Drilling holes in suspension bolts for cotter pins

[Mark_BC]

So I swapped out my rear end the other week and felt really manly about it, then drove 3000 km on the "new" rear end to California and back, no issues except I didn't torque all the bolts properly (upper and lower control arms, panhard bar) so they kept coming loose. I lost one nut for the upper control arm before I noticed the first time but luckily the bolt was still half in there.

I had to check and tighten every few hours while off roading. I pulled out the 2' breaker bar to really torque them down nice and that seemed to solve the problem but now I'm paranoid they are going to come loose. I added some rust inhibitor on the threads to keep them from seizing which may be contributing to the loosening.

There is some bolt length that sticks through after the nut goes on so I'm wondering if it's a god idea to drill a hole in that and put in a cotter pin so if it does loosen my axle won't fall off...

 

[bennett707]

Don't think that is really necessary. I'd start with tightening things appropriately (mistakes happen, but fix the mistake first), add some loctite if you feel inclined.

 

[Toyotayoda]

Don't think that is really necessary. I'd start with tightening things appropriately (mistakes happen, but fix the mistake first), add some loctite if you feel inclined.

2nd the loctite idea, those nuts had it from the factory, so it could have worn off during removal and install.

 

[octanejunkie]

Yes on proper torque and loctite

NO on drilling hardened bolts

 

[Unner]

Do you have a torque wrench? If not get one, and use that to set the bolts to the proper torque specs in the FSM. Lot's of people ignore OEM torque specs, but trust me they put a lot of time, effort, and money into finding exactly how tight the bolts need to be. They have specialists whose only job is to work on torque specs.

 

[TheDurk]

I had all those out, and a bunch more, when I did my frame swap. It all went back with anti-seize at FSM spec torque. Nothing has come loose and it has been a year and 10k miles.

[MENTION=148927]Toyotayoda[/MENTION] I don't believe any of those had Loc-tite from the factory. Toyota did not apply Loc-tite on the assembly line. They only used pre-coated bolts when thread locker was called for, and those are noted as non-reusable in the FSM. This was not the case with the bolts mentioned.

I'd like to know the source for that assertion because I don't believe it.

 

[JZiggy]

I had all those out, and a bunch more, when I did my frame swap. It all went back with anti-seize at FSM spec torque. Nothing has come loose and it has been a year and 10k miles.

[MENTION=148927]Toyotayoda[/MENTION] I don't believe any of those had Loc-tite from the factory. Toyota did not apply Loc-tite on the assembly line. They only used pre-coated bolts when thread locker was called for, and those are noted as non-reusable in the FSM. This was not the case with the bolts mentioned.

I'd like to know the source for that assertion because I don't believe it.

Agreed. Have not run across much factory loc-tite on the Yota yet.

You could also consider swapping the nuts out for nylock or distortion lock nuts *of appropriate grade* and then you can still use anti-seize.

 

[octanejunkie]

Unless there is a crush-component, like a pinion crush sleeve, or a specific OEM settings, torque measurements can usually be estimated based on the size of the fastener, fastener material/hardness and thread pitch and what it is clamping.
Just as an example: https://www.boltdepot.com/fastener-information/bolts/US-Recommended-Torque.aspx

This is not to say that you should forego OEM specs forevermore, just that if you don't know you are better following some guideline somewhere versus losing fasteners or worse, like wrecking and killing someone due to not properly tightening a fastener.

Obviously common sense should include knowing what you are fastening, like a 10mm bolt clamping a stamped steel or cast aluminum valve cover requires much less torque than the same 10mm bolt one clamping a brake backing plate to a spindle.

On that note, use of thread lockers requires some knowledge of which thread locker you are using (green vs red vs blue) and what is required to defeat it when you want to open the fastener. Don't use a thread locker that breaks down with heat in an area that sees extreme heat, and don't use one that requires heat to loosen in an area where you cannot apply that heat without causing collateral damage.

It's sciencey, but with enough experience common sense can prevail.

 

[Toyotayoda]

I had all those out, and a bunch more, when I did my frame swap. It all went back with anti-seize at FSM spec torque. Nothing has come loose and it has been a year and 10k miles.

[MENTION=148927]Toyotayoda[/MENTION] I don't believe any of those had Loc-tite from the factory. Toyota did not apply Loc-tite on the assembly line. They only used pre-coated bolts when thread locker was called for, and those are noted as non-reusable in the FSM. This was not the case with the bolts mentioned.

I'd like to know the source for that assertion because I don't believe it.

well you must not have used new bolts and nuts in the past, because a astounding number of chassis nuts come with a penetration grade thread lock on them. and the nuts and bolts that do not have it are equipped with some sort of locking mechanism, or washer. My first assumption about this post was that the OP used his 6-8" ratchet to tighten chassis bolts and wonders why they came loose, but not want to put guys on blast like that I recommended some thread lock, much better idea than f------ anti seize.

 

[TheDurk]

well you must not have used new bolts and nuts in the past, because a astounding number of chassis nuts come with a penetration grade thread lock on them. and the nuts and bolts that do not have it are equipped with some sort of locking mechanism, or washer. My first assumption about this post was that the OP used his 6-8" ratchet to tighten chassis bolts and wonders why they came loose, but not want to put guys on blast like that I recommended some thread lock, much better idea than f------ anti seize.

What I took out was what Toyota put in. No doubt whatsoever. I am the only wrench to touch this truck since new.