Did I do something stupid?

-
Pentarockstar

Pentarockstar

Well-Known Member
Joined
Oct 8, 2010
Messages
127
Reaction score
30
Location
usa
I have a 69 340 swinger 4-speed. Around ten years ago I put on Mopar performance leaf springs. The other day I was looking it over and I noticed that the right side was soggy. After looking under it, I saw the two leaf springs are different. The left side has more leafs. Are these backwards?
 
Pentarockstar said:
I have a 69 340 swinger 4-speed. Around ten years ago I put on Mopar performance leaf springs. The other day I was looking it over and I noticed that the right side was soggy. After looking under it, I saw the two leaf springs are different. The left side has more leafs. Are these backwards?
Click to expand...
It sounds like it, yes. If they are SS springs, the car should favor the driver's side in the rear so that when it launches, the car will straighten up from the torque of the drive train. If you can see the part numbers, even is for one side, odd is for the other......I just cannot remember which is which. I am sure someone will tell us shortly.
 
i think odd numbers on drivers and evens on pass side. all based on sitting in drivers seat. i pulled torsion bars from 2 cars toady and odds were on drivers side.
 
The leaf springs with more segments goes on the right rear. The torque of the engine lifts the left front. This applies greater downforce to the right rear. The springs were designed to keep the car level for equal down force. All Super stock springs are installed as I mentioned. Read below right spring gets more bias control

leaf springs 001.jpg
 
Last edited:
Thanks guys. Yeah I thought so. I just use the car for cruising around, had it for 25 years. It means to much to me to beat on it.

Thanks oldmanmopar! That is a great explanation. I will swap them out. I am also hoping this changes my pinion angle. It is pointing up.
 
Pentarockstar said:
Thanks guys. Yeah I thought so. I just use the car for cruising around, had it for 25 years. It means to much to me to beat on it.

Thanks oldmanmopar! That is a great explanation. I will swap them out. I am also hoping this changes my pinion angle. It is pointing up.
Click to expand...
It should be point up relative to the ground, but that's the end of it. It actually points down relative to the drive shaft, which is correct.

That said, be careful when you re-torque the leaf spring U-bolts. Their torque spec is low. Only 45 LB FT. That is to allow some slip of the springs between the shock plates for proper rear suspension operation. If you over torque them, it will cause the rear suspension to bind and basically render it useless.
 
Be careful when you count. I have 002/003 springs. Count at the spring perches cause the leafs are in different positions and some of mine start right at the perch position and will fool you. From the rear my pass side spring appears to have 4 leafs and the driver side appears to have 5. At the perch they both have 5. I am sure mine are on the correct sides.
 
The orginal style U clamps are nice, if they have good threads its worth restoring and using them. Chrysler put some effort into their design. They are flat in the U with a waffle pattern, provides the correct clamping and friction on the tube with the book value for the torque you apply to the nuts.
What torque it should be with a plain round U clamp ...? goodness knows.
Be careful not to crimp the axle tube, the force applied by the base of the U is very concentrated on a narrow space with a round section clamp.

Dave
 
I looked under there and pulled the part numbers. 4120863 is on the right and 4120864 is on the left. They are backwards. So, I will hang my head with shame and swap them around.

Yes it does seem odd the U-bolts are only tightened to 45 FP.
 
I did a bit of research on the part numbers i found. According to mopar performance, Mancini racing and Summit 4120863 is correct for the right side. Now i am confused....
 
Pentarockstar said:
I did a bit of research on the part numbers i found. According to mopar performance, Mancini racing and Summit 4120863 is correct for the right side. Now i am confused....
Click to expand...
According to my Mopar Chassis manual, P4120863 is for right side, P4120864 is for left side. So it appears they are not backwards. They are correct as you installed them 10 years ago.
 
Pentarockstar said:
I will recount to make sure and look at the parts numbers.
Click to expand...
Did you recount the number of leafs at the perch? If the pictures on Summit are correct, then they both have 5 leafs. The bottom leaf on each spring looks kind of like a half leaf. The difference being that "half" leaf points forward on the 863 spring and points rearward on the 864 spring. That can be deceiving when counting leafs as I said earlier. My P3412002 (right) and P3412003 (left) have that same design. The right spring (002) has that half leaf pointing forward same as the 863 picture I see. So I am still thinking your 863 spring goes on the right side as you have it. Take a look and tell us what you see.
 
@DC 340 Yes, It is exactly as you say. There is five at the axle on each side. The half leafs come from the front on the 863 and from the back on the 864.
 
Pentarockstar said:
@DC 340 Yes, It is exactly as you say. There is five at the axle on each side. The half leafs come from the front on the 863 and from the back on the 864.
Click to expand...

Then IMO you have them installed correctly as they sit. I would leave them alone.
 
Best solution? Call ESPO Springs and Things and order a set of 6 leaf springs. Take the Super Stock springs and put 'em up for sale to somebody with a drag car...
 
DC 340 said:
Did you recount the number of leafs at the perch? If the pictures on Summit are correct, then they both have 5 leafs. The bottom leaf on each spring looks kind of like a half leaf. The difference being that "half" leaf points forward on the 863 spring and points rearward on the 864 spring. That can be deceiving when counting leafs as I said earlier. My P3412002 (right) and P3412003 (left) have that same design. The right spring (002) has that half leaf pointing forward same as the 863 picture I see. So I am still thinking your 863 spring goes on the right side as you have it. Take a look and tell us what you see.
Click to expand...
So, @rbkt65 said "I think odd numbers on drivers and evens on pass side. all based on sitting in drivers seat."
Right Spring 002? Now Yours are Backwards?
 
eekvonzipper said:
So, @rbkt65 said "I think odd numbers on drivers and evens on pass side. all based on sitting in drivers seat."
Right Spring 002? Now Yours are Backwards?
Click to expand...
Mine are Set as @DC 340 Suggested with the 003 on the Left-Side and Mine is Also a Lil Soggy on the Right-Side.
Am I Backwards too? Extra Spring Forward on the Right (002) Extra Spring to the Rear on the Left (003)
I can't remember how I decided on this last year when they went in...
Seemed Right, Now it looks wrong? Opinions are like **sHoles, They are Needed! Lol

Btm.jpg


Right Spring 002.jpg


Rear.jpg
 
eekvonzipper said:
Mine are Set as @DC 340 Suggested with the 003 on the Left-Side and Mine is Also a Lil Soggy on the Right-Side.
Am I Backwards too? Extra Spring Forward on the Right (002) Extra Spring to the Rear on the Left (003)
I can't remember how I decided on this last year when they went in...
Seemed Right, Now it looks wrong? Opinions are like **sHoles, They are Needed! Lol
Click to expand...

The P3412002 definitely belongs on the right (pass side). P3412003 belongs on the left (driver side). The table above from Oldmanmopar shows that. It is also shown that way in my Mopar Chassis manual.
 
You must log in or register to reply here.
-

Back
Top