Fox T-Bird/Cougar Forums

Back in October I replaced the spring isolators on my Thunderbird and the rear end went up. It wheel to fender gap is about 3/4"-1" higher than the front (around 2.25" in the front, almost 3" in the rear).
(http://i198.photobucket.com/albums/aa33/thunderjet302/Thunderbird%20web/rearup_zpslfwoeasv.jpg) (http://s198.photobucket.com/user/thunderjet302/media/Thunderbird%20web/rearup_zpslfwoeasv.jpg.html)

I would like to get some springs to lower the rear of the car. I plan on running Maximum Motorsports adjustable rear control arms so I can set the correct ride height: http://www.maximummotorsports.com/Extreme-Duty-Adjustable-Rear-lower-Control-Arms-1983-1989-Thunderbird-P1444.aspx

So these are the factory replacement springs for an 87-88 Thunderbird: http://www.oreillyauto.com/site/c/detail/MOO0/8599/03360.oap?year=1987&make=Ford&model=Thunderbird&vi=1430183&ck=Search_03360_1430183_3405&pt=03360&ppt=C0361

These are for an 87-93 Mustang: http://www.oreillyauto.com/site/c/detail/MOO0/8621/03360.oap?year=1987&make=Ford&model=Mustang&vi=1133918&ck=Search_03360_1133918_3405&pt=03360&ppt=C0361#itemDetailTab_

These are for an 87-93 Mustang: http://www.oreillyauto.com/site/c/detail/MOO0/7331/03360.oap?year=1993&make=Ford&model=Mustang&vi=1134111&ck=Search_03360_1134111_-1&pt=03360&ppt=C0361#itemDetailTab_

Can I run the Mustang springs to get a 1-1.5" drop and then adjust it out with the control arms or are the Mustang springs too "weak" for my application?

Well I'm fairly certain that MOOG doesn't make replacement rear springs for 94-04 SN95 Mustangs that aren't cargo coils. I'd like to run 94-04 Mustang GT coupe or Bullitt springs in the rear of my Thunderbird. I may have to try ordering them from a Ford dealer unless someone can find the part number of those springs from MOOG, which I can't seem to find.

Yes I would rather buy brand new springs than used ones. Because I'm crazy :crazy:

Apparently one can buy 2001 Mustang GT Bullitt spring new from Ford for $98.37 each: http://www.fordparts.com/Commerce/PartDetail.aspx?n=o6u4JAHAiY118ZW%2fPpAp0A%3d%3d&id=333636090&m=2&search=true&year=2001&make=Ford&model=Mustang

Edit: No you can't. I tried to order them. I get this pop up:

All of the SN95 rear springs are obsolete from Ford now, I checked the various part numbers earlier this year after buying my TC.  Might be some dealers in the U.S. that still have some on the shelf, I can't do a U.S. dealer search from up here in Canuckistan.


cheers
Ed

I wonder if I could just use the Moog 8621 spring and just use the adjusters to set the ride height? I'm just a bit worried about the load rating on the spring vs the Thunderbird springs as my car is one of the heaviest foxthundercats.

Actually I may have found a solution: http://www.maximummotorsports.com/MM-Road-Track-Spring-Kit-1996-98-Conv-1999-04-GT-Conv-P1095.aspx

The spring rate is similar to Bullitt/Mach 1 springs and I can just order the rear pair.

This is possibly another option, Moog CC835: http://www.oreillyauto.com/site/c/detail/MOO0/CC835/03360.oap?year=1995&make=Ford&model=Mustang&vi=1134166&ck=Search_03360_1134166_3405&pt=03360&ppt=C0361

It's listed as a replacement for a 1995 Mustang GT. If I can't find a good pair of SN95 Mustang GT springs I may give these a shot.

When I did mine, I used all four from a 86 Mustang GT. I had to add a 1/2" poly spacer on the rear to get the ride height I wanted.

1999 mustang springs all around.

(http://i216.photobucket.com/albums/cc205/Vinnietbird/1476092_10203087322370382_522808182_n.jpg) (http://s216.photobucket.com/user/Vinnietbird/media/1476092_10203087322370382_522808182_n.jpg.html)

I've got basically SN95 springs with poly isolators in the front (Moog 8598) but I'm having trouble finding some stock like new SN95 rears. I can't run stock Thunderbird springs with the Maximum Motorsports rear arms as they will raise the car too much.

