downsr
Well-Known Member
Can someone tell me what the u bolts torque at on a 70 duster with espo heavy duty springs.
leaf spring torque
- Thread starter downsr
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It is less than you think. I believe around 45 or 55 Ft Pds . but please check your FSM on that. They need to slide some .
Yes, much less than you think. I was quite surprised when I found out how low the spec really was. I loosened mine and re-torqued properly.
mderoy340
Well-Known Member
50 ft lbs at ride height. After you drive the car a few times check the torque again.
Here's from the 70 Plymouth Service Manual:
cannucky
The Guy With No Birthday
This above....45 lbs with the car on the ground
mopowers
Well-Known Member
Stupid question, but what does it matter if the car's weight is on the spring if the whole reason to only torque them to 45lbs is to enable the spring to 'slide.'
ir3333
Well-Known Member
45 isn't a lot.
...light torque to prevent the axle tubes from deforming?
...light torque to prevent the axle tubes from deforming?
cannucky
The Guy With No Birthday
Couldn't tell you for sure , I'm don't know that allowing the spring to slide is the reason .All I know is thats what Ma Mopar calls for .
The springs don't actually slide in the manner you think. Since there is a center pin, they cannot slide, per say.
Best way I can describe it is this. Take two yard sticks. Clamp one end tightly with vise grips. Bend the yard sticks. Then remove the vise grips and do it again. You will see the difference.
It's about letting the front and rear segments do their separate jobs. If the plates are over torqued, the suspension will bind. If they are torqued in the air, the suspension will bind.
None of this is a CIA secret. If yall would spend 10 frikkin dollars on the MP suspension manual, you would learn a lot. It's all in the book.
Best way I can describe it is this. Take two yard sticks. Clamp one end tightly with vise grips. Bend the yard sticks. Then remove the vise grips and do it again. You will see the difference.
It's about letting the front and rear segments do their separate jobs. If the plates are over torqued, the suspension will bind. If they are torqued in the air, the suspension will bind.
None of this is a CIA secret. If yall would spend 10 frikkin dollars on the MP suspension manual, you would learn a lot. It's all in the book.
mopowers
Well-Known Member
I still don't quite understand how the suspension will bind if the u-bolts are torqued without the spring under load. I've seen plenty of springs installed and torqued on the rearend and installed in the car as an assembly without an issue. Heck, didn't the factory do it that way?
Now, the front and rear leaf spring eyes, that's another story. Those need to be torqued at ride height.
Now, the front and rear leaf spring eyes, that's another story. Those need to be torqued at ride height.
Fisher
Old Guy with a Cool car.
A 7/16-20 ubolt is 45 lbs, i have 1/2-20 on my duster mine are 65 lbs.
Not according to the factory service manual. They are 45 LB FT.
I don't know how to explain it any better. I don't know the physics of it, so I cannot put it into better words. If you don't believe the Mopar suspension book and almost every other leaf spring article you can find, I don't really know what else to tell you.
I didn't mean that in any smartass way at all. I don't know how else to put it into words. Other than to say I have tried it several ways and the only way that allows the rear suspension to work without binding is torquing the u bolts to 45 LB FT with the weight on the tires, or jack stands under the rear axle. As long as the weight is on the springs.
I didn't mean that in any smartass way at all. I don't know how else to put it into words. Other than to say I have tried it several ways and the only way that allows the rear suspension to work without binding is torquing the u bolts to 45 LB FT with the weight on the tires, or jack stands under the rear axle. As long as the weight is on the springs.
Fisher
Old Guy with a Cool car.
I tend to torque by the spec of the fastener.
In this case, that is incorrect.
Fisher
Old Guy with a Cool car.
Never been wrong yet? Oh well each to their own.
It's your car. Build it like you want to. I am just trying to help.
Factory used what is sometimes referred to as, "scored" nut on their U-bolts. 2 very small square indentions on the outside are created with so much pressure that the threads inside are distorted. These nuts are not going to loosen. In fact without heat applied you may not get them off without twisting/degrading their U-bolt. What is correct for your aftermarket parts,,, Ask that mfgr would be best.
69_340_GTS
Well-Known Member
Toplock or "distorted thread lock nuts":
Where can this manual be bought? I'd like to get one
cannucky
The Guy With No Birthday
Why the hell would I buy a book when I have FABO ? Either way READING IS FUNDAMENTAL , if you don't comprehend the english language download a dictionary .
See RRR I still don't have to buy a book LOL !
See RRR I still don't have to buy a book LOL !
Well said. You can also dent/damage the axle tubes if they're too tight. I noticed less creaking and popping when I re-torqued mine.
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New springs need to relax so to speak. Torque to spec then drive the car normally 20 miles on street. And youll be surprized how things settle/move to retighten. My 3 cents.
Mancini has them for 10 bucks. It is the Mopar suspension manual, ninth edition......unless there has been a tenth.
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