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  1. #1
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    Default Somewhat comprehensive aftermarket rear spring guide

    I have been sifting through reams of information trying to sort out all of the rear spring options for these cars. I've mostly been looking at them from a wagon perspective, but a lot of this applies to the sedans and coupes as well. Basically there are about 5000 different rear spring options for these cars. My goal is to try to condense all of the groups of springs into this list with cross references between manufacturers. Some of these springs are discontinued and may no longer be available. I have found that even if a spring is discontinued by one supplier there are usually other suppliers that still make the same part under a different part number. For instance I can go down to my local O'Reilly tomorrow and get the equivalent of the CC823 or CC821 if I wanted to. The 8797 appears to be the only one that I can only find NOS and no longer sold new. Strangely I believe Precision is owned by Moog which has discontinued a lot of these springs, but for some reason they sell them under the Precision name? I could only find the Precision springs listed at O'Reilly. They may be available elsewhere. I've also seen the Moog CC springs sold under other brands probably going back to the 80's on that though.

    The best I can tell the 8797 is the same as the OEM rear wagon springs for the 83-86 LTD/Marquis.
    The 8599 appears to be the same as the OEM rear spring for the Fairmont/Zephyr wagons. It was also apparently used on the T-Bird and Cougar. I think the 8597 is the OEM equivalent to the sedan rear spring for F/Z and LTD/Marquis. Obviously the LTD LX is not included in this. I don't know what those received stock from the factory. This list only applies to stock style replacement springs. If you want to try aftermarket performance springs from a Mustang let us know how they work, but I use my wagon to haul my family and all of our crap for vacations so it needs to have decent load carrying capacity.

    If you find more part numbers or errors, let me know and I will edit this post to try to keep everything together.

    Here goes.

    Moog CC823
    Mevotech SMS823V
    Precision Coil Spring SP08138 (O'Reilly Auto Parts)
    Centric 630.65038
    Lesjofors 4427536 (they list wire diameter at .657")


    Free height: 12.63Ē
    Installed height: 10.25Ē
    Spring wire diameter: .6875"
    Load to compress from free to installed height: 808lbs
    Spring rate: 340lbs per in. (variable rate)
    - these are the wagon "cargo coil" aftermarket heavy duty option


    Moog CC821
    Mevotech SMS821V
    AC-Delco 45H3017
    Precision Coil Spring SP08136 (O'Reilly Auto Parts)
    Centric 630.61036
    Lesjofors 4427535 (they list wire diameter at .610")

    Free height: 12.29Ē
    Installed height: 9.25Ē
    Spring wire diameter: .625"
    Load to compress from free to installed height: 804lbs
    Spring rate: 275lbs per in. (variable rate)
    - these are the sedan "cargo coil" aftermarket heavy duty option


    Moog 8797
    AC-Delco 45H2082
    Duralast RCS8797S


    Free height: 13.25Ē
    Installed height: 10.25Ē
    Spring wire diameter: .590"
    Load to compress from free to installed height: 850lbs
    Spring rate: 266lbs per in. (constant rate)


    Moog 8599
    AC-Delco 45H2040
    Centric 630.65037
    Lesjofors 4427507

    Free height: 13.33Ē
    Installed height: 9.5Ē
    Spring wire diameter: .590"
    Load to compress from free to installed height: 926lbs
    Spring rate: 249lbs per in. (constant rate)


    Moog 8597
    AC-Delco 45H2041
    Centric 630.61037
    Precision Coil Spring SP08648 (O'Reilly Auto Parts)


    Free height: 12.75Ē
    Installed height: 9.5Ē
    Spring wire diameter: .560"
    Load to compress from free to installed height: 726lbs
    Spring rate: 224lbs per in. (constant rate)
    Last edited by KevinVarnes; 07-06-2022 at 12:15 PM. Reason: Added Lesjofors part numbers to list.
    '89 XR-7 5 Speed
    '95 SC 5 Speed
    '91 Crown Vic P72 351W
    '97 Thunderbird
    '85 Ford LTD Squire

  2. #2

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    Good info. Thanks for putting this together.
    83 TC "Clone"
    85 Marquis LTS

  3. #3

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    You are a gift from above for doing the leg work for people to have a 1 stop reference. Took me ages to sift through and find what I was looking for when I looked.

