MkIII brakes dont work

xAimz · 11-25-2010, 11:11 PM

I have a 1991 supra, and im having problems with the brakes.
when i press the brake pedal it goes all the way down, and doesnt seem to slow the car down. the guy that i bought it from says it might be the master cylinder.
Is there a way i could find out exactly whats wrong, could it be the master cylinder or do i need to bleed the brakes.
what Dot brake fluid does mk3 use?

Sonyps307 · 11-26-2010, 02:58 AM

Sound like master if it was air in the lines the pedal would feel Spongy

btwilson86 · 11-26-2010, 03:12 AM

Our Supra's use Dot 3 brake fluid. Try bleeding the brakes first. Air in the lines doesn't always result in a spongy pedal. While you are bleeding the brakes, inspect the rubber brake hoses at each of the wheels for any splits or cracks. Move them around a bit and make sure they are still flexible. Brake hoses are often neglected, and therefore a common failure point on 20ish year old cars.

If the brake lines are in good shape and bleeding the brakes does not fix the problem, remove the master cylinder and bench bleed it. If that doesn't fix it, then that is likely your issue.

CanadianBak'inSupra · 11-26-2010, 03:24 AM

i remember my first master cylinder, was on my 85, and i didnt know what a bench bleed was, had to take it off and bleed the master, dam that was a mess...

btwilson86 · 11-26-2010, 03:29 AM

Yeah, it's a PITA but you can rarely get away without doing it. I got lucky on a Jetta, never again though

xAimz · 11-28-2010, 01:19 AM

Is there a certain order to do it?
some say it doesnt matter, some say to do rear R, rear L , front L then front R.
do i also gotta disconnect negative?

907mge · 11-28-2010, 01:39 AM

Start with the longest line first and so on.

Green7mgte · 11-28-2010, 03:13 PM

were the brakes recently changed on the car before you purchased it?

what happends on older vehicales (happened to mine)
is when you change the brakes the peddle goes down to the floor. the peddle fallowing the same range of motion, over time anything beyond that gets dried out. so your basically overextending the piston in the master cylinder and rupturing one of those o rings. happens, can be rebuilt. but buying a new one for 60 bucks, why go through the hassle. Mc w/ ABS

good technique to put a block of wood behind the peddle so it doesn't hit the floor. but if you replace your master cylinder this shouldn't become a problem again for another 20 years.

xAimz · 11-28-2010, 03:40 PM

I have no idea, the brakes are crossed, are those stock?
like the car WILL stop, but first you gotta push the pedal in, then pull out then pump again for them to work.

<3

Green7mgte · 11-29-2010, 01:13 AM

the brakes are crossed??.. are what stock??

first things first is to bleed the brakes. then see if its the mc. dedicate an hour and you can get it solved.

11-25-2010, 11:11 PM	#1
xAimz Intake Join Date: Nov 2010 Location: florida Posts: 30	MkIII brakes dont work I have a 1991 supra, and im having problems with the brakes. when i press the brake pedal it goes all the way down, and doesnt seem to slow the car down. the guy that i bought it from says it might be the master cylinder. Is there a way i could find out exactly whats wrong, could it be the master cylinder or do i need to bleed the brakes. what Dot brake fluid does mk3 use?

11-26-2010, 03:12 AM	#3
btwilson86 Super Moderator Join Date: May 2007 Location: Billings, Montana Posts: 1,034	Our Supra's use Dot 3 brake fluid. Try bleeding the brakes first. Air in the lines doesn't always result in a spongy pedal. While you are bleeding the brakes, inspect the rubber brake hoses at each of the wheels for any splits or cracks. Move them around a bit and make sure they are still flexible. Brake hoses are often neglected, and therefore a common failure point on 20ish year old cars. If the brake lines are in good shape and bleeding the brakes does not fix the problem, remove the master cylinder and bench bleed it. If that doesn't fix it, then that is likely your issue. __________________ 1989 7MGTE R154 Targa Top White Package w/Blue Interior Driftmotion 57trim CT26, Upgraded Intercooler, 2.25" Hard Pipes, 3" Turbo Back Exhaust with Test Pipe, HKS VPC w/GM 3 bar MAP sensor, APEXi S-AFC, Walbro 255lph fuel pump, ProSport EVO Series Boost / Fuel Pressure / AFR gauges, Lotek a Pillar Gauge Pod, HKS Type 0 Turbo Timer, Eibach Lowering Springs, Tokico Illumina II TEMS struts, custom powder coated Motegi Racing TrakLite wheels

