jcosta

I have been rebuilding my 88 Anniversery ed. and I am now moving onto the brakes. They have always been a little weak so I have been reading about replacing them with some 4 piston calipers.

I noticed on Mazdatrix that rebuilt 4 piston calipers for 1 side is $480 BUCKS!!! WOW!!

I saw a pair of used ones which look like they are in pretty bad shape for $60 but then I can get a rebuild kit for $32. I have the time so would you guys recommend I go that route? It would also give me a chance to get them painted.

I saw a few posts about rebuilding them and painting them but they are so old all the pics are gone!

Thanks for the advice!

SleepeR1st

iTrader: (1)

I dont mean to hijack your thread, but how good are the TII brakes really? Obviously i tested mine myself, but in terms of other vehicles, is it worth it upgrading the calipers or just going with slotted rotors?

jcosta

I don't mind! Hijack away . I would like to know the answer as well. I have heard that slotted rotors will make you burn through pads faster.

I also have a TRD Matrix and the brakes in that car are 10 times stronger than my Rx-7 and the rears are drums. I know the matrix is much lighter but the brakes in my Anny have always felt a little weak to me. The pedal is soft and the stopping power just doesn't seem to be where I believe it should be so I figured why I was at it I would upgrade the cals.

farberio

iTrader: (7)

Alternately you can calipers as cheap as you want, and get reman'd ones from (insert car place here) for around $100 each.

farberio

iTrader: (7)

Unless you feel you have an absolute need to upgrade the brakes you don't need too. Most people don't surpass the TII brakes.

kungfuroy

iTrader: (6)

uhm if you have a real 10thAE, they come with 4 piston front calipers stock.

jcosta

Well if that is the case then, DUH, I feel dumb!

It sat still for about 4 years. I just had the engine rebuilt and it has probably been 5 years since I changed out the pads so I couldn't remeber but I didn't think it had 4 piston calipers.

Guess I will just rebuild and paint!

Thanks

Icemark

If the brakes are soft, chances are either the flexible lines are worn and buldging (or are SS) or you have air in the lines or calipers.

Bleed the old brake fluid (which should be done every 2 years anyway), first and if that doesn't work, replace the flexible lines with new rubber ones from Mazda.

Black91n/a

CHANGE THE PADS! That can be a BIG cause of weak feeling brakes if by weak you mean poor stopping power.

Also, unless you can tell me the last time you changed your brake fluid was within 2 years you should give it a good flush and make sure there's no bubbles in it. Also, replacing all the lines with either new stock lines or get some braided SS lines will help give a firmer pedal. Also, build yourself a brake master cylinder brace, it makes a world of difference.

You can get rebuilt calipers from your local parts store for a lot less than from Mazdatrix, or you can probably get a rebuild kit there too and just rebuild your own calipers.

I have effectively the same brakes you do, but with a smaller MC, and my brakes feel as good as or better than my uncle's Porsche Cayman S. The problem isn't that you need to upgrade, it's that you need to do some maintenance.

https://www.rx7club.com/2nd-generation-specific-1986-1992-17/how-diy-brake-master-cylinder-brace-718744/

lastphaseofthis

iTrader: (8)

i though stainless steel brake lines are to replace the rubber lines that over time bulge as you said, are ss not an upgrade???

Icemark

SS are fine if you are racing and replace them every race season, but most people using them on the street don't.

I have consistently seen SS lines fail, or leak within 2-3 years (some in less than a year), yet the factory rubber hoses I have seen last 20 years with no leaks.

IMO, SS flexible lines are not an upgrade. When you look at how much more they cost than the factory lines, and how often they fail, that alone rules them out. And the majority of the people that say they give better brake feel, are the same kind of people that had crappy worn out lines or never bled their old lines, or claim that wiring open your aux ports gives you more power.

lastphaseofthis

iTrader: (8)

well said!

driftinfc

this is probably the most direct bolt up swap you will encounter with your fc. besides the 4 piston calipers the only other things needed are the 4 piston brake hoses and a brake line to complete the connection between the 4 piston caliper and the brake hose. i would recommend using the rubber oem brake hose instead of a stainless steel hose. rubber wont rust like the ss lines do.
you can pick up brake lines at any auto part store. theres only one small problem you might run into. one side is a metric thread while the other is a 3/16ths standard so you might need to special make it. just buy two lines one with metric threads and one with the standard thread and combine them.
the other thing i would recommend is new rotors. the rotors are the same between the two set ups but rx7 rotors are not recommended to be machined and keeping the old rotors on will cause the pads to wear more rapidly. mazda did design the rex with an aluminium hub and steel rotor which is two metals that chemically bond.

