Author Topic: Tortured spring perches. Solutions?  (Read 1327 times)

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6667fan

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Tortured spring perches. Solutions?
« on: November 13, 2021, 08:00:50 PM »
I had the factory perches reinforced, (boxed), before flogging car at track a few years back. I was monitoring them and tightening the U bolts after trips to the track. Eventually the perches collapsed to the point where the pinion angle was considerably out of whack. I have ordered some new perches from Ballistic to replace the beat factory ones. Any tips/suggestions beyond replacing the perches?


https://www.ballisticfabrication.com/products/leaf-spring-perch
« Last Edit: November 14, 2021, 07:23:06 AM by 6667fan »
JB


67 Fairlane 500
482 cid 636/619.
Tunnel Wedge, Survival EMC CNC heads, Lykins Custom Hydraulic Roller, Ram adjustable clutch, Jerico 4-spd, Eaton Detroit True-Trac, Moser axles, Ford 4.57 9 inch
11.206@123.73

Posi67

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Re: Tortured spring perches. Solutions?
« Reply #1 on: November 13, 2021, 10:55:02 PM »
I killed mine way back in the late 70's. At least you did think to do the reinforce route but there are so many cars even being raced that are waiting for disaster to strike. In my case, I got some 3" channel and a buddy who could weld built some really beefy perches that are still on the rear today. Also interesting is the chassis guy who did my back brace tied everything together and one U-bolt goes through the brace. A very tough setup IMO. Downside was when I ordered my CalTraks I forgot about the extra width and had to get a second set of mount plates with the holes farther apart.




John67427

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Re: Tortured spring perches. Solutions?
« Reply #2 on: November 15, 2021, 11:57:55 PM »
You will be fine with the new perches. They are similar to the Calvert perches. I crushed the factory perches with a mild street 428 that I had in the car many years ago. Ruined a $400 Strange drive shaft. FE’s torture the drive line when added horsepower is applied. Just verify your pinion angle so they are welded on properly for your setup.

JamesonRacing

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Re: Tortured spring perches. Solutions?
« Reply #3 on: November 16, 2021, 07:16:50 AM »
If you are not using 1/2" U-bolts, now would be a good time to replace them.  7/16" U-bolts are not a drag racer's friend.
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6667fan

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Re: Tortured spring perches. Solutions?
« Reply #4 on: November 16, 2021, 08:07:00 AM »
John, the perches will be put on in the stock orientation. There are some shim sets hanging on the wall. Did not have any in previously and car seemed fine going down track,( before perches got real bad). I can’t check pinion angle in my barn and complete housing has been removed for the repair job. Pinion angle should be checked after installation.

David, I ordered some new Calvert 1/2” x 20 x 7” U bolts to replace the stretched 1/2 x 20s that were in there. Considered 5/8” but did not wish to hog out the Cal -Trac plates to accommodate them.

Thanks much to you both.
JB


67 Fairlane 500
482 cid 636/619.
Tunnel Wedge, Survival EMC CNC heads, Lykins Custom Hydraulic Roller, Ram adjustable clutch, Jerico 4-spd, Eaton Detroit True-Trac, Moser axles, Ford 4.57 9 inch
11.206@123.73

6667fan

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Re: Tortured spring perches. Solutions?
« Reply #5 on: March 15, 2022, 08:52:41 PM »
I brought the whole Ford housing to the same guy who has been doing third member work for me for the last 45 years. He had no problem putting the new Ballistic perches on the housing but asked me what I was going to break on the factory rear next. ( this was as we were looking over the twisted 31 spline passenger side axle). He suggested that maybe it was time to consider aftermarket parts. I went into his shop hoping to get this rear set up with some 35 spline axles, new perches and a new ring and pinion, ( the old Ford is 4.57s were getting clunky).

Long story short, he rebuilt the third member with some new 4.30s I had, a spare 31 spline axle he had and welded up/ ground the backing plates. It’s a spare now as I bit the bullet and bought a new Strange third member.



JB


67 Fairlane 500
482 cid 636/619.
Tunnel Wedge, Survival EMC CNC heads, Lykins Custom Hydraulic Roller, Ram adjustable clutch, Jerico 4-spd, Eaton Detroit True-Trac, Moser axles, Ford 4.57 9 inch
11.206@123.73

Jb427

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Re: Tortured spring perches. Solutions?
« Reply #6 on: March 20, 2022, 09:07:37 AM »
Make sure you get a set of the lower spring plate like posi67 has in his photo they are about 1/4" thick i run the same ones you should be able to get them with or without the cal-trac mounts
money well spent

6667fan

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Re: Tortured spring perches. Solutions?
« Reply #7 on: March 21, 2022, 07:17:52 AM »
Yep, I have them via the Cal-Tracs. Very burly.
I was concerned at first that the new 3” U bolts for the Strange rear would not work with the Cal-Trac 2.75” Fairlane housing spacing on the plates but they went in.
JB


67 Fairlane 500
482 cid 636/619.
Tunnel Wedge, Survival EMC CNC heads, Lykins Custom Hydraulic Roller, Ram adjustable clutch, Jerico 4-spd, Eaton Detroit True-Trac, Moser axles, Ford 4.57 9 inch
11.206@123.73