    Also a little side nugget: I used the CC823 springs for the rear of my LTD sedan, and I do NOT recommend them for sedans. Iíve been fighting driveline angle issues because they raised the rear of the car close to 2Ē. The sedans just donít have the weight to truly take advantage of the load and stiffness of these springs. It also has nearly 0 suspension travel. Just giving a small warning to look into something a little lighter for the non wagon cars.


    Sent from my iPhone using Tapatalk
    1984 LTD LX, 160k mile Explorer 5.0, Comp XE264HR-14 cam, Alexís Parts springs on stock GT40 3 bar heads, Unported Explorer intake, 1 5/8 shorty headers, off-road H-Pipe, Spintech 9000 mufflers, Holley Terminator X Max, J-Mod 4R70W, Mustang 8.8 w/ 3.73s, Tubular front and rear control arms, front coilovers, Turbocoupe rear coil springs

  4. #4
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    I just hope somebody finds this useful. I updated with the Lesjofors part numbers. I also added some AC-Delco part number cross references. I know gmatt has the AC-Delco 45H3017 springs in the rear of his '86 LTD wagon and he seems to like them ( http://vb.foureyedpride.com/showthre...1986-LTD-Wagon ). After doing some searching the best I can figure is they are equivalent to the Moog CC821 springs. I am leaning toward using the 821 springs in my wagon especially after reading wdanison's feedback and others on the CC823. I may need the 823's if I ever moved to the torque arm rear suspension, but that is a way off.
    '89 XR-7 5 Speed
    '95 SC 5 Speed
    '91 Crown Vic P72 351W
    '97 Thunderbird
    '85 Ford LTD Squire

  5. #5

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    Great info, thanks for posting!
    79 Zephyr, 4.6L 4v/4r70w swap, with team z front and rear suspension, 8.8 and upgraded brakes and coil overs. Running Holley Terminator X Max.

  6. #6

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    Quote Originally Posted by KevinVarnes View Post
    I am leaning toward using the 821 springs in my wagon especially after reading wdanison's feedback and others on the CC823. I may need the 823's if I ever moved to the torque arm rear suspension, but that is a way off.
    Yeah, looking at the specs on the 823's I might need those on the TBird. I redid the rear suspension and un-splayed the uppers when I did the panhard bar install. I'm needing a bit more roll stiffness in the rear.
    83 TC "Clone"
    85 Marquis LTS

  7. #7
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    I see Eibach and SVE springs listed on LMR. Ford Performance springs are available at American Performance.

    Did not realize this was non-mustang.
    Last edited by KevinK; 07-07-2022 at 10:23 AM.
    Fox Body/3rd Gen MCA Gold Card Judge
    84 SVO 24K miles, 85 Mclaren Capri Vert. 84 GT Turbo Vert.
    88 Mclaren Mustang Vert 20K miles, 89 Mustang LX Sport Vert,
    03 Mach 1 7900 miles, 74 Mustang II, 69 Mustang, 67 Mustang, 14 Mustang CS/GT,
    15 F150 FTX Tuscany, 16 F250 Crewcab, 67 Tbird 47K miles

  8. #8
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    Yes, I see those springs, but the Mustang rear springs seem to be a different world from us misfit "other" fox body guys. The rear Mustang rates (at least just looking at stock replacement style springs) are much lower than what our cars seem to run. Not saying that they wouldn't work, but I don't want to give up load carrying capability on my car.

    For what it is worth, this is a pretty good quick reference for Moog springs if you know their part number: https://www.moog-suspension-parts.co...il_springs.asp

    I just picked up some 821 springs so we will see how they do on my car. I'll probably start a new thread in the suspension forum for recommendations for front springs where I am guessing we are probably closer to Mustang world.
    '89 XR-7 5 Speed
    '95 SC 5 Speed
    '91 Crown Vic P72 351W
    '97 Thunderbird
    '85 Ford LTD Squire

  9. #9

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    On the front you should be able to just use Mustang stuff. From what little info I could find, my LX came with what were basically just the front springs from Fordís B or C kit they had for the mustangs. I donít have any spare mustang springs to compare them to so take that for what it is worth.

