New rear leaf springs - installation?

[orlowted]

Hello - Just got a set of heavy duty 5 leaf springs for the rear of the car. Any words of wisdom on installing these??? It does not look like it is going to be a quick and easy replacement.
TJ

[rbohm]

first get new front spring bolts and new shackles as well. you may have to cut the old bolts out. if you do use a sawzall. you should also get new ubolts as well as the old ones may either break or need to be cut due to the nuts being rusted in place. also use lots of penetrating oil like pb blaster. when you put th enew bolts in place, lube them with wheel bearing grease first as it will ease installation, and future removal. dont torque the bolts to spec untill the car is on the ground and you have bounced it a few times to get the springs to ride hieght. also remember to drive the car for a few months before you change the ride hieght as the springs will settle some(about 3/4"). if you plan on using lowering blocks, make sure the u-bolts you get are long enough to allow for the use of said lowering blocks.

[mustangII460]

and.....get urathane bushings. Takes alot of body roll out. You'll be glad you did. Also get a rear sway bar.

[orlowted]

All Good words to work by- Thanks!!!
Sway Bar - I never thought of that. Is it worth the money...I saw one for about $90.00?

One last thing - Does anyone have an article or link on how to do the spring swap? I am not real confident on doing it...

TJ

[mustangII460]

Urathane bushings and sway bar will make the back super tight. Well worth the money.


Jack up backend, can be done from center section. Remove wheels. Set jack stands under frame rails to let the rear unload or come down. When the rear is as far down as possible, blocks under it. You want the rear to drop until the springs hold it from going any farther.

I like to hit the front bolt, u-bolts, shackle last. Same order putting new one in, front to back.

The big bushing bolt will probably want to stay in with the nut comming off. Usually the bolt will kinda unscrew itself out of the bushing. Or put a big screwdriver where the nut was, push and turn the bolt to thread itself out. Sounds kinda screwy.


*Word of caution* the back will set a little higher now. Go easy on the test drive. May feel a little squirily. Now you need front coils.

Its a great job for any beginner. Go For It!

[Rev]

What I did was to get 5 leaf mid eye springs and 3/4" sway bars from Mustang Plus. I did do the front at the same time with 620 coils/front rebuild with poly spring insulation/ spring saddles, tie rod ends, etc, etc. I think thre whole thing was $1200 or so a few years ago.

I did have to cut 1/4 or so off the front coils to get it right though (trial and error).

Rev

Note: put in a 1 1/8" sway bar in front. That's what I did with no relocation of the front upper a-arms, and it handles good.

Rev

[orlowted]

I got the springs out in about 30 minutes...It was not hard at all. I have new shackles and Poly Bushings on order and am looking into the rear sway bar. Thanks for all the advise....It was really a smooth process (except for the 10 degree concrete floor)...
TJ

[kchex]

if you use urethane bushings be sure to add a little lubricant inside of them. keeps the sqeaks out

[orlowted]

Well - the springs are in with new bolts, poly bushings and shackles...the only problem is that the car sits about 2-3 inches lower in the rear than it did before I did the swap. I did not use any blocks or spacers because I thought the heavier springs would raise it up a bit. I even used the higher mounting hole on the shackle. Now the front sits higher than the rear...Not quite the look I was going for. I must admit though..the rear is tight as as can be which is what I wanted. Any thoughts...Should I lower the front or jack up the rear. I am still puzzled why the old 4 leaf springs were so much higher???

TJ

[mustangII460]

If the rear sits where you can run the tire/wheel combo you want, Id leave it. Should have been only one hole/way to assemble the shackles, unless not OEM shackles. . Maybe there lies your problem.

Can you post a pic?

[orlowted]

They were not OEM replacements...I upgraded to what I thought was better ones....
Here is a pic...the 2 holes are for the ride height...
Make any sense???

[rbohm]

yep, using the bottom holes will give you about 3/8-1/2" higher ride hieght.

[orlowted]

I thought the higher mount on the shackle would make it OK, but still too low. It just looks funny. I have to assume that the curvature on the new springs was just not as high as the old stock ones. That is the only way this could have happened. Now the question - How to get it back to the proper height? Should I get different shackles or try to raise the rear in another way. I don't want to compromise safety in any way. I guess I could leave it the way it is, but I am not happy with the look.
TJ

[KiltedBanshees93GT]

Dont the springs settle a certain amount? What kind of drop should be expected for the new springs? Though I guess aftermarket shackles could throw things off.
(I'll be doing this eventually, call it vested interest)

J

[orlowted]

I had expected the springs to be a bit high after installation and they would settle into a normal ride height, but they started out low. I guess the only advise I can offer after doing this is to compare the arch on the replacement springs to the original. If they are not arched as much or more - then you are going to end up with a lower ride like I did. I measured the shackles...the new ones are 3/4 inch longer in hole space than the original ones meaning that the car should sit about 3/4 inch higher. I am blaming it on the springs themselves. Although the process went very smooth - my results are dissapointing. Tight as a drum, but too low for my satisfaction....