacting the ability to put in a Time-Sert. FWIW, I haven't read any horror stories with Heli-Coils, but the general sentiment is Time-Sert is made from more durable components, and given the bolt is holding the freaking brake caliper in place, I'm not taking any chances. The additional ~$60 is worth my life .

Post #52 and #56 have the correct bolt size stated. It's a 12-1.25 x 35mm, and not a 10mm.

Mike

 

[96RedRunner]

If you can go up one more drill size without hitting the threads, you got this.

-Charlie

Look closely at last pic he's real close to threads now on left side of hole.

 

[TheDurk]

For future reference:

and that part number is 90105-12175.

That tells you it is M12. Works for washers and nuts, too.

ALL Toyota M12 bolts are 1.25 pitch.

Full list:

6 mm diameter - 1 mm pitch (iso course) - requires 10 mm wrench to fit head / nut
8 mm diameter - 1.25 mm pitch (iso course) - requires 12 mm wrench to fit head / nut
10 mm diameter - 1.25 mm pitch (iso fine) - requires 14 mm wrench to fit head / nut
12 mm diameter - 1.25 mm pitch (iso other) - requires 17 mm wrench to fit head / nut
14 mm diameter - 1.5 mm pitch (iso fine) - requires 19 mm wrench to fit head / nut
16 mm diameter - 1.5 mm pitch (iso fine) - requires 22 mm wrench to fit head / nut

So, yes M12x1.25. This is the one size that is tough to find in auto parts/hardware stores, as this is the only non-standard pitch.

The length you need to measure.

Here is the scoop on grades/torque ratings....

NUTS & BOLTS: Sizes and wrench equivalents - Toyota FJ Cruiser Forum

You're welcome.

 

[96RedRunner]

[MENTION=283658]varol1[/MENTION], Another option to drilling next size up, use a triangle shape file file a groove in bolt in thinnest area without getting into threads.
hammer and chisel then.