I did some computer work and just made $200. I have a long list of things I need, but the one that has worked it's way to the top of the list is getting that lean fixed, then the front alligned, and new tires. So, I will get the 4-leaf springs from JC Whitney. Which shackles are recommended (AutoKrafters, I assume) and what is the lowdown on the rubber? I hear that one squeeks, but how bad? What about this "poly-graphite" stuff? I want to do this right this first time. So any suggestions or comments would be appreciated. Part numbers would be GREATLY appreciated. I know this has been addressed on multiple threads, but really, is the squeek so bad that I can hear rear rubber over my exhaust, and is it worth the squeek to gain in any performance?
Polygraphite squeeks worse than anything. If you apply the stuff they give you, which is the stickiest stuff known to man, they will eventually start squeaking again. I recommend a quality OEM type rubber, like MOOG. Dont squeak and last a long time.
The rubber is good for, what, 20, maybe 25 years? I keep getting suggestions to go with just the stock rubber. With all the ads for poly graphite etc, I would think that something is better. I guess not. So, just go with the JCWhitney springs, and rubber and shackles from AutoKrafters? What size is stock for the 74? AutoKrafters shows 3-1/2" and 4" center-to-center shackles.
"Polygraphite" squeaks, just not as bad as regular poly-urethane. The rubber bushings that come with the JCW leafsprings are fine, and will make the ride a little less harsh. . You might want to check to see if ESPO (Springs-N-Things) has the rear shackles you need. I believe you want the shorter of the two you described--unless you want the rear to be raised higher than stock. You should also get new U-bolts as well. To answer your other question about urethane squeaking; it's not a real loud obnoxious squeak, but personally I don't like it and probably wouldn't use them if I had it to do over. It doesn't squeak the whole time you are driving down the road, only on dips and when pulling turning into driveways...
we just put new leafs under my buddys mav and we used rubber i dont remember the kind ill try to get that for you. but JC Whitney was the cheapest. I dont care for shackles though to much hp and they brake not my cup of tea.
I don't want xtra long shackles, just stock size. I figure with the extra leaf and larger rear tires, I will get the rear lift that I want. I don't need any extra squeeks in my car. I have one right now that is driving me nuts, and cannot find where it is...but that is for another thread
Try espo spring and things i think thay have both. I used poly-whatever and greased them up and thay have not squeeked yet but i dont drive it alot.
Scott; I used poly bushings when I redid my springs....used but very good stockers, and I replaced them with the stock stuff shortly thereafter. The poly bushings rode very hard, and they squeaked, even with a lot of the lube they came with. I am happy with the stock bushings, but then again, I don't race my car. Good luck!
Scooper: For what its worth - Herb Adams, in his book Chassis Engineering (HP Books, 1993) says that "Urethane bushings prevent deflections, but because urethane is a sticky plastic, the use of urethane bushings usually results in a suspension that is not free to move [rotational shear, which is why they have to be lubricated]. This binding is made worse when the lubrication is forced out of the joint over time. Graphite-filled urethane does not solve the problem." He concludes that if you aren't ready to step up to custom nylon bushings, you are better off with stock rubber. Urethane bushings will certainly feel stiffer, but remember that to develop traction, your tires have to stay in contact with the road, and some degree of looseness in the suspension helps with this. I thought I might try American Pony's Midolyne bushings, but haven't yet. They sell parts for Mustangs, so you'd have to check interchange. The link to their site is www.americanpony.com Good luck with your new springs!
I ordered the 4-leaf springs from JCW, then Autokrafters for the 4" shackles (listed as the stock part for my year) new rubbers (non-urethane) come with them, and got a brake pedal cover (burned off in my fire a few years ago) and a turn signal cam (finally). Should be able to level this thing out in the next week or two. The difference in price between the 3-1/2" and 4" shackles was $20 each vs. $47 each!!! It lists that the bolts and bushings come with the 4", but not clearly listed as coming with the 3.5, so I assume I am paying more for the rubber? Thanks for all the science and reports of irritants with the urethane. I would have hated to spend the extra money for what is supposed to be better, and then been upset with the performance and noise.
Only reason I installed urethane is because they last almost forever (they don't crack or rot over time like rubber does), it wasn't for the stiffness factor. I just didn't want to have to replace them again later....
