GSL Rearend
#2
Lives on the Forum
I put one into my 85 GS and love it. It does have the limited slip, which is great, and also disc brakes. Installation was a breeze... This swap is well worth it in my opinion.
#3
Leaking oil like crazy!
iTrader: (1)
Join Date: Sep 2003
Location: Utah
Posts: 698
Likes: 0
Received 0 Likes
on
0 Posts
Just make sure it is from an 84 or 85. Otherwise it will not be a direct swap as mazda changed the rear ends for the last two years (bigger axles if I remember correctly)
If its from an 81 to 83 just send it to me as I've been looking for one!
Good luck.
If its from an 81 to 83 just send it to me as I've been looking for one!
Good luck.
#9
counting the days...
Join Date: Mar 2005
Location: Canaan, CT
Posts: 186
Likes: 0
Received 0 Likes
on
0 Posts
1. definitely worth it... I have one waiting to get swapped into my GS
2. Yes it does(already answered) and it is a solid rearend... they all were far as I know
I'm not sure on this one, but you may need to snag the proportioning valve or whatever contains it as you would be switching from drum to disk brakes...
Can someone answer for sure?
#10
Stu-Tron Get Yo Groove On
iTrader: (4)
1. definitely worth it... I have one waiting to get swapped into my GS
2. Yes it does(already answered) and it is a solid rearend... they all were far as I know
I'm not sure on this one, but you may need to snag the proportioning valve or whatever contains it as you would be switching from drum to disk brakes...
Can someone answer for sure?
2. Yes it does(already answered) and it is a solid rearend... they all were far as I know
I'm not sure on this one, but you may need to snag the proportioning valve or whatever contains it as you would be switching from drum to disk brakes...
Can someone answer for sure?
#11
Too old to act my age
Join Date: Feb 2005
Location: Tulsa, Ok.
Posts: 3,164
Likes: 0
Received 0 Likes
on
0 Posts
81-82 drum/disc both used the same PV, however, starting in 83, the disc rear had a different PV, while the drum continued to use the same as the older cars. The master cyl, on the other hand, is different between drum and disc.
As for guy asking about an 80 model, you will need a special rear chassis to axle brake hose.
As for guy asking about an 80 model, you will need a special rear chassis to axle brake hose.
#12
Lives on the Forum
I'm sure I'll get a little flaming for this, but I did not change the master cylinder or the proportioning valve when I did my swap. Brakes work great, even while racing. I couldn't be happier with the braking performance just the way it is...
#13
Just 1 Rx-7 isn't enough
Join Date: Feb 2008
Location: Colorado
Posts: 89
Likes: 0
Received 0 Likes
on
0 Posts
What all do I need to swap
I have a complete 82' GSL Rear end and I want to swap it into my 85GS. What all do I need to swap. I have the parking break cables. I also have the master cylinder do I need to switch it as well?
#15
Too old to act my age
Join Date: Feb 2005
Location: Tulsa, Ok.
Posts: 3,164
Likes: 0
Received 0 Likes
on
0 Posts
FWIW, the only "real" difference between drum and disc MC, is the residual pressure valve in the drum unit. It is (normally) located under the large hex head plug that the rear line bolts into (front of MC), and can be removed to convert a known good drum MC to disc.
#16
Leaking oil like crazy!
iTrader: (1)
Join Date: Sep 2003
Location: Utah
Posts: 698
Likes: 0
Received 0 Likes
on
0 Posts
Is there a place to get these, or do I have to come up with something myself? So if I get a rear end from an 81-82 gsl, do I need to get the driveshaft or will mine work? Thanks.
#17
Too old to act my age
Join Date: Feb 2005
Location: Tulsa, Ok.
Posts: 3,164
Likes: 0
Received 0 Likes
on
0 Posts
As for the driveshaft, 79-82 used the same, while 83-85 was different.
#18
So I should try to find out what year this GSL is first? make sure it's an '84-85 so my differential will match? And if possible get the Proportioning valve?
