scathcart

There are a lot of threads out there on the 929 master cylinder, praising its results: the majority of these represent installations in FD applications.

Several threads in this subforum describes how great and easy it is to mount a 929 MC onto an FC, but all of these threads read the same way:
"I've HEARD that all you need is to bend a new brake line, use a MC from a 1993-up 929, and you need a S5 brake booster."
It seems that next to no one has actually tried this despite all of this. One of the cars I am working on needs a new MC, so the owner bought one for a 1993 929 for me to install.

Now its time to clear up some of the myths on this board.

The 1993 929 MC, whether ABS or non-ABS version, only has two outputs. The rear fitting is a flare fitting, the front only fits a banjo bolt. This MC will NOT bolt onto an S5 Master cylinder; the pushrod is much different, and uses an o-ring seal, unlike the S5's.


In searching, it seems the only people to actually accomplish this mod have been S5 TII users.
This makes perfect sense, as the S5 TII uses a completely different brake booster and master cylinder design from the rest of the FC's. The S5 NA master cylinder is swappable with the S4's, so the brake booster must be of the same bolt pattern and rod extension, so I don't know here this "S5 brake booster is vastly different" myth came from.
Whether or not the 929 Master cylinder bolts up to the S5 TII brake booster is yet to be determined, but of this you can be certain:

The 1993-up will NOT fit a S5 NA , S4 NA, or S4 TII brake booster. Looking at the parts fiche's, it sure looks as though the 929 cylinder will bolt right up to the S5 TII brake booster, but I cannot confirm this. Also, the main plumbing off of the master cylinder is greatly different, requiring a banjo fitting to be installed, and a tee fitting plumbed after the proporting valve.

I have no idea if a 1992-prior 929 MC will fit, but I think I will be going a different route with the MC anyway.

Black91n/a

Good to know, thanks for the information.

vipers

iTrader: (8)

thanks for the info... i have a s5 t2 master and booster sitting in my backyard, so ill have to "buy" a 929 master, test fit it..then return it just to confirm whether it fits or not.... (on the booster).. im not gonna touch rebending the lines to fit.... ill try to do this sometime next week when i get some time.. unless someone chimes in who has actually dont this before.. not a " i know someone, who knows someone, who shot someone that did this before"

scathcart

The problem with just rebending a line is getting a banjo bolt fitting on there. I think the ABS systems used banjo fittings that you could grab the fitting from.

drft_180sx

THANKS SO MUCH! you just saved me a whole bunch of time, as because i was searching for the parts of this "myth" upgrade.

ilike2eatricers

I have an S5 TII running a 929 MC already. Been running this for a year now and great results at the track. If you search for my posts I explained what needed to be done.

Juiceh

iTrader: (4)

So this would work on an S5 convertable too then? Since the convertables share the same brakes system as the TII minus the ABS.

run_rabbit_run

ilike2eatricers: through reading previous threads, it was assumed that this swap was possible S5 TIIs and FDs (as there were reports of it being done)...however, there was no mention of the N/A crowd.

Now we know.

Juiceh: good call on the convertable brake system. Can anyone confirm this?

ilike2eatricers

I was just responding to this part of his post

run_rabbit_run

gotcha. i think he was referring to what he had found himself (not having a S5 TII booster to test it on)

Black91n/a

In the FSM it lists different brake boosters for the NA and TII cars. It is NOT dependant on the calipers, it is purely dependant on whether or not it's a factory turbo car. ALL NA's, 4 pot and single pot got the smaller MC and it's associated booster. I saw no mention of the vert in there, so I'd assume it's got the normal NA setup, unless someone can confirm otherwise?

RotaryResurrection

iTrader: (8)

No, the MC is still a standard one. Only ABS cars got the funky master and booster which he is saying works with the 929 MC.

I know of a local guy that tried it on his 10AE and did not suceed either. I have never bothered to check, personally...I have never found a properly working stock brake setup to be insufficient.

