Bolt Sizing Question: LCA Bolt and Track Bar Bolt

I was installing a lift on my 2000 XJ this weekend and had some bolt carnage. The track bar bolt on the axle end broke while torquing it down after install my adjustable track bar and I had to cut the rear bolt to free my lower control arm because the bolt was fused to the bushings sleeve and no amount of love from a BFH, heating or penetrating lube would free it.

So I was wondering if anyone could tell me the correct size and pitch of these bolts so that I can pick up some grade 8s at Fastenal and get my jeep back together. Thanks a Bunch!

LCA bolt size is M14-2.0x110, be sure to get grade 10.9. Anything less is likely to fail, which would be bad juju.

Here's a handy chart for you: Kelley's WIP fastener sizing

As far as your trackbar goes, I believe it's a 9/16 x 4 1/2" Grade 8 bolt (at least that's what my JKS adj trackbar uses). This is assuming that you're talking about the trackbar mount on the frame end, I don't recall what size the axle end is.

The OEM lower trackbar bolt is M10x1.5. I don't remember the length, but it was not standard, about 85 MM. You should measure the length of the one you broke. Do not use a smaller bolt. It must fit the axle bracket exactly and be torqued to spec, or it will woller out the hole in the bracket. The torque spec from the 1990 FSM is 74 ft#. That spec from the 2000 FSM is 40ft#. I think 74 is way too much, but you decide.

What brand of trackbar are you running? The latest RE trackbar mounting kits have gone to a 1/2" bolt and larger ID bushing to match, requiring the installer to drill out the axle bracket. I don't have the install instructions here in front of me, but remember the torque for this larger bolt is around 70 ft#. Again, make sure the torque is correct.

Mike and MoFo thanks for bolt specs and that handy chart. I running a JKS track bar (OGS126) they say 85 ft/lbs for the frame end greasable bolt and factory specs which is 40 ft/lbs on the axle end. I'll just measure my lenght and pick up one along with a new LCA bolt. Thanks Again!!

Mike is right. Grade 8 is nowhere near hard enough for that application. IIRC, the original bolt in my 94 was closer to a metric 12.9, not a 10.9 hardness. Like MoFo says, that bolt has to fit very closely, or the bolt will start to chuck back and forth in that bracket.

ChiXJeff said:

Mike is right. Grade 8 is nowhere near hard enough for that application. IIRC, the original bolt in my 94 was closer to a metric 12.9, not a 10.9 hardness. Like MoFo says, that bolt has to fit very closely, or the bolt will start to chuck back and forth in that bracket.

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I'm kind of just thinking about going to the dealer tomorrow morning and getting stock bolts. They can normally get them in a day, if not that same day but they weren't open when I finished working on it yesterday and they're not open today either. Thats not very convient because most folks work on their stuff on the weekend. But my XJ currently serving double duty as a trail rig and daily driver because my commuter car took a deer at 70 mph and is in the shop so I need to atleast put the jeep back together to get to work for a day or two.

There are a few fasteners on my XJ where I very much prefer OEM fasteners, this is one. Another one is the front hub bolts (both hard and a profiled shank.)

ChiXJeff said:

Mike is right. Grade 8 is nowhere near hard enough for that application. IIRC, the original bolt in my 94 was closer to a metric 12.9, not a 10.9 hardness. Like MoFo says, that bolt has to fit very closely, or the bolt will start to chuck back and forth in that bracket.

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Hi. New here. When I did my LCA's the axle hole was already wallowed out. I got a 9/16ths bit and drilled out the collars in the new control arm bushings and the bolts slid through the axle mounts without modification. I'm a newb mechanic and used Gr. 8. Now I read this thread. After doing some research I see that Gr. 10.9 or 12.9 are reserved for metric bolts? Now what would I do to bring these bolts up to the correct hardness?

Thanks

You're good as you are. For bolts, SAE grade 5 is roughly equivalent to metric grade 8.8, and SAE grade 8 is roughly equivalent to metric grade 10.9. Your replacement bolt is also bigger than the stock size, as well as being about the right strength class.
When my track bar axle bracket hole wallowed out, I moved up one bolt size, which happened to be from metric to SAE. I drilled the bushing sleeve to take this slightly larger bolt. Works great.

4xBob said:

You're good as you are. For bolts, SAE grade 5 is roughly equivalent to metric grade 8.8, and SAE grade 8 is roughly equivalent to metric grade 10.9. Your replacement bolt is also bigger than the stock size, as well as being about the right strength class.
When my track bar axle bracket hole wallowed out, I moved up one bolt size, which happened to be from metric to SAE. I drilled the bushing sleeve to take this slightly larger bolt. Works great.

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Phew. Thanks. When I read that I might have used too soft a bolt, I started freaking a little. I appreciate your feedback and look forward to reading here. Thanks again bob

A grade 8 9/16" bolt should be fine.

For what it is worth, the hole in my axle side mount was larger than the stock M10x1.5 bolt when I got it. I welded the thickest 5/16" grade 8 washers I could find over the holes (5/16" because they were an almost perfect clearance fit on a 3/8" grade 8 bolt, check for fit before using) hit it with some rustoleum and assembled it. Been working great for 3 wheeling trips and several months. When I replace the bushing I will likely drill the sleeve out and upgrade to 1/2" or 7/16" grade 9.

kastein said:

A grade 8 9/16" bolt should be fine.

For what it is worth, the hole in my axle side mount was larger than the stock M10x1.5 bolt when I got it. I welded the thickest 5/16" grade 8 washers I could find over the holes (5/16" because they were an almost perfect clearance fit on a 3/8" grade 8 bolt, check for fit before using) hit it with some rustoleum and assembled it. Been working great for 3 wheeling trips and several months. When I replace the bushing I will likely drill the sleeve out and upgrade to 1/2" or 7/16" grade 9.

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Thanks. I thought about welding washers. I have a couple other mounting points that have similar issues (luckily none as critical as this one). Maybe I'll give that a shot.

Thanks again