I put '03 Mustang GT convertible (sn95) springs all around in my '88 Cougar XR7 last year that I found at a wrecking yard from a wrecked car with only 40,000 kms on it and the springs were like new-no rust.  The front height stayed the same - about 2 1/2" top of tire to fender, but the rear end was slammed, only about 1/2" from top of tire to quarter panel.  Not sure why this happened but be careful when changing springs.  I thought I did my homework but it didn't work out for me even though many guys on here have had great success with sn95 springs like ^vinnies^ thunderbird.

Were they from a V8 or V6 car? The springs were different between the two.

(http://www.turbochuck.com/webimages/projects/83%20TBird/10_17_09_3.jpg)

Motorsport C-Kits in the front. Rears are SN-95 V8 convert (96-98). The RLCA mounting point on the rear axle is lowered about 3/4", so that brought things down a bit, as well.

All 4 were from a '03 Mustang GT 4.6L v8.

Moog part # 8598 in front and 8599 in the rear.

Full Moog spec list:
http://i280.photobucket.com/albums/kk191/V8Demon/Car%20Tech/MoogSpringsspecsheet-1.png
http://i280.photobucket.com/albums/kk191/V8Demon/Car%20Tech/MoogSpringsspecsheet-2.png

I've got a set of 98 Mustang GT springs sitting here. Once maximum Motorsports decides to ship the adjustable rear lower control arms I ordered (should be next week) I'll get to swapping. If the car sits too low even with the control arm perch adjusted to it's highest setting and the 98 GT springs I'll just start cutting some of the coil off on the stock springs till I get what I want :hick:

Hrmmmm.

Well, the rear of our cars is a bit heavier than the 94-04 cars, even the V8 converts. The load rating is lower on the Mustang springs, so that could be an issue. I had some #'s someplace on the stock ratings from the rear springs in my old '84 XR-7, and the load rating was pretty high.

I've been running the SN-95 v8 rear springs in the back of my TBirds/Cougars for almost 15-20 years now, and that's with a lower spring perch on the RLCA, and have had no issues.

Cross referencing the charts I posted above with the ones below shows 250 lbs/inch for the 84 XR7.  IIRC the SN-95s were right around 200.....

(http://i280.photobucket.com/albums/kk191/V8Demon/Car%20Tech/Moog-Tbird-Springs.jpg)

(http://i280.photobucket.com/albums/kk191/V8Demon/Car%20Tech/Moog-Cougar-Springs.jpg)

Well, Load Rating is different than the Spring Rate.

On the older spring tags, you could interpolate the ratings from the numbers on the springs (They were in N and needed to be converted to lbf). I think they changed the code format in '99.

I want to say that the TBird/Cougar rear springs have, on average, a load rating of 100-200 lbs more than the Mustang ones. This is with equivalent spring rates. I seem to recall at least a 900lb load rating on the XR-7 springs.

If you have a fully optioned car and have a bunch of stuff in the trunk, you will be at the limit with Mustang rear springs.  This is why I always steered towards the V8 convert ones.  It was easier to pick the right ones when the spring tags were easy to decipher.

I ended up getting some 1" aluminum spacers for the lower spring seat and that brought the back end up to a good height.  Maybe one day I'll go for the adjustable rear arms.  But now I need to deal with the front as the '03 Mustang GT springs didn't lower it much at first but now are settled in a did lower the front about 3/4", but I have to be careful because I have 8" wide rims on the front with a 245 tire and I'm sure if I go too low the tire will hit the fender.  I know where I can get some brand new factory '03 mustang mach 1 front springs, these should sit about a 1/2" lower than a regular GT spring that I have in there now.  If they don't cause tire rub should give me the right height.  Fingers crossed!

Chuck what are you talkin about with the lowered control arm?

Your stance is my new goal with my car.

To finish this off the 98 Mustang GT springs worked great. I had to crank the control arm perch about an inch to get the car level front to back. With the adjuster at it's lowest setting the tires were tucked into the wheel well deeper than on Chuck's car. The cool thing is there is still about 1.25 inches of height adjustment left on the spring perch. You know just in case I want to jack the rear end way into the air :hick: