Caliper mounting bolts are single use

Came across this today and thought it was worth sharing. I don't recall ever seeing this mentioned in any of the brake threads or youtube videos covering brakes. Screen shoots are straight from the service manual. Use the information as you see fit.

Disc Brake Caliper Bolt (Front)
90105A0336
Disc Brake Caliper Bracket Mounting Bolt (Rear)
90119A0282

 

Eh. Been changing my own brakes all my life and I lost count on how many times I’ve removed and reused the caliper bolts. Just have to be sure to clean up the threads and reapply thread lock when putting back together. Never had a single issue ever on any vehicle. Just changed the rotors on the Tundra and reused the bolts. Never thought anything of it.

 

I figured this would be the reaction of most on here. You are right, reusing caliper bolts is pretty normal and I have done it myself on other vehicles.


There is a major difference here though IMO. Most of the time the service manual doesn't specifically say the caliper bolts are single use. Usually the vehicle's service manual say to re-install the bolts and torque to spec.

I posted this to share the information as most people just post the torque spec and that's it. What anyone does with the information is not my concern.

 

Yea. Guess since it’s a TTY bolt, they’re just covering their ass. Ironically though, I remember watching some YouTube videos on swapping rotors on the Tundra and a couple in particular were done by actual Toyota technicians. All of them re used the caliper bolt. Haha.

 

Don’t thing they are TTY because there aren’t different TQ specs as a TTY bolt would require. It’s probably because they come with thread lock, which most people don’t put, including me. In all the years of doing my own brakes I have never use TQ specs or thread lock, never an issue. And I can guarantee that not even the techs at Toyota use new bolts or TQ anything.

 

Yea. Probably so on the thread lock. I’ve always used thread lock when putting back together. But I’ve never torqued them to spec. Just get em good and tight. Haha.

 

The torque specification does not indicate if it is TTY. the give away is when they say not to reuse the bolt. While torque plus angle is commonly associated with TTY bolts, they can still be TTY with a "regular" torque spec. Conversely, just because the torque spec is torque plus angle, it is not necessarily a TTY bolt.



Honestly are we surprised the dealer techs didn't do something according to the manual?

 

How did you get access to a modern Tundra service manual? Sorry if this has been answered in the past as I am new to this.

 

I agree on them coming with thread lock. I know replacement calibers for trailers have new bolts with thread lock. My brother had the front pads replaced on his Ford and the dealer did not properly tighten the caliber bolts. It did not end well.

 

Besides the leftover thread lock residue, maybe the 130 lbf-ft of torque stretches the bolt beyond or near its elastic limits ... hence the new bolt requirements for safety purposes ... just in case.

 

Ding ding ding.....we have a winner

Based on the quick check I did (and making a few reasonable assumptions), they are going past the elastic limit at 130lbf-ft. Not by much, but enough to justify the language in the manual.

 

Good thing I came across this thread. Was on the trail when the truck started making rattling noises. Checked under the truck and one of the bolts literally just fell out - didn't break or anything. The other bolt was finger loose. The crazy part is that I retorqued all of my brake bolts, as I usually do along with other bolts, before I left for the trip. I added loctite on the remaining bolt and used the one big bolt from the rear seat as a temporary replacement.

Ordering 10 new bolts to replace the others and to carry as spares. Also ordering a new to me brake caliper. Will be using blue loctite going forward.

 

I just removed my caliper brackets and those bolts took a bit more persuasion than I figured they should - likely due to thread lock. I saw that my 2015 version of the FSM called for their replacement and contacted he Dealership to buy new ones - they don't stock them. I don't think the Toyota techs replace them. My FSM says torque the fronts to 73 ft-lbs and 70 ft-lbs for the rear which is what I did. I see your 2016 version says 133 for the front and 123 for the rear. I have a 2017 but the 2015 FSM is what I got from Rockauto. Why the change in spec? Guess I will retorque them....while I'm at it, will order new ones.

 

In general I reuse those bolts but when you think about it, 133 ft/lbs is pretty high for those bolts, they probably spec no reuse because they are close to yield strength at that torque. A bolt is very much like a spring, it actually is a very tight spring, and like any spring if you stretch it too much it wont come back to its original position. So the bolt may loosen up in service. If have never seen it happen and I have done more brake jobs than I can remember. But as Cruzer mentioned it can happen. Loctite is a solution, kind of. I'll probably order the bolts shortly thou for when I do the brakes.

