terryks

Hey,
Going to be swapping the suspension and rear axle from my 85 SE parts car to my super clean 85 GS. Any How-to's around that someone may have put together? From what I have read, my 85 GS should be one of the easiest models to swap it into. Any advice or tips appreciated.
Will my GS master cylinder work? Porportioning valve? Brake lines etc?

Rogue_Wulff

I'm sure there is a writeup floating around. As for the master cylinder, the drum brake models have a risdual pressure valve in them, for the rear brakes. This can be removed easily, or the SE unit can be swapped. The proportioning valve on earlier models was the same part number, whether it was a drum brake or disc, according to the parts ficsh I have. The lines should be the same, up to the rubber hose from the body to the axle, which will need to be used from the SE. Park brake cables will aslo be needed from the SE.
I believe the spindles are the same for all 84-85 cars, which simplifies the front swap. Rotors and calipers/mounting brackets are all that is required, if I recall correctly.

terryks

Thanks!
Hopefully someone will post up a how to if there is one floating around.

Blake

I'm not sure a write-up is even necessary. This is really one of the more simple things you can do. Lots of heavy lifting and large fasteners, but simple and straight forward. I will offer some tips, however.

First, make SURE the -SE rear end is serviceable. A lot of times, someone will install something and then find out it was junk. I have done that myself, just because someone said it was good when they sold it to me. Anyway, drain the fluid and take a good look at it. Is is glittery metallic? Any metal chunks? Does is smell burnt (not just the normal rotten egg smell of gear oil)? Is it foamy? If you have ANY doubts, pull the pumpkin and inspect the internals. Look for chipped or broken teeth, unusual wear, cracked caps, etc. Measure backlash and pinion seal drag if you can. Look at the axles while they are out and perhaps change the bearings. If you can't do this, then see about taking it to a friend (or shop, if necessary) that can. You are probably okay trusting in the honesty of the seller, but I've been burned too many times to even think about installing something without an inspection. The same holds true with engines, trannies, etc.

Next, be sure you have the e-brake cables from the calipers to the clevis connection. This is about 18 inches or so, and there should be some rubber bulkhead grommets where they run through the framerails. If you don't have them, the drum brake cables will not work; you need disc brake e-brake cables. These are sometimes a PITA, but bear with it. You might find it easier if you loosen the adjuster at the e-brake handle. Obviously, the e-brake handle should be down.

An impact gun is very handy. At least have a stout 1/2 inch breaker bar. You can get away with just large box wrenches, but you still need a backup wrench and it makes more sense to buy one box wrench and one socket than two box wrenches the same size...more flexibility, less expense. Anyway, you will want 17mm, 19mm and 21mm at a minimum. It may help to know that 19mm equates closely to 3/4 inch and 21mm is basically 13/16 inch. 13/16 is the same as your wheel nuts and spark plugs, so you might already have something in the tool bag.

Pull the rear shocks completely out; don't just disconnect the bottom. It only takes 5 minutes more and will save you 30 minutes later.

Clamp the brake lines so you don't drain all the fluid out of the MC. Once you get an air buble in there, your life will suck. You can buy specialty clamp wrenches, but angle-needlenose vicegrips work great if you grind the jaws smooth. These also come in handy when you work on fuel and/or coolant lines. You only need one.

That's all I can think of right now.

Buffumguy1

Yep pretty much has been said. I just did this swap in an 84. Worked out well. I did swap the whole spindle assembly in the front, maybe not necessary, but it helped to clean up the parts. I'm back on the road. Car is much cooler with the new wheels and tires that the SE bolt pattern allows. Good luck and post some pics when done.

84RX7'nSTi

Crap, I did not do this during my swap some months ago. Where is this pressure valve located on the master cylinder? The car seems to brake fine with it installed thus far. However, I would rather swap it out if it is recommended.

Regarding the swap, it is straight forward part exchanging, but takes some time to finish the job. I swaped over the complete front strut assemblies to make it easier. The complete rear end took time and power tools make the job easier, as well as an extra hand. I however, did not swap the rear shocks, but I can see how this would save time and make the job easier. The parking brake cables were the biggest PITA for me.

