stripped crank bolt, possible damage to crank threads
I discovered my Steeda UDP had backed out away from the block about the distance of a belt groove. I intended on replacing the original bolt with a new one but, I needed to press the UDP back up to the block. so, I put a couple of washers on the old crank bolt and tightened it down and I stripped the bolts threads. it was a PITA to remove the bolt and pulley, but they are finally off. stripped about 1/4" off the old crank bolt. I can't tell if the same is true for the inside of the crank.
I plan on retapping the threads in the crank and re-installing the pulley.
does anyone think that if I had stripped 1/4" of the crank threads, retap the threads and install a new bolt, will it hold up to the torque requirement of the new bolt? If I did strip the crank threads, is there a fix?
thanks
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2005 Mustang GT M5 -I reject your reality and substitute my own-
If I remember correctly, the correct torque sequence is tighten to a certain torque, back off one turn. Tighten to a lesser torque and then plus 90 degrees rotation. The 90 deg. part is to properly stretch the bolt. That part may cause you a problem if your threads are not 100%.
Frank
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2008 GT Premium, Vapor Metallic, 5-speed stick w/MGW, GT500 front end, spoiler and replica wheels. Sequentials, GTA's, FRPP M6066M463V8 Whipple - can't wipe the smile off my face.
If I remember correctly, the correct torque sequence is tighten to a certain torque, back off one turn. Tighten to a lesser torque and then plus 90 degrees rotation. The 90 deg. part is to properly stretch the bolt. That part may cause you a problem if your threads are not 100%.
Frank
Here are the specs:
Stage 1: Tighten to 90 Nm (66 ft. lbs.)
Stage 2: Loosen 360 degrees.
Stage 3: Tighten to 50 Nm (37 ft. lbs.)
Stage 4: Tighten an additional 90 degrees.
I think that process says more about the bolt than the job it is doing. I can’t think of one reason why a bolt that holds a pulley on needs to be anything special. There is close to zero strain on that bolt aside from when it is pulling the pulley on to the crank. In theory the pulley could be bored/drilled for an interference fit with the crank and installed by heating it up and slipping it on. You probably wouldn’t even need a bolt to hold it to the crank (of course it would be silly not to use one though).
If it were my car I would drown that sucker in green Loctite ad put it back together.
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Under Construction. Better, Stronger, Faster than it was before.
thanks for the advice gentlemen. I am going to Northern Tool tomorrow to get the tap and finish up this repair. this has gone on for three days now. working on the problem till I get to a point I don't have the tool. by then all the stores are closed and my wife takes me to work the next day. get tools on the way home, work until I discover I need another tool.
a vicious circle.
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2005 Mustang GT M5 -I reject your reality and substitute my own-
I did that. I went to four different stores before realizing there is a Northern Tool store close by that closed at 8. I should have gone there first, if I had thought of it.
I was just wondering if it is SAE or metric.
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2005 Mustang GT M5 -I reject your reality and substitute my own-
I did that. I went to four different stores before realizing there is a Northern Tool store close by that closed at 8. I should have gone there first, if I had thought of it.
I was just wondering if it is SAE or metric.
Its metric
M12X1.5X48MM
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07 REDFIRE GT 5 SPEED 3.55 gears
C&L Racer CAI XCAL2/Seq signals/GTAs/Steeda UDP/CHE K Member Brace W/Torq Links/J&M LCA/Spider DS/PRO.50 Shifter Hurst handle & "T"/Meziere EO2/ARH LT catted H /Prothane MM/Delet Plates/SLP BOSS 429 Scoop/Accel COP/PowerSlot/Hawk Pads/Tokico D-Spec/CHE Panhard Bar Brace/Steeda Adj. Panhard Bar/BMR F/R Sway Bars/Cervini ducktail spoiler/BMR UCA Mount/CHE UCA/GT\CS Rear Cover/AMChrome Bullets 18x9/10s/Nitto 255/45&295/45
Tillman Dyno Tune 307HP/322TQ
I think that process says more about the bolt than the job it is doing. I can’t think of one reason why a bolt that holds a pulley on needs to be anything special. There is close to zero strain on that bolt aside from when it is pulling the pulley on to the crank. In theory the pulley could be bored/drilled for an interference fit with the crank and installed by heating it up and slipping it on. You probably wouldn’t even need a bolt to hold it to the crank (of course it would be silly not to use one though). .
I wouldn't go that far. The bolt obviously backed itself out. I think the proper stretch on the bolt is quite important.
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It's better to burn out than to fade away - The Kurgan
stripped crank bolt, possible damage to crank threads 
