XHD spring problem??

[Tejas]

Here is a weird problem I hope you guys can help me out with.
You may have seen that I got my narrowed rear-end mocked up last week.
It turns out that the right tire was sitting ¼” farther forwards than the left tire.
I figured that I screwed up welding the spring relocation boxes in so I took everything apart and started measuring everything to find where the problem was.
Good news – Everything I welded was spot on, within 1/32”
Bad news – The right front spring eye to center pin measurement is ¼” shorter than the left one.
Question – WTF??!!
I know the springs are made bias (one is heavier than the other) but shouldn’t the front spring eye to pin measurements be equal?
I bought mine from Mancini but these are the part numbers that are painted right on the springs.

P4510268 — Right (1964–75 A-Body)   
P4510269 — Left (1964–75 A-Body)   

Please help a guy out with a cockeyed rear end!

[73swinger]

ummm, was the weight on the car when you measured? I don't know for sure but would guess that because the springs are biased they may hang diffferently when weightless. I would see if the prob is still there with weight on the wheels

[Tejas]

There was a little weight on the springs but not much, the car is still mounted to the rotisserie.
I don't think that would be it, the measurement would be off by the same amount whether the springs are hanging free, weight on them or sitting on the workbench.
I guess
Or something
Or not
I don't know
HELP!

[73swinger]

I dunno, just thought it might be something to check before the shit hit the fan. Oh and BTW, I bought the exact same springs from Mancini as well. of course I didn't measure anything to that degree of accuracy before installation, but it seems to drive okay. Passenger side sits slightly higher, but only till I mash the pedal

[Tejas]

I dunno, just thought it might be something to check before the shit hit the fan. Oh and BTW, I bought the exact same springs from Mancini as well. of course I didn't measure anything to that degree of accuracy before installation, but it seems to drive okay. Passenger side sits slightly higher, but only till I mash the pedal

Are your tires located in the wheelwells equally?
Would you mind getting a tapemeasure and checking it?

[73swinger]

gimme a minute I'll go check it now

[Tejas]

 

[73swinger]

yeah, they're pretty damn close. If not right on. I've got about 2 1/4 inches from the lower front chrome lip, to the front square edge of my tire on both sides. Remember though, that the passenger side sits about 1/2" higher and therefore that spring HAS to be a little longer. And this is on a 73 Swinger so the measurement may not be the same on different year cars

[Tejas]

Well I'm glad yours isn't cockeyed. 
I think I'm going to have to call Mancini and talk to them about exchanging one or both of my springs.
Thanks for your help.

[Tejas]

Any other suggestions before I call Mancini?

[abqdart]

I just woke up so I hope I aint repeating something you already said you did....did you try laying the springs on the ground upside down so you have an arch. measure from spring eye to spring eye (center to center) and then drop a plumb bob from your register pin put a mark on the floor and measure from front spring eye to pin. Use a chalk/snap line to square everything up first of course. When you measured for your spring box's, did you use a good location like the T-bar sockets to get your front to back and cross to cross points? I dont know if that is clear enough for what I am trying to explain....It took me 6 months and 2 attempts before I got mine square...of course I was taking my sweet old time with it.....like really sweet old time..

[Tejas]

Yes I did measure the springs last night after I took everything back apart, they are upside down on my workbench.
The left spring has a front segment measurement of 20" which it's supposed to.
The right spring has a front segment measurement of 19 3/4" this is where my problem is.

Yes I did reference from the T bar sockets straight back and diagonally and came out within 1/32" on every measurement I made.
I'm confident that my boxes are located correctly.

Thanks for asking those questions and double checking my work, it's always good to have another outlook on things. 

[Tejas]

Well I called Mancini's tech line and told them about my problem.
He checked some measurements of the springs he has in stock and they are the same as mine, 1/4" shorter on the right spring.
He said that this was due to the extra arch in the right spring and it would flatten out and be equal when the weight of the car was on it.
I told him that it may be 2 more years before I have the total weight built into the car to confirm this and he said to write his name and date down in case there is still a problem in the future.
I'm having a hard time swallowing all of that but I'm not sure I have another choice.
Sounds like I need to get the front suspension on it, mock the engine and trans into place and get it on the ground.

Has anybody else run into this kind of problem before?

[mischiefdart]

I would think that the passenger side spring would need to be a 1/4" longer if it had more arch not shorter.

[Tejas]

I would think that the passenger side spring would need to be a 1/4" longer if it had more arch not shorter.

It's just the front segment that is shorter. 19 3/4" vs 20"
I don't get it either.

[kawazuki8097]

Not really what I wanted to hear.....
Tejas - my timeline is similar to yours. I have a set of XHD's I got about two months ago still sitting on the floor under the car. I'll check them when I am next at the garage to see if my measurements are the same as yours.

[Tejas]

Good, thanks.
I would really like to know if anybody else has run into this.
I'm hoping it's a non-issue, maybe most of the guys that have installed XHD springs did it on a complete car that they drove right away and it really does equal out when the weight is on the springs.

[73swinger]

He said that this was due to the extra arch in the right spring and it would flatten out and be equal when the weight of the car was on it.

That's what I suggested wasn't it? I measured mine for you the other night and they were close to perfect front to back. I won't take them off the car for you though

[Tejas]

Well as it turns out you first suggestion is probably right!
I did some more research and learned how to properly measure leaf springs.
http://www.eatonsprings.com/measuring.htm
It may be common knowledge to some people but I didn't know it 'till today.
I'll pull it all back apart tomorrow morning and check them.
I have a feeling that they will be equal and there will be no problem when the whole weight of the car is on them.
Thanks for the measurements and help, I wouldn't ask you to take your car apart though.

[73swinger]

well, you could try.... . I hope it works out for you. It's funny you know, I jusy took them outta the box and slapped em on( after checking part numbers of course) and everything worked out fine. Just lucky i guess

[jess13]

I think I have seen this before,  and it turned out to be fine & was the way they needed to be.  WHen the weight is on them it will all work out,  they might have to settle a bit after the weight is put back though.  But they will end up with a differnt arch from side to side,  and the one side will be higher,  but the rear end will be inline.  But its the way it needs to be for leaf springs to work good.

Jess

[Tejas]

Yep, looks like it will be a non-issue.
I took everything back apart and measured them again using a sewing tape laid along the arch of the springs and they both came out to 20" exactly.
It looks a little funny now but everything should line up as I get weight built into the car.
I'm glad I don't have to worry or wonder about it anymore.
Thanks for all the help!