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Moser 12-bolt TA bolt issues and ?

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Old 01-13-2008, 07:37 AM
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Default Moser 12-bolt TA bolt issues and ?

I have been hearing some clunking coming from the rear under light acceleration, but thought maybe I had a rod end failing. So today while changing the oil I decided to look into the problem and found that my Spohn TA was broke at the lower mounting plate, one bolt was completely missing from the top of the mount and the other bolt was half way out. Needless to say I found my clunking.

Lesson: Don't let little things become big things.....

I searched and the accepted fix seems to be clean everthing real well, make sure the mount fits snug to the mounting pad on the rear and then red lock tite and saftey wire the bolts. No problem. Lower bolt holes are in good shape. But, the threads on my upper rearmost bolt hole are damaged, I cleaned them up with a thread chase, then ran a bottoming tap into the hole, but I don't think they will hold 97lbs of torque (Moser spec). Is it acceptable to heli-coil is this application? These bolts seem to be under lots of stress, both shear and tensile? Or is there enough material to go up one bolt size. Stock is 1/2X13. Could I go to 9/16x12 or 5/8X11?

Would studs work in this location and have any benefits over a bolt?

Thanks
Chris
Attached Thumbnails Moser 12-bolt TA bolt issues and ?-torquearm004_edited.jpg   Moser 12-bolt TA bolt issues and ?-torquearm001_edited.jpg  
Old 01-13-2008, 06:39 PM
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Decide to keep it simple and simple heli-coil the offending hole and be done with it. Ordered a new mount from Spohn and bought the necessary stuff to saftey wire bolts on re-assembly. A few more pics attached.

The broken mount, not only broke but upper plate is bent, the repaired hole, the three remaining bolts holding the old mount in (ugly)

I think I got really lucky with this one. Could have been a lot worse

Chris
Attached Thumbnails Moser 12-bolt TA bolt issues and ?-tamountfull.jpg   Moser 12-bolt TA bolt issues and ?-tamount008_edited.jpg   Moser 12-bolt TA bolt issues and ?-tamount005_edited.jpg   Moser 12-bolt TA bolt issues and ?-tamount004_edited.jpg  
Old 01-14-2008, 09:20 AM
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I've fought torque arm bolts now for a little over 3 years on my different 12 bolts. Many different people say to tack weld the bolt head to the torque arm but for ease of removal I never wanted to do that and the tops would be impossible to do. Red loctite was never the answer for me either. Even with locks and loctite it never made a difference. For me at least, I just ended up using hillman grade 8 lock washers on grade 8 flats and tightened them up as hard as i could. But every oil change I always made sure the bolts were tight. Just keep an eye on them.
Old 01-14-2008, 11:23 AM
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Originally Posted by 1QWIKBIRD
I have been hearing some clunking coming from the rear under light acceleration, but thought maybe I had a rod end failing. So today while changing the oil I decided to look into the problem and found that my Spohn TA was broke at the lower mounting plate, one bolt was completely missing from the top of the mount and the other bolt was half way out. Needless to say I found my clunking.

Lesson: Don't let little things become big things.....

I searched and the accepted fix seems to be clean everthing real well, make sure the mount fits snug to the mounting pad on the rear and then red lock tite and saftey wire the bolts. No problem. Lower bolt holes are in good shape. But, the threads on my upper rearmost bolt hole are damaged, I cleaned them up with a thread chase, then ran a bottoming tap into the hole, but I don't think they will hold 97lbs of torque (Moser spec). Is it acceptable to heli-coil is this application? These bolts seem to be under lots of stress, both shear and tensile? Or is there enough material to go up one bolt size. Stock is 1/2X13. Could I go to 9/16x12 or 5/8X11?

Would studs work in this location and have any benefits over a bolt?

