I have almost the same problem, hope some one could help me out. I over tighten all the bolts and sad to say I stripped one of the bolt. Now how can I remove it out?

 

Can anyone give me a quick lesson on using a rethreading tap chaser? Do you use a drill or manually turn it with a socket wrench? Do you keep turning the length of the bolt hole? I assume the rethreading is done via a tightening motion? This is what I'm using: https://store.snapon.com/Rethreading...0-P662833.aspx

Any good videos on the subject?

Any help would be appreciated. Toyomoho?

 

First, confirm the rethreading tool has the same thread pitch as the bolt! If not one can be attempting to retread the hole to another pitch.

The threading tool is basically a tap with duller cutting teeth. The teeth forces the damaged thread material out of the way but will not cut new threads. As such the torque might be greater then a cutting tap.

Might find a nut having good threads and the same thread pitch and dia. Then use the tool to practice installing it (getting it to engage the threads) get a feel of what threading torque is required without actually needing to rethread. Then do the same with a good threaded bolt hole.

Don't use a power tool! If need more torque install a socket on the tap and use a tee wrench or other handle.

It's not a tightening action unless the tool hits the bottom of a blind hole, then or course stop.

Since material is being pushed out of they way the torque needed might increase with the depth of the tool into the hole. Use oil (whatever you got) on the tap threads to reduce friction and binding.

When you first install the tool, make sure it is inline with with hole and not at an angle. Watch the tool to make sure it stays inline with the hole.

 

Thanks again Toyomoho!

 

OK, so the saga continues.

Rethreading alone did not work. I had to drill out each and every hole, retap and use inserts. I have one bolt hole left - the hardest hole to reach. It cannot be accessed by a traditional drill as one of arms of the frame of the car (where the engine mounts bolt in) is approximately 2.5" underneath the bolt hole.

I can fit the Snap-on rethreading tap in it and turn it, but the bolt still over torques each time. Any suggestions? Right-angle drills are even too tall (on the short end - about 3.5"-4"). The hole threads and bolt holes are 6mm. Do I buy a 7mm rethreading tap and try to rethread, even through the hole isn't drilled out, then try to fit the 6mm insert in there? I'll have to cut the insert tool so that I can get the insert in. What do you think, Toyomoho?

 

Nicko, are you indicating that you keep breaking the bolt? How are you determining that you are over torquing it?

 

Perhaps the threads were too damaged to clean up with the rethreading tool.

How much work do you want to put into this process?

Do you know what the applied torque is before over torque occurs?

A few suggestions:

There are tools called angle drills/pork chops that when used with a short drill bit don't need a lot of clearance. See link below:

Angle Drills (Pork Chop) Archives - Applied Fasteners and Tooling

There are ALL kinds of variations of these tools. Ebay may sell these as aircraft industry surplus items plus threaded drills. Use an English drill size closest to the metric size to save time finding metric sizes or grind down the diameter.

Loctite has a form-a-thread package, but have not used it. See link below:

Loctite Form-A-Thread Stripped Thread Repair Kit 4.8 ml

There are epoxy materials that can be used to fill the hole, then be drilled out and tapped.

Install a metric stud, modified if required (cut as short as possible to clear chassis but still allow a nut to be installed). Thread the stud into the hole using a Loctite permanent locker material. This material works well once cured! For best results clean hole and stud of oil, debris, etc.

Cross thread an English thread stud into the hole to bind it in and an install an English nut.

Don't recommend trying a 7 mm tap in a 6 mm hole.

What would I do? I have port chop tools and drills but being lazy would try a metric stud first. If I can't easily find a stud, then use a fully threaded shank metric bolt and cut off the head. Then clean up the threads were cut and install with the Loctite material. When using the Loctite prep the stud and hole per directions and fully cure before installing nut.

 

Toyomoho - to clarify, near the bottom of your message you are saying that I should install a metric stud OR a standard (English) stud, correct? What size English stud? Would this work for metric:

Crown Bolt M6 - 1 x 20 mm and 6 mm - 1 x 7.5 mm Alloy 27.5 mm Metric Double End Stud-54688 - The Home Depot

And a 1/4" for standard? Will it thread into bolt hole threaded for metric? It will cross-thread (jam), correct?

I am amazed at how unavailable a simple stud is locally. Everywhere I look says it won't be shipped to me until 4/20.

Also, there are two existing studs (that they originally had on the car) and one of them can be turned about a 1/16-turn backward by hand. Do I need to fully back this stud out and use Locktite on it? Or, can it just be tightened with an adjustable wrench (the studs are square at the bottom)? Or does it matter once the nut reaches full torque?

To answer your and DIYDADs question, I bought a torque wrench (in-lbs) and I can't get to the 80-in lbs torque before it over torques.

 

I am stating if possible find a metric stud. If you can't find an "official" stud, then find a metric bolt having a fully threaded shank (they do exist and called a tap bolt) and cut off the head to make your own stud.

If you can't find a metric stud and want a quick and dirty repair method find an English threaded stud of similar diameter and try to install this. Yes, it will cross threat but it might hold enough to allow a nut to be torqued up.

Of course suggest as stud or cutting off the head of a metric bolt first.

The two existing studs are just a stud threaded into a threaded hole. If the threads are OK, just snug up the stud in the hole and call it good. Don't over torque!

The Locktite material is recommended because the hole you may want to put the stud into has a problem with the threads not allowing a bolt to torque up. With a stud, you hopefully are only going to be installing it once (unlike a bolt). If so and the hole treads have a problem, you might try what is effectively gluing it into the hole with this Locktite material.

The studs installed in holes having good threads don't need this additional glue holding power.

Alas I confess I never use a torque wrench on these small bolts on an oil or trans pan unless a critical application. This being if the fastener is under or over torqued something bad will happen or quality control requires an official torque setting. This is not the case here.

My experience has been torquing these small small bolts with a torque wrench has the gasket or sealant squeezing out too much or at times the bolt strips out as you have found out the hard way. This off course is contrary to good practices but unless a critical application, I don't care.

I profess using a torque wrench as many people tend to greatly over torque small bolts while under torquing large bolts. An accurate torque wrench (yes may be hard to find) prevents both.

For an oil pan gasket I rely on the gasket and using form-in-place gasket material. Then the purpose of each bolt is to hold the assy in place until the gasket material cures. The pan has enough bolts the when combined, the pan is not going to fall off if one is under torqued.

As to the bolt issue, the torque is 48 in lbs, not 80. This could explain you problem.

 

Toyomoho, where did you obtain the 48-in lbs setting? I have a Chilton manual, which states it must be 80-in lbs. However, I have also found a 69-in lbs figure online. The bolts come with washers, which according to this puts them in the 6T class (69 in lbs): http://www.scribd.com/doc/8036642/To...cations#scribd

What you're saying makes good sense - the bolts act to hold the pan in place until the silicone cures.

I'll do some triple-checking on the proper torque, then give it a go! Thanks again!!