Advice on lifting rear end on a 66 Newport?

[Gerald Morris]

Greetings C-body Moparians! Constantly reminded of WHY I HATE air shocks every morning when I must air up my leaky Monroes, I want to implement a GOOD solution to the problem of lifting Mathilda's rear end 3 inches or so. I like running 235/75/15s in the back, as they do well with Tucson's crappy pavement, but these leave FAR too little room between them and the fender; thus the desire to lift.

I've found several extended shackles which look promising, and I plan to install Monroe "load levellers" (the ones w the coil spring reinforcement, 58577s currently) My concern is that these might not be long enough if I lift the rear end on extended shackles. I also worry about increased shear from side to side on the shackles themselves, and plan to get the stoutest I can find for the purpose.

My question is: Is this a sound scheme to lift the rear end the desired 3-4 inches, or should I just go to a spring shop and be done with it? We have a decent one in town.....

 

[CBODY67]

Longer shackles do NOT work on Chrysler rear suspensions, period. NOT for the amount you desire. "Load Levelers" are not supposed to raise the rear end that much either. They are supposed to be pretty "invisible" until you put a load in the rear end, the center of the spring (coils close to each other) compress and engage the stiffer coils (farther apart).

If your air shocks are leaking, find out of the leaks are at the fittings or from the diaphrams.

But it appears the tires are too much for the car, width-wise. In the rear, you have the "hard points" of the wheel house/fender skirt on the outside and the leaf spring on the inside. The station wagons used 9.00x14 tires on 14x6 wheels (14x6.5 in '65). I've got P245/70R-14s on the 14x6.5 wheels on my '67 Newport with no clearance issues, but they are TIGHT enough that I can't use a hand scrub brush to do the whitewalls inside the wheel well when I'd wash it.

Lifting the body that much will effectively put the front suspension into significant negative caster, even if it is set correctly at normal ride height.

So, possibly, either new air shocks (as the other two possibilities just don't work on Mopar assymetrical-mount rear leaf springs, by observation, and the spring/shocks aren't designed to "lift" the rear end. Now, the load levelers can somewhat compensate for sagged rear leaf springs, but not to lift above normal ride height ), P225/75 tires, and/or wheels with different backspacing to better center the wheels in the wheel wells.

Back in the '60s, when longer shackles were popular to raise the rear end of a car for wider rear tires, they worked fine when the rear leaf springs were "center mounted", but with the assymetrical mounting of the Chrysler rear leaf springs, that extra length in the shackles just resulted in the rear part of the leaf having a negative arch to it.

Perhaps not what you were wanting to hear, sorry.

CBODY67

 

[Gerald Morris]

Longer shackles do NOT work on Chrysler rear suspensions, period. NOT for the amount you desire. "Load Levelers" are not supposed to raise the rear end that much either. They are supposed to be pretty "invisible" until you put a load in the rear end, the center of the spring (coils close to each other) compress and engage the stiffer coils (farther apart).

If your air shocks are leaking, find out of the leaks are at the fittings or from the diaphrams.

But it appears the tires are too much for the car, width-wise. In the rear, you have the "hard points" of the wheel house/fender skirt on the outside and the leaf spring on the inside. The station wagons used 9.00x14 tires on 14x6 wheels (14x6.5 in '65). I've got P245/70R-14s on the 14x6.5 wheels on my '67 Newport with no clearance issues, but they are TIGHT enough that I can't use a hand scrub brush to do the whitewalls inside the wheel well when I'd wash it.

Lifting the body that much will effectively put the front suspension into significant negative caster, even if it is set correctly at normal ride height.

So, possibly, either new air shocks (as the other two possibilities just don't work on Mopar assymetrical-mount rear leaf springs, by observation, and the spring/shocks aren't designed to "lift" the rear end. Now, the load levelers can somewhat compensate for sagged rear leaf springs, but not to lift above normal ride height ), P225/75 tires, and/or wheels with different backspacing to better center the wheels in the wheel wells.

Back in the '60s, when longer shackles were popular to raise the rear end of a car for wider rear tires, they worked fine when the rear leaf springs were "center mounted", but with the assymetrical mounting of the Chrysler rear leaf springs, that extra length in the shackles just resulted in the rear part of the leaf having a negative arch to it.

Perhaps not what you were wanting to hear, sorry.

CBODY67

Actually, that's fine. I'm GLAD to be warned off this fool's fantasy! I'll get the springs re-arched, reinforced or replaced then instead. I never expected the load levelers to give me any extra height, but like them for the bit of extra spring. If I get the springs redone/reinforced, then that may even become moot. I LIKE the idea of 225/75 tires too. I just dropped the front ones down from that to 215/75s to good effect, (picked a couple mpg up right off!) so a modest reduction in rear tire size might be just the ticket then. The air shocks did alright for their first year, but they have become more problematic lately. I suppose I can just re-run the line, little O rings and crap.

Heaven FORBID I should diddle up my front end after the work I put into it this past January. She rides arrow straight and true right now, w just enough positive caster and a slight bit of toe for really nice driving!

Much obliged. This is why I posted my query before spending a cent in this direction.

