GSL/GSL-SE Rear End Swap
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Joined: Jul 2015
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From: In a house.
GSL/GSL-SE Rear End Swap
I've been reading, and I can't really find the answer to this question, so basically, if I have a 1985 RX7 GS, how hard would it be to swap a LSD rear end from a GSL or a GSL-SE?
To the best of my knowledge, all you need is the rear end with brakes and the like attached and the handbrake cables. Everything Else should bolt up. It is also recommended that you get the correct master cylinder and proportioning valve for disc brakes.
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Joined: Sep 2013
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From: Tampa bay Florida
Since you have an 85 gs you already have the fat axle rear end so no need to swap housing unless you have an automatic. If you have disc brakes i think you should have the lsd as well. I'm not exactly sure what trim levels had lsd. However all you need to do if you don't have an lsd is swap the center section. Lots of center sections fit from miata torsen to kia 4.7 to fc some require more work than others (ie custom drive shaft or drive shaft swap). But a gsl-se lsd into your car is just plug and play.
I have an ex automatic 82 with swapped gsl-se axle housing but gsl half shafts and brakes. That way I keep the 4x110 bolt pattern but gsl-se lsd and gear ratio.
I have an ex automatic 82 with swapped gsl-se axle housing but gsl half shafts and brakes. That way I keep the 4x110 bolt pattern but gsl-se lsd and gear ratio.
SO you do NOT need a different master cyl. your master cyl will work fine.
YOU DO NEED HOWEVER a disc brake proportional valve,, this is the piece on the side of the master cyl. this sends different pre pressure to the rear brakes depending on if you have a drum or disc rear. some people have said it doesn't make a difference, well then their prop valve isn't working correctly. if you do have a working Drum prop valve and put a disc rear in, your rear disc brakes are going to drag due to the extra pressure that drums need from the prop valve (ive experienced this).
so the proportional valve from a disc brake car, the disc brake e brake cables, and the complete rear end too. also you'll need a different drive shaft if your rear is from an 81-83.5 year car and you're putting it in an 83.5-85 car.
like others said if you have a se rear, you'll have a new bolt pattern
fun fact, if you have an 83.5-85 drum rear (large axle) you can take the lsd unit from a se and just swap it into your drum rear. (same with gsl lsd gears) so you can get the lsd in 3.9 or 4.1 without having to swap everything else, just the pumpkin in your rear
YOU DO NEED HOWEVER a disc brake proportional valve,, this is the piece on the side of the master cyl. this sends different pre pressure to the rear brakes depending on if you have a drum or disc rear. some people have said it doesn't make a difference, well then their prop valve isn't working correctly. if you do have a working Drum prop valve and put a disc rear in, your rear disc brakes are going to drag due to the extra pressure that drums need from the prop valve (ive experienced this).
so the proportional valve from a disc brake car, the disc brake e brake cables, and the complete rear end too. also you'll need a different drive shaft if your rear is from an 81-83.5 year car and you're putting it in an 83.5-85 car.
like others said if you have a se rear, you'll have a new bolt pattern
fun fact, if you have an 83.5-85 drum rear (large axle) you can take the lsd unit from a se and just swap it into your drum rear. (same with gsl lsd gears) so you can get the lsd in 3.9 or 4.1 without having to swap everything else, just the pumpkin in your rear