Mike

trochoid

iTrader: (6)

A little heads up in installation. If the control arms are off the body, connect them loosely to the rearend first. Set the reaend on a floor jack, roll it under the car and connet the lower controlarms first, then the upper, finally the watts link arms. Do not tighten down any of the suspension bolts until the car is sitting on the ground. Check that the rear end is centered under the body, then tighten the suspension bolts.

Everything else can be tightened while the body is still on jackstands. Do the control arms and watts link last.

Rx-7Doctor

iTrader: (13)

Alittle correction to Blakes otherwise proficent write up.

You will need the e-brake cables off the Se, i know the ones up to 83 off disc brakes will not work. I do not know if the 84-85 disc brakes ones are the same as the Se or not.
As far as clamping the brake hoses with needle nose vice grips. I do not recomend it. It can damage the internal wall of the hose and cause it to collapse. Recommended to use the appropriate clamps deisgned for that usage.. As far as bleeding goes, if you purchase speedy bleeder screw it won't make any difference if there is air in the system. They are one way bleeders and it makes it so much easier to bleed brakes.

Something that you guys have overlooked on the swap. If you are not upgrading springs on your car and are using the existing stock ones when you already have the larger spindles. You will be losing out on the stiffer springs that the Se's came with. Also the Se struts are stiffer, but won't make any difference if you are upgrading.
Also on the rear the springs are taller and stiffer, so if you are not upgrading at that time it would benefit you to use the complete swap over components. The shocks of course on the rear are all the same.

Rx-7Doctor

iTrader: (13)

Alittle correction to Blakes otherwise proficent write up.

You will need the e-brake cables off the Se, i know the ones up to 83 off disc brakes will not work. I do not know if the 84-85 disc brakes ones are the same as the Se or not.
As far as clamping the brake hoses with needle nose vice grips. I do not recomend it. It can damage the internal wall of the hose and cause it to collapse. Recommended to use the appropriate clamps deisgned for that usage.. As far as bleeding goes, if you purchase speedy bleeder screw it won't make any difference if there is air in the system. They are one way bleeders and it makes it so much easier to bleed brakes.

Something that you guys have overlooked on the swap. If you are not upgrading springs on your car and are using the existing stock ones when you already have the larger spindles. You will be losing out on the stiffer springs that the Se's came with. Also the Se struts are stiffer, but won't make any difference if you are upgrading.
Also on the rear the springs are taller and stiffer, so if you are not upgrading at that time it would benefit you to use the complete swap over components. The shocks of course on the rear are all the same.

Blake

How are they different? Length? Clevis? I will admit I have never swapped an SE suspension without the SE e-brake cables, so I speak subject to correction. I have done non-SE disc brake swaps into 12A cars, as well, but they looked identical to the -SE cables. I have both SE and non-SE disc brake rear ends in the shop right now, so I'll go take a look when I get a break...

I disagree. Properly *modified* vice grips with the angled needle nose head function no different than hose clamp pliers. I've done this for years and I learned the trick from Rob Golden, who was a Mazda dealer shop foreman for 10 years before he started his rebuilding business. Obviously, you have to be carefull, like with anything you do, but it's not remotely harmful if done right.

Speed Bleeders are awesome, but they will not do a good job of pressure bleeding an MC with an air bubble in it. A bad bubble inside the MC is not very likely, but when it happens you will never want to risk it again. Getting one often requires removing the MC to bench bleed it, or half a day of pumping the pedal. Speed Bleeders, in this case, are worse than standard bleeders and an assistant to open and close them. The Speed Bleeders require a relatively high pressure differential to overcome the spring closing the valve, and compressing a column of air may not do the job or at least make it harder. I love speed bleeders for normal use but they are not much good for dealing with air in the MC. As a rule, I don't like to risk anything when prevention takes 10 seconds. Just my $0.02. Your mileage may vary.

Rx-7Doctor

iTrader: (13)

The lenght of the cables are longer on the Se.
As far as the vice grips they exert too much clamping pressure which can rupture the reinforcement in the hoses. Standard clamps which are generally either the twist type that pinch off the hoses or pinch off pliers do not exert the pressure that vice grips do.
And you are correct if a air bubble gets in there it is a PITA to get out. However if the bleeders are just dripping from normal pressure and you do not press on the pedal before reassembly and do not allow the master cylinder to empty you will not have an air bubble.
Just my experience from working on cars for over 30 years.