 

[cantflip]

Actually, that's fine. I'm GLAD to be warned off this fool's fantasy! I'll get the springs re-arched, reinforced or replaced then instead. I never expected the load levelers to give me any extra height, but like them for the bit of extra spring. If I get the springs redone/reinforced, then that may even become moot. I LIKE the idea of 225/75 tires too. I just dropped the front ones down from that to 215/75s to good effect, (picked a couple mpg up right off!) so a modest reduction in rear tire size might be just the ticket then. The air shocks did alright for their first year, but they have become more problematic lately. I suppose I can just re-run the line, little O rings and crap.

Heaven FORBID I should diddle up my front end after the work I put into it this past January. She rides arrow straight and true right now, w just enough positive caster and a slight bit of toe for really nice driving!

Much obliged. This is why I posted my query before spending a cent in this direction.

Have them make you new springs, since they're local you could have them do the install too... there is no better way.

 

[polara71]

Replace the springs, add an inch over stock height .

 

[commando1]

Replace the springs, add an inch over stock height .

x2

 

[Gerald Morris]

I thank ALL you Elder Moparians for your sage advice here. This is what brings me back to this forum so often.

 

[300rag]

I thank ALL you Elder Moparians for your sage advice here. This is what brings me back to this forum so often.

Elder?

Why i oughtta.....

 

[live4theking]

I had springs rearched once, I'll never do it again. Buy new springs.

 

[commando1]

Elder? View attachment 181340 Why i oughtta.....

Yah, Elder. You know.... The guys who buy new Challengers with Slush-O-Matics.

 

[78Brougham]

I had springs rearched once, I'll never do it again. Buy new springs.

I've never known them to work out. Did it once when I was just starting out. Never again. And hearing all the bad stories always reinforced that decision. Go new or not at all.

 

[300rag]

Yah, Elder. You know.... The guys with bum knees who buy new Challengers with Slush-O-Matics.

 

[live4theking]

I've never known them to work out. Did it once when I was just starting out. Never again. And hearing all the bad stories always reinforced that decision. Go new or not at all.

It was an inexpensive option that proved to not be worth a nickle of what it cost me.

 

[CBODY67]

It used to be that a "serious" spring shop actually put the leaves in their kiln, to get them glowing red. Then they'd remove them with tongs, place them on a curved fixture. Then beat them to match the curve on the fixture before they cooled much. When that was done, then they be quenched in a tub of water (fire, smoke, and all). Then they'd further cool prior to final assembly.

In more recent times, the kiln was not in operation. The re-arch was done by using a hydraulic press "punch" to put little bends in the leaf until it had the correct arch. "Cold Press"?

These processes will work for the symmetrical leaf springs, where the front and rear sections, from the axle mounting point, are equal. I doubt it would work well on a Chrysler leaf spring where the front section is shorter than the rear section. Which might be why the re-arch didn't work too well?

The problem with re-arching is that the springs sagged for some reason and they'll probably do it again if the reason for the sag is not cured. That's my suspicion.

CBODY67

 

[Gerald Morris]

All good advice on why NOT to waste money on re-arching. Then new springs really are the thing. I suspect after 53 years, they're simply a bit fatigued. I saw that PST has some meant for C-body Mopars. I might go with that. Time to research prices on spring sets for a 66 C body Mopar here....

 

[traintech55]

When I have raised the rear ride height, I used a good spring shop to rearch the springs, but had the lower leaf replaced with a thicker one.

 

[Zymurgy]

Here is where I bought mine 5 years ago, there are a few good ones out there. Very happy with mine everything bolted up perfectly. You can go an inch higher than factory arch. Chrysler Leaf & Coil Spring Applications - EATON Detroit Spring

 

[Gerald Morris]

Here is where I bought mine 5 years ago, there are a few good ones out there. Very happy with mine everything bolted up perfectly. You can go an inch higher than factory arch. Chrysler Leaf & Coil Spring Applications - EATON Detroit Spring

Thank you! I've found a couple others via the Google oracle. This General Spring I found outfit looks promising. I notice that for the Newports most of these companies have a "one size fits all" approach I don't like. Good to see Eaton has some variety based on the different permutations. The price is a bit higher though not beyond the figure I've seen for some others.

I'll likely consult our local shop, Arizona Spring for a reference. Tilly's old ones aren't THAT bad, fortunately. My motivation is largely based on the desire to drive with the 235/75/15 tires I like in the rear, which ARE a bit snug with the fender well. I need to get the radiator replaced before I get into spending hard earned $$ on the rear suspension right now.

Did you install your own springs? Your comment reads as if you might have. I prefer to do all the wrenching I can with Mathilda, both as an economic measure and for insuring job quality. Again, many thanks.

 

[Gerald Morris]

When I have raised the rear ride height, I used a good spring shop to rearch the springs, but had the lower leaf replaced with a thicker one.

THIS is an approach I'm contemplating! I also am considering adding an additional leaf. Given that my old springs are NOT in terrible condition, this approach has much appeal to my wallet, IFF it will do for me what I want for some years.

 

[Zymurgy]

I did install it myself, it was probably the easiest thing I have done on my 66 300. One thing I can say for Eaton, the price when I bought it including all the shackles and bolts. Everything was the same or beefed from the factory parts I took off.

Here is my old thread. My new leaf springs are installed