    Iím interested in see how the CC821 turn out for you, Iíve been looking to replace the 823 and get some more travel back in my rear.


    Sent from my iPhone using Tapatalk
    1984 LTD LX, 160k mile Explorer 5.0, Comp XE264HR-14 cam, Alexís Parts springs on stock GT40 3 bar heads, Unported Explorer intake, 1 5/8 shorty headers, off-road H-Pipe, Spintech 9000 mufflers, Holley Terminator X Max, J-Mod 4R70W, Mustang 8.8 w/ 3.73s, Tubular front and rear control arms, front coilovers, Turbocoupe rear coil springs

  10. #10

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    The Mustang stuff works on the front, but they can tend to be a little low. My "normal" street spring for any Fox is the FMS C-Kit fronts. They're the 650# linear rate ones. Thick coil and shorter free height. I've used them on TBirds/Cougars (80-85) , as well as the '80 Z7 I had. In all instances, I needed to add a little more spacer on top, even with good new isolators.

    I'd use them on the LTS, but it came with new(er) Steeda "Sport Kit" front springs. They're also rated at 650# but are definitely a different design than the C-Kits. With the C-Kits, I need no compressor to reinstall the springs. With these Steedas, I definitely needed a spring compressor to get them back in place.
    83 TC "Clone"
    85 Marquis LTS

  11. #11
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    I'll have to go back through my FSM's to see if I can find a ride height measurement because I feel like this thing sits pretty low with the stock springs. It would be helpful to know where I am at in the front before buying springs. I definitely don't want to go any lower than it sits right now.

    I'll update how the 821 springs do once they get here and I can install them.

    I know you like the C springs, but I worry they are going to be too stiff for this car. My wife absolutely loves driving the car and I'd hate to change that for her with stiff springs. I have to believe the B springs would be a decent upgrade over the tired stock springs, but still give a reasonable ride. I also only have the Koni S.TRT struts and shocks so I don't want to get too crazy with spring rates. Part of my selfish reasoning for hoping to be able to use aftermarket lowering springs and retain the same ride height I have now is so I can get away with just using that Maximum Motorsports spring installation tool and not have to fight them too much.
    '89 XR-7 5 Speed
    '95 SC 5 Speed
    '91 Crown Vic P72 351W
    '97 Thunderbird
    '85 Ford LTD Squire

  12. #12

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    Quote Originally Posted by KevinVarnes View Post
    I know you like the C springs, but I worry they are going to be too stiff for this car. My wife absolutely loves driving the car and I'd hate to change that for her with stiff springs. I have to believe the B springs would be a decent upgrade over the tired stock springs, but still give a reasonable ride. I also only have the Koni S.TRT struts and shocks so I don't want to get too crazy with spring rates. Part of my selfish reasoning for hoping to be able to use aftermarket lowering springs and retain the same ride height I have now is so I can get away with just using that Maximum Motorsports spring installation tool and not have to fight them too much.
    For me the B's are too low of a spring rate. These Steedas I have on the LTS actually ride quite nice. Even with the sub-optimal Monroe front struts the PO put on there. This is with 45-series Z-rated tires on there too. It's a "little" low, but I also think the rear is currently too high (Stock LTS springs in the back).

    Somewhere I have specs for the 96-98 SN-95 stock springs. I used to use a lot of the V8 vert springs on the back of the Tbirds as they had a decent load rating to them.
    83 TC "Clone"
    85 Marquis LTS

  13. #13
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    Some guy in a brown truck showed up at my house and left some LTD parts for me today. Behold I present to you the Midas Comfort Coils part number CC821. Obviously made by Moog. The box looks like it's been sitting on a shelf in a muffler shop since 1983.

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    I thought about filling out the warranty card that came with them, but I'm guessing it would just be RTS'd. The new springs measured .630" on coil diameter. Old springs measured .590" coil diameter. 9 coils versus 8-ish for the stockers. I don't have my spring calculator program to run the numbers to see how much the added coils cancel out the increased wire diameter, but overall the numbers seem to match up pretty well with what I have up above for the CC821 and 8797 springs. You can see the overall height of the new spring is about an inch shorter than the stock piece.

