IRS Lower Control Arms

[John J Phillips]

I am installing the IRS on a MKIV complete kit. For the installation of the rear lower control arms, the manual says, “screw the rod ends with jam nuts into the lower control arm. Screw the forward joint in all the way then back out 4 turns. Later, after installation is complete and the rear axle measurement is completed the instructions say to turn all the control arms the same number of turns so alignment is not needed after the installation. My questions centers around the rod ends in the lower control arm. Is one backed out four turns (the forward joint) and the other screwed in tight? If so, there is no adjustment inward on the rear joint. Or, am I being too literal and they are both backed out 4 turns. Thanks in advance for your thoughts.

[2bking]

The 4 turns on the forward joint is the starting point for adjusting the toe which is done using the rear joint. If all is perfect, the rear joint will end up about 4 turns out as well. Both joints will be screwed in or out to set track width. Because the rear leg isn't parallel to the front one, the number of turns setting track width will be different at each joint. No spacers are used on the back joint until all the alignment is complete. The front leg will be close to parallel to the frame and will need to be spaced back using the shims. I think the manual says to start with two forward shims. Mine required more to get clearance between the frame and leg.

[John J Phillips]

Your explanation makes perfect sense. Thanks for your help!