Just bought a 90GTU with 72k miles on it.

Got a screaming deal on it (at least for where im located).

Car is in very good shape, this is the 2nd rex ive owned. I had an 87 SE 1st couple years of college.

I did a search on this but didnt find the specific info I was looking for.

I want to convert the brakes to the 4-piston setup.

Since this is already a 5-bolt car what all is reqired for the conversion.

I plan to order a brake upgrade kit (x-drilled rotors, performance pads, all around, and new braided lines).

I will also be ordering a full set of remanufactured unloaded calipers.

Do any other lines need to be changed? Does the master cylinder need to be changed?

Thanks in advance fore the help!!

 

Bump (can anyone help me)

 

You need the proportioning valve from a car that has the 4-piston setup. It's the little silver thing next to the master cylinder, that has brake lines going through it. Without it (I was told), your front-to-back braking, uh, "ratio" (how much pressure goes to the front brakes vs. to the rear brakes) would be different than it should.

 

i've done the swap, here's what you need:

- the calipers & brake pads (the pads are diff from the single piston ones)

- the short hard line for the brake fluid (single piston brakes have a rubber line all the way...if you get braided lines, you still need this hard line)

i didn't change my master cylinder and i haven't had any problems (although i'm sure it wouldn't hurt if you did).

if you are getting a brake upgrade kit, it's important to note that while the front rotors are the same if you have 4 piston or single piston brakes, the rear rotors are different.

4 piston brakes had vented rear rotors which are NOT compatible with the solid single piston rear rotors.

 

shouda got a GXL mine already has the 4 piston brake stock :p

 

He cover it all up, however on mine; I never changed the solid rear disc, in fact all rear calipers are the same

 

yea i thought all rear brake calipers are 1 piston

 

i believe they're 2. i think the second gens have fixed calipers all the way around, which means a piston is on each side whereas sliding calipers only have them on one side.
am i right on this ?

 

I just took off the whole spindle with everything on it and swapped it like that

 

OK

I finally got around to doing this and doing more research so I thought I would do a short writup.

This is only dirrectly applicable to single piston solid rear rotor S5 cars.

Started with a 90 GTU, single piston setup. Solid rear disks.

What is needed minimum for the swap.

1. Front 4-piston Calipers (I recomend using remanufactured and either paying the core, or if you can find a set of junk ones for cheap and send them back as cores that is what I did payed 10$ to get 100$ back in cores)

2. Front brake pipes: (hard line mounted to the calipers) They are about 12$ each from Mazda, worth it for new in my oppinion.

3. Vented Rear brake rotors: (I would recomend an upgrade on all 4 rotors especially if you plan to spend any time at the track) cryogenically treated brake rotors either blanks or sloted rotors are best. X-drilled ARE TOTAL CRAP for track use. I cracked one in less than two sessions (not days, 30 min sessions). For great cryo rotors visit www.frozenrotors.com.

4. Rear Brake caliipers: (The 4 pistion cars have vented rear rotors and the rear calipers are different vented rotors vs non-vented)

5. Front pads: (i would do all 4 wheels at once and do an upgrade to whatever suits your needs, track, autoX, street/strip)

6. Front brake calipers hardware kit: (enough for both sides) almost any auto parts store can get these. This stuff does not come with all remanufactured rotors so you will need it and it is good to have a couple extra kits around.

7. I belive you can reuse all of the rubber lines but I upgraded to stainless steel flex lines and ordered the ones for a 4-piston car.


Again my S5 already had the 5-lug setup so I was half way home over a 4-lug S4 car.....

All of this stuff save pads you could get from a boneyard donor car. I did not do this because I have never had any luck with used hydrulic parts and just end up sending them in as cores after purchasing remanufactured ones.

 

Can I get an Archive?

 

Hey, what are you gonna do with your old single piston calipers. I'm in Mankato, and my rear calipers are all crapped up. Don't throw them away.

Someone had mentioned that all single piston rear calipers are the same throughout the years. I have an 86 that I'd like to put your calipers on, if they work.

 

This is a rotary forum and talk of pistons is not allowed. Why settle for 4, 8 would be better :-)

 

Dude, read the thread, it's about brakes.

 

Correction to #6:

Front brake Hardware does not come with all remanufactured front brake calipers. (not remanufactured brake "rotors")

 

I converted my 87 Base model to the 5 Lug hubs and 4 piston calipers and did not change the proportioning valve. have absolutely no problems with the brakes.

The rear calipers are all Single Piston. There is a difference between the vented and non vented Calipers in the rear.

I think I paid $200 from a salvage yard for everything required to upgrade to the 5 lug with 4 piston calipers. This was about 9 years ago though.