E_Dub

I agree with what you said^ From my experience, the boosters and mc are all the same (with exception to the abs boosters and mc) I know this for a fact for all s5.

E_Dub

I agree with what you said^ From my experience, the boosters and mc are all the same (with exception to the abs boosters and mc) I know this for a fact for all s5.

Black91n/a

I can see how the larger TII MC and booster would be worthwhile on a car with the 4 pot calipers to give shorter pedal throws and a firmer pedal, but I can't see how going as large as a 929 MC would be worth the trouble with stock brakes. When I need a new MC I'll probably just upgrade to a TII MC and booster.

Where I've seen it for the FD's is where it's used in conjunction with bigger brakes and bigger calipers that need more fluid and have more leverage. The larger radius and pad area can make them touchy and grabby at low pedal efforts with the stock MC. The 929 MC helps with that and it pumps more fluid to satisfy the big calipers so that the MC won't bottom out. It gives better feel and higher pedal efforts.

I suppose a larger MC could also help keep the pedal from sinking as much when fade happens, allowing more fade to occur before it becomes a serious issue.

ilike2eatricers

You hit all the nails on the head. Installation of the 929 MC wasnt too difficult. I'll outline it briefly here for anybody searching (this is all off the top of my head so I may have left out some small details).

Installation
-929 MC unit itself is direct bolt on to S5 TII booster
-you'll need 2 banjo bolt->1/8" flarenut adapters (can be found on FD/FC ABS units)
-you'll have to fab or bend the stock brakeline which is fairly simple and cheap (few bucks for short length of brakeline with flarenuts already on them)

Adjustment:
-basically you'll need to play with the adjustment of the piston rod that pushes the cylinder because the stock S5 TII master cylinder is 15/16" while the 929 is 1" (pushing alot more fluid in a shorter time/distance of travel). Easily done with a wrench to loosen the locknut and then you just turn the rod. Takes a bit of time to test and see where you like it best. Issues that came up with this were some freeplay in dead pedal because brakes engaged or dragging brakes. If you take the time to adjust it until it's just right you'll have neither of these issues. Brake pedal does take some getting used to after but it's been a great upgrade for me and helped alot with brake fade at the track.

run_rabbit_run

anyone know of a larger diameter MC that is compatable with a S5 N/A booster?

Roen

iTrader: (2)

I'm probably bringing this thread back from the dead but I'd still like to find out how to adapt the 929 MC to NA FC's. Is there away to swap the turbo brakes onto the NA platform and then switch out to the 929 MC?

Juiceh

iTrader: (4)

You need an S5 TII brake booster. It is the ONLY 2nd gen brake booster that the 929 MC will work with. The s5 TII brake booster can be swapped into an NA FC. Some new hardlines will have to be fabricated too.

HotRodMex

iTrader: (3)

I might.

I'm glad this got brought back form the dead as I am in the process of doing this modification (I wouldn't really call it an "upgrade," but that's a discussion for another day) on my newly aquired Vert. I have experience with doing this type of modification, seing as how I did it to my 89 MX6 (using an MC from a 93-97 626 4cyl base, W/O ABS, manual...yes it had to be that specific) and again on my girlfriends 90 Montero (using 92-97 3000GT MC).

The MC in question would be the same one I used on the MX6. If everything lines up like it's looking to, then all that it would need is a $3 brake line. My Roomate has to get his FD out of the garage and then I can begin, but trust I will post with the results of the project.

scathcart

I found a larger bore master cylinder that bolts directly on, and offers a greater pedal feel than even the 1" 929 cylinder. Some simple brake line work, and you're good to go.

I just like secrets.

ilike2eatricers

how much larger?

scathcart

1.03" compared to the stock 0.875".

Roen

iTrader: (2)

Will you share where we can obtain this master cylinder and corresponding brake booster?

scathcart

No. I'm a jerk.

Brake booster is any stock RX-7 brake booster, except for the S5 TII brake booster.