I've searched and I'm still unsure of a couple details about this swap. I know about the e-brake cables, swapping brake lines, master cylinder and prop valve. Two things I don't get.

1. Do I need to pull the upper and lower arms and Watts link too, or do I use the ones on the '79?

2. I want to use the '79 driveshaft. I just need to swap the flange from the '83 shaft to the '79 shaft, right? It looks pretty straightforward in the manual. Are there any gotchas I need to know about?

 

On the lower control arms, inspect the balljoints and use the ones in best condition.

Watts link = either or. Be sure to use lock-tite.

Driveshaft = as you already know, 83 is an odd-year. If the 3rd member flange is the same as the 79, then I would leave it alone. If not, use flange holder (some sort of bar to keep it from turning) while loosening the large nut and count the number of turns. Be careful when switching flanges, as it can change the specs on the R&P.

 

I would match the driveshaft instead of changing the flange. I may have one laying around. Swap the watts and control arms with the best bushings, unless you plan on replacing them.

 

I believe the threads are different on the brake lines from the 79 to the 83. You might need to do the valve up front also. When I did the swap, my front brake system had to be changed also because of the thread difference. You can always force it and it will work if you don't intend on ever using the valve in the front again after taking it out... I did that once too... not a good idea but when you're broke anything goes

The driveshaft is the same, you shouldn't have any problems other than the braking system.

 

Thanks, guys. I have a bushing set that came with the '79, so I'm going to use new bushings. I hear they're a PITA to remove, but I'm planning to take my time, clean up and paint the rear end, so I'll do it right. I wanted to use the '79 shaft because it has replaceable u-joints. On the other hand, it'd be nice to skip messing with the flange. Am I right about the u-joints? As far as I know, the '83 shaft is good, but assuming it's stock it has about 30k more miles than the '79.

Wackyracer, you're talking about the LCA in the front, right? I am going to swap the front suspension too, since I have new rotors, pads, bearings and struts on the GSL. I had planned to use the LCAs from the '79 but maybe I should just put new ball joints in there while I'm down there anyway.

 

I'm swapping the whole braking system, which kinda sucks because the flex lines and some of the hard lines on the '79 look almost new.

 

I hated the disk system on the 79 anyways, its a good upgrade

 

I saw some thread around here where they were using a torch to burn the bushings out... might help.

This upgrade is actually really easy to do, I did it in a thunderstorm cuz a wheel bearing died on the original rear end and I lost a wheel at about 80 mph. Wasn't much left of anything on the original rear end after that I had to have a car so I went and got the rear end and brake stuff from a local junkyard and threw it on in about 2 hours. I decided to uprade since both rear ends were same price and I wanted full disk hehe.

 

I can show you a few tricks on getting the bushings out if you want to bring them up.

 

Brake line thread pitch is different and you have 3 options:
(1) keep the stock brake lines and purchase a new set of brake lines from mazdatrix/or get custom lines.

(2)cut the ends of stock brake lines and re-flare it using an 81+ end fittings.

(3)take everything from the donor including brake proportioning valve/master cylinder except for the brake booster. The 81+ brake booster is larger so you cant use it. If you do, you will need to relocate the clutch M/C.

btw, on 81+, the brake line bracket is welded on the fender well.

 

i have a complete set of fb brake lines in good condition i just removed.
you can have them if you want them.