Help!! major brake problem....

bigal0043 · 09-28-2005, 01:20 PM

alright so i was driving home last night from school and the brakes went completely soft.. like went to the floor... but i could pump them to get pressure... after i got it pumped to stiff again i held it in to see if i was losing pressure but wasnt... it only seems to loose pressure when i dont use it and after like 15 mins of driving.. it is fine before everything seems to get warmed up...

but it happened again when i was in the city but on the way to work... on the highway getting off the exit..

and once it lost pressure u have to pump it for the rest of the time in the car till the car cools down... any ideas?? i was thinking an air pocket maybe???

the brake pads are pretty thick so its not that and it is not losing brake fluid it is completely full..

rnoswal · 09-28-2005, 02:16 PM

Well that usually means the brake master cylinder is bad. The piston inside has seals and the seals are letting the fluid go by and then no pressure. It could actually be leaking into the brake booster and that is why you don't see any fluid on the outside. If you pump them up for now, it will hold, but this won't last all that long. Another symptom is after you pump it up is putting slight pressure on the brake and see if it slowly goes to the floor, just another sign of master brake failure.

Let us know how it goes.

Russ

bigal0043 · 09-28-2005, 02:37 PM

i hope it is just a break in a line somewhere then.. but it is weird that it just started to happen out of no where...

how much is a new master cylinder... think it would be cheaper to find someone who has a used one.... can i rebuild one??

joel w · 09-28-2005, 08:57 PM

remanufactured is about $40 +- and new is about 120+-
they make rebuild kits but i would not recomend them. atleast with a remanifactures the liability is on them if it fails. brakes are important!!!, I would not want to risk mine and other peoples lives to save a few bucks? Just my opinion..

. here is a pretty good online auto dealer, ive used them many times. and there competitive in price to the local guys

http://www.rockauto.com/catalog/cata...&parttype=1836

rnoswal · 09-29-2005, 01:47 PM

If it was a broken line then the pedal wouldn't go to the floor because, depending on if it is the front or rear that is gone then the other will still work. Safety feature. Go to the parts store and buy one from them. They are fine and have a warranty. If you want to check to make sure there are no broken lines, just pour in some fluid and put it on dry pavement, step on the brakes a few times and if it is leaking you will see a wet spot on the ground. If it is the master cylinder, sometimes if you look under it, on the brake booster you will see a trail of wetness and bubbled up paint.

Russ

SupraMan1784 · 09-29-2005, 02:23 PM

i think the master cylinder is shot...rnoswal said it right...the seals are shot too thats why its goin soft, pump it enough times and it will create a seal on its own..which is why the pedal got stiff again, rebuilding the master cylinder should fix the problem....but also check the lines...might have a small leak, or some air in teh lines

rnoswal · 09-29-2005, 03:17 PM

Hmmmmmmmm just too many 3" exhausts out there under the names....lol. Again, I wouldn't try to rebuild the master cylinder. You never know if the cylinder is pitted or worn too much. The rebuilt from the parts stores are your best bet, sometimes it is a huge hassle getting that C-clip back in and if you haven't done a few, you might put a piece or two in wrong, so just to be safe.......u know.

Russ

89supra · 09-29-2005, 07:13 PM

just a suggestion, i don't know if it will solve the problem. it probably wouldn't hurt to bleed the brakes in case there's any air in the brake line that might be causing the inconsistancies in braking power.

AutoXMan · 09-29-2005, 10:15 PM

I'd put money on it that its the master cylinder, has happened twice to me in different cars, and was not much to fix at all, the symptoms you describe are the classic master cylinder problems.

mrnickleye · 09-30-2005, 12:13 AM

[QUOTE=rnoswal]Hmmmmmmmm just too many 3" exhausts out there under the names....lol. Again, I wouldn't try to rebuild the master cylinder. You never know if the cylinder is pitted or worn too much. The rebuilt from the parts stores are your best bet, sometimes it is a huge hassle getting that C-clip back in and if you haven't done a few, you might put a piece or two in wrong, so just to be safe.......u know.

YEA !!! I don't even have 3", its 2 1/2" ........I tried to find out how to change that to something else, like on SM, but ????

Anyway...you guys are correct in that the master cylinder is most likely the problem. But...the leak-down is 'internal'...so no external leaking.

Buy a remanufactured one, be careful not to get air in the lines. If you do, the ABS (if you have it) will F*** up and you'll have to deal with that.

I suggest that you go have it checked and replaced at a 'good' (not a ripoff one like Midas or Pepboys) shop. Let them take on the resposibility of making sure its working properly when its completed. It should not be more that 1 hours labor, and about $60 for the part. (That's all I'd charge at my shop.)

09-28-2005, 01:20 PM	#1
bigal0043 3" Exhaust Join Date: Jul 2005 Location: Plattsburgh,NY Posts: 85	Help!! major brake problem.... alright so i was driving home last night from school and the brakes went completely soft.. like went to the floor... but i could pump them to get pressure... after i got it pumped to stiff again i held it in to see if i was losing pressure but wasnt... it only seems to loose pressure when i dont use it and after like 15 mins of driving.. it is fine before everything seems to get warmed up... but it happened again when i was in the city but on the way to work... on the highway getting off the exit.. and once it lost pressure u have to pump it for the rest of the time in the car till the car cools down... any ideas?? i was thinking an air pocket maybe??? the brake pads are pretty thick so its not that and it is not losing brake fluid it is completely full..

