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leaf spring bolts through the unibody

sharq

sharq

NAXJA Forum User
Location
Tampa Bay
im thinking about using extra long bolts and going all the way through the frame for the fornt leaf spring bolts on my '93. had a hell of a day yesterday getting the old ones out. if i go through the frame ill have access to the nut. gonna weld some washers to the frame to help reinforce the new holes.

good idea? bad idea? why?
 
im not sure i understand what you mean. the bolt will still go through the existing bucket side then though the bushing, then one side of the unibody frame rail and then finally the other side of the unibody frame rail. the nut will be exposed on the inside of the rail. if i ever need to take the bolt out again it will be much easier. its going to have to be like a 7 inch long bolt.
 
X2. Also, due to the frame rail collapsing if you tighten the bolt properly, you will likely be unable to achieve proper torque on the bolt if you do this, resulting in the load being placed on the sides of the bolt and the bolt holes instead of directly from the bushing sleeve to the frame.
 
kastein said:
X2. Also, due to the frame rail collapsing if you tighten the bolt properly, you will likely be unable to achieve proper torque on the bolt if you do this, resulting in the load being placed on the sides of the bolt and the bolt holes instead of directly from the bushing sleeve to the frame.
Click to expand...

i see what you mean. that make sense. maybe ill just weld some new nuts inside the frame rail then. was hoping i wouldnt have to. oh well :(
 
You could weld a sleeve all the way from the pocket where the old nut used to be, across the frame rail to the other side, and then throw a washer on the end of that, but I think it'll end up being more trouble than you'll save by doing it, unfortunately.

Aren't vehicles fun to work on?
 
heres an idea. if i weld a plate on the opposite side of the rail it should reinforce it. could drill a hole in the plate for the bolt. this would be for the inside of the rail.
 
I had the same problem with mine.. 3 impact sockets and 3 hours later..they were out. I think you'd be fine welding a tube through the frame rail. then a nut on the opposite side. If you have to do it again, you'll be glad you spent the time to make it serviceable.:doh:
 
tigerShark said:
heres an idea. if i weld a plate on the opposite side of the rail it should reinforce it. could drill a hole in the plate for the bolt. this would be for the inside of the rail.
Click to expand...
You need something straight through - if you just put a plate on the frame rail it'll still flex. You need a straight column of metal (effectively) from the old nut pocket to the place where you're now putting the nut.

EDIT: Remember that you're putting a significant amount of torque on those bolts (somewhere above 70 foot pounds IIRC)... here is some math:
The leaf spring bolts are M14x2.0mm. This means they have a circumference of 44mm, give or take.
A torque of 70 foot pounds will be equivalent to 3048 pounds applied to a 7mm (radius of bolt) lever. Since 44mm of rotation at this distance from center will result in 2mm of movement lengthwise, multiply by 22... that bolt is under approximately 67 thousand pounds of tension when properly torqued, though this does not take into account frictional loss.

My math is probably off here (waiting for a mechanical engineer to tell me I'm an idiot and answer this properly) but regardless that bolt is under a hell of a lot of tension, and unless you put a sleeve through, it's not going to work right.
 
Last edited:
looks like im going to weld a nut to a washer and weld the washer to the frame side of the pocket. ill have to cut out some of the pocket to recess the nut inside. im also going to grease the inside of the bushing so i dont have this problem again.

thanks for all the replies. naxja rules.
 
The bolt lives in a pocket along the side of the frame rail. You can access this pocket through the floor and then you can cut a little bit of the metal above the nut.

Now you can use a wrench (7/8")? to remove the nut. You can now replace the the bolt and nut when ever you want to.

Then just screw an access plate over the hole.

Here is a picture from when I was welding a new section of the floor in. It might give you an idea of what it looks like.

hanger.jpg
 
1990heepxj said:
lol last time i tried to unbolt my front spring bolts i twisted my 1/2 to 3/8 adapter and blew out a socket
Click to expand...
What I want to know is why you were trying to move a two decade old 14mm high strength bolt with a 3/8-drive socket. Not exactly the right tool for the job...

I had to stand on the end of an 18" breaker bar to get mine to move at all at first. After a few turns I could use my hands instead.
 
MoparManiac is a genius. everyone listen to him.
 
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