Question about bolts needed for hitch.

[ChiefRudy]

My father has a 2005 kj limited. Where putting a hitch on this weekend and the bolts that's came with it are M12 x 1.75 x 40. My father went to test the bolts and he said they don't fit. Now I'm gonna take a guess and say the wholes in the frame need to be cleaned of rust but I just want to confirm if we have the right bolts or not.

Thanks

 

[tjkj2002]

Correct size,make sure they are grade 10.9 or higher,grade 8.8 will not cut it at all.Just get a tap and clean the threads and install.

 

[TwoBobsKJ]

The link below is a video of a hitch installation on your '05 - the link to the video is just below the picture of the hitch. The beginning of the video deals with your issue exactly - and as Troy said above you may need to get a tap to clean out the weldnuts. And follow Troy's advice on the bolt grade too.

Hitch Installation Video - 2005 Jeep Liberty

Bob

 

[ChiefRudy]

Thanks for the info guys. My father cleaned out one the wholes in the frame but still swears the m12 bolt isn't going to fit. I have an 06kj I remember using m12 on mine.

 

[ridenby]

Pretty much have to use a tap to get them cleared enough.

 

[ChiefRudy]

Pretty much have to use a tap to get them cleared enough.

I know. But he doesn't believe me.

 

[tjkj2002]

I know. But he doesn't believe me.

Now what hitch was bought? I know a few aftermarket ones come with SAE bolts instead of meteric bolts.The only hitch I have seen that comes with the correct bolts is the OEM hitch,all others either come with SAE bolts or grade 8.8 metric bolts.

 

[ChiefRudy]

We got the hitch on with the bolts supplied. We ran a tap up the wholes and cleaned the threads. Nice to prove him wrong hehe :-D

 

[dude1116]

Hey guys! Sorry for the ignorance but what's a tap??? Looking to get my hitch installed this weekend.

 

[hectikart]

Hey guys! Sorry for the ignorance but what's a tap??? Looking to get my hitch installed this weekend.

a tap "taps" threads into metal...or cleans them out in the case of a rusted hole on the frame

Tapping Basics : How-To : DIY Network

 

[dude1116]

Ah I see. So they're different sizes, according to the thread diameter?

 

[dude1116]

Anyone have a size needed for this application? I can't seem to get a handle on the size measurements for these.

 

[tommudd]

Bolts are M12X1.75X40 bolt
so just need a tap for that size

 

[Fastpitcherus]

A tap is a beer dispenser.

 

[sevenhelmet]

A tap in that size can be very difficult to find. I was able to borrow a thread cleaning kit from my local O'reillys that had the correct sized thread in it and did the trick.

Troy, what's the problem with grade 8.8 bolts- are they not strong enough? I would think a proof load of 85,000 PSI is plenty strong to tow a 5,000 pound trailer.

 

[tjkj2002]

A tap in that size can be very difficult to find. I was able to borrow a thread cleaning kit from my local O'reillys that had the correct sized thread in it and did the trick.

Troy, what's the problem with grade 8.8 bolts- are they not strong enough? I would think a proof load of 85,000 PSI is plenty strong to tow a 5,000 pound trailer.

That very tap size came with my tap&die kit,actually a very common size in the automotive industry.

As far as the 8.8 bolts,they are equal to grade 5 bolts.Both will fail before a metric grade 10.9 or grade 8 bolt will even start to deform,stretch,or anything else that could cause failure.A 8.8 bolt in the M12 size is not all that strong and will start to stretch if torqued according to the specified torque range for those hitch bolts on a KJ(100lbs-ft),after that it's just time before they fail and they will fail if used to the max.

 

[tommudd]

I never had any issues finding that size , have bought three so far over the years / different parts stores / no issues

 

[sevenhelmet]

As far as the 8.8 bolts...

That's good to know, I think I have 8.8 bolts on my hitch right now p:

 

[HoosierJeeper]

No biggie, just replace them one at a time.

 

[sevenhelmet]

Thank God I anti-seized the threads when I put them in. They're torqued down pretty well.