09-28-2005, 02:37 PM	#3
bigal0043 3" Exhaust Join Date: Jul 2005 Location: Plattsburgh,NY Posts: 85	i hope it is just a break in a line somewhere then.. but it is weird that it just started to happen out of no where... how much is a new master cylinder... think it would be cheaper to find someone who has a used one.... can i rebuild one?? Last edited by bigal0043; 09-28-2005 at 02:41 PM.

09-29-2005, 02:23 PM	#6
SupraMan1784 SP58GT Join Date: Jun 2005 Location: Dirty Jerz Posts: 691	i think the master cylinder is shot...rnoswal said it right...the seals are shot too thats why its goin soft, pump it enough times and it will create a seal on its own..which is why the pedal got stiff again, rebuilding the master cylinder should fix the problem....but also check the lines...might have a small leak, or some air in teh lines __________________ Now: Saving for an MKIV Broken Rides: (Sold) 91 supra turbo 5speed with a 1jzgte motor 421whp 400(399) ft*lbs of torque on tap @ 15 psi "Always outnumbered, never outgunned."

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09-28-2005, 02:16 PM	#2
rnoswal Lexus & 550's Join Date: Apr 2005 Location: Bossier City LA Posts: 556	Well that usually means the brake master cylinder is bad. The piston inside has seals and the seals are letting the fluid go by and then no pressure. It could actually be leaking into the brake booster and that is why you don't see any fluid on the outside. If you pump them up for now, it will hold, but this won't last all that long. Another symptom is after you pump it up is putting slight pressure on the brake and see if it slowly goes to the floor, just another sign of master brake failure. Let us know how it goes. Russ

09-28-2005, 08:57 PM	#4
joel w Lexus & 550's Join Date: Aug 2005 Location: In the shadows Posts: 506	remanufactured is about $40 +- and new is about 120+- they make rebuild kits but i would not recomend them. atleast with a remanifactures the liability is on them if it fails. brakes are important!!!, I would not want to risk mine and other peoples lives to save a few bucks? Just my opinion.. . here is a pretty good online auto dealer, ive used them many times. and there competitive in price to the local guys http://www.rockauto.com/catalog/cata...&parttype=1836

09-29-2005, 01:47 PM	#5
rnoswal Lexus & 550's Join Date: Apr 2005 Location: Bossier City LA Posts: 556	If it was a broken line then the pedal wouldn't go to the floor because, depending on if it is the front or rear that is gone then the other will still work. Safety feature. Go to the parts store and buy one from them. They are fine and have a warranty. If you want to check to make sure there are no broken lines, just pour in some fluid and put it on dry pavement, step on the brakes a few times and if it is leaking you will see a wet spot on the ground. If it is the master cylinder, sometimes if you look under it, on the brake booster you will see a trail of wetness and bubbled up paint. Russ

09-29-2005, 03:17 PM	#7
rnoswal Lexus & 550's Join Date: Apr 2005 Location: Bossier City LA Posts: 556	Hmmmmmmmm just too many 3" exhausts out there under the names....lol. Again, I wouldn't try to rebuild the master cylinder. You never know if the cylinder is pitted or worn too much. The rebuilt from the parts stores are your best bet, sometimes it is a huge hassle getting that C-clip back in and if you haven't done a few, you might put a piece or two in wrong, so just to be safe.......u know. Russ

09-29-2005, 07:13 PM	#8
89supra Stock Join Date: Sep 2005 Location: apex, nc Posts: 8	just a suggestion, i don't know if it will solve the problem. it probably wouldn't hurt to bleed the brakes in case there's any air in the brake line that might be causing the inconsistancies in braking power.

09-29-2005, 10:15 PM	#9
AutoXMan Stock Join Date: Sep 2005 Posts: 6	I'd put money on it that its the master cylinder, has happened twice to me in different cars, and was not much to fix at all, the symptoms you describe are the classic master cylinder problems.

09-30-2005, 12:13 AM	#10
mrnickleye 1000whp postwhore Join Date: Jun 2005 Location: Mojave Desert, Calif. Posts: 1,705	[QUOTE=rnoswal]Hmmmmmmmm just too many 3" exhausts out there under the names....lol. Again, I wouldn't try to rebuild the master cylinder. You never know if the cylinder is pitted or worn too much. The rebuilt from the parts stores are your best bet, sometimes it is a huge hassle getting that C-clip back in and if you haven't done a few, you might put a piece or two in wrong, so just to be safe.......u know. YEA !!! I don't even have 3", its 2 1/2" ........I tried to find out how to change that to something else, like on SM, but ???? Anyway...you guys are correct in that the master cylinder is most likely the problem. But...the leak-down is 'internal'...so no external leaking. Buy a remanufactured one, be careful not to get air in the lines. If you do, the ABS (if you have it) will F*** up and you'll have to deal with that. I suggest that you go have it checked and replaced at a 'good' (not a ripoff one like Midas or Pepboys) shop. Let them take on the resposibility of making sure its working properly when its completed. It should not be more that 1 hours labor, and about $60 for the part. (That's all I'd charge at my shop.)