Toyota Celica Supra Forum banner

1 - 20 of 62 Posts

·
Registered
Joined
·
1,613 Posts
Discussion Starter #1
So, I've been having alot of brake problems over the last few weeks, and finally had enough of it. At the suggestion of Damon Saul, when I striped out my mk III Parts car this winter, I took the master cylinder also. At the time Damon said to me only this about installing it: "It's a little bit of work to swap it over, but not too bad." So I kinda threw it on the shelf until this passed weekend, when I decided to tinker around and try to fix my brakes. I did this while I was on some serious painkiller (to the point that I was loopy enough to argue with Norbie that water would burn!..LOL)This swap is in a word...easy as pie. Heres the steps to put it on...

Before doing any of this, I suggest you spray everything down with WD-40 or something similar...15 to 20 years of rust, grime and crap tend to make bolts not wanna release ;)

1) drain the old master cylinder of fluid with either a turkey baster or something similar. This way, you don;t have to worry about the major mess if ya dump it accidentally.
2) remove the old brake lines from the original master cylinder. There should be 2 of them. One will come into the top towards the end of the master cylinder, and the other should be on the "Drivers side" of the master cylinder, about half way back. These are both 12 mm nuts I believe.
3) the Base of the master cylinder is held to the power brake boost by 4 12 mm nuts. the top right one can be a bit of a pain in the ass to get at, but with an extention and a swivel or "A wobbler" extention, makes it no problem.
4) cut the wiring that goes to the level sensor in the cap. Cut them as close to the cap as ya can, to leave you some wiring room to connect the new cap.
5)If ya haven't already, clean out the new mastercylinder with some brake clean. mine had some sludge in the bottom of it, as well as some old fluid in the metal base, so I sprayed enough brake clean into the resevoir to build up a smal lpuddle, and using a long thin metal punch, I worked the pumping action of the cylinder until all the brake clean had come out clean. Then dry out the cylinder and clean it up so it looks good underneath your hood.
6) Installation is almost the exact reversal of installation. The only difference you will notice is that the brake line that comes into the master cylinder on the side about halfway back will need a smal lbit of maneuvering to get it to screw in.
7) Fill up the resevoir, bleed the lines, and you should be good to go! This may also be a good opportunity to flush and refill the system. I decided to use Castrol GT LMA brake fluid. It exceeds DOT 3 and 4 fluid by a decent margin in most categories.

I can't comment as to whether or not there is any improvement over stopping ability or anything like that as I am waiting on new front calipers fro my car (broke the bleeder valves off both of the front calipers, and then broke an easy-out off in one of the calipers trying to remove the broken valve...) but I will say this... the mk III master cylinder is EASILY 1/4 the weight of the mk II one. I will have it completed this coming weekend and I'll give you impressions of it then.
 

·
Registered
Joined
·
268 Posts
Wow it fits in just like that eh? Pretty nice, I'm sure it has a good bit of pressure advantage over the mk2 one considering our calipers are a fair bit bigger (they still shoulda been better from factory but hey)

And lighter too eh? Might as well put 1 in if you have it as a spare, or a good junkyard part for people with blown factory mk2 ones.
 

·
Super Moderator
Joined
·
10,546 Posts
cool, sounds good Bob. Just an idea for #1 there, chances are you're going to do a brake fluid swap when you do this anyways so instead of making a mess with a turkey baster just bleed all of the fluid out through the bleeder screws like you would if you were doing a flush by itself. Let us know if it seems to make any performance difference.
 

·
Registered
Joined
·
1,613 Posts
Discussion Starter #4
Well, I finished it a bit ago, and WOW what a change!!

Just as a rough guide I went up to 60 and stopped in a little less than the distance from one telephone pole to another... which (in theory anyway) is supposed to be 100 feet. Now, I know 90-some feet seems a bit quick to stop in, and I agree... so take that measurement with whatever grain of salt ya want. I also put on new calipers, rotors and pads on the front.... nothing special, just good quality OE replacements.

Also, as for using the fluid in the old cylinder to flush out the system... I wouldn;t recommend that...especially if your car was ever neglected... When I pulled mine off, there was nearly 3/8" of sludge and slime in he bottom of the old master cylinder..all of which would have been pushed intot he brake lines if I had done that. Its not really all that messy with the turkey baster, if your careful, take your time, and work over a rag to catch the small drips.
 

·
Registered
Joined
·
7,111 Posts
thats great news Bob

long time no post :wink: its good to hear from you again

Do you think that adding some SS break lines will better the stopping power?
 

·
Registered
Joined
·
1,613 Posts
Discussion Starter #6
Thanks for the Welcome back Zank.. been busy as hell lately.

As for the SS lines..I can't imagine them NOT improving... Soon as I fix my headgasket (yeah.. blew the HG the other day... so until the new motor is ready, I have the Wifes Grand Marquie), thats next on the list.
 

