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 71 LeMans Sport rear springs
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NOTROD
Buffalo

USA
64 Posts

Posted - 06 Feb 2016 :  6:06:21 PM  Show Profile  Reply with Quote
My car seems awfully soft in rear. The springs look okay and the car sits nice and level side to side, with a slight rake toward the front. When I bought the car it had air shocks and I believe they were factory due to having a schraeder valve mounting boss near the fuel filler neck and the system all intact.
One of the shocks was dead so I took them off and replaced them with a regular gas shock. I'm wondering, is it possible that the factory used a slightly softer spring in combination with air shocks? I've found "firm ride" springs that will fit the car, but I don't want anything that will change the ride height.

Phil
The Great White Buffalo

USA
7222 Posts

Posted - 06 Feb 2016 :  9:52:09 PM  Show Profile  Reply with Quote
Put some Bilstein shocks on it.

Bowties are for Pee-wee Herman. "Chevy": even the name sounds cheap, but not as cheap as your Pontiac will be with an LS transplant.
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cortcomp
Coyote

USA
5338 Posts

Posted - 07 Feb 2016 :  10:06:44 AM  Show Profile  Visit cortcomp's Homepage  Reply with Quote
I ran bilstein's all around on my 71 (when it was stock height and when lowered 1.5"). I thought they were a great street shock.
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Phil
The Great White Buffalo

USA
7222 Posts

Posted - 10 Feb 2016 :  1:47:54 PM  Show Profile  Reply with Quote
Agree, they really change the characteristics of the car for the better. Quality stuff and still reasonably priced compared to gimmick shocks.

Bowties are for Pee-wee Herman. "Chevy": even the name sounds cheap, but not as cheap as your Pontiac will be with an LS transplant.
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NOTROD
Buffalo

USA
64 Posts

Posted - 10 Feb 2016 :  4:01:53 PM  Show Profile  Reply with Quote
I confess. I didn't spend a whole lot on shocks when I was rebuilding the car. Too many other things to buy and funds were limited...like always. Thanks for the advice guys, I'll check it out. Is it possible that springs are different since it had air shocks on it?
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Phil
The Great White Buffalo

USA
7222 Posts

Posted - 11 Feb 2016 :  12:13:28 AM  Show Profile  Reply with Quote
Not really. It could be the opposite however. That is, the springs are worn out and someone used air shocks as a crutch.

Bowties are for Pee-wee Herman. "Chevy": even the name sounds cheap, but not as cheap as your Pontiac will be with an LS transplant.
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cortcomp
Coyote

USA
5338 Posts

Posted - 11 Feb 2016 :  1:52:16 PM  Show Profile  Visit cortcomp's Homepage  Reply with Quote
I don't think air shocks were a factory deal, unless i'm mistaken? Someone likely added them at some point. However model, engine, A/C or not, all affected which springs it got. Detroit Eaton Spring is a WEALTH of info and advice on that topic.
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DanM
Buffalo

80 Posts

Posted - 23 Dec 2016 :  10:22:45 AM  Show Profile  Reply with Quote
The 71 Lemans Sport rear end is actually fairly light. I haven't checked the front/rear weight distribution with a scale but I bet you its as much as 60/40.

I believe the factory rake was flat or even backwards, yuck, but don't quote me. I didn't get my Lemans from the factory. But my point is if your rake is slight to the front then your rear springs are probably fine. The fronts might be sagging possibly. Mine did but I liked it cuz it lowered the center of gravity which helped handling. If the front control arms are parallel to the ground you are right on the money. Mine got to the point where the skid pad below the oil pan was too low and the control arms actually pointed up and out. I could barely fit a floor jack under the front end. The rake was more drastic rear to front until I replaced my front springs and everything is back to normal still with a touch of rake toward the front.

Fresh shocks are cheap, all things considered.

More importantly do you have a rear anti-sway bar? If not I highly recommend one. You will need to upgrade your rear control arms to boxed control arms to handle the bar. That won't stiffen the rear end up-down but it will do wonders for the side-to-side, a.k.a. cornering.

Finally, 70 series tires will make the car squishy. 60 series tires are much nicer. With the 14" rims you probably have like me, the best you can get are 60 profile tires. 245/60R14 BF Goodrich Radial T/A

71 LeMans Sport Convertible with 310,000 miles driven year round since 1994.
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DanM
Buffalo

80 Posts

Posted - 23 Dec 2016 :  10:24:43 AM  Show Profile  Reply with Quote
AC and engine section only affected front springs. All Lemans and GTOs had the same rear springs.

71 LeMans Sport Convertible with 310,000 miles driven year round since 1994.
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NOTROD
Buffalo

USA
64 Posts

Posted - 25 Dec 2016 :  10:42:53 PM  Show Profile  Reply with Quote
Wow Dan, you jumped in on a really old post! I'm glad you did though. Your sway bar suggestion reaffirms exactly what I have been planning to do. To be honest I really don't want to stiffen it in the up and down direction because it just floats down the road. Cornering is another story though...float=bad. If I hit any bumps while cornering, even at low speed, it feels the back end is trying to "scoot out" from underneath me. It's not terrible, but I don't like it.

My front springs are good. The car sits up nice all the way around. I actually have 15" Rally II's on the car with 255/60's on the rear and 245/60's on the front. Again, I'm sure the springs are OK and if it had the same size tire all the way around I'm sure it would sit level. Thanks for your input!


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