Alright I searched awhile back and an 1980 pontiac firebird master cylinder with four wheel disc(since I have four wheel disc on toy axles now with toy calipers front and rear) was the right choice. I also remember something about a hole you have to plug with something which seems like a pain in the ass to do. There was an upgrade that was just like the 1980 which doesn't have the third hole but what year?
Now to my point you can search but when you stand in front of the parts guy at Napa you can still say something dumb like 1987 pontiac firebird master cylinder with four wheel disc. I got the master cylinder in and it looks like it will bolt up with a little hogging of the holes and has no third hole. Is this the better one to use or take it back for the 1980? Are the specs or throw of the piston different then the 1980? I got a bunch of people coming by today and need to get some stuff done quick if at all possible. HELP!

i think the main importance is the size of the bore;1 3/16",1 1/4",
and you will need an after market proportioning valve for to adjust the rear brakes;jegs or similar ..

so these master cylinders of which you speak, they bolt up to the sammy brake booster? cuz I need something more, and didn't know which one to get. I'm less concerned about hogging out the mounting holes and more concerned with the middle of the thing fitting snugly inside the brake booster for a good seal.

I run that same M/C and mine works great. I had to plug that hole up with some kind of puddy that hardens like steel after it dries. Can't remember the name of it but I remember it used to hiss before I plugged it and now it doesn't.

you need to slot the ears that bolt to the booster (must be a pre 88.5 booster) and the hole that needs to be block is done easily with a tap and a set screw
other wise it fits nice and works great
http://www.zuwharrie.com/gallery/albums/userpics/10186/19.jpg

so these MC's fit right into the sammy's booster? a good tight fit?

yes

I bought a 80 firebird MC for a 4 wheel disc car and it had a tiny little extra hole. not even 1/8" size, so when I rtv'd it up I made sure that was covered. No problems in one month of DD duties. Im not using prop. valve either and have only noticed the back lock up under a test of really hard braking in the rain.

toy 4 pistons, vented in the front, GM disc/caliper back

You can get the Subi MC "new"...(no core)...(with resevoir)...from NAPA for about 70 bucks...

http://partimages2.genpt.com/partimages/640315.jpg

http://partimages2.genpt.com/partimages/640310.jpg

Forget the Firebird one! Sure its an "old school" solution thats lots of people have used - BUT its far from ideal!

Use a Subaru Impreza (1 1/16 dia) or Mazada 929 (1" dia.) Master Cylinder - way better fit! Metric fittings, low level switch, bolt on without mods and seals properly to the booster.

Here's the Mazda 929 Master cylinder swap we did on Elotsip's Sami. http://www.pirate4x4.com/forum/showthread.php?t=495302&highlight=mazda Unfortionately these are kinda expensive to buy new - so junkyard is the way to go. Later I found out the RX7 guys swap to this MC also. (RX7 have a 7/8 dia MC). Plus it requires this funky banjo to metric flare fitting which is no big deal if your getting a junkyard one.

But on my current Sami - I'm using the Subie one. Hands down its the best one I've seen for a bolt in application with no mods other than the plunger. The lines are even on the correct side!
http://www.pirate4x4.com/forum/showpost.php?p=7368757&postcount=146

Some other MC swaps are mentioned here....
http://www.pirate4x4.com/forum/showthread.php?t=384732

While a dual reservior is a great idea - I would rather have a low level switch ANYDAY as it tells you when you have a problem. then you just hop out and plug it with a brake line cap and top the reserve off. without a low level switch - you'll probably find out that you only have one axle braking in the most in-opportune time!

BTW I believe the subie reservior has a small divider inside the reservior.... but not 100% positive as I haven't looked at mine in a while.


You can get a firechicken one from auto zone for $18.
The biggest advantage to the GM master is that the master cylinder reservoir is divided so that if you lose a line in the front you won't lose your rear brakes and vise versa. The subi just like the stock zuk you lose a line you get air in the whole system

87 doesn't work your not just hogging out the holes for the bolts its a little wider at the bore and does not slide in.
So now I'm back to square one..oh well. Anyhow for clarity I have a bunch of stainless steel lines but they are sae. I have a line lock which is sae. I already have metric to sae converters installed at all four toy calipers. There is no reason to run a metric master cylinder at this point. Any better non metric master cylinders than the 1980 firebird?

you used a 80 master with 4 wheel brakes right? i used a 87 booster on mine
also where did you get it ? its auto zone part number M1745
http://www.zuwharrie.com/gallery/albums/userpics/10186/2.jpg

so you can use the stock sammy booster or an 87 firebird booster with a 1980 firebird master cylinder?

so you can use the stock sammy booster or an 87 firebird booster with a 1980 firebird master cylinder?

I run a 80 firebird master cylinder on a stock 91 samurai booster with no proplems.

sammy booster w/ firebird master

You can get the Subi MC "new"...(no core)...(with resevoir)...from NAPA for about 70 bucks...

http://partimages2.genpt.com/partimages/640315.jpg

http://partimages2.genpt.com/partimages/640310.jpg

X2 on the subi. I got mine off ebay for $25. Mine actually says 1 1/8 bore so it's plenty big for rear disc. Bolt hole line up perfect you just need to make a new longer push rod. I made mine out of an old valve cover bolt with the head cut off. A couple of test fits to get the rod in the correct position and it was done. I'd say from pulling in to pullout you could do this mod in 30min. since no cutting and reflaring of the tubing is necessary.

sammy booster w/ firebird masterthanks just trying to go sae as you can read earlier. Ordered it last night. Appreciate the help

Would the Subi MC work with a Toyota rear end with drums?

does this mean that there is no prop valve? just running lines straight to the rear disks? use prop valve if running drums?

does this mean that there is no prop valve? just running lines straight to the rear disks? use prop valve if running drums?

I still use one with disks makes it easier to dial in

will be some chev hydro-boost tech coming soon! as i finally got all my drive train and such figured out. so pics and such will come soon.