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Stripped throttle position sensor hole, what to do?

zachtyler

NAXJA Forum User
Location
California
My TPS has held securely, but the bottom hole is stripped. I can rotate the screw to where it gets tight, then it becomes loose, then tight, so-on and so-on. So, I rotate it to just before it becomes loose in an effort to secure the TPS as much as possible. Haven't had any issues. However, I would like to fix the issue so I don't have any problems down the line. Is it possible to run a tap through the hole? As I recall, the screws are a weird size. I'm new to using taps, would I need to remove the throttle body and drill a hole, then run a tap through? Which size would be best? Maybe an M5? I know that is slightly bigger than the TPS screws.
 
if you can find a slightly larger screw to fit through the TPS, tap it for whatever that size is.

or, fill the hole with JB weld, tighten the current screw the same way you have been until just before it gets loose. Then,
go to a junk yard and get a Throttle body in decent shape, so next time you decide to replace the TPS you just swap it on instead.
 
A little trick for stuff like that. Clean out the hole with spray brake cleaner before assembly, Acetone is even better. Stuff the hole with a little epoxy glue, JB Weld, Loc Tite two part epoxy glue is even better. Sightly grease the screw, just a thin coating. Snug and forget. A little luck and you can remove and reinstall that screw if you don't over tighten. Grease the back side of the TPS just in case some of the epoxy oozes or spreads.

I've used this trick a lot, especially for stripped out plastic screw holes.

Epoxy threads hold better than you'd think.
 
Helicoils are the best, most permanent, most professional answer.
 
I have used them down to 4-40.

Ace Hardware offers a small kit that contains the drill, tap, inserter, and some coils. The last time I got one it was around $25. McMaster Carr also sells them.
 
A little trick for stuff like that. Clean out the hole with spray brake cleaner before assembly, Acetone is even better. Stuff the hole with a little epoxy glue, JB Weld, Loc Tite two part epoxy glue is even better. Sightly grease the screw, just a thin coating. Snug and forget. A little luck and you can remove and reinstall that screw if you don't over tighten. Grease the back side of the TPS just in case some of the epoxy oozes or spreads.

I've used this trick a lot, especially for stripped out plastic screw holes.

Epoxy threads hold better than you'd think.


Or epoxy in a stud (or screw with head cut off) and use a nut on it instead.
 
I have used them down to 4-40.

Ace Hardware offers a small kit that contains the drill, tap, inserter, and some coils. The last time I got one it was around $25. McMaster Carr also sells them.

yes, I have helicoils that go down to M3 (have used on aluminum bicycle frames)

Now where it is... yeah. Was looking for it a while back, it's in a safe place.

in that case, that would be my first choice.
 
permanent fix is get another throttle body from the junkyard. Gluing a stud, and helicoil, both good fixes but they will have to be redone after the chemicals break down (decade+)

Or get another jeep, LOL. Steel filled epoxy has outlasted every rig I used it on, even used it on a carburetor once in wet gas areas.
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Or epoxy in a stud (or screw with head cut off) and use a nut on it instead.

I like that idea.:clap:

A little trick for stuff like that. Clean out the hole with spray brake cleaner before assembly, Acetone is even better. Stuff the hole with a little epoxy glue, JB Weld, Loc Tite two part epoxy glue is even better. Sightly grease the screw, just a thin coating. Snug and forget. A little luck and you can remove and reinstall that screw if you don't over tighten. Grease the back side of the TPS just in case some of the epoxy oozes or spreads.

I've used this trick a lot, especially for stripped out plastic screw holes.

Epoxy threads hold better than you'd think.

Sounds like what I might have tried!!!! Love the grease idea!! I would also be inclined to fill it with steel filled epoxy, then drill and thread it for such a light duty screw. But I like your version better. Might be hard to fill the hole properly with the epoxy for a drill and thread, but then again, a fine thin pick tool might work.

I would never have tried a heli-coil on something so small. But after reading this thread, who knows.

Obviously an over sized screw seems to be an option too.
 
If it is a blind hole you will need a "bottoming tap" for the Helicoil, the kits usually come with plug taps.

If this is a one off just buy the kit and cut the end off the tap with an abrasive wheel and dress it on a bench grinder.
 
I had the exact same problem on my (renix) throttle body. The bolt is a M8-24 x 1". I ran a 10-24 tap down the hole (no need to remove or drill anything), and replaced with a 10-24 bolt (i.e. one size larger). It has held perfectly ever since.


Don't know if you have an HO or if the sizes are different, but I imagine not.
 
I had the exact same problem on my (renix) throttle body. The bolt is a M8-24 x 1". I ran a 10-24 tap down the hole (no need to remove or drill anything), and replaced with a 10-24 bolt (i.e. one size larger). It has held perfectly ever since.


Don't know if you have an HO or if the sizes are different, but I imagine not.

I've got an 89 Renix. Good to know. Will try that soon, hopefully. You just ran the tap into the existing hole/threads? No drilling or anything?
 
I've got an 89 Renix. Good to know. Will try that soon, hopefully. You just ran the tap into the existing hole/threads? No drilling or anything?

No need for drilling - your threads are already slightly enlarged/stripped, so just run the larger tap carefully until it bottoms out. This should clean out the threads and make sure the larger bolt fits. Your mileage may vary of course, but that's all you should need to do.
 
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