Helicoil5521-7 7/16-14 Inch Coarse Thread Repair Kit

The supplied inserts are 1/2" long. I purchased this kit and went to an industrial supply house on line and purchased the 7/8" inserts. Getting the hole and threads straight is very important so I used the head with a few bolts installed as a guide for the drill going into the head. Then I drilled a piece of 1" plastic with the same drill bit and used the supplied tap to strip out the threads on a drill press. First securely clamp the plastic onto the table of the drill press. Get the tap spinning and slowly lower it into the plastic without threading it. The resulting hole will be a good fit to keep the tap aligned square to the block. Clamp the plastic block over the hole and tap it. Everything worked well and the head is back on and torqued to specs.

I had some threads stripped on a transmission bellhousing. With the helicoil repair kit I had the stripped threads replaced in no time. This item is very easy to use and the end result is stronger than the original aluminum threads.

Worked like a charm. Helps to watch a YouTube video if you haven't done it before.

I purchased this Helicoil insert kit to fix some aluminum bolt holes that I had striped out on a transmission bell housing. Overall this kit works excellently and I have no complaints. This kit was much stronger than I thought it would be and allowed me to torque the bolt down to spec without a hitch. I would recommend this kit to anyone looking to fix stripped threads and would offer the advice to use a cutting lubricants regularly while cutting the new threads. A drill bit is not included and in this case it is not an easy one to find 29/64ths I believe. There are also no instructions with the kit, but it is a pretty straight forward process. Drill the hole to the recommended size, use the tap to cut new threads, and use the installation bolt to turn the new threads into place. I give this kit 4/5 stars, because it does not include the drill bit!

Once you get it in it works great. You can torque the bolt down snug. The tap is total crap, snapped with almost no pressure, pulling up with a tiny 3/8s wrench. Managed to tap the tap out of the hole and ground what was left down to start again. I hit the hole with some BP blaster to lub it up, worked great after that.

Used this on a 1948 Ford 8N tractor when one of the head bolts stripped out...still used head bolt sealer and copper coat on the gasket and block/head surfaces to be sure it sealed when torqued down. Happy its holding so far!

This was the first time I used a helicoil kit. I had a few lower intake bolts break off on a Ford 302 lower intake and ended up damaging the threads getting it out. The Helicoil kit made it super easy to fix though. Just drilled it out and tapped it. The coils go in super easy and you can stack a few if needed.Definitely going to get more when I need em.

Used these to repair some stripped bolt holes on my old Ford 8N. Worked great. Have used these on several occasions and never had a problem installing or with bolts holding fast in the inserts. These are lifesavers when working on older tractors and other farm equipment. Just make sure you get the right size and thread for your needs, as the difference in packaging for different sizes is sometimes pretty subtle. Follow the instructions and you are back in business with new threads. I use a little red threadlocker on the insert when installing to make sure the insert stays put during removal of the bolts in the future.