Brake problems

wishgirl10 · 05-19-2012, 09:43 PM

Hi everybody. I'm new to this forum and I'm looking for some help. I have an 86 supra that my boyfriend has rebuilt the engine on (it had a rusted cylinder) and now it's finally running. The biggest problem right now is that the brake pedal is super soft. He's already bled the brake lines and gotten a lot of air out of the lines and he's rebuilt the back brakes because they weren't pushing out before, but now that's fixed and back on the car and the pedal is still super soft. There's enough brake fluid and everything in it. So what we're wondering now is if there's some kind of air bleeder box somewhere on the car (other than the bleeder valves on the calipers). Anyone have any information or ideas?

btwilson86 · 05-20-2012, 06:03 AM

Welcome to the forum!

Although air in the lines is one of the more common problems, another cause of a really spongy feeling brake pedal is a bad brake master cylinder. It should be inexpensive to rebuild or replace, just be sure you bench bleed the cylinder prior to installation.

Green7mgte · 05-20-2012, 01:47 PM

agreed.. the brake master cylinder can be thought of as a large plunger with a few rubber rings around it.. If not used for a long while those rings dry out, crack or don't hold seal properly. When you go to bleed them they fail and your left w/o brakes.. Thats why some mechanics, while bleeding the brakes, place a block of wood under the break peddle. To stop the peddle from hitting the floor and pushing the plunger in the BMC to its furthest position, if it hasn't been done for a very long time.
Happened to me.. put on a new BMC and that should solve you're problem. If you had a leaky caliper or something, you would see signs of it on your rims. If you had a leaky line some place. probably see it on the garage floor.

Indeed on bench bleeding. here's my thread on me bumbling my way through it..http://www.toyota-supra.info/forums/...-brakes-2.html

wishgirl10 · 05-20-2012, 09:53 PM

Ok, thanks for the info guys. Very helpful.

Any ideas where we can find a master cylinder rebuild kit? Autozone only has the replacement master cylinder, which we'll get if we have to, but we're trying to save $.

Green7mgte · 05-21-2012, 12:19 PM

Quote:

Originally Posted by wishgirl10

which we'll get if we have to, but we're trying to save $.

supra and save money.. you're in the wrong car! lol..
check ebay id imagion.. good luck =)

cre · 05-21-2012, 03:44 PM

Quote:

Originally Posted by wishgirl10

Ok, thanks for the info guys. Very helpful.

Any ideas where we can find a master cylinder rebuild kit? Autozone only has the replacement master cylinder, which we'll get if we have to, but we're trying to save $.

Call around. Napa usually has rebuild kits for things that other stores don't.

Green7mgte · 05-21-2012, 04:29 PM

that is a very good point.. Napa can usually get their hands on odd ball stuff..but for a price. I know I can go to my local autozone and get any sort of gasket I need.. but napa will fly me in the actual part if I cant find it anyplace else. Strange how that works.

05-19-2012, 09:43 PM	#1
wishgirl10 Stock Join Date: May 2012 Location: Los Angeles, CA Posts: 2	Brake problems Hi everybody. I'm new to this forum and I'm looking for some help. I have an 86 supra that my boyfriend has rebuilt the engine on (it had a rusted cylinder) and now it's finally running. The biggest problem right now is that the brake pedal is super soft. He's already bled the brake lines and gotten a lot of air out of the lines and he's rebuilt the back brakes because they weren't pushing out before, but now that's fixed and back on the car and the pedal is still super soft. There's enough brake fluid and everything in it. So what we're wondering now is if there's some kind of air bleeder box somewhere on the car (other than the bleeder valves on the calipers). Anyone have any information or ideas?

05-20-2012, 06:03 AM	#2
btwilson86 Super Moderator Join Date: May 2007 Location: Billings, Montana Posts: 1,034	Welcome to the forum! Although air in the lines is one of the more common problems, another cause of a really spongy feeling brake pedal is a bad brake master cylinder. It should be inexpensive to rebuild or replace, just be sure you bench bleed the cylinder prior to installation. __________________ 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

05-20-2012, 01:47 PM	#3
Green7mgte Supra Forum Moderator Join Date: Nov 2009 Location: Green-Ohio Posts: 1,297	agreed.. the brake master cylinder can be thought of as a large plunger with a few rubber rings around it.. If not used for a long while those rings dry out, crack or don't hold seal properly. When you go to bleed them they fail and your left w/o brakes.. Thats why some mechanics, while bleeding the brakes, place a block of wood under the break peddle. To stop the peddle from hitting the floor and pushing the plunger in the BMC to its furthest position, if it hasn't been done for a very long time. Happened to me.. put on a new BMC and that should solve you're problem. If you had a leaky caliper or something, you would see signs of it on your rims. If you had a leaky line some place. probably see it on the garage floor. Indeed on bench bleeding. here's my thread on me bumbling my way through it..http://www.toyota-supra.info/forums/...-brakes-2.html __________________ 92 Ma71 7mGTE Auto. SafcII Supra FAQ Supra MKIII FAQ Classified Section guidelines :

05-21-2012, 04:29 PM	#7
Green7mgte Supra Forum Moderator Join Date: Nov 2009 Location: Green-Ohio Posts: 1,297	that is a very good point.. Napa can usually get their hands on odd ball stuff..but for a price. I know I can go to my local autozone and get any sort of gasket I need.. but napa will fly me in the actual part if I cant find it anyplace else. Strange how that works. __________________ 92 Ma71 7mGTE Auto. SafcII Supra FAQ Supra MKIII FAQ Classified Section guidelines :

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
Brake light problems	corytebeau	MKIII Supra	6	11-19-2011 04:54 PM
MKIII Wilwood 12.9" Rear Brakes With Parking Brake	ARZ	Arizona Performance	0	08-25-2010 06:34 PM
Brake light switch and neutral safety switch problems	jtown125	MKIII Supra	26	05-02-2010 04:22 PM
Wilwood MKIII Rear brake kit	ARZ	Arizona Performance	0	03-16-2007 07:46 AM
brake problems	gomezmk	MKIII Supra	1	09-11-2006 06:13 AM

05-20-2012, 09:53 PM	#4
wishgirl10 Stock Join Date: May 2012 Location: Los Angeles, CA Posts: 2	Ok, thanks for the info guys. Very helpful. Any ideas where we can find a master cylinder rebuild kit? Autozone only has the replacement master cylinder, which we'll get if we have to, but we're trying to save $.