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rear leafs to stiff

3K views 12 replies 6 participants last post by  IanRiordan 
#1 ·
i bought a set of high arch leaf springs (add 2-4in in ride ht.) from jc whitney thinking i would like the ride height, which i do, but the rear end is real stiff. which suxs because i was trying to get rid of the air shocks. you can put all your weight on it and it barely moves. plus the shocks called for this model car (63 fairlane) are to short now. i found another set of shocks that fit but they are huge. and now i am bouncy bouncy bouncy. so de-arch? how do i know how much? help please....and i already know i am we todd did.....
 
#2 ·
2112jb said:
i bought a set of high arch leaf springs (add 2-4in in ride ht.) from jc whitney thinking i would like the ride height, which i do, but the rear end is real stiff. which suxs because i was trying to get rid of the air shocks. you can put all your weight on it and it barely moves. plus the shocks called for this model car (63 fairlane) are to short now. i found another set of shocks that fit but they are huge. and now i am bouncy bouncy bouncy. so de-arch? how do i know how much? help please....and i already know i am we todd did.....
Hey it's me again....

I don't mean to be a smart aleck.... but I have been doing 63 Fairlanes for decades.

did that JC Whitney spring thing.. they suck.... JCWhitney sucks.....
I never put the springs on, as I saw they were crap truck springs made in Mexico...... and after 19 phone calls I still had to eat 34 dollars shipping to return them, and wait 65 days for my $$$$ refund. I have never bought another thing from JC and never will.

Build yourself a set of springs out of your stock springs with a second main leaf. You'll like it. If you are interested, I'll tell you why and how, and save you a lot of anxiety.

Been there, done that,
63 Fairlane 2 dr ht Fuelie 5.0 HO T-5.
x
 
#4 · (Edited)
Leaf Springs too stiff, too high

2112jb said:
well crap.........i do not have the original springs anymore..........de-arch?
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OK, first- Here's what I did that worked. I cut the eyes off a main leaf at the apex of the eye and added it to the spring pack making it # 2, leaving out the original shortest (5th) leaf. I still have 5 but there are 2 main leaves. I turned the old 2rd and 3th leaves front to rear to make the front of the spring stiffer, and the rear more flexible. I clamped the front of the leaves so that the springs act like semi flexible ladder bars/sway bars. (think mopar super stock springs @ 1963 -- I hate traction bars etc. hanging down, this works, and is stealthy) Stock rear shackles. Polyurethane bushings front hole and shackles.

If I were to do it again I would have drilled the center bolt hole in the main eye leaf back 1/2 inch or even 3/4 since I was getting a custom drive shaft anyway. Lots of diff clearance to the trunk pan. This makes the wheelbase 116 for nascar like the factory late 64-67 cars did and for a little more tire clearance at the front. (I don't need it but it would look better and would be free$)

I eliminated the rubber spring wrap pad between the axle pad and the spring. (Mustangs didn't have them) That elimated the flex there for wheel hop problems. All I had to do was tack weld a flat washer into the axle pad hole so that the center bolt head fit perfectly into that washer hole to keep the spring centered. Dorman makes great quality U bolts, plenty long, cut to fit after totally done.

This raised the car up to stock height with no noticable stiffness. My wheel well is about 1/2 inch below the lip of the 14 inch wheels.
I also run Gabriel air shocks with only 10 psi because they are 50/50 action and fairly stiff to control body lift and unloading. They inflate individually so that I can preload the right rear if desired.

Oh and it hooks traction really well on the launch and doesn't unload.

I did a front end rebuild with disk brakes/sway bar too,

and this thing rides like a Lincoln and handles extremely well in the mountains, better than it has any right to.
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Yours:

Dearching will NOT change the spring rate/stiffness any significant amount, only the ride height.

try the above=
You said, all your weight and the rear barely moves down.... They are too stiff consider pulling out a leaf or even two,

maybe just the 3rd or 4th leaf, or ----even both the 4th and the 5th. The shortest is not doing much anyway, chuck it. They are pretty stiff so go down to 4 leaves total, maybe even only the 3 longest ones..... . Like I said Try to keep the longest leaf ends toward the front... for front clamping and keep rear half more flexible for ride. This should lower it some.

If you have to dearch= the way the spring places do it is, place your springs on the floor lying on their side. Chalk an arc along the assembled spring main leaf onto the floor. Disassemble the spring..... Compare the free main leaf to the chalk mark.. Make a new chalk arc in another location. Sledge hammer cold the main leaf gradually to make the spring straighter. Keep a constant radius. Use an anvil or railroad rail. Guess... take out the amount of radius equal to about 2/3 of the amount you think the rear is too high at the wheel well. If it is 3 in too high, take out 2 inches of arch. Remember you are making the spring softer by taking out the other leaves too. Compare to 2nd leaf, you might have to dearch it too. When the 2nd leaf fits into the main leaf with about 1/2 gap at the bolt the arch is correct.

Make another chalk mark on the floor for the finished new main leaf arch radius. Make the other spring to match this one.

Reassemble. Compare to the original assembled spring arch. See if it is flatter to your guesstimate... If it doesn't look flat enough, do it again... This sounds hokey, but it is the exact way the major spring arching/rebuilders have done it for 6 decades. But they had lots of practice. You get to guess and then do it over, LOL.

If you got the JC Whitney springs that I did, the front rubber bushings do not take the standard diameter poly bushings, neither do the shackle ends.

This is an aaallllll day job, and not much fun.. don't you wish you had bought 65 HIPO springs from Eaton/Detroit Spring fo $ 500 ??

Let me know in this thread what else I can do for you. Glad to help with anything.

Maybe this will help someone in the future. Works for any leaf spring car.

x
 
#7 ·
well i am going to try to return them. i appreciate all your input. but i think the fastest easiest way out would be just to buy another set from derborn or auto krafters.....springs n things.....thats what i get for going cheap, i found replacements at several suppliers and went with whitney due to pricing...... :pain:
 
#8 ·
2112jb said:
well i am going to try to return them. i appreciate all your input. but i think the fastest easiest way out would be just to buy another set from derborn or auto krafters.....springs n things.....thats what i get for going cheap, i found replacements at several suppliers and went with whitney due to pricing...... :pain:
Keeop in touch, Let me know before you order from Eaton Detroit Spring. They will custom make what you want for the same price....
 
#10 ·
i found i local shop that can do it, or so he says......i say that because he was supposed to call me back, but did not... i am a little Leary of letting someone work on my car esp. if they don't return phone calls.. makes them seem unreliable.
 
#12 ·
Mrwood said:
Gee i had a set of springs from JC that worked great, in fact had them on two cars, and never had a problem. I have bought parts from them since the late 1960s, and have never had to send a part back. Maybe you just got a bad set of springs.
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Ya they looked like truck springs, about the same size, but Heavy duty. The leaves were thicker than stock, not tapered, and the end bushing holes were different diameter and would not accept after market bushings.

The problem was that I had to make 19 phone calls (no kidding) and eat $ 34 shipping and wait several weeks to get my money back. They were rude and generally told me to go #$%^&* myself. I bet I spent 3 hours on the phone. They ran me from extension to extension, person to person, one time I was on hold for 17 minutes, and finally hung up and called back.... they are a bunch of ---- theives.

I will never ever buy anything from them again. period.
 
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