Dearching leaf springs?

[miketyler]

I need to drop the rear of my 70 at least three inches. Rather than putting the drop blocks under the car, was considering dearching. I called a spring shop today and they said they can do it. What do I need to know before I make a decision on this? I was reading that Rick Flores is running the 17x11 TTII wheel with the 315/35-17 tires. He said he had his springs dearched 3" and then had a 1" drop blck installed to get the ride height shown below.

So tell me about dearching. Does it leave the spring strength intact or ? Any reasons why I shouldn't dearch?

[AzPete]

Instead of that, there is a way to de-arch them using another set of old springs and placing them between your leaves and upside down. Cannot find the old post but it is described somewhere on this place.....

My experience with de-arching was never good...always uneven side to side.

[Grabber70Mach]

Instead of that, there is a way to de-arch them using another set of old springs and placing them between your leaves and upside down. Cannot find the old post but it is described somewhere on this place.....

My experience with de-arching was never good...always uneven side to side.

This?

http://www.stangnet.com/mustang-forums/544275-lowering-rear-car-w-o-blocks-long.html

[AzPete]

This?

http://www.stangnet.com/mustang-forums/544275-lowering-rear-car-w-o-blocks-long.html

That works....thanks.

[Grabber70Mach]

Your welcome, glad to help.

[miketyler]

Thanks, I have read Latamuds article a few times on this. It seems like a little more work not to mention coming up with a second set of springs. Still good info but I was more interested in dearching and the experiences people had with the this type modification. 

[buening]

No direct experience with de-arching, but take a peek at Opentrackers reply on #38 of the above Latamud link.  You can basically shorten your leafs to get a drop, but this also reduces your spring rate and makes things a bit softer.  What did the spring place quote you for the dearch?

[miketyler]

$50-$75 depending on if they have to replace a leaf. No heating involved, he said they do it using a cryo method. I need to get more details

[buening]

Wow I expected much worse.  Is that for both springs?  I think that'd be the way to go.  You may check with them to see how it affects your spring rate.

[miketyler]

I need to call them back and confirm pricing on single or in pairs. One place I called cautioned against dearching 3+ inches stating it displaces the axle moving it back and out of center with wheelwell as well as nearly removing most of the upward spring travel. I found Rick Flores number yesterday, am going to call him and see if he can give me some details on how he did his dropped cars. 

[miketyler]

Talked to Rick briefly as he was out or heading out of the country. He had his springs de-arched 2.5". So I took my springs off this weekend and plan to get them done this week as I want to start the car in two weeks.

I called one other spring shop and described my application and the guy there told me dearching springs that much isn't good. He told me that it reduces the amount of shackle swing inviting bump stop incidents and displaces the wheel out of center of the wheel well opening.  Also, he wanted $100-$125 per spring to dearch.

Have any of you dearched and seen these things he describes? 

[buening]

Mike are you using stock springs or reverse eyes?  I'd recommend starting with reverse eye springs and then determine how much you need to drop the car.    What that shop said makes sense, as you are essentially lengthening the spring. Since the front is fixed, the rear shackle must move backwards due to the lengthening.  Since it is lengthened, you are pushing the axle further back since the front point is fixed.

Take a string from one end of the spring to the other end and measure the distance from the string to the top of spring at the axle location.  De-arching 2.5" may result in a near flat spring, or will become flat or reverse curvature during suspension travel. I have a feeling this is what he is talking about with the shackle swing, as when the spring is nearly flat the shackles don't move.  The reverse eyes basically flip the eye at the front of the spring, building in an automatic drop compared to new standard springs.

[Midlife]

Re-arching the springs will run you about $100-$150.  For just a few bucks more, you can buy reverse eye or correct arched springs new without the problems mentioned above.

[miketyler]

Am using stock springs and they have lots of spring to them. What is the real drop on reverse eye springs? I guess it can vary depending on what you started with but I need to get this rear where its going to be so I can get on with this build. Maybe Latamuds inverted spring addition is something to consider. He didnt mention anything about that in the article that I recall?   