Midwest 7's

iTrader: (4)

im pretty sure all the disc rear ebrake cables are the same. why would the length change?

Rx-7Doctor

iTrader: (13)

They are not the same!!!!!!!! Ok, lets theorize this. Why are they longer? Larger diameter rotors means that the calipers sit further outwards from where a non-Se rotor would fit. Meaning that they (cables) would have to be longer to attach properly.

Blake

I won't disagree about the possibility, but I do disagree that it is inevitable. You can exert as much or as little pressure as you wish. If the angled needle nose plyers are modified (ground smooth and slightly rounded) and you are careful not to over-clamp them, it is perfectly safe. Again, just my $0.02.

Midwest 7's

iTrader: (4)

i dont know much about therorizing but i do know that i had se cables sitting on my shelf for months and i put some from an 81 gsl right by them and there was no difference. surely those couple mm in difference can be adjusted by the hand lever.

Kim's FB

Good info, and just when I need it. I stil have a gsl-se in the garage waiting on me to drop the suspension. So the fronts I only need the rotor, caliper, and caliper bracket? That's sweet if that's right. Or would it be easier to swap out the whole assembly?


Hey guys, the right tool for the right job:


But a girl didn't just tell you that. hehehe j/k

Blake

The GSL rear ends in the shop both had cut parking brake cables (they were from a junkyard), so I could not compare them directly, but I did verify that there are three part numbers in the Mazda system. One for drum brake models, one for GSL and one for GSL-SE, so it would apprear there is some difference. Whether that difference is significant or not, I cannot say. The best case is that it is within the adjustment range and the worst is that you lengthen or shorten the bare wire portion under the car as necessary and re-swag it. Stuff like this is minor.

Midwest 7's

iTrader: (4)

i dont think it is because i had got the cables all mixed up since i thought they were the exact same. then i sold the se rear end to my friend and gave him a couple cables from the pile and they worked flawlessly. unless he by some coincidence got the 2 se cables i think they are the same. they sure appeared to be the same.

Rx-7Doctor

iTrader: (13)

again, they are not the same. I have done numerous se swaps the se cables are longer and there is no adjustment that changes that. I have tried with gsl cables, they are too short. I have had them side by side, end of story.

Buffumguy1

I'm also interested about this. I just changed over the dist. block by the master cylinder. Do I need to change more?

Siraniko

iTrader: (13)

This is just my experience with swaps.

SA conversion: need complete front and rear end (disc to disc) along, e-cable, brake lines, proportioning valve and master cylinder. KEEP the SA brake booster as the FB ones wont fit. Actually it will be you will need to relocate the clutch master. I took the complete brake lines so I dont need to shorten/reflare the front brake lines due to different thread pitch. Besides, we have plenty of donor in Socal junkyards.

GS conversion: front and rear plus e-brake cable only.

I've done both upgrades many times with no problem. My last conversion is my 84 GS with 85 GSL upgrade. With the e-brake, I only swapped the end cables which goes thru the frame.

terryks

Thanks for the wealth of info guys. I may have been misunderstood in my first post. I am pulling all the swap parts from a complete SE that I have. I will use the SE cables.

dbragg

iTrader: (7)

one question.

i was told on months ago that i couldnt take my spare GSLSE axles and instal them in my 84 GS rearend. they said the drum axles mounted differently than the disc axles. i never checked as it was just a way for me to get a spare SE axle.

is it possible for terryks, or anyone else, to put the SE axles in a drum brake rearend housing?

personal experience is great

Rogue_Wulff

The residual pressure valve in the M/C is located under a large hex-head plug. This can be on the bottom or side, depending on the various years.
Removing it is simple. Remove the plug, and a spring/plunger will come out. Set the spring/plunger aside, and put the plug back in, and rebleed the system.
All this valve does, is maintain a slight amount of pressure to the rear brake cylinders on a drum brake setup. Even with the valve left in the M/C, you will not notice any ill effects with the disc brake rear. The amount of pressure maintained by the valve is a very minor amount, and basicly just keeps the rear wheel cylinders from contracting too far.

Rogue_Wulff

If I recall correctly, the drum brake setup uses 4 retaining bolts, while the GSL disc uses only 3. Even the housing is different between S/GS drum, and the GSL disc.
I also believe the SE axles are a little longer than the non-SE, along with the housing being wider on the SE.