I have a 1985 Trans Am that has RPO codes F41 and Y99 for suspension/handling. The spring codes are 6DB and 7XY for front and 8UZ and 9UZ for rear. Here come the questions:

Why do the two front springs have different letters. I have seen other posts on RPO codes for other cars like this but most seem to have the same two letters for the front same as my rear ones do.

I had to have the front springs replaced when I got the car last month. The garage only babbled about number of coils when the purportedly received the "wrong" springs which were 8 coils and finally got the "right" springs when 6 coil springs. With these springs the front end is too high. I know it may take a bit of time for new springs to settle but reading this forum and others I have also come to understand there is more to getting the correct springs than number of coils.

If I assume the correct springs were installed and were installed properly, would replacing the rear springs help to level it out? Would new rear shock also help (I think one of mine is leaking since I found a small pool of oil under the drivers side rear).

Can springs from a WS6 car be installed with success on a non-WS6 suspension car, in particular the rear ones?

I am clearly and admittedly a novice about this stuff and I am hoping that the collective wisdom of more knowledgeable guys than me can help point me in the right direction on this stuff.

 

All third gen springs are interchangable. There are quite a few people running V6 springs in front to get their nose down with a motor swap. You can actually use a 4th gen spring in the rear, but not the front.

As for leveling it out. With the springs being new, only new in the front, putting brand new springs in the rear might raise it up more. On a 20+ YO car the springs are going to sag. And new ones will sit higher than old ones.

As for the shocks, are you sure it was oil and not brake fluid? Did you track down the wet spot on the car? It could be multiple things leaking there and not necessairly shocks.

 

I jumped to the conclusion it was a leaking shock because the spot was right under that area. Fluid was fairly dark in color. I guess I throw the car up on some ramps and take a closer look. The car was inspected a month or so ago and the mechanic said the brake lines were all in pristine condition. So I never even considered brake fluid leaking.

Thanks for mentioning that.

 

Mystery solved. i decided to take the car back to where the inspection was done. What i thought was a leaking shock was just penetrating oil they sprayed on the shock when the inspection was done that finally worked its way down the shock and dropped off. That explains why it was really only once I noticed a appreciable amount.

Friday I am having the WS6 rear springs installed in hopes that a stiffer spring will level the car out a bit more.

 

Spring rates have nothing to do with the number of coils - it has to do with many other aspects, including material used, thickness of coils, etc. A 6 coil spring could very easily have a "rate" twice as high as a 10 coil spring.

Spring rates are also rated on a certain ride height. So putting 1000lbs on a spring rated for 1500 lbs (or visa versa) tells you nothing about the spring itself - you have to put enough weight on the spring to compress it to the rated ride height before the spring rate can be determined as correct or incorrect for a particular car.

 

no, number of coils is very important to spring rate.

here is a pretty useful calculator
http://www.pontiacracing.net/js_coil_spring_rate.htm

 

Well like everything so far, the rear springs did not go as planned and were a problem. The ones I bought which were apparently WS6 were fully an inch to inch and half shorter than the supposedly stock springs already on my car. With the existing rear springs she rode low on the back as it was so even with the WS6 ones on, the height would not have improved (assuming they were actually stiffer) and maybe even lowered her again. I will readily admit I know little about springs (but I know a hell of a lot more than I did before this journey) the gauge of the existing springs actually seemed thicker than the WS6 springs. So anyway I bit the bullet and bought brand new ones (no ideae what they are since the garage ordered them) and now the ride height all around is much better and the car leveled out pretty good.

So either what I was told were WS6 were in fact not WS6 or the various springs these cars had from the factory were not as interchangebale as I have been led to believe. Either that or my car has one funky suspension!