Too much lift - new Dobinsons' Leaf Springs '78 40

[TuckerHudson]

My mechanic did a reversal of a shackle reversal and was able to bring my 78 40 to ~ stock height of 2", down from 4-5".

Our leaf springs were compressed and worn out so we replaced them with Dobinsons HJ40-7L-F Front & Rear Medium Load Leaf Springs.

Now - the truck sits even higher than it did before we swapped them. Maybe 5-6.5" - need to measure. What % of height gets reduced as the new springs settle in? How long should I expect to take (miles).

The rear shackles kit (new) is on order and I know that the current ones are lifted and worn - but wasn't sure how much difference that could account for, especially if the front shackles were swapped to new Dobinson's. The new rear shackle kit is still on backorder.

thx

 

[pb4ugo]

I think stk fj40 shackles are approx 2 3/4 pin to pin. Any shackle dimensions over stk raises the vehicle by 1/2 that amount. Going back to a stk lenghth could hurt the spring if it flattens out and the shackle is too short.

 

[TuckerHudson]

My mechanic did a reversal of a shackle reversal and was able to bring my 78 40 to ~ stock height of 2", down from 4-5".

Our leaf springs were compressed and worn out so we replaced them with Dobinsons HJ40-7L-F Front & Rear Medium Load Leaf Springs.

Now - the truck sits even higher than it did before we swapped them. Maybe 5-6.5" - need to measure. What % of height gets reduced as the new springs settle in? How long should I expect to take (miles).

The rear shackles kit (new) is on order and I know that the current ones are lifted and worn - but wasn't sure how much difference that could account for, especially if the front shackles were swapped to new Dobinson's. The new rear shackle kit is still on backorder.

thx

View attachment 3614911

View attachment 3614912

View attachment 3614913

View attachment 3614914

View attachment 3614915

 

[shawnfj40]

You probably know that the angle on your shackles is to vertical. They should be clocked to the other side of center. Both front and rear. The shackle length in back may or may not help. The front though it appears that your shackle mount on the front is taller than stock. With your current location of your spring mounts it appears that the spring is too short for your setup. I think you will either have to get the frame mounts correct or get a special length spring.

 

[TuckerHudson]

You probably know that the angle on your shackles is to vertical. They should be clocked to the other side of center. Both front and rear. The shackle length in back may or may not help. The front though it appears that your shackle mount on the front is taller than stock. With your current location of your spring mounts it appears that the spring is too short for your setup. I think you will either have to get the frame mounts correct or get a special length spring.

Will use this while I look into it. Tvm

 

[shawnfj40]

Here’s what that front mount should look like.

 

[TuckerHudson]

Here’s what that front mount should look like.

View attachment 3615040

How much "incorrect" lift / too-tall height could this be causing? Your setup, while correct, seems "taller" measured end to end?

 

[shawnfj40]

I set about 2 1/2 inches above stock. I have 2 inch of spring and about 1/2 on the shackle. I run 33 inch tires.

 

[shawnfj40]

My point in showing you was the shackle angle and the actual factory spring hanger. Are you sure the shop got the actual distance correct eye to eye on your spring hangers?

 

[TuckerHudson]

My point in showing you was the shackle angle and the actual factory spring hanger. Are you sure the shop got the actual distance correct eye to eye on your spring hangers?

I will check. Is there a reference I should give him? Thx for following up.

 

[shawnfj40]

Let’s call it 42 inches center to center.