Forum Index => The Library => Topic started by: Reggie on January 09, 2008, 11:38:45
Title: Suspension: Eliminating the Iso-Clamp System
Post by: Reggie on January 09, 2008, 11:38:45
Eliminating the Iso-Clamp System
Below, excerpted from a thread by Bill55az (https://www.dippy.org/forum2/index.php?action=pm;sa=send;u=22), are details on how eliminate the Iso-Clamp rear suspension system by adapting F/J/M shockplates to smaller spring locator pins. Bill55az (https://www.dippy.org/forum2/index.php?action=pm;sa=send;u=22) used this method to swap Dakota truck rear springs to his 1979 Volare Wagon - aka the "Chick Magnet".
The Iso-Clamp system on all F/J/M cars has large flanged holes in the upper shock plates, which lock into large 1 9/16" holes in the axle spring perches. The F/J/M spring bolts are much much longer than Dakota or earlier Chrysler products, and they have a large top hat style bushing on either end to lock into rubber Iso-Pads, which in turn, lock into the large flanged holes in the shock plates. When eliminating the Iso-Clamp system and converting to springs with smaller locator pins, a problem arises because shock plates on sway bar-equipped F/J/M cars have special brackets which are needed to mount the sway bar.
In order to keep the special F/J/M swaybar shockplates and positively lock the smaller spring locating pins, Bill55az (https://www.dippy.org/forum2/index.php?action=pm;sa=send;u=22) found some large shoulder nuts in the junkyard that were large enough to just fit into the large flanged holes in the shockplates and welded them in. Since the shoulder nut thread size was very close to the standard Dakota spring center bolt, he opened up the insides of the bolt holes with a round file. He also trimmed off the old F/J/M shock mounting tabs from the shock plates and used B-Body shock plates on the bottom of the springs. Because F/J/M shockplate u-bolt holes sit farther apart than u-bolt holes on Dakota or earlier Chrysler products, you will need to notch the F/J/M shockplates in towards the springs to allow the holes align with the B-body shock plates. You can also keep your F/J/M springs if you want to by trashing the bushing and using a shorter thru bolt.
To recap this method:
The stock F/J/M axle locates on modified F/J/M cop car shock plates
F/J/M cop car shock plates are modified as follows:
Large shoulder bolts are welded into the large holes to positively lock them onto the Dakota spring pins.
F/J/M cop car shockplates are notched in towards the springs to allow the U-bolts to clear. This has to be done because B-body U-bolt holes are located closer together than F/J/M shock plates.
The stock F/J/M shock mounting tabs are trimmed off
B body lower shock plates are attached to the bottom of the springs with U-bolts.
B body rear shocks are mounted to the B body shock plates and to the stock upper F/J/M shock mounting location.