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    I don't know why you guys didn't tell me how easy it is to change rear springs on these. I would have done this years ago had I known.

    I took some before and after measurements to see what effect the springs would have. I can pretty confidently say I lost 1/4" to 1/2" in ride height. Not completely unexpected given the measurements from above. Did I increase the load carrying capability of the car at all? Hard to say, but I'd be inclined to say probably not much if any based on my scientific bounce up and down on the trailer hitch test.

    This tells me the original springs on my car may not be sagging as much as I thought. They have settled probably less than an inch (in the rear at least) over the years. The numbers above seem to be fairly accurate. Granted the CC821 install height is probably measured on a sedan. The difference in load between the sedan and wagon I cannot say. It also tells me that if I want to change the front springs I will probably have to stick with stock height Mustang springs. I don't want to be laying frame with this thing and I think it sits low enough as is.

    I may see if I can find a reasonable deal on the 823's and swap those in. If they get me back the 1/2" I lost and maybe a little more then I would be pretty happy with that.

    Here is how the car sits now.

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    '89 XR-7 5 Speed
    '95 SC 5 Speed
    '91 Crown Vic P72 351W
    '97 Thunderbird
    '85 Ford LTD Squire

  14. #14

    Default Somewhat comprehensive aftermarket rear spring guide

    Quote Originally Posted by KevinVarnes View Post
    Some guy in a brown truck showed up at my house and left some LTD parts for me today. Behold I present to you the Midas Comfort Coils part number CC821. Obviously made by Moog. The box looks like it's been sitting on a shelf in a muffler shop since 1983.

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Size:  57.8 KB

    I thought about filling out the warranty card that came with them, but I'm guessing it would just be RTS'd. The new springs measured .630" on coil diameter. Old springs measured .590" coil diameter. 9 coils versus 8-ish for the stockers. I don't have my spring calculator program to run the numbers to see how much the added coils cancel out the increased wire diameter, but overall the numbers seem to match up pretty well with what I have up above for the CC821 and 8797 springs. You can see the overall height of the new spring is about an inch shorter than the stock piece.

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    I don't know why you guys didn't tell me how easy it is to change rear springs on these. I would have done this years ago had I known.

    I took some before and after measurements to see what effect the springs would have. I can pretty confidently say I lost 1/4" to 1/2" in ride height. Not completely unexpected given the measurements from above. Did I increase the load carrying capability of the car at all? Hard to say, but I'd be inclined to say probably not much if any based on my scientific bounce up and down on the trailer hitch test.

    This tells me the original springs on my car may not be sagging as much as I thought. They have settled probably less than an inch (in the rear at least) over the years. The numbers above seem to be fairly accurate. Granted the CC821 install height is probably measured on a sedan. The difference in load between the sedan and wagon I cannot say. It also tells me that if I want to change the front springs I will probably have to stick with stock height Mustang springs. I don't want to be laying frame with this thing and I think it sits low enough as is.

    I may see if I can find a reasonable deal on the 823's and swap those in. If they get me back the 1/2" I lost and maybe a little more then I would be pretty happy with that.

    Here is how the car sits now.

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    If youíre wanting to try out the 823s then Iíd be more than happy to do a swap with you.

    Then Iíll post the results of how my sedan sits with the 821s vs the 823s.


    Sent from my iPhone using Tapatalk
    1984 LTD LX, 160k mile Explorer 5.0, Comp XE264HR-14 cam, Alexís Parts springs on stock GT40 3 bar heads, Unported Explorer intake, 1 5/8 shorty headers, off-road H-Pipe, Spintech 9000 mufflers, Holley Terminator X Max, J-Mod 4R70W, Mustang 8.8 w/ 3.73s, Tubular front and rear control arms, front coilovers, Turbocoupe rear coil springs

  15. #15
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    Ah, ha. I was wondering if you would want to try to swap, but I couldn't wait to get my grubby little paws on the 823's so I ordered some from O'Reilly. They are supposed to be here on Tuesday. I suppose I could just return them when they come in.
    '89 XR-7 5 Speed
    '95 SC 5 Speed
    '91 Crown Vic P72 351W
    '97 Thunderbird
    '85 Ford LTD Squire

  16. #16

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    Well I canít say that I really blame you for your impatience! Lol

    Iíll just end up ordering some 821s at some point anyway, but with the cost of fuel being what it is I donít really get the car out much so waiting isnít a big deal.


