Check your Nuts!
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Joined: Feb 2003
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From: Dallas, TX
I just rechecked my BMR T/A and UMI crossmember nuts last night and they are still tight as ****. On adjustable versions, how tight should the nuts be that connect the torque arm to the rearend bracket? I couldn't find that anywhere in the instructions and that might be whats causing my light banging.
Joined: Jul 2006
Posts: 381
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From: Oshawa (Home of the 5th-gen)
TECH Resident
Joined: Feb 2003
Posts: 827
Likes: 0
From: Dallas, TX
Joined: Jul 2006
Posts: 381
Likes: 15
From: Oshawa (Home of the 5th-gen)
Also, looking at those pictures above, I have my doubts that that is the UMI kit. A) there are no lock washers, B) it doesn't even look like there's enough thread left to have a washer in place, and C) the nuts don't look nearly as tall (thick?) as the ones that UMI supplied. Their bolts must have been at least ~1/4" to ~1/2" longer, since when installed, with lock washers and taller nuts, there were still a couple thread pitches exposed.
TECH Resident
Joined: Feb 2003
Posts: 827
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From: Dallas, TX
Flat washer came in mine...and while maybe not necessary I'd rather have the lock washer on a good flat surface than pushing around the hole in the TA bracket. Either way, definitely need the lock washer.
Joined: Jul 2006
Posts: 381
Likes: 15
From: Oshawa (Home of the 5th-gen)
I DO know that there were lock washers for sure 
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FYI lock washers don't do jack. In college my friends senior design thesis was on lock washers and their ability to help keep fasteners from coming loose. Most threaded fasteners retain their torque due to the friction between the treads of the male and female fastener. The load on the treads is created by bolt stretch. When the fastener is torqued to the proper load the tensile load on the bolt/nut creates a high normal force on the threads which is supposed to keep them from coming loose. The lock washer, or split ring washer works on the premise that it's a spring and that it adds to the tensile load on bolt/nut. Well considering how much tensile load is already being generated by the bolt nut vs. how little a split ring washer can add one can see that the split ring washer doesn't contribute much.
My friend proved that the vibration resistance and the break away torque are not affected by the addition of a split ring washer. However, loc-tite makes a huge difference because it "glues" the two threads together which increases the frictional load between the two which makes them more resistant to backing out.
All the OEM's know this. This is why they either use lock nuts or they put an adhesive patch on the bolts. For example, the caliper pin bolts have an adhesive patch. While the PHR nuts are a crimped locking nut. i.e. it's not perfectly round.
BTW, my camber bolt came loose this past weekend. It's gonna be loc-tited in place once I re-set the alignment. So check ALL your nuts!
My friend proved that the vibration resistance and the break away torque are not affected by the addition of a split ring washer. However, loc-tite makes a huge difference because it "glues" the two threads together which increases the frictional load between the two which makes them more resistant to backing out.
All the OEM's know this. This is why they either use lock nuts or they put an adhesive patch on the bolts. For example, the caliper pin bolts have an adhesive patch. While the PHR nuts are a crimped locking nut. i.e. it's not perfectly round.
BTW, my camber bolt came loose this past weekend. It's gonna be loc-tited in place once I re-set the alignment. So check ALL your nuts!
Agree totally with you on the lock washer premise. I recommend thread locker(which if done right I have never had a problem coming loose) or wiring the bolts if you have the ability.
What about the flanged bolts like used in the trans mount? I notice they are serated on the seated side. Does this aid in retention?
Sort of on topic ...
Everyone does insert the T/A bolts from the top, right?
Even if your nuts do come loose or even off, gravity will help get you safely stopped.
Sort of on topic ...
Everyone does insert the T/A bolts from the top, right?
Even if your nuts do come loose or even off, gravity will help get you safely stopped.
I have had almost every bolt under my car come loose. Especially if it's something that I loosened then retightened. After finding loose nuts after every race, I did something about it. I put a nylock nut on top of every suspension nut I've got. If I couldn't get another nut on there, I put loctite. If it was something I wouldn't take off normally (torque arms, swaybars, etc.), I tack welded the nuts.
I haven't studied them so I'm not sure. But just thinking outloud here. In order for the serated teeth to bit in they have to dig into the metal. If one tightens the fastener system (nut and bolt) by rotating the nut and holding the bolt steady (the prefered method for more repeatable torque readings) then the serations just displace the metal when the nut is rotated. However if one were to rotate the bolt and hold the nut steady, then the serations could hob into the metal. This may help increase the initial break away torque.
I haven't studied them so I'm not sure. But just thinking outloud here. In order for the serated teeth to bit in they have to dig into the metal. If one tightens the fastener system (nut and bolt) by rotating the nut and holding the bolt steady (the prefered method for more repeatable torque readings) then the serations just displace the metal when the nut is rotated. However if one were to rotate the bolt and hold the nut steady, then the serations could hob into the metal. This may help increase the initial break away torque.