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leaf spring bolt size PLEASE

xjnewbi

NAXJA Forum User
Location
Jersey Shore
I feel like an arse, but my frame side (not shackle side) leaf spring mounting bolt sheared off. I can't get the remaining piece of bolt out of the weld nut. Can anyone please tell me what size bolt I need. Definitely going grade 8 because I don't want to do this again.

Trust me I searched. I found a few threads on how to cut open the mounting box/bracket but nobody mentions bolt size. This is a factory part that was retained when I installed my lift. I even checked the parts list from my build sheet but it says to reuse factory bolt.
 
5-90 - far as I know, at least to 87 and probably all the way to 84.

The same exact bolts are used for the LCAs as well (both ends.)

The only piece of info Eric missed is that the nuts are staked to keep them from unscrewing by themselves.
 
How far back does this screw size go? Need to know where to start it for my table...

I don't think this will help much, but my stock bolt is a hex flange head with "ABC 9.8" stamped in it. Threads start 2 5/8" from the flange (and extend into the area that sheared off) Remainder of bolt is still in the bracket and captive nut so I can't see it at the moment.
 
I found an OEM replacement on teamcherokee.com - as kastein mentioned, the same bolt as the LCA mounting bolt. The bolts look identical - sold in pairs $7 and $4 ship/handle. Pricey for 2 bolts but it will cost me more in gas to get to my nearest junkyard to wrestle a rusted to hell bolt out. I'll let you know how it works when they come in.
 
I get mine out of WJs these days - one of the nuts (pass side, frame end) is one of those dizzyingly stupid tag nut contraptions chrysler likes so much, but the others are all fine. Even here in the northeast I can get them 100% rust free and they come out easily. Same exact bolts.
 
Before you start cutting, how much bolt is still sticking out of the "frame"? I snapped one of my bolts when I was installing my lift and had ~1/2" sticking out and was able to weld the bolt back together. The heat from the weld also helped to break the bolt free. Once I had it threaded out I had to cut the bolt (the weld wouldn't fit through the hole) but it saved me from having to drill out the bolt or hack up my floor. Just another option.
 
Before you start cutting, how much bolt is still sticking out of the "frame"? I snapped one of my bolts when I was installing my lift and had ~1/2" sticking out and was able to weld the bolt back together. The heat from the weld also helped to break the bolt free. Once I had it threaded out I had to cut the bolt (the weld wouldn't fit through the hole) but it saved me from having to drill out the bolt or hack up my floor. Just another option.

That seems like a pretty good idea - problem is I don't know how to weld and I don't have a welder. What sucks even worse is that I was storing my Father-in-Laws welder in my garage for the last 2 years and he just sold it last month!

Thought about going to Fastenal, but I checked out their website and wasn't able to locate the bolt. I guess every store would be different so that's still an option.

I'll have to keep the ZJ donor as an option in the future but I would spend more money and time getting to my closest junkyard
 
I actually said WJ, but now that you mention it I believe ZJs use the same bolts on at least the front CAs and probably the rears as well.

Oem part numbers are 3420 2118 (bolt) and 1150 2814 (nut) in case you need to order some from a dealer/web dealer, can probably find them cheaper than teamcherokee. Try metricspecialties as well.
 
I actually said WJ, but now that you mention it I believe ZJs use the same bolts on at least the front CAs and probably the rears as well.

Oem part numbers are 3420 2118 (bolt) and 1150 2814 (nut) in case you need to order some from a dealer/web dealer, can probably find them cheaper than teamcherokee. Try metricspecialties as well.


Hey Kastein, thanks for the OEM part numbers and the website. You did originally say WJ but I automatically thought ZJ b/c my wife drives one so I could use hers as a donor - she would love that!

ehall - thanks for that info too - I noticed on 5-90s site that he lists the LCA bolt at 110mm and you had previously said that the OEM is 120mm. Lots of good info and advice here, THANKS everybody
 
I'm pretty sure they're the same part number and thus the same exact part, but I don't have my parts catalog on hand to prove it.
 
