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Fuel pump install - sending unit module bolt torque

Old May 8, 2018 | 01:23 PM
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Default Fuel pump install - sending unit module bolt torque

This may be less of a question and more of a cautionary tale, but here we go. I just installed a new Racetronix fuel pump kit in my '99 coupe. I used the instructions from Lingenfelter, which say to torque the sending unit module-to-tank bolts down to 62 in*lbs. My new seal kit came with the breakaway bolts, but I had a "I think I'm smarter than GM" moment and thought "I have an inch-pound torque wrench, what do I need breakaway bolts for?" I decided to reuse the original hex head bolts instead of the new goofy-looking breakaway bolts. The original bolts appeared to have been installed with blue Loctite, so I cleaned them up, dabbed a little fresh Loctite on them, and installed them in the correct pattern. They turned, and turned, and turned, and turned, for what felt like way too long, but eventually reached 62 in*lbs. I didn't think about what a lubricating effect the fresh Loctite would have on the threads, especially at such a low torque value. The new gasket is visibly deformed--it's pushing out at the bolt heads. I'm not sure whether I stripped the brass threaded inserts. I hope not, but even if I didn't, it seems like the gasket is deformed due to the excessive torque, and maybe the tank could be too? I think my options now are:

1) Just pour gas in it and see what happens. Maybe it won't leak? It's probably been overtorqued, but it's installed, and removing it again might only cause more problems at this point, especially if the threaded inserts are damaged.

2) Remove the original bolts, make sure all the threads are clean and dry, and reinstall with the breakaway bolts.

3) Same as 2, but with a new gasket as well, just in case.

I think I know what the right answer is, but let me know what you guys think...thanks.
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Old May 8, 2018 | 03:25 PM
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After replacing my tank..... I will not torque over 40 in-lbs. I tried 55 and it cut the new gasket and leaked weeks later. Then I found out I had stripped the threads on at least three of the holes on the tank. Swapped tank and put old gasket back on. No more leaks and learned my lesson.
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Old May 9, 2018 | 12:42 PM
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Thanks for sharing your experience. Just out of curiosity, did you use any Loctite, or were those torque values dry?

Here's what I'm dealing with. The wavy/squished appearance of the gasket after torquing down is what has me worried.


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Old Aug 26, 2018 | 10:40 PM
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Well, I went with option 1. It's working great and has not leaked yet. I consider myself very lucky; I hope I never have to touch it again. I still encourage others to learn from my mistake. Don't use loctite, and for a fool-proof install, use the breakaway bolts as well.
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