Different Step Bar Bolting Holes?
 

I recently upgraded to an '09 H3 Alpha with Offroad Pkg from my '07 I-5 Offroad. I switched out my 305-70X16 tires to the '09, and also grill guard. Everything went fine, but when I went to install my step bars onto the new 3, the tapped holes didn't match. There were holes in the frame in the same location, but one of them wasn't tapped and the others were a different size.
I couldn't believe this could be true. Anyone else come across this?

im going to toss out some "stuff",if any or all sound stupid,pls scuse me!

front holes are wider spaced than rear,did u reverse steps!?

different size means?? ,,different space?

not threaded,r u sure??

last yr some guys insisted that some bolts/holes were english,some metric!!!!!

they insisted that 3/8 was right(wrong!) i showed pix of 3/8 and 10 mm,the slight difference.
more to follow,,,

i decided to mak my 07 steps useful, lower(i know,puke!),so i made 4 plates and lowered them the distance btwn the front bolts,which took some figgering on the rear. it worked for me but i did see off road guys throw up at the sight.
the point is they were level on the 07 which i traded a yr later,kept my "lowering blocks"

when i put them on the 10, it was winter and i never looked past the ice/snow till spring. they looked low in rear,,,and measured 3 fingers low!! the plates fit the truck,i redrilled to adjust,have NO, ANSWERS to that one. if the 10 step brackets were diff why did they look ok in stock form?? i made the switch immediatly when i got 10 so maybe they were f.u. on the 10 by dealer ??,and i didnt see the first day?? mysteries

not tapped really,,,could be a factory f. u. if no steps were ever there,made on monday after the 4th ya know!

The mounting holes should not be different sizes. So if yours turn out to be different , something is messed up.

Before addressing that though:

-I agree with drtom, make sure you've got the rails on the correct sides of the truck. (It's kind of a dummy check, and I don't think this is your problem... but it never hurts to take a step back and think.)

-Next thing I would check is the condition of the holes. I know when I installed my rails, I had to do some work on cleaning up the holes. GM thought it would be awesome to fill them with crap so I couldn't thread a bolt into them. Take some solvent / PB Blaster and a wire brush to the hole. After a good scrubbing, see if the bolts will fit.

It may be that one of the holes isn't threaded, but it could also just be caked with crap.

-The one hole, you said it was the wrong size. What do you mean? Is it too big and the bolt just slides in and out? Or do the threads seem wrong?


That all said, if your mounting holes are screwed up, they can be retapped. If the one hole is too big, you could drill it out a retap it bigger and just buy a bigger bolt for that one hole or install a helicoil.

I hope this helps!

I could have had the step bars switched as they sat in the garage a couple of weeks but I don't think so. The longer black rubber or vinyl step area was by the front door and shorter black step pad area was by the back door.

There are two mounting brackets on each bar, located off the front and rear of the bar. Each bracket has two holes drilled, one upper and one lower. The holes matched up to the holes on the new frame. But the rear upper hole on the frame wasn't tapped, and it was large enough diameter that I could just stick the bolt into it. The rear lower hole, was tapped, but too small of a diameter to thread the bolt into it. Both front holes on the frame were tapped, but just slightly too small for the bolts. (10mm vs 3/8"?)

But there was another problem. What I believe was the fuel line, that runs adjacent to the frame was located in a slightly different location. There was a brace/bracket welded to the frame that held the fuel line in place. It held the fuel line tight against the frame where the bracket needed to fit flush.

There is also a single tapped hole on the frame at about a midway point between front and rear. Making me think initially that possibly there was a third mounting point for the '09 bars. Of course, I after researching I realize that is not the case.

It looks like I may have to tap the larger hole and get a bolt to fit. Then find some smaller bolts (10mm vs my 3/8"?) that fit the smaller holes.

So much for making an easy switch.

Can you get a picture of your frame on the driver and passenger side?

pls dont get confused by my mention of 3/8 bolts i said that to make a strong point about there being ONLY metric bolts used, 10 mm as my memory works. 3/8 go in but are WRONG.
its raining or id go look at my rear bolt area because it seems there was an xtra hole nearby,not used,but if yours line up they must be right.

the driver front was almost impossible to assemble

nothing surprises me anymore

The frame itself is not tapped. There are clearance holes in the frame with weld nuts on the inside of it. The large hole you're seeing is made for the bolt to pass through to the weld nut. Apparently during production, yours missed getting this nut. I think the fuel line you're referring to is actually the parking brake cable. When step bars are added aftermarket, there is a tubular spacer with a long bolt that relocates it away from the frame providing clearance for the step bar bracket.

right!!

Yes, I'm sure now that you mention it, it was the parking brake cable. It was a struggle, but I was able to pull it down far enough to get it out of the way to attach the bar, but then I ran into the bolt hole problem.

The rear hole does appear to have missed the weld nut behind the hole. But what is strange is that the bolts that came out of my '07 don't fit into the tapped holes on the '09. Maybe I'll see if I can find a bolt size that does fit the nut correctly and just tap the "nutless" hole.

But with daily temps of 100 deg here in H-town, it is hard to get motivated to crawl under the H3 after getting home from work.

All the H3s use the same size Nerf Bar/rock rail bolts. 10MM x 40MM 1.50 pitch, grade 8.8.


What you need to know, as was touched on by beitodesstrafe, is it takes some REAL WORK to install the bolts in a virgin frame. They will not go in all by themselves, it takes some elbow grease. You can snap off a bolt head if you are not careful, and that is where having a stud puller is handy.

If you do not have access to a stubby 10MM 1.5 pitch tap, then use a clean bolt and start it after spraying the frame holes with PB Blaster. Turn in some, back it out, clean the bolt threads with a rag, spray the hole again, turn in some more, and repeat until you have all the bolts in the full mountingh depth. Then begin to actually mount the bars.

IMHO the factory bolts are longer than necessary, so you could go to a hardware store and buy 20MM length to save your knuckles if you have a particularly stubborn hole.

What seams like should be a simple job is a PITA until you have done it about 3 times. Good luck.