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Length of 2" lift subframe bolts

PostPosted: October 23rd 2013, 4:46am
by gavio
Hi All:

I finally found some class 10.9 (grade 8) 12mm bolts in a 150mm length, but they didn't have the right 14mm bolts.... I found a place that has the 14mm bolts in a 140mm length (class 10.9) - I think I read somewhere that 140 is long enough, but can't find that reference....

Can anyone confirm?

Re: Length of 2" lift subframe bolts

PostPosted: October 23rd 2013, 7:32am
by 97cargocrawler
This thread has info:

https://www.astrosafari.com/viewtopic.php?f=40&t=9480

I bought my first set of bolts from Fastenal. That place is a total ripoff. I bought my second (correct size) set of bolts from McMasterCarr for about 1/4 the cost and they are every bit as good as the bolts from Fastenal. Something to consider.

Re: Length of 2" lift subframe bolts

PostPosted: October 23rd 2013, 4:24pm
by gavio
Unless I'm lookin' at something sideways, the longest 14mm screws McMaster has are 100 mm in the class 10.9 (grade 8) strength - I can find them 140 mm at bolt depot..... They (and other places) do have long enough bolts in class 8.8 (grade 5), though...

So, question is: Is it worth the sacrifice in strength to get the extra 10 mm in length?

Re: Length of 2" lift subframe bolts

PostPosted: October 23rd 2013, 4:35pm
by 97cargocrawler
Might as well go with class 12.9:

Part Number: 91290A778 $3.16

Product Detail
Black Class 12.9 Socket Head Cap Screw, Alloy Steel, M14 Thread, 150mm Length, 2mm Pitch
SOLD IN PACKS OF 1 (you need 2)

***Don't forget you need a 12mm HEX bit
Part number: 5677A53 Hex Bit Thin Wall Power Socket, 1/2" Sq Drive, 12mm***

Get your 12mm to match:

Part Number: 91290A646 $10.54

Product Detail
Black Class 12.9 Socket Head Cap Screw, Alloy Steel, M12 Thread, 150mm Length, 1.75mm Pitch
SOLD IN PACKS OF 5 (you only need 4)

***Don't forget you need a 10mm HEX bit***

These are the same (but shorter) bolts I'm using for my 3" blocks. You don't need to use socket head cap screws but they have a much higher tensile strength than regular cap screws.

You may also need large fender washers and split ring lock washers (I used these but they are probably not necessary):

91190A570 1 Pack Black Stl Lock Washer For Sckt Head Cap Screw, M12 Screw Size, 18mm Od, 2.35mm Min Thick

91190A580 1 Pack Black Stl Lock Washer For Sckt Head Cap Screw, M14 Screw Size, 21.1mm Od, 2.8mm Min Thick

91100A180 1 Pack Metric Znc-plated Steel Large-dia Flat Washer, M12 Screw Size, 37mm Od, 2.7mm-3.3mm Thick

91100A240 1 Pack Plain Stl Flat Washer,m14 Screw Sz,44mm Od,3mm Thk

Re: Length of 2" lift subframe bolts

PostPosted: October 23rd 2013, 4:42pm
by gavio
Hmmm, interesting.... These are also only 140 mm long - so perhaps that's the answer to my question - is 140mm long enough to get it all put back together when doing the work?

BTW, thanks cargocrawler for always being around to help get questions answered.....

Re: Length of 2" lift subframe bolts

PostPosted: October 23rd 2013, 5:00pm
by 97cargocrawler
Oh, shizzle. I thought you wanted 140mm....let me edit my post for 150mm...

Re: Length of 2" lift subframe bolts

PostPosted: October 23rd 2013, 5:27pm
by gavio
:D

I'd be perfectly happy with 140 mm if I can confirm that they're long enough when you're under there putting it together.... I haven't done it before, but in my mind, it seems like thy oughtta be fine - 2 inches longer that the stock bolts would be 146 mm.... Anyway, the selection is certainly better with the socket-head screws like you suggested - wonder if that's gonna be a pain to tighten up.....

Wonder also if I'm obsessing too much about the damn screws already - I gotta laugh sometimes at what a GEEK I am! :D

Geez....

Re: Length of 2" lift subframe bolts

PostPosted: October 23rd 2013, 6:56pm
by 97cargocrawler
I'd certainly ponder my purchase for a while. I bought $80 worth of useless bolts my first shot. Second time around I got it right for $20. Go with your gut.

You will definitely need some heavy duty hex bits to torque the bolts. The 14mm need to be torqued to 114ft.lbs or something close.

Be sure to use some Blue Loctite as well.