driftinfc

sorry ps3 wouldnt let me type all in one box. they chemically bond when exposed to excessive heat. so some cutting and prying might be in order. but you can also prevent this from happening by applying anti sieze around each hub before installing the new rotors.
if you have any other questions or need more in depth explination on this job just ask. also i purchased my calipers at advance. auto zone has a loan a tool brake line flair and cutting set so you can make the lines for free, but advances lines are easier to flair *hint *hint. and i got the hoses next day from the dealership. they were the most expensive part but still less than 80 for the pair.
also the breaking gained from this upgrade in my opinion was phenomenal and i was very happy when i was finished a road tested it. the only other thing is i had to purchase an additional anti rattle spring set cause the ones that came with the calipers was missing one and they were squeaking like hell before i got the additional pin that was missing.

DavidHolmesIII

4 pistons are just in front right?

farberio

iTrader: (7)

Correct.

jcosta

Well I replaced the fluid. The pads look very thick but they are pretty old. Like I said it sat still for a few years. I also did the brace from the post Black posted. That seemed to help a little but they still feel to spongy. Could I need a different set of pads. They are old and I am sure when I bought them I just bought some generic off the shelf pads. Will that make a big difference?

Thanks!

rx-711

iTrader: (2)

definately do a rebuild on them it is simple and cheap

Rx7Ridah

iTrader: (8)

i would verify that all the brake calipers are moving freely. removed the caliper from the knuckle, then insert a piece of wood (like a 2X4) in the middle and slowly have an assistant press the brake pedal. all the pistons should move inward toward the 2X4 at the same rate. you need the wood in there to stop the pistons from completely blowing themselfs out of the bores. one of my rx7s had sat for about 9 months and the 2 pistons in each one on the front were frozen, and both of the backs bound up. rebuilds run about $75 from local parts suppliers (advance auto parts, autozone, kragers, ect) for the front and i forget on the rears. it will make a huge difference when everything is working right. also plan on bleeding all the brakes and check pads for even wear and rotors for warping or pitting/grooving. you may just wind up changing it all.

Hybrid G

iTrader: (4)

ok just to clarify

The refgualar 1988 TII comes with 2 piston calipars

The 1988 10th ani TII comes with 4 piston

Is this correct?


hybrid

farberio

iTrader: (7)

No, all TII's come with 4 piston front brakes. There is no such thing as an OEM 2 piston caliper.

jcosta

Your saying the rebuild is $79. Is this the same kit you used?

http://www.partsamerica.com/ProductD...pe=223&PTSet=A

I am also going to swap out the rotors. I didn't realize they were so cheap. $30 bucks for vented rotors and $20 for the back.

http://www.partsamerica.com/ProductD...pe=221&PTSet=A

pfsantos

iTrader: (1)

Another thread to loose all the noobs in confusion...

The 86-88 GXL's, 87-91 TII's (TII's started in model year 87), and 88 10th Anniv. all had 4-piston calipers up front, and single piston calipers in the rear that accomodate *vented* rotors. In 89-91, all FC's were 5-bolt, but only TII and GTUs had the better brakes.

Just to clarify, the four piston calipers have two pistons pressing on either side of the rotor. All other calipers (front and rear) have single piston "floating" calipers. Floating because as the piston pushes out, the caliper moves in thereby pressing the outer pad against the rotor.

edit: OP, as said, change fluid, clean things up, have a good look at the caliper, brake booster/vacuum line, and check the calipers for seized pistons (that's where I'd put my money). If you need to rebuild them and you don't have experience, just buy rebuilt ones if they come with a good warranty.

pfsantos

iTrader: (1)

^^ rebuilding isn't too hard, but add in the sometimes needed cost of pistons if they're bad, and smoothing out the bores if needed. Sometimes a caliper is just not rebuildable. Having said that, if it's not your DD, and you have time, could be a learning experience. But make sure you know what you're doing or have someone who knows give you a hand, since these are brakes we're talking about.

jcosta

It makes sense to just buy rebuilt. I found some remans for $48 for the front and $29 for the back. That is only $28 more than the rebuild kits I found.

I forced all 4 pistons out on the front left and then pushed on the brake to see if they all came back out. The all came out evenally but I had to mash pretty hard to get them to fully enage.

I am just going to bite the bullet and replace the lines, calipers and rotors and that way I won't have to worry about it for a while.

I have K&N shocks and Eibach springs. The shocks in the back are adjustable. Some of the reman calipers mention stiff suspension or adjustable. What do they do to the caliper that would make a difference?

thanks again!