And is the a Brake Master Cylinder necessary? or was someone saying you can convert a master cylinder for drums over to rear disc.
And is the a Brake Master Cylinder necessary? or was someone saying you can convert a master cylinder for drums over to rear disc.
#19
Famous Taillights
iTrader: (3)
Just to clarify, 83 was the mid year change. So some early 83's had the small flange and axles while later 83's had the larger flange and axles. The rear end with hoses and e-brake cables are all that is necessary(with matching driveshaft if applicable). The Master Cylinder and Proportioning valve are optional
#21
Too old to act my age
Join Date: Feb 2005
Location: Tulsa, Ok.
Posts: 3,164
Likes: 0
Received 0 Likes
on
0 Posts
So I should try to find out what year this GSL is first? make sure it's an '84-85 so my differential will match? And if possible get the Proportioning valve?
And is the a Brake Master Cylinder necessary? or was someone saying you can convert a master cylinder for drums over to rear disc.
And is the a Brake Master Cylinder necessary? or was someone saying you can convert a master cylinder for drums over to rear disc.
A simple wat to see which style driveshaft is needed, look at the flange that the driveshaft bolts to. 4 threaded holes = 81-82. 4 non-threaded holes = 83-85.
I have heard that early 83's had the smaller flange like the 79-82, but the Mazda parts microfiche doesn't support this. Nor does it support the mid-83 axle size change that is often reffered to here. Not sure who is *really* correct, the experts here, or Mazda's parts list.
The brake master cyl is not 100% needed. There is only one internal difference between drum and disc MC. There is a residual pressure valve (often called a check valve) in the rear brake section. It can be removed, if desired. I drove my car for about 3 months with a drum MC and PV without any issues. The MC went bad, so I replaced with disc brake unit.
The proportioning valve, according to the parts microfiche, is the same from 81-82 for drum or disc, but 83-85 did use a different PV for disc. This means the the PV is not 100% required, but if one can be found from a 83-85 GSL, it might be best to use it. I'm not sure if the GSL and GSL-SE used the same PV, but the MC seems to be the same.
#23
Racing is life!
iTrader: (2)
Join Date: Jan 2003
Location: Grapevine, TX
Posts: 2,173
Likes: 0
Received 0 Likes
on
0 Posts
Edit, look here backing plates are different. http://mrmazda.no-ip.com/interchange.html#AXLE
Last edited by cpa7man; 06-08-08 at 08:34 AM. Reason: correction
#24
Too old to act my age
Join Date: Feb 2005
Location: Tulsa, Ok.
Posts: 3,164
Likes: 0
Received 0 Likes
on
0 Posts
The axle shafts will interchange between drum and disc, as long as they are both the same diameter. The 79-83 had small axles, while the 84-85 had larger axles.
The axles are totally different between big and small, the entire length is different diameter.
So, as long as you aquired a LSD center from an 84-85 model, yes it could be placed in your current drum brake rearend housing.
The axles are totally different between big and small, the entire length is different diameter.
So, as long as you aquired a LSD center from an 84-85 model, yes it could be placed in your current drum brake rearend housing.
#25
the name is Stan
iTrader: (1)
I did this swap on my 85 GS. Along with NEW discs, pads, bushings, RB springs, RB sway bars, shocks, and SS brained lines.
My rear brakes WILL LOCK UP FIRST under panic braking on the streets.
(don't ask how i know)
While on the track or twisties i'm am better able to modulate with the pedal.
Just a great, great mod to do. No more whimpy one tire peal-outs. Character of the car has changed.
Conclusion - I will get the proportioning valve once I have a chance.
My rear brakes WILL LOCK UP FIRST under panic braking on the streets.
(don't ask how i know)
While on the track or twisties i'm am better able to modulate with the pedal.
Just a great, great mod to do. No more whimpy one tire peal-outs. Character of the car has changed.
Conclusion - I will get the proportioning valve once I have a chance.
Last edited by Rotary-MG; 06-09-08 at 01:12 PM.