123.afro

id like to have disc brakes in the rear. 1985 gs 12a. whtas the best way to go about this?

djessence

get the gsl rear endnd hubs, or convert everything to se hunbs and u can have bigger brakes too

Hades12

Get an SE rear and swap it in.

Crit

iTrader: (6)

Don't go with the SE rear unless you really want to change your bolt pattern, junk your current tires, buy the whole setup (wheels, tires, front suspension) as well as the rear axle.

If you go GSL, you'll need to swap your rear end and parking brake cables.

If you go GSL-SE, you'll need to swap your rear end, front spindles, wheels and tires (the tires are by far the most expensive part of the swap)

GSLs are more common, have a better LSD unit, and will make your life much simpler. Having a GSL-SE suspension sounds nice, but doesn't make sense unless you have access to the whole setup cheap AND you need to buy new tires for your car anyway.

justint5387

iTrader: (1)

If you get a SE rear end, you will get the more popular 4x114.3 bolt pattern. If you want to keep the wheels you already have, get the GSL rear end, they have LSD and disc brake also. Doesn't matter which rear end you swap in, you need to get the ebrake cable from it. The GSL-SE rear end has vented brake disc in the rear, so it gets better cooling.if you do the GSL-SE rear end swap, you should also do the front brake swap also, because you want to have the bigger brakes in the front and matching bolt pattern. If you want to swap the SE front brakes, you just need the backing plates, calipers, rotors, and pads off the SE and it should bolt up.

Crit

iTrader: (6)

By the way, if you DO come across a junkyard, most have preferential pricing for a full spindle with hub, caliper and rotor as a bundle, plus it's less work. If it were me swapping an SE suspension, and I've been in the same position once before, I'd just take the strut top nuts loose, remove the steering knuckle bolts, disconnect the brake line, and take the whole chunk. Usually easier and cheaper, but your results may vary.

Kentetsu

I swapped a GSL rear into my 85 GS this year. Wonderfull results. Better brakes that don't need much attention to keep working right, and the LSD makes the car a blast to drive. Well worth the effort...

warwickben

iTrader: (1)

wow i was hopeing this would help me out but got me more confused then befor.

i have a 1980 sa that has the stupid 4x110 bolt patten, i dont mind dealing with that,

i found a set of bigger rims that i like and there free .

if any one is willing to explain/make a list of all the parts i would need to convert to rear disk brakes hit me up with a pm or post on this thread. please can i do it with out getting a new rear end

Crit

iTrader: (6)

Well, you've got a different thread pitch at the rear of your car than the FBs, so you can do the same thing and swap a GSL rear into your car, but you'll need to order up a rear brake line. All you need is the rubber line that goes from the rear hydraulic circuit, on the pumpkin of the rear end, and connects to the body, just above the diff. RB, Pineapple, Mazdatrix, etc all know how long and what threads you'd need. Everything else should be a bolt-in swap, provided you take the parking brake cables from the donor car as well.

BTW, and this is a question for everyone, will his small-bearing driveshaft bolt up to a big-bearing pinion flange? I've never thought about it, and it would be the only hiccup that I can think of. If it IS a problem, then you'll just need to find a small-bearing GSL rear end. If it's not, then any GSL rear would work.

justint5387

iTrader: (1)

You will need the bigger bearing driveshaft to swap the bigger bearing rear end, if your car has a smaller bearing one. If you car has a smaller bearing driveshaft, it will bolt up to any smaller bearing GSL rear end.

K-Tune

iTrader: (26)

i have a rear disk setup for 85. axles, rotors, calipers.

warwickben

iTrader: (1)

thanks, for the info. its going to be tuff for me to find the parts around my neck of the woods. damm new england. i talked to a bunch of junk yards and they all said pretty much the same thing they sent there 1st gen rx out for scrap metal.

MosesX605

I did this swap a couple years ago now, here's what I did:

Scored myself a complete GSL rear end out of an '81, which means that I didn't have to swap driveshafts and the rear end assembly is a good 50 pounds lighter than the '84 and up units.

HOWEVER...

If you get the '84 and up, you can also get a Torsen down the road that will bolt into your rear end and the assembly is stronger and generally more durable than the old small axle/bearing unit.

Anyhow, so I scored an '81 axle assembly, including the calipers and the parking brake cables. I replaced all the hard and soft brake lines, the rotors and rebuilt the calipers. The hardlines were all done by hand with a brake line bender and some patience, but it's a worthwhile task as sitting in a boneyard for years was not kind to lines and they were nearly corroded through in some places. In order to mate the coarse-threaded brake line on the chassis to the find-threaded brake line on the axle, I constructed a coupler, using one of the old coarse-threaded ends from the discarded '79 axle and a short length of new hard brake line with a fine threaded end. This was mated to the Y block that joins the two rear brakes together so that I could use the flexible axle to chassis brake line from a '79 to make the connection.

I didn't change the master cylinder nor did I change the proportioning block. Some people say that you should, because the drum cars ran slightly higher rear brake pressure than the disc cars, but I've driven the car for three years in both street and competition and haven't found a problem.