Leaf Spring Sag, 1970 Fury Convertible

1970FuryConv

Old Man with a Hat
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· Inflate 2 front 235-70R15 tires, 2 Rear 275-60R15, all 28” high: 35psi

· Pinch weld behind front tires 9” both sides

· Pinch weld in front of rear tires 8 3/8” both sides

· Rear Spring Sag: the measurement pictured is 8 3/8”. It’s at the pinch weld in front of the rear tire. I just paid a lot of money to have the front end aligned, camber, caster, toe, height. The same measurement at the pinch weld behind the front tire is 9 inches. I have the original 5 leaf rear springs on the car. Do you think that going to a 6 leaf spring will compensate for the 5/8 inches of Spring Sag? Thanks and if anyone has a measurement for this height in front of the rear tire with new 6 leaf springs I would be grateful to have it. Please specify if ordered for stock ride height. Many Many Thanks! Ben
PXL_20210203_190926962.jpg

PXL_20210203_190920888.jpg
 
Definitely get new springs. Why bother screwing around with old saggy springs? Band-aid approach at best. You spent the money elsewhere, why skimp now?
 
· Inflate 2 front 235-70R15 tires, 2 Rear 275-60R15, all 28” high: 35psi

· Pinch weld behind front tires 9” both sides

· Pinch weld in front of rear tires 8 3/8” both sides

· Rear Spring Sag: the measurement pictured is 8 3/8”. It’s at the pinch weld in front of the rear tire. I just paid a lot of money to have the front end aligned, camber, caster, toe, height. The same measurement at the pinch weld behind the front tire is 9 inches. I have the original 5 leaf rear springs on the car. Do you think that going to a 6 leaf spring will compensate for the 5/8 inches of Spring Sag? Thanks and if anyone has a measurement for this height in front of the rear tire with new 6 leaf springs I would be grateful to have it. Please specify if ordered for stock ride height. Many Many Thanks! Ben
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:BangHead::BangHead::BangHead::soapbox:
 
@polara71, @LocuMob
Hi Dave & Scott
I am planning to trash the old springs and buy new. That's a given. I am trying to compensate for 5/8" but leave the car level. Dave, I know you go 1" over stock height. I am trying to figure out whether 6 leaf springs will leave the car level or if I need to go 1" over to get level. Ben
 
@polara71, @LocuMob
Hi Dave & Scott
I am planning to trash the old springs and buy new. That's a given. I am trying to compensate for 5/8" but leave the car level. Dave, I know you go 1" over stock height. I am trying to figure out whether 6 leaf springs will leave the car level or if I need to go 1" over to get level. Ben
IMHO, to get the car level, get the standard arch springs.

If they end up being too low, your front end is too high and you just need to crank the torsion bars down and vice versa, but I'll bet they will be fine.

They might be a touch high at first, and they will need to settle as the car is driven.
 
BTW, don't add a leaf in the expectance of adding height. If you want a harder ride or heavier duty spring, OK, but really (again IMHO) go for whatever the HD version of the leaf spring offered for your car was rather than playing the guessing game of more leaves.
 
@polara71, @LocuMob
Hi Dave & Scott
I am planning to trash the old springs and buy new. That's a given. I am trying to compensate for 5/8" but leave the car level. Dave, I know you go 1" over stock height. I am trying to figure out whether 6 leaf springs will leave the car level or if I need to go 1" over to get level. Ben

Ben, adding a spring doesn't add height. Adding a spring or springs adds rigidity to the ride.
 
I replaced my old saggy springs with new ones from Eaton Detroit Springs. Had the 1 inch arch added to them.
Raised the back of my Fury 1.75 inches, exactly where I wanted it to sit.
Perfect fit.

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I replaced my old saggy springs with new ones from Eaton Detroit Springs. Had the 1 inch arch added to them.
Raised the back of my Fury 1.75 inches, exactly where I wanted it to sit.
Perfect fit.

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View attachment 436355
Awesome answer. Thank you.
Eaton was my 1st choice
2021-02-04 Eaton Detroit Springs

· Leaf Spring with front bushing installed ML725, $519 for pair, made in USA

· Shackle kit includes both rear bushings, IKCC1000 $74.95

· $741.95 including Fedex $148, order with Kim. Think shipping is high but decided to go with it.

· 3 week turn, Let’s hope it works
 
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Mine were delivered 23 days and were exactly as described.
I got the install kit but mine came apart so easily that I reused my originals except for the bushings.
 
@1970FuryConv -- I'll be interested in your experience. I plan to replace the spring on Snow White, my 1970 N-code Polara 'vert this coming spring (no pun intended).

If you have not already done so, have a look at this thread re: shackles: Rear leaf spring shackles
 
@1970FuryConv -- I'll be interested in your experience. I plan to replace the spring on Snow White, my 1970 N-code Polara 'vert this coming spring (no pun intended).

If you have not already done so, have a look at this thread re: shackles: Rear leaf spring shackles
Thanks for the link, Michel
All the parts are supposed to be OEM spec, stock height.
ESPO makes some springs in Mexico. I paid more at Eaton because all Eaton springs are made in Detroit. I wanted to be sure of what I was getting and to try and support American workers in this difficult time. I'll report on how it goes. Ben
 
Before and after pics would be most interesting. Any pics of the way it sits now?
 
Not giving advice on the direction you should take since you seem to have all the advice you need.
To add to the conversation, I had my springs rebuilt and ended up with an extra 1.5” high in the rear which I’m not a big fan of the look.
Everyone has told me that in a couple of years that they will sag again and I wasted my money having them re-arched/built.
So far going on 5 years & 15,000 miles later, they haven’t dropped down a 1/4” yet:p

I’m actually thinking of adding a couple of spacers to lower the rear body to get the look back and increase the caster for the front end
 
Not giving advice on the direction you should take since you seem to have all the advice you need.
To add to the conversation, I had my springs rebuilt and ended up with an extra 1.5” high in the rear which I’m not a big fan of the look.
Everyone has told me that in a couple of years that they will sag again and I wasted my money having them re-arched/built.
So far going on 5 years & 15,000 miles later, they haven’t dropped down a 1/4” yet:p

I’m actually thinking of adding a couple of spacers to lower the rear body to get the look back and increase the caster for the front end
I had the same problem of a ridiculous rake after I added an extra factory main leaf on my 65. I compensated by running a much shorter tire on the rear - has a mild rake unless the trunk is full when it'll now ride level.
 
My springs were flaaaat!
I jacked the Indy up until it was were a wanted it, measured from the wheel well.
Just to make it level I needed an inch and a half.
 
Before and after pics would be most interesting. Any pics of the way it sits now?
Hi Turbo
1st 2 pics are from December 2020 after wheel align and height adjust
PXL_20201201_193516550 f.jpg
PXL_20201201_193729279 f.jpg

older, but directly from the side. Prior to align. It's not off by much. Hope the 6th leaf fixes the problem, but does not over arch and lift the rear too much.
ps3.jpg
 
I see what your saying. In looking at it the rear sits about the same as my Fury but I lowered my front end a bit before an alignment so there is a very slight rake. My rear leafs are straight but I am curious where in the factory service manual does it say what the height of the car should be? What do you experts think here, does the rear end look too low or does the front end look too high ,or maybe a little of both??
Very nice car by the way and I am looking forward to your solution and results.
 
I have only been able to find the height measurement for the front to set your torsion bars.
Then the rear height becomes a preference thing. Too high you will have positive caster (or is it negative? Anyway your top ball joint is forward of your bottom ball joint) and wander all over the road. Too low you will bottom out on every bump.
 
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