Possibly stripped threads on my throttle body

[GregBelleville]

I removed the throttle body on my 99 TJ 4.0 this afternoon as I've been battling a high idle.

Anyway, I went to reinstall the throttle body and one of the 4 bolts that fastens the throttle body to the manifold wouldn't completely tighten, I can just continue to turn it almost with just hand strength.

What's weird is I took the throttle body back off and threaded the same bolt directly into the manifold and I was able to tighten the bolt down fine that way, it just hits a point when the throttle body is in between that the bolt no longer threads in.

What are my options here, I'm hoping I didn't completely screw myself! Could I shorten the bolt a bit or get a shorter bolt?

 

[macleanflood]

Couple options...helicoil it... basically drill it out and put in an insert to the correct thread size.

Next would be drill and tap it to the next size.

TIG weld the bad threads and drill and retap to the correct size.

Throw a couple of toothpicks in the bad hole...trim them flush...install the throttle body and bolts.

Epoxy.

-Mac

 

[flyinfish]

I removed the throttle body on my 99 TJ 4.0 this afternoon as I've been battling a high idle.

Anyway, I went to reinstall the throttle body and one of the 4 bolts that fastens the throttle body to the manifold wouldn't completely tighten, I can just continue to turn it almost with just hand strength.

What's weird is I took the throttle body back off and threaded the same bolt directly into the manifold and I was able to tighten the bolt down fine that way, it just hits a point when the throttle body is in between that the bolt no longer threads in.

What are my options here, I'm hoping I didn't completely screw myself! Could I shorten the bolt a bit or get a shorter bolt?

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Since you had success in grabbing a few good threads with out throttle body installed, you should be able to use a slightly longer bolt through housing and washers on top of throttle body housing to fine tune bolt depth if needed.

 

[GregBelleville]

Since you had success in grabbing a few good threads with out throttle body installed, you should be able to use a slightly longer bolt through housing and washers on top of throttle body housing to fine tune bolt depth if needed.

Is there a best way to determine the bolt size? Usually I just go to home Depot with the bolt and thread it into their bolt sizer, not sure if there are other options.

 

[Rickyd]

Is there a best way to determine the bolt size? Usually I just go to home Depot with the bolt and thread it into their bolt sizer, not sure if there are other options.

I would first shine a flashlight in that hole and see what is going on. You probably removed the top wraps of thread. Then you can put a bit of wire,or anything that will fit in the hole and mark it at the throttlebody flange. That will give you an approximate depth to find a bolt for. Keep in mind you want it to tighten,not just bottom out in the hole.

 

[GregBelleville]

Sounds good, I'll give it a shot measuring home depth then seeing if a longer bolt works before resorting to more extreme methods.

 

[Sgt Jarhead]

Sounds good, I'll give it a shot measuring home depth then seeing if a longer bolt works before resorting to more extreme methods.

I have a new helicoil sized for the bolts to the TB if interested. Just let me know.

 

[GregBelleville]

I have a new helicoil sized for the bolts to the TB if interested. Just let me know.

Thanks! Is it a set similar to this one?

 

[GregBelleville]

I have a new helicoil sized for the bolts to the TB if interested. Just let me know.

Do you happen to know the size?

 

[MikeE024]

Do you happen to know the size?

Thanks! Is it a set similar to this one?

View attachment 489071

2001-2006 uses m6x1x30 screws according to WeRMopar. The TB screw info is not displayed for prior years.

When possible, i’d use a timesert over a helicoil on a through hole. Don’t know what depth you need, but here’s a link in case it helps.

 

[Sgt Jarhead]

Do you happen to know the size?

the one I have is an M6x1

 

[NskLJ]

Sounds good, I'll give it a shot measuring home depth then seeing if a longer bolt works before resorting to more extreme methods.

Pull the throttle body, tape off the intake hole then retap all the holes and retry installing the throttle body. You can also swap the bolts around to see if another bolt will tighten. If not helicoil is your best bet.

 

[GregBelleville]

Pull the throttle body, tape off the intake hole then retap all the holes and retry installing the throttle body. You can also swap the bolts around to see if another bolt will tighten. If not helicoil is your best bet.

When you say tape it off, do you mean from underneath? I'm assuming to prevent metal shavings falling into the intake manifold? Sorry if these are dumb questions, this is going to be my first time attempting to repair a stripped bolt hole.

So it's also possible to retap the hole with the same size it is currently before resorting to drilling it out to a larger size, helicoil, etc.?

 

[NskLJ]

When you say tape it off, do you mean from underneath? I'm assuming to prevent metal shavings falling into the intake manifold? Sorry if these are dumb questions, this is going to be my first time attempting to repair a stripped bolt hole.

So it's also possible to retap the hole with the same size it is currently before resorting to drilling it out to a larger size, helicoil, etc.?

Yes tape off the intake, run the same size tap down the holes the retry it if not you can buy a helicoil kit for the one size you need. The kit will come with drill, oversized tap, inserts and an installer. I usually red loctite the inserts in then just put the bolt in.
This kit isn’t the right size but an example.
https://www.amazon.com/Helicoil-5521-4-Coarse-Thread-Repair/dp/B0002SRE8Q/?tag=wranglerorg-20

 

[MikeE024]

If you don’t go the timesert route, this is another alternative to a helicoil that folks seem to like

 

[NskLJ]

If you don’t go the timesert route, this is another alternative to a helicoil that folks seem to like

Those are good options, just need to make sure there is enough metal for the drill. Those use a 12mm drill where a helicoil uses a 8.3 mm drill

 

[NskLJ]

When you say tape it off, do you mean from underneath? I'm assuming to prevent metal shavings falling into the intake manifold? Sorry if these are dumb questions, this is going to be my first time attempting to repair a stripped bolt hole.

So it's also possible to retap the hole with the same size it is currently before resorting to drilling it out to a larger size, helicoil, etc.?

Where are you located in so cal and what is your timeframe on repair?

 

[GregBelleville]

Where are you located in so cal and what is your timeframe on repair?

I'm in Anaheim. I was going to look at it today as I was planning a run out to calico next Saturday.

 

[GregBelleville]

Ok, here's an update. I went to home Depot and picked up this m6 1.0x30 mm cap screw which matches the size and length of the TB bolt, however, you'll notice the end of the bolt isn't tapered and Threadless, so it's the same length but has a few mm of extra threads.

I was able to thread the new bolt in to the TB and according to the FSM it looks like the torque spec is only 90 in lbs which I was able to torque it to just fine. Does anyone see any issue with not having the taper at the end of the bolt for done reason?

On a side note I attempted to torque down the other 3 bolts and a second hole stripped on me, so I think this TB got over tightened at some point.

If there aren't any concerns with this bolt then it looks like I'm heading back to home Depot for 3 more.

 

[MikeE024]

Ok, here's an update. I went to home Depot and picked up this m6 1.0x30 mm cap screw which matches the size and length of the TB bolt, however, you'll notice the end of the bolt isn't tapered and Threadless, so it's the same length but has a few mm of extra threads.

I was able to thread the new bolt in to the TB and according to the FSM it looks like the torque spec is only 90 in lbs which I was able to torque it to just fine. Does anyone see any issue with not having the taper at the end of the bolt for done reason?

On a side note I attempted to torque down the other 3 bolts and a second hole stripped on me, so I think this TB got over tightened at some point.

If there aren't any concerns with this bolt then it looks like I'm heading back to home Depot for 3 more.

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Just a heads up, the torque for a zinc-plated 8.8 M6-1 screw is 79.2 in/lbs (6.6 ft/lbs).