11-26-2010, 03:24 AM	#4
CanadianBak'inSupra Official hall monitor / search nazi - NO SOUP FOR YOU! Join Date: Oct 2009 Location: Canada, BC Posts: 837	i remember my first master cylinder, was on my 85, and i didnt know what a bench bleed was, had to take it off and bleed the master, dam that was a mess... __________________ 1984 supra - 1uzfe - w58 - 4.10 - 1 piece aluminum shaft.

11-26-2010, 03:29 AM	#5
btwilson86 Super Moderator Join Date: May 2007 Location: Billings, Montana Posts: 1,034	Yeah, it's a PITA but you can rarely get away without doing it. I got lucky on a Jetta, never again though __________________ 1989 7MGTE R154 Targa Top White Package w/Blue Interior Driftmotion 57trim CT26, Upgraded Intercooler, 2.25" Hard Pipes, 3" Turbo Back Exhaust with Test Pipe, HKS VPC w/GM 3 bar MAP sensor, APEXi S-AFC, Walbro 255lph fuel pump, ProSport EVO Series Boost / Fuel Pressure / AFR gauges, Lotek a Pillar Gauge Pod, HKS Type 0 Turbo Timer, Eibach Lowering Springs, Tokico Illumina II TEMS struts, custom powder coated Motegi Racing TrakLite wheels

11-28-2010, 03:13 PM	#8
Green7mgte Supra Forum Moderator Join Date: Nov 2009 Location: Green-Ohio Posts: 1,297	were the brakes recently changed on the car before you purchased it? what happends on older vehicales (happened to mine) is when you change the brakes the peddle goes down to the floor. the peddle fallowing the same range of motion, over time anything beyond that gets dried out. so your basically overextending the piston in the master cylinder and rupturing one of those o rings. happens, can be rebuilt. but buying a new one for 60 bucks, why go through the hassle. Mc w/ ABS good technique to put a block of wood behind the peddle so it doesn't hit the floor. but if you replace your master cylinder this shouldn't become a problem again for another 20 years. __________________ 92 Ma71 7mGTE Auto. SafcII Supra FAQ Supra MKIII FAQ Classified Section guidelines : Last edited by Green7mgte; 11-28-2010 at 03:17 PM.

11-26-2010, 02:58 AM	#2
Sonyps307 Lexus & 550's Join Date: May 2010 Location: Baltimore Posts: 526	Sound like master if it was air in the lines the pedal would feel Spongy

11-28-2010, 01:19 AM	#6
xAimz Intake Join Date: Nov 2010 Location: florida Posts: 30	Is there a certain order to do it? some say it doesnt matter, some say to do rear R, rear L , front L then front R. do i also gotta disconnect negative?

11-28-2010, 01:39 AM	#7
907mge 20psi boost Join Date: Dec 2009 Location: Harrisburg Posts: 759	Start with the longest line first and so on.

11-28-2010, 03:40 PM	#9
xAimz Intake Join Date: Nov 2010 Location: florida Posts: 30	I have no idea, the brakes are crossed, are those stock? like the car WILL stop, but first you gotta push the pedal in, then pull out then pump again for them to work. <3

11-29-2010, 01:13 AM	#10
Green7mgte Supra Forum Moderator Join Date: Nov 2009 Location: Green-Ohio Posts: 1,297	the brakes are crossed??.. are what stock?? first things first is to bleed the brakes. then see if its the mc. dedicate an hour and you can get it solved. __________________ 92 Ma71 7mGTE Auto. SafcII Supra FAQ Supra MKIII FAQ Classified Section guidelines :

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