[buening]

Yeah it pretty much depends on what springs you currently have.  If they are a 5 leaf with a higher spring rate, you'll get more of a drop with reverse eyes compared to a standard 4 leaf. Supposedly it will lower 1.5" over stock. Ideally you could use the reverse eyes and run a 1" lowering block to get you to your 2.5" drop.  I'm running fairly new standard 4 leafs on mine and here is where it sits without any mods to the leafs or drop blocks (for reference):

[miketyler]

Talked to Rick again today on both points. De-arching stock springs on his 69 pro touring car did not offset his wheel in center of wheel well, nor did it create any increased bump stop issues. He drove his car like this on the street and strip. 

I figure these are stock springs and if it turns out to be wrong, I can always buy reverse eyes.

[miketyler]

Got the springs dearched and I think I have it where I want it. I still have interior and fuel tank out. I bounced the heck out of the car and coudn't get it to bottom out. That might change with a full tank of gas. New rear ride height is right at 24 1/4. I took the wheels off the Cuda to test fit with. They are 17x11 with 7" backspacing. I may go with a different tire to add breathing room on the leafspring and wheel lip.



 

[miketyler]

another

[67 Fastback]

I like that.
Bill

[Grabber70Mach]

Really like it.  I think you nailed it. 

[buening]

VERY NICE!  I think you nailed that stance for sure.  Thats about the height I'm planning on.  Are those 315 tires?

[miketyler]

yes, 315/35-17 Sumitomos. Am thinking on 295's for a little more room on the springs and fender lip. 

[SELLERSRODSHOP]

 been watching this with alot of interest. been wanting to do the same thing, but can't find any spring shops here willing to do the procedure (they all want to sell me new springs though..) i currently have homemade 2" rear blocks installed to get my height down. if you can, post up the measurement from the hub centerline to fender lip. that will give a more universal comparison for those with different tire sizes. i'm running 285/40's which are within 1/4" in diameter of the 315/35's, but just a bit narower on 9.5" rims.

[miketyler]

Wow - that looks pretty good for just 2" blocks. Will get those dims today.

I meant to say, the pics are with my modified springs and 2" drop blocks. Once installed and loaded, they are nearly straight but surprisingly still have a lot of spring action. Admittedly, I did get about 1/8" height variation between the springs after dearch. I will probably use a shim plate or shave the block for the lower side. I am running an SSBC rear disc conversion and that possibly has increased my trac width. Also, I will have to run 1/4 spacer on both sides to get the tire away from the spring. This will necessitate the need to roll (or even cut and re-tack) the top 8-10" of quarter fender lip. Man, this is some work.

While I like the height it is at, am not sure how driveable the car will be. I only have 1-1.5" off the bump stop. I bounce the hell out of it and cant get it to hit though. Maybe a different story when I add the tank, gas, and interior.  Also not sure how much swing/sway I will get with no rear sway bar. Would really like to retain my sway bar but the factory configuration places the end links outboard of the springs and that fouls the wheels immediately. My Cuda has a larger factory rear sway bar and it's end links are mounted on top of and in the in the center of the leaf spring safely clearing the wheel assembly. Has anyone modifed their sway bar to keep it all under the car?

       

[buening]

I think I mentioned this before, but look into the aftermarket style of sway bars.  From the looks of them it appears they clamp brackets to the leaf springs, in which the end links hook to.  Hard to tell from the parts picture and not have one of everything installed.  Maybe others here have an aftermarket rear bar installed.

I plan on fabricating either a watts or a panhard rod setup for my rear to keep everything centered.  You'll find that with 315's you will rub when going around the twisties at their rated speed limit.   I'm also reworking the front lower inner corners of the wheelhouse to clearance it a bit.  This is the main location of my rubbing incidences.

Wow, so that was with dearching AND 2" blocks??  Jeremy's car is low in the weeds, maybe he could chime in on if he just used lowering blocks or what.  He has a pic on that wheel thread you put together Mike.