I already have a thread going in the other engine conversion section, but it's off topic and out of the way, so it's probably not getting much attention.

I have an 84 FB with the "big bearing" spindles that I want to put 4 lug FC components on. I think my best route is the ReSpeed big brake conversion kit, which is built to use TII parts with the 5 lug hubs and rotors. Am I correct in assuming that I should be able to use 4 lug components with this kit, all the same? People do 4 lug to 5 lug conversions on FC's, simply by replacing the hubs, rotors and calipers, so I think all of the spacing is the same between the two setups. The kit comes with caliper brackets to fit TII calipers, so would a single piston 4 lug caliper fit this bracket, or would a TII caliper fit on the 4 lug rotor? Are the 4 and 5 lug rotors the same diameter, thickness and backspacing to the hub?

I'm trying to avoid using a hub adapter which would add unwanted thickness/offset to my front end, as well as more chance for failures.

Thanks!

 

the 4 lug hub should work just fine. the 4 lug rotor is smaller than the 5 lug rotor, but you can redrill the 5 lug rotor to 4 lug, and use the 4 pistons, or actually i think the 4 lug rotor and single piston caliper would fit too

 

This will help you: http://www.aaroncake.net/RX-7/4lug4potbrakes.htm

 

Hmmm. Seems that in order for me to go from 5 lug to 4 lug I would need to eaither machine off 4mm of material from the rotor hats, which doesn't sound possible, or make spacers for the caliper bracket to move the calipers out 4mm. This may be possible, I will have to look at it more closely to see how I could achieve this.

Thanks guys for the help. I'm not surprised AaronCake was of help in this issue.

Actually, my brain is quite confused by this now. I'm having a hard time doing this procedure backwards, then also considering it's not a direct FC 5 lug to 4 lug swap, but into an FB, so slightly different. I'll roll it around in my head for a while. I may still just go with the cheap and easy route and use adapters.

Bah! Thinking about it more, I guess once I swap over to 4 lug FC hubs, which should bolt right up to my spindles, and the ReSpeed caliper brackets, up to that point, the rotors and calipers shouldn't be able to tell it's an FB, not an FC 4 lug car. So with brackets allowing the TII calipers, the rest of the swap should be exactly as in the guide, shouldn't it?

 

Actually, I shouldn't even need the spacer between the hub and rotor, since the ReSpeed kit places the TII calipers to work with the 5 lug rotors/hub. And the 4 and 5 lug hubs are the same, since people do 4 to 5 lug hub swaps on the 4 lug FC spindles, so the spindles must be the same on all FC's. So really all I should need are 4 lug hubs, 5 lug rotors, TII calipers and the ReSpeed kit.

 

Now the fun part of the build... finding the damn hubs. I'm always trying to find the parts that seem to be non existent in the world. If anyone has, or knows of someone who has a set of 4 lug hubs they want to get rid of, let me know please. I can find 5 lug hubs all day long though.

 

Actually I have a set of 4-lug hubs.. No idea what shipping would be. I'm in Tualatin, OR 97062
And I'm not sure how to remove them from the rear. I could probably get the whole knuckle off..

 

Pm sent.

 

Well, I got all of my parts... except the hubs, as I imagined it would be. You would think with all of the 4 to 5 lug conversions, there would be plenty of people willing to make a few bucks selling their old 4 lug hubs. All I need are the front ones.

-ReSpeed SA/FB Big Brake Kit
-ReSpeed Big Brake Line Kit
-Remanufactured 4 piston calipers
-CarboTech AX6 pads
-New 5 lug vented rotors to be redrilled
-All new bearings, seals and nuts/retainers

Surprised I got away with this as cheaply as I did. Only at about $600 now, plus whatever the hubs end up costing me. Not bad to be able to use my 4 lug wheels, and to upgrade from the puny little stock single piston slider calipers to the big 4 piston monsters.

I guess I also have to worry about the master cylinder now, not sure if the one for the FB would be up to the task. Wonder if the TII master would fit an FB without much work. Don't see why not.

 

I believe the GSL-SE front equipment is the same size as the 4 lug FC front equipment.

But why not go 5 lug out back too? You can get the 5 lug axle shafts installed in the rear and put the bigger FC brakes in the rear too.

 

They may be the same, but I know for sure the 4 and 5 lug FC stuff is the same, so I'm going with that. The rear will be a Ford 8.8 with SE brakes. Should be good enough.

As I have to buy all of the brake parts anyway, I may spend a little extra and get the ReSpeed rear big brake kit too and run the bigger ones in the rear too.