I've been looking for a couple hours now and my head now hurts, lol. I just want to know the Moog replacement rear coil springs for my '71 Supreme 2 door coup, 350 w/ AC.

Here's what I think it is: Moog 5385. Is this correct?

Or does anyone know the stock spring height installed so I can figure out if mine are sagging? The 5385s claim 9" installed.
Also, I was underneath having a look and the driver's rear coil spring is dislocated on the top. Maybe that happened when the rear shocks were last replaced (if they ever were)?

Thanks guys.

 

Any reason that you don't go to the Eaton spring website? They were the original supplier.

 

The current (I'm assuming original) springs measure 9.5" installed so no, I don't think the 5385s are correct.

 

I wasn't aware. I'll look into it. Thanks.

 

Eaton MC1369 but they don't give any height specs and I can't find them anywhere else. I may call them in the morning.

 

From your picture it does not look like your rear is sagging unless its held up with airshocks.

 

No sir, no air shocks. But here's the deal; The wife, her brother, and I are heading out on the road. The last time we did this a moderate bump in the road would make the rear of the car bottom out. Sounded like a loud "thud". I want to get some new shocks on it (likely the KYB gas-a-just) but wanted to know if the springs needed replaced while I'm under there. And that dislocated spring made me wonder if they're losing their springy-ness.
I actually like the rake of the car from the driver's side but I'm wondering if that's the dislocated spring too.

 

I don't understand the dislocated spring description. Is it out of the pocket? Shocks would help keep it from bottoming out.

 

If you are loading the car for trips now and then you may wont to go with a cargo coil or variable rate spring that will hold up the back better under a load and still give you the ride you want.

 

I'll get a pic, stand by....

 

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@lemoldsnut; I'll do some more research before deciding. We do load the trunk pretty full when we take our trips.

 

You need to jack up the car by the rear pumpkin and set the frame on jack stands just forward of the rear wheel wells and disconnect the shocks. Lower the rear end down and place the rear springs back in the correct position. Jack the rear end back up, reconnect the shocks, and all should be correct again.

Note, the spring should not move around when the rear end is dropped and shocks are connected.

 

I used to have this happen every time I had the tires rotated and balanced. For some reason, the free height of my springs was not tall enough to keep them in the perches and they would fall out when the car was raised by the frame rails. You might have the same problem.

 

Rod, I can see how that would be a problem but I don't think that's the case here. I've had the car supported forward of the wheel wells a couple of times but with the shocks connected and those springs won't budge.
Eric, I'll get that spring repositioned when I do the rear shocks.
Also, Copper is (hopefully) coming down to help me install a new ring and pinion. This is why I wanted to verify my springs are in good shape. I was thinking I might replace them anyway and add an inch to the heights but would that lower the front and cause steering and tire rubbing issues?

 

Interesting note: I've always likes the stance of the car when looking at the driver's side but not so much the passenger side. I wonder how much higher that side of the car is because of the spring dislocation.

 

Probably a 1/2" higher. It will only take about 30 minutes to fix that.

 

Yup, I checked, 1/2" higher. What's the current thinking on shocks? I recently read that the KYBs are too stiff for a street car. I'd love a set of Koni or QA1 adjustables but those are some serious coin.

 

This car has coil-over shocks in the rear. Is that common or was someone trying to compensate for sagging springs? I guess I'll have to pull the springs and measure the uncompressed height.

 

Disconnect the coil over shocks and see how far it drops. Chances are your springs are weak. I would go with a set of variable weight cargo coil springs and heavy duty set of shocks.

 

If I understand suspension systems at all, and I'm pretty sure I don't, it shouldn't drop at all, yes?

 

Right. Normal Shocks should not support the car, merely dampen movement.

 

The coil over shocks will raise the car, its just how much.

 

Randy! How are ya bud? I was just reading your post about replacing your springs, lol.

So it sounds like I'll definitely want to replace the springs because I like the stance it has now. I'll disconnect shocks and take some measurements. Difficult though, I don't have a flat floor in the shop and we have a gravel driveway

 

Just got done spraying Build Primer on my 66 Project.

I'm sure there must be some flat ground somewhere in Illinois??

 

Haha! Like one of my students once said, :I can watch my dog run away for a week".

 

I'm looking at these Hotchkis shocks. A bit pricey but I want a good ride.

http://www.summitracing.com/parts/hss-71010009

But my question is this: if I raise the car one inch with taller springs, can I still use these shocks? If not, how do I look for a shock for a '71 CS that's been raised an inch?

 

Ouch, those are spendy. I put KYB's on my Red 66 and the ride is very solid but comfortable.
Raising the height by 1" will not affect the shocks, they have plenty of travel.

 

The gas-a-justs? I read they were way too stiff. But much more spender friendly.

 

The ones I used are the low end Excel-G. Rock Auto has a great price on them.

 

Man, RockAuto does have good prices. I think I'm going to go with the gas-a-just shocks front and rear. The wife likes to got to Missouri and the body-roll can get pretty bad.
Yup, just ordered them. Now, how does one go about ordering replacement springs that are an inch higher? Same spring rate, just a little taller? Who has the best price? You're pretty good at finding the deals, Randy ;-)

 

The only help I can offer is this Moog spreadsheet. You can sort by any of the columns. Find your stock spring specs and then look for one with taller installed height. Jegs has about the best prices on Moog springs that I have found. Good Luck!

 

Thanks Randy. You da man!

 

Actually rockauto also has great prices on springs.

 

When I use their filter; Olds\71\Cutlass Supreme\5.7 L\Suspension\Coil Spring\Rear Coup 2 dr. I get a constant spring rate part number 6321. Does that sound about right? I'll use the database to see if I can get the same thing but an inch taller (one inch taller installation height, yes?)
This stock spring lists 8.5" install height but I measured 9.5" in the car. Might be the dislocated spring causing this.

 

Unfortunately, this method isn't yielding much. I can go up to a 10" installed height but load jumps from 689 lbs to 1257 lbs. That seems like a lot. I can also go with a 9" installed height, just a half inch up, nut the load drops to 616.
What about using new stock springs and coil spring spacers?

http://www.summitracing.com/parts/sp...-size/5-7l-350

Is that a nono?

 

I believe the Moog CC501 springs is what your looking for. The Moog 5419 are the Vista Cruiser springs. The Moog 5385 are for a 442.

 

The 501 has an install height of only 8". Is it the thicker bar diameter and heavier load capacity that makes them taller (less compression)?

 

I'll call Moog in the morning and see if they can steer me to the correct spring.

 

Try 5401 rears , 129lb spring rate which is close to the standard spring .Install height of 7.5" and 727 lb load .Spec'd for 68-69 Cutlass .Just put these on my 72 , very nice with the 15" tire just at the wheelwell .

 

I was hoping for a little more lift than that, reoldsman. I don't have that cool 442 look so I'll have to make it up somewhere's else ;-) But thanks.