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Are the strut to knuckle bolts-nuts TTY??

2.5K views 28 replies 15 participants last post by  forlorn  
#1 ·
I want to make a camber adjustment, but it looks like the two bolts for the strut need to be loosened in order to move the camber adjustment screw. Are these parts TTY or can they be reused?
 
#12 ·
Torque + degrees usually means a TTY bolt.
 
#21 ·
Though I am one, you don't need an ME to test this. Just do as I did for the rear X-member and diff bolts. Buy a couple, measure them, install ONE using torque procedure in FSM. Then, remove bolt and re-measure and compare with unused one. If it is longer than it started, it has yielded. If not, it hasn't. It's really not complicated.

gorgbroza's post is pretty much spot-on.

There are bolts designed to be installed past their yield point. They almost always have reduced shanks to guarantee where the stretch will happen. With a constant diameter shank, if it stretches it is going to stretch in the threads because the root is the smallest diameter. The amount of stretch in the threads is something less than consistent and reliable. The stretch also happens along a much shorter length of shank which decreases the fatigue life. With a reduced shank bolt, the shank is a smaller diameter than the thread root and therefore has less cross-sectional area. When tightened, this smaller CSA is where the stretch occurs. It also occurs over a longer length of shank and increases fatigue life compared to having the stretch happen in the threads.
 
#22 ·
Ok, so it sounds like reusing them isn't a big deal... assuming they arent stretching immediately. But there is a limit to how many times they should be reused IF they start to yield after a certain number of uses. Anyone had one fail on them?? If so, how many times was it reused? I'm thinking I'm going to give it a 3-limit reuse... I cant see them failing after one use or anything. And there seem to be a lot of people reusing them indefinitely without issues :mullet:
 
#23 ·
I haven't heard of any failures of the knuckle bolt, just slippage. I would only reuse them once or twice, and on every use apply red loctite.

I stopped reusing my bolts after I had bolt slippage at Fontana in Turn 1, which corded one of my kumho v710s. :mrrg: $25 for bolts versus $220 a tire, I'll take the bolts. No slippage yet, I'm crossing my fingers.
 
#24 ·
In many cases the GM manual states "discard old bolts" because they have a thread locker applied to them when new. In a shop the time to thoroughly clean and reapply threadlocker is more expensive than new bolts.
 
#25 ·
I reused them when installing springs on my struts... I just tightened the crap outta them. They arent that hard to check the torque again later... just remove the wheel.
 
#26 ·
Before removing those bolts, always clean the exposed thread with
a wire brush. They accumulate brake dust and this binds up in the thread
so the nut seizes up after a couple of turns.

I destroyed three bolts before I worked this out. They looked clean,
but weren't. Fortunately the nuts come off far enough for you to
be able to slip a hacksaw blade under there.

The same applies to the lower nut on the endlinks. Bodycount: 1.
 
#28 ·
TTY?

No

/thread