Cleaning rusted threads

[redkow97]

I found a used hitch for $40 on CL and picked it up.  4-bolt installation, but the nuts welded to the frame of the car are rusted to shit.  I can't get the bolts to thread.  I have tried penetrating oil and WD40 with a tooth brush, but I'm not getting up in there very far.

Any suggestions?  I'm getting close to buying a tap and die set and new hardware, but with nuts welded in place, and a setup that needs to withstand a couple thousand pounds of force, I'm a little hesitant to go that route.

[Tonik]

steel wool, CLR, vinegar, hydrogen peroxide. If you use the last two be sure to wd 40 them afterwards to protect them from new rust.

[redkow97]

perhaps a "thread chaser" instead?

[Tonik]

Good idea, forgot about those.  Just make sure it is an actual thread chaser and not a tap/die.  Many people less smart than you and I use the terms interchangeably.

[redkow97]

I don't know what size the bolt holes are though... I have had a hell of a time finding a corolla parts fiche to look up anything.  The hitch installs using the mounting points for the rear tow hooks.

[redkow97]

My other thought was a small wire brush that would fit on my dremel. 

 

having trouble finding one small enough though...

[3.504]

Thread chaser would be ideal.

I'm going to guess (since it's a Toyota Corolla) that you'll likely need an M10x1.25 thread chase.

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[ohiomike]

Kroil penetrates nicely.

 

[whaler]

Kroil is great as stated above, but 50/50 solution of ATF and acetone is by far the best.

For your current problem chase the threads.

[motocat12]

http://www.instructables.com/id/Inexpensive-thread-chaser/

[redkow97]

9 hours ago, 3.504 said:

Thread chaser would be ideal.

I'm going to guess (since it's a Toyota Corolla) that you'll likely need an M10x1.25 thread chase.

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This is a 'weld bolt' inside the frame rail. 

How confident are you?  

[motocat12]

 

https://www.etrailer.com/question-141070.html

Do you know what the bolt size and thread is for the mounting bolts on the 2012 Corolla? Thanks!

asked by: Pete M

Expert Reply:

The Curt Class I Round tube Receiver Hitch # C11265 uses 4 M12-1.25 x 30mm hex bolts. These bolts come with the trailer hitch.

[3.504]

14 hours ago, redkow97 said:

This is a 'weld bolt' inside the frame rail. 

How confident are you?  

its definitely a 1.25 thread pitch

i'm not 100% on bolt diameter. its probably an m10, but could go as high as an m12.

if you really wanted to double check, check the thread pitch, using a thread file, on the bolts that were included in the hitch kit.

[Wolfman1]

I agree on thread chaser, be sure to use Kroil with it.  Try and get as much rust out as you can before using the thread chaser.

[330racing]

I use a rock/parts tumbler from harbor freight.....

[Tonik]

Do they make one big enough for the whole car?  These bolts are welded to the frame.

[motocat12]

43 minutes ago, Tonik said:

Do they make one big enough for the whole car?  Deez Nuts are welded to the frame.

FTFY

[330racing]

No... but that would be cool

[Tonik]

Just now, Isaac's Papa said:

"...less smart than you and me", but I got the gist of your post.

 

The lady with the Masters in English in the room next to me says you are a dumbass.

[speedytriple]

They make em that big, but not much of the car would be left after running it. 

 

[speedytriple]

We have some ball Mills almost that big at work. They turn rocks into dust lol.

[redkow97]

The thread chaser finally arrived from whatever chinese company i bought it from on Amazon.  My initial reaction was not positive.  Probably had more to do with the fact that I was trying to do the job left-handed due to the way the car was parked in the garage.  I spent a frustrating 30 minutes getting 1 of the 4 holes "okay."

I went back out for a second go after putting the Tiny Tank to sleep.   This time I jacked up the rear end of the car, put on the radio, and refined my technique (ratchet to start it straight, THEN put the 10" extension on to get greater range of motion below the body of the car.

 

I have 3 of the 4 bolts in very well.  The driver's side 2 are completely snugged up to German torque.  The passenger's side 2 need to be snugged up ASAP.  The muffler gets in the way on that side, so fitting a 1/2" drive ratchet up there isn't possible.  As a result, I was using a 19mm open-ended wrench that is considerably shorter than my ratchet.  All of this would have been prevented with said 10" extension, but my only 19mm socket is for a 1/2" drive, and the extension is 3/8".   I bought a 19mm 3/8 drive socket on my way into work this morning (driving with the passenger side bolts in as far as the open-ended wrench would get them. seems stable enough for today) and will get the job finished at home after work.

 

Thread chaser worked pretty well.  Not as easily as I had hoped, but a positive result is a positive result.  It was effective.  I kept coating the chaser with penetrating oil, and cleaning it after each use.  that seemed to help.   All in all, it was worth the $6.

[Wolfman1]

I am glad it worked out for you.  The key with the thread chaser is going slow and keeping it oiled so it doesn't bind up or snap.  I have broke a few taps that way by trying to hurry the process.