    Sent from my iPhone using Tapatalk
    1984 LTD LX, 160k mile Explorer 5.0, Comp XE264HR-14 cam, Alexís Parts springs on stock GT40 3 bar heads, Unported Explorer intake, 1 5/8 shorty headers, off-road H-Pipe, Spintech 9000 mufflers, Holley Terminator X Max, J-Mod 4R70W, Mustang 8.8 w/ 3.73s, Tubular front and rear control arms, front coilovers, Turbocoupe rear coil springs

  17. #17

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    This is how it sat with stock springs, and 245/60r15 tires.


    Sent from my iPhone using Tapatalk
    1984 LTD LX, 160k mile Explorer 5.0, Comp XE264HR-14 cam, Alexís Parts springs on stock GT40 3 bar heads, Unported Explorer intake, 1 5/8 shorty headers, off-road H-Pipe, Spintech 9000 mufflers, Holley Terminator X Max, J-Mod 4R70W, Mustang 8.8 w/ 3.73s, Tubular front and rear control arms, front coilovers, Turbocoupe rear coil springs

  18. #18

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    This is with the same tires and 823 springs.


    Sent from my iPhone using Tapatalk
    1984 LTD LX, 160k mile Explorer 5.0, Comp XE264HR-14 cam, Alexís Parts springs on stock GT40 3 bar heads, Unported Explorer intake, 1 5/8 shorty headers, off-road H-Pipe, Spintech 9000 mufflers, Holley Terminator X Max, J-Mod 4R70W, Mustang 8.8 w/ 3.73s, Tubular front and rear control arms, front coilovers, Turbocoupe rear coil springs

  19. #19
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    I had some time tonight so I installed the SP08138 (CC823 equivalent - bonus is they were actually hecho en EUA and they were apparently made about a year ago) onto the rear of the wagon. I think it turned out pretty well. I gained about an inch over the CC821 springs which matches up pretty well with their published specs. Side by side the two springs are pretty close to the same free height. Same number of coils. The only real difference was the .659" (measured) wire diameter on the 823's versus .630" on the 821's. I'm pretty happy with how it sits. Hopefully it gives me the cargo capacity to carry our stuff. I had to leave my circa 90's Monroe air shocks on for the time being since I'm still running the 7.5" rear end and I don't have the proper lower shock mounts to install the Koni's. I liberated the brackets from the 8.8" that will eventually go in the car, but I still need the nuts and bolts to make it happen so off to the junkyard on Saturday.

    Here is how the car sits now:

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    wdanison, I really think the 821's might be what you are looking for for the rear of your car.
    '89 XR-7 5 Speed
    '95 SC 5 Speed
    '91 Crown Vic P72 351W
    '97 Thunderbird
    '85 Ford LTD Squire

  20. #20

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    Hey KevinVarnes, I tried to respond to your PM but it said your inbox was full.


    Sent from my iPhone using Tapatalk
    1984 LTD LX, 160k mile Explorer 5.0, Comp XE264HR-14 cam, Alexís Parts springs on stock GT40 3 bar heads, Unported Explorer intake, 1 5/8 shorty headers, off-road H-Pipe, Spintech 9000 mufflers, Holley Terminator X Max, J-Mod 4R70W, Mustang 8.8 w/ 3.73s, Tubular front and rear control arms, front coilovers, Turbocoupe rear coil springs

  21. #21
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    Sorry about that. I had a bunch more crap in there than I thought. I cleaned some of it out.
    '89 XR-7 5 Speed
    '95 SC 5 Speed
    '91 Crown Vic P72 351W
    '97 Thunderbird
    '85 Ford LTD Squire

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