1st Generation Specific (1979-1985) 1979-1985 Discussion including performance modifications and technical support sections

front brake upgrade

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Old Dec 31, 2002 | 09:43 PM
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From: cordele ga
front brake upgrade

i have a 85 rx7 that i would like to swap to a 5 lug pattern i was wondering if someone could tell me if the second gen parts can be made to work on a 1st gen car would love to have the larger rotors and bigger calipers i know the rear will not work wondering if front end parts will
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Old Dec 31, 2002 | 09:53 PM
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From: Cell Block 4 (LOCKDOWN)
What model do you have?

Why do you want to go to 5 lug?

The GSLSE suspension is a direct bolt in you will just need to change the master cyl,the booster is the same.

What are you tring to acheive?
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Old Dec 31, 2002 | 10:09 PM
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From: cordele ga
i am trying to get better braking i have the gslse suspension now my 85 has a ford 351w stroked to
393 ci
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Old Dec 31, 2002 | 10:32 PM
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Swapping to FC front brakes can be done but it's not really pleasant.

One way is to have machined bearing adaptors made so you can put FC hubs on '84-85 spindles. Has to be '84-85. The bearing spacers would have to be made PRECISELY and of strong enough material. Then you just have to make a caliper bracket and you're in business.

The other way and the way that is easier in that you don't require as much precision is to swap an FC front crossmember in the car so that you can use FC struts and knuckles. This also gets you rack and pinion steering. It also requires some ingenuity with the steering column (the way I've seen it done was to adapt an FC steering column) and you also need to use an FC engine because the front motor mounts are not too compatible with the rack. Of course, if you've got an engine swap going on that makes things slightly simpler.

Master cylinders are identical according to the FSM.
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Old Dec 31, 2002 | 11:07 PM
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Originally posted by peejay
Swapping to FC front brakes can be done but it's not really pleasant.

One way is to have machined bearing adaptors made so you can put FC hubs on '84-85 spindles. Has to be '84-85. The bearing spacers would have to be made PRECISELY and of strong enough material. Then you just have to make a caliper bracket and you're in business.
Ok, now you have me interested. I want to know everything about those adapters. Where can I find pics or CAD drawings of them? What material is sufficient? How complex are they to machine?
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Old Jan 1, 2003 | 05:08 AM
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Ask and ye shall recieve

The entire project is detailed by the crafty guy who did the swap at http://www.mazspeed.com/4pistonbrakeconversion.htm

Enjoy!

Note that this particular gentleman reworked the hubs to retain the stock non-GSL-SE 4x110 bolt pattern. You obviously would not want to do this, and just use standard FC 5-lug hubs and rotors. This would give you a 5x4.5" bolt pattern, perfect for that Ford rearend swap!

Last edited by peejay; Jan 1, 2003 at 05:16 AM.
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Old Jan 1, 2003 | 06:29 AM
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Ok peejay, whats involved in dropping in a Ford rear?
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Old Jan 1, 2003 | 07:02 AM
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From: Cell Block 4 (LOCKDOWN)
Ok now god dam ,2 Calipers...and what master cyl?

Stock booster?
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Old Jan 1, 2003 | 07:33 AM
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Carl: cut off the brackets from a Mazda rear, weld on to a Ford rear in the proper positions, just like any other rearend swap. (I make it sound so simple... I remember one morning where I spent 30 minutes with a torch cutting all of the brackets off of a Chev 12" with a real live gen-u-wine Posi in it. Then 4+ hours with an angle grinder removing the slag and prepping the housing for welding the leaf spring perches onto it...)

I like that 2 calipers pic Notice that he ditched that in favor of the FC brakes! 2 calipers is pretty much pointless until you get into the Really Huge brakes like touring cars use, since you don't have enough of a rotor surface to pad surface ratio. In short the rotor doesn't have enough time to cool before it gets to friction surface again. Not a problem if you don't use the additional braking but, well, what's the point if adding all that weight if you're not gonna USE it?

The 1st-gen RX-7 master cylinder has a 20.67mm bore. The 2nd-gen has a 22.22 bore. That's a pretty hefty difference. But, I'd say, if you went through with the swap, try the 1st-gen master first. If it's too soft or sensitive, then swap in the FC master. I don't know for certain but it might be a bolt-up swap. (If not, well... you get to play around with stuff )
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Old Jan 1, 2003 | 08:05 AM
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Oh yea, its just soooooo easy! LOL
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Old Jan 1, 2003 | 12:03 PM
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Originally posted by peejay
The 1st-gen RX-7 master cylinder has a 20.67mm bore. The 2nd-gen has a 22.22 bore. That's a pretty hefty difference. But, I'd say, if you went through with the swap, try the 1st-gen master first. If it's too soft or sensitive, then swap in the FC master. I don't know for certain but it might be a bolt-up swap. (If not, well... you get to play around with stuff )
I read somewhere that they're a direct bolt-up swap, but don't hold me to it.
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Old Jan 1, 2003 | 05:07 PM
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ya know if someone were to take this idea, AND MAKE A KIT, so we can all have 4 piston calipers and 5 lug wheels....

you'd be filthy rich and make everyone on this forum extremely happy
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Old Jan 1, 2003 | 07:36 PM
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Originally posted by hornbm
ya know if someone were to take this idea, AND MAKE A KIT, so we can all have 4 piston calipers and 5 lug wheels....

you'd be filthy rich and make everyone on this forum extremely happy
Theres a shitload of liability there.. Thats why you dont see a lot of us people doing this, try some shops in Australia, they are noted for their craftiness
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