Crank Bolt Issue

[Redneck1465]

Thanks 93rev I really appreciate your help with all this.

 

[gmorrell]

I want to be able to clean up the threads so that I can get the bolt back in. I have no idea how far the threads are damaged so should I use a different tap or is that the one I should go with?

If you think the thread damage is deep, you may need a bottoming tap, but I seriously doubt that you've damaged the crank threads very deep, it's very hard to hurt these threads.
http://www.amazon.com/Made-USA-1-5-...ref=sr_1_3?ie=UTF8&s=hi&qid=1245855132&sr=1-3

Get the plug tap. Coat it with oil before starting to clean-up the threads.

Edit: When you've completed cleaning up the threads, you will need to flush out the hole, I would use a can of brake clean with an extension tube, just be mindful that it will blow back in your face.

Lightly oil the threads of the crank bolt before you reinstall it, then torque it to spec.

Bottoming taps are designed to put usable threads nearly to the bottom of a blind hole, something a plug tap can't do. When tapping a hole that is not already threaded, you use a plug tap to put usable threads in the hole, then use the bottoming tap to finish threading the bottom of the hole. It's very difficult to cleanly start a bottoming tap in an unthreaded hole, and it requires some smarts to keep the hole clear of chips, which is why we start with a plug tap.

So endeth today's machine shop lesson.

 

[Redneck1465]

Thanks guys, I ordered the tap a few days ago and it should be on its way to me right now. I'll let you know how it goes. Hopefully it will be no big deal and I can finally have my car back after almost two weeks of sitting.

 

[93rev2sev]

Oh...and use antisieze on the threads once you've confirmed that you can thread it back in there...IE...take it back out and coat the threads with antisieze before torqueing it back down.

 

[Redneck1465]

I got the tap today and went down to the barn to begin working on it. I got it to thread in for a few turns very easy and then it got kind of hard to turn so I stopped and did not force it. I took the bolt and threaded it in and it starts to thread now but stops after a few turns. What should I do? Should I just keep working the tap around? I do not want to cross thread the crank. Thanks in advance guys for your paitence with this.

 

[93rev2sev]

Good, you got it started...

Get a brass rotary brush and some acetone. Squirt the acetone in the hole (careful..this stuff eats rubber seals..I use a metal oiling can) and put the brass brush in your drill. Use the rotary brush to clean out the hole and then flush it out with some brake cleaner.

Let's make sure there isn't a bunch of gunk in the threads before continuing with the tap.

 

[rubydist]

And, make very sure you didn't cross-thread it, because if you start it crooked it will go a few turns and then get very hard to turn. If the threads are buggered up, its usually easier to start the tap crooked rather than straight, so be very sure....

 

[Redneck1465]

Yeah I am being extremely careful as soon as it started to bog down I quit. I'll clean it like 93rev suggusted tomorrow and ill see what happens

 

[Redneck1465]

Well I finally got my boss to come and give me a hand with the car. (I was to scared that I was going to cross thread the crank). He got it tapped for me and I should be good to go I am in the process of putting everything back together. Thank you so much to everyone for the help you gave me. It will be great to be able to drive the car again finally.