Rear Leaf Spring Mounting Bolt Replacement Question

I just did the suspension on my 2000 Prerunner. I was going off torque specs from this page: http://www.showstop.org/tacoma/torque-specs.php (no FSM) and it said to torque the front leaf spring bolts to 115 ft-lbs which is pretty high but went ok. There was no listing for the rear bolt that attaches the leaf spring to the hanger so like an idiot I just went with 115ft-lbs and twisted the threads right off the bolt. It looks like Toyota wants to sell the whole shackle for $60 instead of just the bolts. My question is, can I replace this with a grade 8 bolt or do I need to go with the factory shackle pin? It's not really a bolt, it has sort of a splined end on one side and a thread on the other for a nut. Anyone know a part # for just the bolt? Also does anyone know the torque spec for that rear leaf spring bolt?

 

Hint:

The shackle bolts for the springs are 9/16".

You won't find them anywhere.

They are the same bolts that are used to attach trailer springs to their hangers.

Tractor Supply has them and you will NOT twist them off when tightening them.

They are like $12 for 6.

 

Thanks. These are OEM toyota so they're metric, is it ok to replace with SAE? I'd be more inclined to go with a grade 8 metric bolt with lockwasher but then I don't really understand why the front are bolts with nuts and lockwashers but the rear are these funny splined studs, there must be some reason for it I guess.

 

To get the bolt part out of the shackle, youd have to cut it off then drill it out im pretty sure. I think new shackles are in your future.

 

Nah getting the bolt out is easy, I just press the splined bit out with a ball joint press. I just replaced the leaf springs and left the shackles in place, pressed the lower bolts out and then bolted em back in it went real smooth until I over-torqued the damn things.

 

Looks like wheelers sells a variety of aftermarket shackles with regular hex head bolts and nuts instead of these weird splined things ( ) . Unless someone knows better I'm going to take that to mean I'll be just fine with a grade 10.9 metric hex head bolt from the hardware store.

 

Oh I didnt realize they pressed out. Id grab a grade 10.9 metric bolt that will fit from tractor supply and be good to go!

 

Yeah I guess you're not 'supposed' to but it worked fine. Only thing I just realized is that the splined head is slightly larger than the bolt diameter, kind of like a shoulder bolt so I might run into a problem there.

 

Yep the TSC bolts will be stronger. The metric vs SAE size is so small you need dial calipers to tell the difference.

The spline is to keep the back bolts from being tightened so much that the shackles can't pivot. Frozen shackles will result in the frame hanger getting ripped out of the frame. The front ones don't need to pivot, so they can be bolted much more rigid. I hope that makes sense.

 

The torque spec for the shackle bolt is 67 ft/lbs.

The main eye bolt toward the front is indeed 115 ft/lbs. The shackle moves which is why I assume that bolt isn't torqued as heavily.

Here's the torque spec sheets for our trucks with the numbers you need, I have these printed out and in my truck.

 

I just buy the shackle Kits from Toyota one for the right one for the left.

Since the old ones get cut off on every one I touched .

 

Oh yeah I guess it is only 1/4 of a mm undersized to go with 9/16", might make the search easier. Thanks for explaining this, I knew there was a reason, that makes a lot of sense. I'm just kicking myself, this truck has 200k on it, all original suspension and it's so clean that all the hardware spun right out and was reusable (replaced the u-bolts for peace of mind) but then I went and did this... Might have to drop the $60 on a new shackle I'm nervous about the shoulder bolt thing, it's not much of a shoulder but seems like having even a couple mm play in the shackle is a recipe for trouble.

 

Yeah I have that printed too, now that I'm looking at it again it's pretty clear. I guess I got confused because the shackle bolts and the the front leaf spring bolt are the same size (14mm?) so it seemed weird that one would have twice as much torque as the other but I get it now. Was a long day...