 

Guess I need to check the torque on mine. I re used my bolts when I rebuilt my calipers 6 months ago

 

Blue Loctite is for relatively low torque value applications. It's breakaway torque is measured in inch pounds. Red Loctite is for higher torque value applications. It's breakaway torque is measured in inch pounds however they are much higher values than blue provides.

I use blue Loctite on high vibration low torque fasteners such as the floorboard mounting bolts on my motorcycle. Torque spec is 25 lb. ft. Blue Loctite will increase the breakaway torque enough to prevent the bolts from backing out from vibration.

I use red Loctite on brake caliper bracket to steering knuckle mounting bolts for the same reasons except the higher torque values require a higher breakaway torque value.

The backside of the Loctite blisterpack card has a table listing the breakaway torque values for the different Loctite products to aid in determining which one you need for your project.

I hope this helps.

 

The 2015 manual says the specs on that bolt is 70. Not sure how that jumped to 123 seems a lot for caliper bolts.

 

That is kind of strange. I don't even know what the torque specs are for any of the brakes on my 4 vehicles. And I never use lock-tite on the bolts, I actually use a little bit of anti-seize. Up here in the Northeast that has always worked better for me, and honestly, in the 15+ years I've done brakes on my own cars and side work for friends, I've never had a bolt back out with anti-seize and just hand tightening them to "goodentight" specs.

 

+1, I think some folks get too carried away with torquing every bolt. I torque things where torque is critical. Head bolts, pan bolts, suspension components, and lug nuts come to mind. My brother had a brake caliper come loose on a F150. I don't think it was from not torquing but just a dealership tech not paying attention to what he was doing. It happened within probably 30 miles of driving.

 

Yeah anything when I built an engine got torqued, and like you said, suspension parts get torqued, especially if it's a part that has a bushing. Honestly even with lugs I tend to just have a pretty good feel by now what around 90-100 ft/lbs feels like with the 1/2 ratchet I always use. I get the lugs on with the weakest setting on my impact, then "torque" by feel. If the spec is more than that, I push just a little harder lol.

I've only ever seen one caliper come loose, and that was a friend who basically dunked the entire caliper bolts in anti-seize. I mean 100% covered, not just a dab down the threads lol. Obviously with that much it could never hold any sort of torque. But he learned his lesson, and luckily it was his own car.

 

Anyone know the torque for the sliding pin bolts (rear brakes) on a 2019? Thanks!

 

Found this....

https://www.tundras.com/threads/3rd-gen-rear-brake-torque-specs.30941/

 

No, the right TORQ IS 167 Nm.
Check first post.

 

I have no idea why they would need to be tightened that much. The only real force on them is sheering. Any stretching force on the bolts while in use would have to be from the hub and/or rotor flexing. Even then, with pistons on both sides of the caliper one would think the pistons would just compensate and not transfer any torque to the caliper bolts. Torquing a bolt tighter isn't usually a solution for a bolt loosening up. Plus it's screwing into a cast steel bracket. I would be worried about damaging the treads on that. Anyway, I would love to know why Toyota decided to change the torque spec.

 

They did for a reason. In that case follow by manual, that know better l.
I just did my brakes on 18' Tundra and I reuse this bolts and thighned then with 160 Nm, a bit lower spec.
In terms of assemble and disassemble follow by their manual is the best.
But Oil change interval of 10000 , I am not going to listen them.
Just bolts...
Yeah I don't know why is so high, anyway I did as manual said.

 

The torque spec changed on the caliper bolts due to the bolt size changing. 07-15 used an M12 bolt. 16-21 used an M14. The M14 has a higher torque spec and is basically a torque to yield.

I don't think it was an issue here in the states, but overseas the LC200 (which is basically identical as far as brakes are concerned) had some issues with caliper bolts failing or something along those lines. Hence both the 200 and Tundra switching to larger bolts.

Higher torque while not the ideal way to reduce the risk of bolts loosening does have that effect. These trucks have one piece rotors and fixed calipers on the front, so that is bit more demanding than having a floating rotor or floating caliper like the rear. Clamping force is the main source of "strength" to keep your calipers in place during braking, not shear. For reference EACH of the M14 front caliper bolts produces ~14,450lb of clamping force when torqued to spec.

 

That's a some incredible info.
Thank you.

 

Jus t did the brakes, the new bolts are not readily stocked in the local auto parts store, but NAPA was able to match them up by size and thread