Threads in bolt hole for timing belt tensioner pulley stripped

I was putting on my new timing belt tensioner pulley and as I was getting it snugged down suddenly it loosened up and appeared to be stripped. When I pulled it out, there was something gray in between 10 threads near the tip.

if I just screw in the part with the Allen head & no washer/spacer and no pulley it tightens up fine.

A little confusing, but I guess it makes it past the threads that are stripped

At first I thought it was possibly anti-seize on the threads. Now I'm thinking it was either the actual threads or possibly a heli-coil?

it's obvious one of the techs that did my first 2 timing belts made a mess of several nuts and bolts, possibly more

Would you trust a heli-coil on something so critical or am I royally screwed?

 

I think a properly installed time-sert would be a good and permanent fix. Better than a heli-coil for repairing a hole with damaged threads.
https://www.timesert.com/

 

Timesert better than Helo oil for this.

 

This.

But either way, seriously, this is one of those “only time will tell” things. Timesert is probably the only “permanent” solution. If it’ll work to hold the Ferd engines together … and you want confidence … that’s the way to go.

That said, Helicoil will probably hold just fine.

 

Thanks guys.

It looks like they Not available locally? Bit surprised about that

 

Some specialty tools are required, IIRC there’s a kit you can buy, it is spendy. Someone posted a good video showing install on a Ferd on here recently, but I don’t recall where. I think it was @KNABORES who posted but my memory is shit on off-topic stuff.

I’d actually try to locate a shop that is educated in how to install correctly, it may be more cost effective, unless you want to start installing them yourself at a fee.

 

The treads appear to be the same as other 14mm bolt heads. Not extremely knowledgeable in that area about what size that equates to

there are some other kits that are possibly available. Not the timesert brand, but appear to be the same.

not sure I could find a skilled time sert mechanic that does house calls. I guess the alternative is to have it towed just for this

 

I would think that almost any auto repair shop use, and could install for you if you can get the truck to the shop. The hard part.

 

No experience with the timeserts, appear to be like a nutsert but also appears you have to drill and tap / chase new threads for the timesert to be installed. I typically use a tap and die kit to repair bad threads when needed. Then upsize the bolt if possible. Many threads can be repaired in non-HD applications. Things that simply need to seat but carry low load. Like valve covers for instance. Something like spark plugs have to remain the same thread size and pitch, so not a great candidate for upsizing. Not a huge fan of heli-coil as the fix for things, but glad they exist when other options won’t do. I would be adding some thread lock to any of these repairs as insurance.

 

Yeah, the problem is this is similar to a spark plug in that it has to remain the same size. It's not just a nut.



many of the spark plug repair kits appear to work like a timesert. It appears you install a full thread insert sleeve.

 

Yup, it was @weadjust and I got really curious, so I dug and was the person who posted the video. https://www.tundras.com/threads/timesert-repair.142818/#post-3592094

 

That bolt is difficult to replicate in another size, so repair to existing size and pitch is the way. Heli-coil can be done at home by the average mechanic. I would likely go that route myself unless comfortable with the timesert repair. It’s not incredibly difficult as this video shows. He’s obviously got the part being repaired on a bench with a drill press. But could be performed in place on the motor with some patience. Looks like a quality repair.


https://youtu.be/aG_To8Ns8V4?si=cGBoiWMw5giqAy5H

 

Just like any thread repair insert, the key to success is the proper kit tools, and keeping the drill, tap, etc square to the work. If there is adequate space it's not too difficult.

 

yes, I like that.

However, getting that hole perfectly aligned and perpendicular to the surface is critical in this case to ensure there is the same force for the width of the timing belt

 

A mechanic friend has a drill guide and everything needed if he gets back in town in time.

Otherwise I'll have it towed to the shop tomorrow unless they will make a house call

 

Running out of options. I guess I'll just have to wait on my friend. He is good with years of experience on the job with heavy mechanical equipment in an industrial environment and very particular.

I even tried the mobile big rig services. Their comment was oh yeah, we do that all the time. But we only do it on big rigs. Seriously? What's the difference?

 

I'd honestly Heli-Coil it. TimeSert would be better, but Heli-Coil is easy to get and use. I had to use Heli-Coil a torque converter once, and also on a transmission pan over the years. Worked perfectly fine in both those applications.

 

Yeah, I'm satisfied with that option. And one of the mechanics talked to me about it and says it ought to be pretty easy. It shows you the drill bit size and that shouldn't be a problem because the hole is already there. What scares me is the tap.

Like he said - you only get one chance.

 

Tapping a hole is easy. Use cutting fluid on the tap (I've also used motor oil when I couldn't find the actual fluid), apply even pressure as you turn the tap, do your best to keep the tap straight, periodically spin the tap out and clean the cut metal off of it, and if you feel any hard resistance, back the tap out and see what's going on. You do not want to break a tap in a hole.

 

No matter what kind of insert you use, just keep the drill and tap square, and as mentioned above don't force the tap, and after 1 or 2 revolutions back the tap out a couple of turns to clear the swarf out of the hole. It's not as bad as you may think, the drill will want to follow the existing hole and it's only cutting a small bit, just removing the original threads. The biggest problem is usually adequate space to work and being able to see the area to ensure the work stays square. If your friend has more experience, it's worth waiting for his assistance. Good luck, we're rooting for your success.

 

My friend got me straightened out. It's a good thing because I exhausted all other options other than having to have it towed. Which would've meant a return tow back home after they were done Not to mention waiting days because everybody is shorthanded on mechanics and backed up


I would've been fine to do it I'm sure. But I would much rather someone like him with years of experience that has done this on heavy machinery before where it has to be exactly right

 

What'd you guys end up going with? I remember you saying he had a drill guide. You drill it and re-tap to a larger size?

 

Went with a heli-coil. When I do the next one, I'll be prepared and get a timesert.

So yeah, we tapped it but for the heli-coil.

With it be a specialty bolt I'm not sure if Toyota made one oversized

 

Looks like I made it past the critical steps. Ready to put it back together.