Hey Kastein, thanks for the OEM part numbers and the website. You did originally say WJ but I automatically thought ZJ b/c my wife drives one so I could use hers as a donor - she would love that!

ehall - thanks for that info too - I noticed on 5-90s site that he lists the LCA bolt at 110mm and you had previously said that the OEM is 120mm. Lots of good info and advice here, THANKS everybody

The only information on the chart I'd consider "hard" would be the stuff I've measured myself - RENIX-era engines, at the moment. Anything else would be "reports from the field," and measuring techniques can differ (some people try to measure the flange and include it in the screw length. Some people eliminate the dog point on piloted screws. ...)

I suppose I should put up a "how to measure a screw" guide to get some consistency, but I've been working on other things (not the least of which is a fastener primer. I know BillAVista did one, but I want to recall that some sections could be expanded and some simply explained more thoroughly.) Therefore, that's probably where I'll end up putting information on how fasteners get measured as well.
 
Finally got some time to start working on this after work today. Got my LCA bolts from teamcherokee and they will work just fine. Jacked up the truck and unbolted the leaf spring - to my dismay, I find that the frame side leaf spring bolt has sheared right at the inside mounting bracket. Unable to get the remaining portion of bolt out, I opted to follow what others have already done - cut open the bottom of the mounting bracket to access the weld nut. Several smacks later with cold chisel and 3lb sledge, finally popped the weld nut and residual bolt off.

Here is my current problem - the access hole that I cut in the bottom of the spring mounting bracket is too small to get the weld nut and residual bolt out. The OEM bolt is so long that, after it threads through the weld nut, it extends into a hole in the unibody. My advice for anyone doing this, is to sawzaw the bolt at the back end of the weld nut THEN pop the weld nut off. This way you will have 2 smaller peices that will easily fit through the access hole that you cut. I will have to cut a larger access hole or tack weld a small bolt to the broken OEM so I can clamp it with vice grips and use a sawzaw to cut the bolt (then bust/grind the tack weld)

I can't seem to do anything the easy way
 
I don't think this will help much, but my stock bolt is a hex flange head with "ABC 9.8" stamped in it. Threads start 2 5/8" from the flange (and extend into the area that sheared off) Remainder of bolt is still in the bracket and captive nut so I can't see it at the moment.

"ABC" is a maker's mark. "9.8" is the Property Class (SAE does it with hash marks, plus two.) Read the Property Class as:

9.8 = 9x100MPa Ultimate Tensile Strength (UTS,) or 900MPa tension to fail. 8 = 80% yield load to a 0.2% permanent set, so you'd see a 0.2% permanent deformation at 720MPa. (1MPa = 0.1450377ksi, or thousand pounds per square inch. Therefore, 900MPa = 130.53393ksi or 130,533.92psi and 720MPa = 104.427144ksi or 104,427.144psi loading.)

The unthreaded portion of the screw is called the "grip" - and is present because screws are typically threaded to 3d, where d is the nominal diameter of the screw (screw will be threaded to roughly 42m/m from the tip. This does not usually count dog points, and is often rounded up to the next 1/8" - SAE - or 5m/m - ISO.)

I'm willing to be that the screw will have a dog or "pilot" point on it when you get the rest of it extracted - this is common on OEM screws (which is why I don't get rid of them when I find them - unless they've failed.) Aftermarket screws are not typically made with dog points - they're usually special order items (long screws can be had fully-threaded, you have to order them as well. Fastenal should be able to supply you with screws of either variety.)
 
"ABC" is a maker's mark. "9.8" is the Property Class (SAE does it with hash marks, plus two.) Read the Property Class as:

9.8 = 9x100MPa Ultimate Tensile Strength (UTS,) or 900MPa tension to fail. 8 = 80% yield load to a 0.2% permanent set, so you'd see a 0.2% permanent deformation at 720MPa. (1MPa = 0.1450377ksi, or thousand pounds per square inch. Therefore, 900MPa = 130.53393ksi or 130,533.92psi and 720MPa = 104.427144ksi or 104,427.144psi loading.)

The unthreaded portion of the screw is called the "grip" - and is present because screws are typically threaded to 3d, where d is the nominal diameter of the screw (screw will be threaded to roughly 42m/m from the tip. This does not usually count dog points, and is often rounded up to the next 1/8" - SAE - or 5m/m - ISO.)

I don't know about anybody else, but I'm pretty friggin impressed!! I'm glad somebody knows what all that means - I've been schooled
 
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