Caliper spacers and extended axles on 82 GSL? And going to 4x114.3
 

I'm slowing gathering parts for a 5.0 V8 swap for my 82 GSL, and I'm torn on what to do with the rear end. I have a lead on some stock GSL-SE axles, but for what most people are asking for 35 year old parts, it seems safer to get Moser or Yukon to build me some new (stronger) ones. If I'm having custom axles made anyway, are there any concerns about extending them ~1/2" and putting washer-type spacers between the axle housing and the caliper brackets? I figure this would be the time to get me a bit more width for the rear wheels without having to use wheel spacers. Obviously I'd need longer caliper bracket bolts, but that's nothing Fastenal can't solve. I may also have them drill a second bolt pattern (5x114.3?) in case I want to install FC brakes at a later date. Am I missing anything?

What I have in the garage right now if anyone has better ideas:

• Small bearing GSL rear with small pinion flange. Spare large pinion flange. Came installed with the car.
• Big bearing GSL rear with large pinion flange. Axles were poorly drilled out, so no studs or threaded holes. No idea what previous owner was thinking. Have both GSL and GSL-SE calipers and caliper brackets, so have options for brakes.
• Granny's Ford -> large pinion driveshaft
• Front GSL-SE spindles, caliper brackets, and new 4-lug FC calipers (same as -SE; you just can't use the FC brackets)
• 15x7 knockoff SSR Mesh wheels (can't tell what manufacturer, but made in the early 80s)

I really don't want to deal with a full 8.8 swap and the headaches of balancing the brakes, and it sounds like Mosers can handle the power. It'll just be a cammed 5.0 with GT40P heads. Thoughts?

Has anyone ordered axles from Moser or Yukon recently?

The axles aren't really the weak point, it's the rearend housing. When the rearend housing twists and flexes, it both stresses the axle bearings and makes the axles get thinner inside the bearing, and it starts to damage the axle at the differential end where the side gears are holding them.

RICE RACING (all caps for reasons) claimed that the small-bearing rears were actually stronger as a whole, because while the big bearing rears had larger axles, the small bearing housings were less flexible, so the axles lived under less stress.

Makes me think, if you're planning on having axles made anyway, have them made with 26 splines but the small bearing ends, and use the early GSL housing with a late differential I am fairly sure that this will work. The GSL-SE brakes should fit no problem, big-bearing GSL and GSL-SE had the same rearend housing, all differences were made up in the caliper carrier and rotor hats.

I got fed up with breaking increasingly hard to find Mazda parts so I built a 9". It ran... a bit of money, but it will last more than 2x as long as GSL-SE stuff, at which point it will have paid for itself.

Thank you--this is certainly an interesting idea. I don't see any negatives to this one! Except...

Yeah this is what I'm still nervous about. Did you use the brakes off the 9" or make brackets for the FB calipers? Whatever I do, I only want to do it once.

Killing unsprung weight was my goal, so I used a kind of weird mix of parts. The brake rotors are solid disks from a first generation Volvo S40, the calipers are the aluminum calipers from a MkIV Golf/Jetta/New Beetle, which will mate up to the Mazda cables if you clock them down about 30 degrees or so. (S40s used basically the same calipers but in iron)

The only real downside is that 14" wheels don't fit over these brakes... actually 15s are a tight squeeze too.

The rest of the reason why I did it this way is that Mazda calipers are basically NLA. I drove for the previous three or four years with inoperative rear brakes because of this.

GSL axles are 10mm shorter than GSL/SE axles. The difference in length is from the axle bearing to axle flange. I have Moser versions of both and I measured them as well stock axles we had laying around the shop. I used Moser GSL axles to help with tire fitment on the rear of car.

It is very true that these rear axle housing can be bent. I broke a suspension mount a couple of time and ended up with a toe'd out housing. Fortunately, we have a place in KC - Layne Machine Works - that straightens housings. Which makes me think that a housing could be reinforced if it is jigged up and then straightened as necessary after fab work.

Third members can be used with both the small and large axles. You just have to change the side gears in the third member.

Since you are doing a 5.0 swap, have you considered a 8.8 swap? Even the 7.5's where pretty stout - they used the same axles as a 28 spline 8.8.

That's... creative. I need to read up more on proportioning valves and how to get things balanced after doing something like that.

I'll be running 15s if I stick with the GSL-SE rear, but if I go with something else, then that's a good reminder that whatever wheels I find need to clear.

Exactly. I finally found a set of GSL-SE rear calipers, and I'm concerned I'll never find them again if I toast them.

This is exactly what I need if I end up going with custom Yukons from my local shop--thank you! Mine would end up being 10mm+spacer to accommodate some wider wheels.

I wanted this to be more of a Grassroots $2000 challenge type build (so no 8.8), but that plan is quickly going out the window. I'm also hesitant to spend money on the rear before I have the motor running.

Once you factor in the cost of reinforcement and custom axles for a stock rear, having my local axle shop ($45/hr shop rate!) shorten an indestructible 8.8 (and weld the tubes) seems like a much better value proposition. It gets even better if I can find buyers for all my GSL/GSL-SE drivetrain parts and do the front 626 ball joint & FC knuckle swap.

I really appreciate the input. Knowing that people have twisted a stock rears at V8 power levels is the push I need to make it bulletproof (an 8.8) instead of easy (only axles).

I would vote 8.8. Rear disk kits are readily available or you could cobble up stuff from an Turbo-T-bird, 93 Cobra, SVO, or SN95 Mustang. On my application, I adapted FC turbo rear brakes. I had to fabricate caliper brackets from scratch but I got it to work.

As far as rotors go, I use turbo rear rotors and have them drilled to fit my 4x100MM pattern. You could do the same to get the pattern you are using.

Calipers
 

I am trying to help my son with his car. I admit I am not up to speed on Mazdas, so my questions are:

1. if the VW calipers will work, why not reuse the existing rotors?
2. Could you post a pic of how that all fit together?
3. If anyone has the GSL-SE calipers they want to sell, let me know.

I have been looking at possibly fabricating Willwood calipers for his car, and have found most of the parts needed, but that looks like about a $700-1000 setup that he can't afford.

I'm pretty much resigned to the fact I have to go 8.8 if I want the rear to hold up to the power. Thankfully Explorer/Mountaineer rears have disc brakes with 5x114.3 to match FC front hubs--that seems like the most logical option. I'd have to come up with a parking brake solution and set a proportioning valve, but neither of those seem terribly difficult (famous last words, I know).