·
Registered
Joined
·
15,035 Posts
ive searched this thread and the part 2 thread and still seen no one post pics of it swapped onto a mkii. i plan to install one of these along with the residual valve and line lock when i install the ss lines and jk bbk on the front after first flushing the system. i may rebuild a set of extra rear calipers to swap on at the same time as well. should be a really nice upgrade i think, but was wanting to see how the lines where routed.
 

·
Registered
Joined
·
3,051 Posts
look at the pics of my engine bay, been using the mk3 booster and master cylinder for months now. I'm happy.







I found for install, to avoid some of the PITA of bending the lines, i didn't tighten the master cylinder to the brake booster very much to allow me to move it some, got the lines on it much easier than when i did it on my black car a couple years ago.


i'm actually surprised no one noticed i had a mk3 booster when i posted pics a while back.
 

·
Registered
Joined
·
15,035 Posts
is the mkiii booster really wort hthe pita of removing the 4 bolts way up under the dash? im fat so its hard to get up there. lol. thee is a mkiii in the bone yard so i figured id gra the master cylinder and rebuild it and pretty it up for the install. gonna rebuild some extra stock rear calipers too and paint them and get new rear rotors , and ill try to get them cadium coated locally. so far looks like $1300-1400 total on the brake upgrade at once when its all installed. mkiii booster and mc, ss lines, summit line lock, wilwood 2psi resiual valve, several bottles of the castrol lma brake fluid, rear caliper rebuild kits, mc rebuild kit, the epoxy paint for the calipers, misc fittings and lines for the linelock and residual valve install, hawk blue pads for front and porterfeild r4s pads rear and brembo rear rotors and have all 4 rotors cadium plated. should be a totally diff car when thats all on there.
william
 

·
Registered
Joined
·
3,051 Posts
is it worth it, can't really say for sure, never tried just the MC. However the booster itself is a little smaller in some ways compared to the mk2, which would make doing a starter easier too.
 

·
Registered
Joined
·
15,035 Posts
well, if thats the case, ill have to grab a 2nd booster when i get a chance for the blue car as well. all the stuff i mentioned is for the black car.
 

·
Registered
Joined
·
24 Posts
piston size

Does any one know what the difference is between mk2 and mk 3 caliper piston sizes is?
 

·
Registered
Joined
·
15,035 Posts
iirc the piston sizes are the same. though the mkiii has much larger rotors which is why the brakes are so much better
 

·
Registered
Joined
·
168 Posts
from what ive herd, the mk3 has 1", and the mk2 is 15/16"

ill measure up my mk3 master cyl. tonight. pritty sure those specs are correct.
 

·
Registered
Joined
·
15,035 Posts
that'll be nice to know, but he said caliper pistons, not master cylinder pistons
 

·
Registered
Joined
·
15,035 Posts
lol. well, if you can measure a mkiii master cylinder, do it and post, maybe someone else can measure and post the mkii one as well.
 

·
Registered
Joined
·
1,198 Posts
Gentlemen,

It is infact true that (some of) the MKIII's have a 1" piston as opposed to the 15/16" piston of the MKII, but it is only certain years. If memory serves me correct, the early model MKIII's (pre-1990) still maintained a 15/16" bore in the MC, while the later model MKIII's had bore sizes of 1 inch.

I am running the late model MKIII MC on my 86 MKII, and the thing I will tell you is that the braking is different. With the 1" bore MC (comparatively speaking) you will experience increased pedal effort, but with a reduced stroke. The increased pedal effort means you can skip your Stairmaster workout for your right foot...

I went with the MKIII 1" bore so that I could reduce the distance my feet needed to travel when negotiating the pedals (makes for quicker pedal responses)...

Regards,

Carlos
 

·
Registered
Joined
·
24 Posts
Carlos Brown said:
Gentlemen,

It is infact true that (some of) the MKIII's have a 1" piston as opposed to the 15/16" piston of the MKII, but it is only certain years. If memory serves me correct, the early model MKIII's (pre-1990) still maintained a 15/16" bore in the MC, while the later model MKIII's had bore sizes of 1 inch.

I am running the late model MKIII MC on my 86 MKII, and the thing I will tell you is that the braking is different. With the 1" bore MC (comparatively speaking) you will experience increased pedal effort, but with a reduced stroke. The increased pedal effort means you can skip your Stairmaster workout for your right foot...

I went with the MKIII 1" bore so that I could reduce the distance my feet needed to travel when negotiating the pedals (makes for quicker pedal responses)...

Regards,

Carlos
Thanks,

This is what I wanted know.

I've changed the front calipers to some four piston jobs and was looking for an
easy low cost way to get a bigger master cylinder.

also, some people don't understand that when you increase the master cylinder size it decreases the fluid pressure but but moves more fluid, this is why pedal efort increases to get the same clamping force and pedal travel decreases.

Thanks again Carlos,
Jeff
 

·
Registered
Joined
·
168 Posts
Just confirmed the sizes of the bores.

The ma61 master cylider has 15/16" stamped onto the side of the bore, and one would assume that correct :p
The ma70 i have is 1" and fits up nice an easy. The bootser vacum line braket fauls with the resavoir, but is easily fixed with a haxor or metal file
 
1 - 20 of 62 Posts
Top