nope, but the were the bolts provided by exact motorsports. i did not see what the grade was on them, BUT they look exactly like the ones on their site.

i torqued them down to 120lbs as per their instructions. after reading the thread about someone snapping their bolt. i basically loosened them back until i could hand tighten them again. then torqued to 75, then to 105. should be good, i greased the threads a bit before putting them in the first time.

The bolt grade is 12.9

This was the thread...
https://www.clublexus.com/forums/sus...t-failure.html

as far as ive researched, those bolts can handle a lot more than 120lbs. so im not worried (cross fingers)

 

according to the mechanic, the toes are within spec. they were within spec before i installed the camber kit for the rear and the spacers for the front.

you want the rears to be a bit toe in, and the fronts a bit toe out for drivability.

 

u added washer on them bolts?

 

Posted on other thread but you should not go over 100ft lbs with the bolt (lubricated) by taking it up to 120 ft lbs you are dangerously close to the bolt surpassing its yieled point and it wouldn't be a bad idea to replace them.

 

Good numbers especially on the camber. My car sits a bit lower than yours. My rears is 24.5 inches from ground to fender & the fronts are 25 1/4 inches. My car drives fine but in the back of my mind, I wonder why my rear camber is at -2.0L & -1.3R? I feel as if the tech got a bit lazy with my car and did not want to put more effort into it getting things even. How does your car drive?

 

shocker, get an second opinion.... i would, my rear are 24.65 off the ground and my toes are in spec and my fronts are 25... idk but that just me

 

GS300Tom: honestly, i did think of this when i was installing the bolts. i noticed that the head was much bigger on the stock bolts, and so the washers should help compensate that. i think ill do this tommorow. just gotta run to homedepot and find me some washers.

macd7919: yup, i retorqued them to 105 (ok technically 102) i think this should be fine.

dashocker: car seems to drive fine. doesnt really pull to either side. maybe its psychological, but it seems the steering is a bit lighter. as to why you have different camber from right to left, oem factory spec on the programmable alignment machines adjusts the numbers a little bit to correct for the crown of the road. what i did was ask the mechanic to make the right side equal as closely to the left side as possible, screw the crown of the road, ill correct that myself with the steering wheel. i actually wanted my front camber to sit closer to -1.5, but if this is as much as i can get without going to adjustable upper control arms, then ill take it. i had some bad experiences with adjustable upper control arms on my previous car so im trying to avoid it (bolt would always come lose and thus camber goes to crap)

some cars are completely out of alignment at dead stop. eg, old merc benz's have the toe's completely off at rest, but as the car moves, the toe self adjusts. this was told and shown to me by my previous alignment mechanic (whom now works on british cars at some other shop).

 

I will leave it as is as the car tracks & handles fine. -2.0& -1.3 is actually the range for a stock E60 M5. My rear end feels more planted than before.. When things get out of whack, then I will get that second opinion elsewhere..

What is amazing is once you drive off the alignment rack, and the suspension resettles, your alignment specs will change. If you go to the alignment shop tomorrow & compare numbers, you will see a disparity. As long as the car tracks straight & feels composed after the alignment, you should be happy...

 

Just make sure you don't use washers lock washers/shake proof with a 12.9 bolt, a 12.9 bolt is designed to bite into the mating surface, a lock/shake proof washer would prevent it from doing so.

The issue with re-torquing them after they have been over torqued is that the bolt has been stretched past yield. Once it's stretched past yield it will no longer provide a pre-load and is prone to loosening which can cause the bolt to fail under shear stress. The proper pre-load for a M12 12.9 bolt is about 100.5 lbs assuming it was lubricated, 120lbs is 20% greater torque than it required which is a significant amount, hence the reason I suggested replacing them with new ones.

Did Exact specify that you lube them when you put them in? I'm assuming so from their suggested value of 120 as un-lubricated is much higher of a torque for pre-loading. I would be interested to find how they came up with the number of 120 ft lbs. By the use of 12.9 bolts (which is considerable overkill for the application) I'm thinking that when the RCA's were designed they weren't analyzed by using any engineering methods and simple sourced the strongest bolt available. The reason I would come to this conclusion as that the grade of the bolt can be more or less determined from the stock torque spec of 83 ft lbs. This torque spec is what is needed to provide proper pre-load for the oem bolt.

By reverse engineering the calculations indicate that the factory bolt is a grade 8.8 bolt.

 

but our cars aint an E60 m5, keep it in the LEXUS spec imo

 

LOL.. -1.3 is actually within Lexus factory range & -2.0 is just 7 tenths of a degree out of Lexus factory range. I like the compromise.. Half BMW & half Lexus

 

exact did not specify to lube up the bolts, its just something ive always done.

the instructions were to torque both to 75ft lbs, then to torque them again to 120.

i lubed both bolts up before installing them. the 2nd time around, i loosened both, then took 1 out to examine, seemed fine to me, so i reinstalled them, torqing to 75 first, then to 102ish. im sure the bolts will be fine, ill just look for some regular washers tommorow.

 

Ok, it's your car of course but in the future when you are installing bolts remember that lubing the bolt decreases the coefficient of friction to almost half of a non-lubed bolt. What that means is that it takes roughly half the torque to pre-load the bolt as it would if it wasn't lubed. If Exact specified 120 ft lbs on a non-lubed bolt you should have been torquing it to roughly 60 ft-lbs (assuming 120 ft lbs is the correct torque level for that bolt which I highly doubt).

The reason it's important to get the correct pre-load is because bolts stretch when tightened, that's what keeps the bolt tight and is referred to as pre-load, you want the bolt to stretch to the point where it is still providing resistance from loosening. If the bolt is over torqued then it is brought past its yield point (the yield point is the spot where the bolt will not return to it's original length), once this point is passed the bolt is permanently stretched and will not provide any resistance to loosening which can cause failure due to shear. The same thing happens with an under torqued bolt, it's loose so it fails due to shear in many cases.

 

man this sucks haha, why cant exact just chime in... GIVE US AN ANSWER DAMIT!!!!
anyways SorrGwa, are these the SPC rears u got on??? any pics

just read the SPC rear camber kit, it only adds +1 camber... that sucks haha

 

I did a quick search and found this torque spec. online. Obviously it would be better to find the "Actual" manufacturers spec. from Exact's bolt supplier, but nevertheless, this chart does show that 120ft.lbs "can" be within the spec of this bolt.

As for the one person who reported the broken bolt, without an actual failure analysis being performed on that failed bolt, there is no way we can do any more then speculate what the root cause could be. (over torque, torque wrench out of calibration, cross threaded, bolt manufacturer defect, lubricated thread, etc.)

If someone wants to ***-U-ME the root cause of the bolt failure, well you know what they say.

Note: I converted kg.m to ft.lb.

Last comment: I'm not implying that the torque specified is appropriate for the intended application, I'm merely stating that this torque spec shows it is not beyond the limits of the tensile strength for a bolt of this size.