Vintage Mustang Forums banner

1 - 5 of 5 Posts
G

·
Guest
Joined
·
0 Posts
Discussion Starter #1
While researching what I should do about rear leaf springs, I called Eaton Springs in Detroit. They suggested some springs to sell me and even suggested a local shop that does good work. I figured I would take it to the shop before I ordered the springs to make sure I was getting the right parts for what I wanted to do. When I took it in, they said the springs were in great shape and just needed to be re-arched. I was very skeptical about this, but after much discussion they talked me into re-arching and adding an extra leaf to stiffen it up. I saved $100 but hopefully they dont sag again in 3 months or I'll be really ticked off. Now the rear is pretty much level with the front but I'm thinkin' I should lower the front a little. I've heard about the 620# springs. Exactly how much lower than stock is it? Has anyone done this on a 68' that can tell me how much ground clearance they have after the conversion? Thanks!

Mike
The more I learn, the more I realize how little I know.
 

·
Registered
Joined
·
7,032 Posts
620 refers to the rate of the spring, not the height. You can get them in stock height or 1" lower than stock. I recommend Maier Racing for coil springs. Their's come a little long, and you just cut them to achieve the desired ride height. Be aware that the 620 spring has a spring rate of 540 lb/in and the 720 has a spring rate of 650 lb/in. I have the 720's and even in the pot holed streets of northeast ohio, the ride is very acceptable.

http://albums.photopoint.com/j/View?u=1572917&a=11954864&p=42994554.jpg
 

·
Registered
Joined
·
1,667 Posts
The 620's are front coil springs with a 1 inch drop. The options you have for rear leaf springs that I have seen are;
stock 4 leaf stock heighth(these will vary dending on the type of car)
stock 4 leaf with 1 to 1 1/2 inches taller heighth, ok why? LOL
heavy duty extra leaf(5) stock heighth
heavy duty extra leaf(5) mid eye up to 1 inch drop depending on the car

Just for grins I looked in my NPD catalog for your car, 68 vert, V8. They have a fairly compelete selection of springs now. You can't just get somebody's generic spring and expect it to be right. Well, heres their list;
68 289 vert - 5560-27
68 289 vert GT, 390 and 390 GT - 5560-29
68 289, 390, 428 vert GT comp handling - 5560-25

I've seen reverse eyes but these drop the rear end a lot. Maybe guys with tubbed rear ends or low riders do this or have their springs de-arched.

I priced having my springs re-arched with an extra leaf added. They add the extra leaf to make up for the re-arched weak old rusted spring. It came out to about the same that a pair of new mid eye 5 leaf springs cost. I'm installing them myself so I save some on the labor.

My philosophy on springs is that the front and back need to be balanced. In other words, its not good to put a higher rate spring on the front without addressing the rear. Otherwise, you can get into these situations where the car feels odd like its too stiff in the front and too mushy in the back(buckboard effect on bumps). That causes some really strange problems in handling too where the front doesn't roll as much but the rear rolls too much. The same goes for ride heighth in general although I like to lower the front just a bit more than the back on my car to get some rake angle for drag racing

My understanding on re-arching is that its somewhat of a bandaid. Since the metal is ancient and fatigued you're just re-arching old fatigued metal. It will sag again and this time at an accelerated rate. Well thats what I've been told. Maybe some of the metallurgists on here know more or better.


You can see my 65 fastback at: http://hottarod.stangnet.com/
http://members.aol.com/macstang/Gifs/macstang3.jpg
 
G

·
Guest
Joined
·
0 Posts
Discussion Starter #4
I was told the exact same thing by a spring shop here in town about rearching springs; this guy's been doing it for 40 years and he didn't recommend it. Matter of fact, he said if I still really wanted to rearch mine he'd do it for free!

Visit my repair page for Repair info, with pictures! http://home.dencity.com/mustangcub
 

·
Registered
Joined
·
3,047 Posts
I haven't had leaves re-arched, but a spring shop guy once said that cold re-arching is useless. Springs have to be heated according to a proper heating-arching-cooling cycle and when done properly they don't sag. But as said I don't know from experience and I don't know if you already know this heating cycle.

Door handle first when cornering
 
1 - 5 of 5 Posts
Top