Thanks
Chris
Im looking for a strong rear end for my 02 ss, im confused on what to get...I dont know much about them (thats the main problem) a few guys tell me to go with 12 bolt moser, then I got people that tell me to get the 9" and I wont spend as much, its pushing about 550 hp. I was hoping you could help me out
Old 01-14-2008, 11:24 AM
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Im looking for a strong rear end for my 02 ss, im confused on what to get...I dont know much about them (thats the main problem) a few guys tell me to go with 12 bolt moser, then I got people that tell me to get the 9" and I wont spend as much, its pushing about 550 hp. I was hoping you could help me out
Old 01-14-2008, 05:37 PM
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Originally Posted by solo21
Im looking for a strong rear end for my 02 ss, im confused on what to get...I dont know much about them (thats the main problem) a few guys tell me to go with 12 bolt moser, then I got people that tell me to get the 9" and I wont spend as much, its pushing about 550 hp. I was hoping you could help me out
Your best bet would be to talk one of the sponsors. I don't think there is a cut and dry answer. It is a hotly debated topic that is for sure. Do a search and your find plenty of reading material. It really depends on not only your power level, but your application and the rest of the combo. My Moser 12-bolt has been fine, no problems until now and the whole TA mount is an old issue and its just something you have to watch out for. From now on it will be a routine maintenance deal for me to prevent this from happening again. Car has gone mid 1.5 60' times and never complained. I don't have any gear wine (3.90's). That's been my expierence.

Chris
Old 01-14-2008, 05:38 PM
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Originally Posted by pddye
I've fought torque arm bolts now for a little over 3 years on my different 12 bolts. Many different people say to tack weld the bolt head to the torque arm but for ease of removal I never wanted to do that and the tops would be impossible to do. Red loctite was never the answer for me either. Even with locks and loctite it never made a difference. For me at least, I just ended up using hillman grade 8 lock washers on grade 8 flats and tightened them up as hard as i could. But every oil change I always made sure the bolts were tight. Just keep an eye on them.
This is good advice and will become part of my routine maintenance also. No more tighten it and forget about it.

Chris
Old 01-14-2008, 06:06 PM
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Originally Posted by 1QWIKBIRD
Decide to keep it simple and simple heli-coil the offending hole and be done with it. Ordered a new mount from Spohn and bought the necessary stuff to saftey wire bolts on re-assembly. A few more pics attached.

The broken mount, not only broke but upper plate is bent, the repaired hole, the three remaining bolts holding the old mount in (ugly)

I think I got really lucky with this one. Could have been a lot worse

Chris
that tq arm mount broke cause youre using the wrong bolts, you probably got a grade 8 bolt then added washers to it. I did the same thing and broke 2 tq arm brackets on my moser. I took the rear end to a rear and place here in town and they replaced those bolts with the type of bolt that flanges out kind of looks like a bolt with a washer on it. Those bolts you have there will back out then it will cause the bracket to become weak then it breaks. Dont ask me how those bolts are any different but that was 2 years ago and i havent had any problem since. The guy at the shop said he got those bolts from a 9" then helicoiled (sp) it and added some loctite and i havent had any problems since. But before that when i just got some regular bolts and washers they would back out and the tq arm mount would break.
Old 01-14-2008, 06:42 PM
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Originally Posted by 6']['9
that tq arm mount broke cause youre using the wrong bolts, you probably got a grade 8 bolt then added washers to it. I did the same thing and broke 2 tq arm brackets on my moser. I took the rear end to a rear and place here in town and they replaced those bolts with the type of bolt that flanges out kind of looks like a bolt with a washer on it. Those bolts you have there will back out then it will cause the bracket to become weak then it breaks. Dont ask me how those bolts are any different but that was 2 years ago and i havent had any problem since. The guy at the shop said he got those bolts from a 9" then helicoiled (sp) it and added some loctite and i havent had any problems since. But before that when i just got some regular bolts and washers they would back out and the tq arm mount would break.
I'll check mc-master carr..they'll what you speak of. Something like this with the large shoulder?
Attached Thumbnails Moser 12-bolt TA bolt issues and ?-92316a716l.gif  
Old 01-15-2008, 05:43 PM
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thats them!!
Old 01-15-2008, 07:11 PM
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Originally Posted by 6']['9
thats them!!
Sweet....thanks for the info.



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