# Rear Suspension



## Jim (Oct 30, 2008)

My rear springs on the 67 were weak so I decided to change them. I looked up through several sources and ordered some MOOG springs. I received them but they don't fit, they are too short. The springs I took off are approximately 18.5" free. The new ones I bought were around 15" (whatever MOOG says are supposed to fit the 67) I installed them anyway just to see how it sat. Clearly, it is way to low. I need to go back with the size of the old ones I took out. I don't understand why there is an descrancy. I'm not sure its the originalk rear end but I thought an A Frame GM would be the same regardless if it fit under the Goat. Anyone ran into this? Any words of wisdom?

Thanks

Jim :cheers


----------



## pontiac (Mar 6, 2011)

measure yours and exchange them for taller. QED


----------



## Jim (Oct 30, 2008)

That's what I am going to do. I just wanted to try to understand why thee is a discrepancy.


----------



## leeklm (Mar 11, 2012)

Couple of thoughts... is it possible that your springs were previously replaced, maybe with station wagon springs or similar? (that was the case with my car). Also, I think many of these aftermarket springs are somewhat generic, and designed to "kind of fit" many applications. I replaced my front springs with Moogs, which sit higher than stock specs, but needed with my 225/70/15 tires.

I replaced my rears with stock replacements, but needed a little more lift to match up with the higher front end. Like many here, I installed a set of $80 air bags, which provide unlimited adjustments for heavier loads in the trunk, extra passengers, etc. i used existing holes under the rear bumper to install the air valves, so no drilling or mods to install the air bags. Maybe took 30 min start to finish.


----------



## BigDuke0767 (Mar 1, 2011)

I had the same problem but I needed new springs so I put summit brand springs on which come to find out are made by moog. The car sat way too low so I searched around for a taller spring but nobody could seem to help so I put a set of air shocks on and it's sitting where it should.


----------



## 70_GTO_JUDGE (Dec 8, 2010)

you were likely provided the correct springs. when springs are wore out, they are sprung open and will be larger. The replacement spring will lower the car since it has been raised by worn out, sprung springs. I replaced mine with moog springs, a note in the box said these may appear smaller then the one that come out of the car/ Ames confirmed this.


----------



## gjones (Oct 8, 2012)

*Springs*

So then it would be safe to assume that if the front end is now higher than the rear with the new springs, then the front springs would also need changing?


----------



## jasonblair (Nov 22, 2004)

I've personally never had a time when worn springs become "sprung open" and larger. Every time my springs have worn out, they compress more, and the car sags lower. That is my experience... not limited to the GTO.


----------



## geeteeohguy (Feb 2, 2008)

Jason, you are correct. Old tired springs never expand, they contract and settle, and get shorter. That is why the car sits lower. If a shorter spring provide greater ride height, it's simply because it is a stiffer spring rate than the original spring, and that off-sets the lower overall height of the new spring.


----------



## rickm (Feb 8, 2012)

convertible rear coil springs installed in a early hardtop or coupe will give the car a nice stance. an old gto trick from the '70s.


----------



## Oldeboy (Sep 17, 2012)

I put the Hotchkiss 1901 springs in over the winter. 1" lowering. actually they look to have the a very similar ride height to the 44 year old originals I took off. just much firmer... especially in front.


----------



## 67GTOCoupe (Mar 6, 2013)

I am in the process of redoing and cleaning up the rear suspension and brakes on my 67. I just got a set of new Moog springs also and they stand a little under 15' out of the car also. My car had the stock shock absorbers removed and the previous owner had installed some aftermarket shocks with spring helpers built in. I had to wonder why someone would have done this when changing out the springs in a 4 link set up is a 30 minute job? Mabye this has been a problem for sometime getting the correct height springs. I hope not. I have more work to do before I jack my rear axle back into place but I hope the car sits right with these springs or I'll be upset.


----------



## kilkm68 (May 5, 2011)

I replaced the weak front springs with a set of high performance springs from Ames last year. When I got them out of the box I thought they had sent the wrong springs, the were much shorter than the originals but bigger diamater. I called Ames and they confirmed they were the correct springs for my 68 convertible. They also told me old worn springs would expand, which made no sense to me. After installing the springs I still thought the front end sat too low and called Ames. They sent me the clearance specs from the body manual and I was surprised it was correct. I had just installed a new set of ceramic coated headers with electric cut outs and was worried about clearance. I got on line and ordered a new set from Detroit spring with a +2 in lift. It lifted the front way up, so much I had to lift the rear a little to even it out. I have lots of groung clearance now and no worry about damaging the headers. Detroit spring has a wide variety of springs for many different applications if you want to lift your car up.


----------



## 70_GTO_JUDGE (Dec 8, 2010)

Talk to AMES and or Moog regarding the issue, old worn out springs are indeed sprung and will be larger. Its easy to tell if a car has bad springs, it sit up higher than it should. Dont take my word for it, make a call


----------



## 70_GTO_JUDGE (Dec 8, 2010)

kilkm68 said:


> I replaced the weak front springs with a set of high performance springs from Ames last year. When I got them out of the box I thought they had sent the wrong springs, the were much shorter than the originals but bigger diamater. I called Ames and they confirmed they were the correct springs for my 68 convertible. They also told me old worn springs would expand, which made no sense to me. After installing the springs I still thought the front end sat too low and called Ames. They sent me the clearance specs from the body manual and I was surprised it was correct. I had just installed a new set of ceramic coated headers with electric cut outs and was worried about clearance. I got on line and ordered a new set from Detroit spring with a +2 in lift. It lifted the front way up, so much I had to lift the rear a little to even it out. I have lots of groung clearance now and no worry about damaging the headers. Detroit spring has a wide variety of springs for many different applications if you want to lift your car up.



correct


----------



## geeteeohguy (Feb 2, 2008)

Cars with worn out/tired springs do _not_ raise up. They get _lower_. That's why it's called _spring sag_, not 'spring raise'. In over 35 years in the auto repair industry, working on 1000's of cars, I have NEVER seen worn/tired springs raise the ride height of a car as they got old. It's against the laws of physics. Tired/worn springs will cause the car to sit lower.


----------



## Indecision (Oct 24, 2010)

geeteeohguy said:


> Cars with worn out/tired springs do _not_ raise up. They get _lower_. That's why it's called _spring sag_, not 'spring raise'. In over 35 years in the auto repair industry, working on 1000's of cars, I have NEVER seen worn/tired springs raise the ride height of a car as they got old. It's against the laws of physics. Tired/worn springs will cause the car to sit lower.


Anti-gravity is a bitch. :willy:


----------

