no break presure... need input

[labeledsk8r]

OK... well i JUST got my car back from getting the new clutch in... so today was the first day truely driveing it.... so im going along.. and i notice the car is haveing trouble stoping.... meh figured it was normal and continued my day.... well im driveing along and i go to stop for a red light... it catches a tiny bit... but i was still doing about 20 by the time i hit the light.... so ebrake was pulled to stop (and yes i tried pumping the breaks aswell) . i have tried driveing it around... and the car stops... but its got almost no pressure at all... almost as if its only useing the pesure of the pedal to stop... to me this sounds like break booster.... BUT im not a break expert... theres no leaks in the system.... the fluid i still full and no signs of a leak or missing fluid.... so does this sound like a break booster?? or what else could go rong to do this... and remember it stoped fine so it seemed last night...

**edit** and yes i just relized i spelled pressure rong rofl

[Vanilla Sky]

Does it feel like you have to stand on your brakes, or does your foot hit the floor?

[labeledsk8r]

Does it feel like you have to stand on your brakes, or does your foot hit the floor?

foot goes to the floor.... feels like theres a leak... but theres no fluid loss

[Vanilla Sky]

I'm going to guess air. It doesn't take much of a leak to give you a really soft pedal. You could also have a rubber hose that's failed, but not ruptured.

[labeledsk8r]

hmmm so how should i test and pin this down...? just jack it up and look for small wet points on the break lines? doesnt seem like its lost any fluid at all

[DBMaster]

Check the spot where the master cylinder is bolted to the vacuum booster. I am on my third master cylinder. They seem to last about 100,000 miles and then develop a slow leak at the piston seals. If you see any fluid at all running down the booster you have a faulty master cylinder. At first your brakes work fine, but when the engine compartment gets hot and the fuild viscosity decreases it will start leaking more and you will lose fluid pressure.

[Vanilla Sky]

Jack it up, grab a brake line, and feel it as someone gently presses the brake pedal. The hose shouldn't expand much, if any. If you find a bad line, replace in pairs.

If that doesn't show anything, bleed your brakes.

[labeledsk8r]

Check the spot where the master cylinder is bolted to the vacuum booster. I am on my third master cylinder. They seem to last about 100,000 miles and then develop a slow leak at the piston seals. If you see any fluid at all running down the booster you have a faulty master cylinder. At first your brakes work fine, but when the engine compartment gets hot and the fuild viscosity decreases it will start leaking more and you will lose fluid pressure.

well it does seem to work fine when the car is cool... ima go look at that right now... shit.. i hate working on breaks... last time i put a master cylinder in it took almost 2 damn days (was on a ford) blah.. kk ima go check

[labeledsk8r]

ok i just looked at it... doesnt seem to be wet.... BUT under the break booster were it conects to the master cyl looks like something has been running dow nit badly... its like rusting in a leak patern.... im really starting to think this guy did a bunch of patch work to sell off this car to me lol.... um does break fluid burn up easy?? becuse mayby its just burned fluid... but it really looks and feels kinda like rust

[forrest89sei]

ok i just looked at it... doesnt seem to be wet.... BUT under the break booster were it conects to the master cyl looks like something has been running dow nit badly... its like rusting in a leak patern.... im really starting to think this guy did a bunch of patch work to sell off this car to me lol.... um does break fluid burn up easy?? becuse mayby its just burned fluid... but it really looks and feels kinda like rust

The Reservoir seals on my dad's Mercedes did that, Wouldn't Look wet but if you moved the reservoir around you would see fluid, overtime it leaked down the break booster and caused it to rust

[labeledsk8r]

Jack it up, grab a brake line, and feel it as someone gently presses the brake pedal. The hose shouldn't expand much, if any. If you find a bad line, replace in pairs.

If that doesn't show anything, bleed your brakes.

crap... well how would air of gotten in there to need a bleed

The Reservoir seals on my dad's Mercedes did that, Wouldn't Look wet but if you moved the reservoir around you would see fluid, overtime it leaked down the break booster and caused it to rust

does this mean i need to replace it?? or could this of been from a past leaking one...?

[forrest89sei]

crap... well how would air of gotten in there to need a bleed



does this mean i need to replace it?? or could this of been from a past leaking one...?

I ended up having to replace his, I noticed the pressure Improved when I did also

[labeledsk8r]

well i just went out and checked the lines by touch without jacking it up.... front left expanded a bit but nothing to bad.y.. the rest stayed about the same... the rear right seems to be starting to crack meaning its probably the orignal.. but no fluid there... i also shook around the booster... didnt seem to see fresh fluid... but the pedal can still go to the floor with no real resistence to the foot... i cant seem to find wet fluid at all... i think i might just replace the lines AND the brake booster... looseing breaks at that light scared the shit outa me and i dont feel like chanceing that again...

[forrest89sei]

I'd Pickup this Master Cylinder http://www.napaonline.com/masterpage...Cylinder+-+New
And if you need lines, i got 4 BRAND NEW Stainless Steel ones I'd sell for $40 shipped if your interested, Good luck man

[Hauntd ca3]

if it were the booster packing up
the pedal would feel like a brick at all times and you would hear a hissing noise when you press the pedal
if you got the rust thing happening on the booster under the master cylinder the seals are tired and it would prob suck in a wee bit of air each time you let off te brakes which would prob explain the shit pedal feel
what the pedal feel like with out the motor running?
replace the master cylinder first and get a shop to do a pressure bleed on the system and see how that feels

[AccordB20A]

does ur engine idle higher or run like shit when u pump teh brakes??

[Vanilla Sky]

That's a master cylinder issue. Replace the master cylinder AND the booster. The booster itself probably isn't bad, but I'm more than willing to bet that it's had brake fluid leak into it.

It's not bad replacing the master cylinder and booster on these cars. I did my first booster in about 2 hours with minimal tools.

[labeledsk8r]

does ur engine idle higher or run like shit when u pump teh brakes??

yes the idel jumps up when releaseing the brae.. and the car looses about 100 rpms when pressing in the break... so i know its trying to boost...

forrest i thin i might take you up on that deal for those break lines...... i iwll be looking into a booster and even anew cylinder im not looseing breaks again....

um can a caliper go out and give this same result???

[DBMaster]

The first time mine went bad it was still under the extended warranty. The second time I replaced it with a new one very similar to what forrest posted. Mine was about $60 also. I bench-bled it and then bled each wheel after installing it - no problem at all. Mine has the rusted area on the booster, too, but yours may have been caused by a previous master cylinder. You really don't have any way of knowing if it has been replaced before, do you? Is the rusted area wet with fluid? If it is I can say with 100% certainty that you need to replace the M/C. If you are even thinking about a rebuilt unit you are far better off getting a kit and doing it yourself, but it is much better to go with a new one for this part.

The rebuild kit is $32.79 at Rock Auto.
If it cost that much to rebuild it the new one sounds even better.

[lostforawhile]

yes the idel jumps up when releaseing the brae.. and the car looses about 100 rpms when pressing in the break... so i know its trying to boost...

forrest i thin i might take you up on that deal for those break lines...... i iwll be looking into a booster and even anew cylinder im not looseing breaks again....

um can a caliper go out and give this same result???

master cyl also check your rear brake cylinders if they go bad you will get air in the system,and they go bad all the time. they are cheap.if your booster is bad you will still have brakes, you probably have an internal leak in the master cyl. if the rear brake lines are cracked replace them now!! i had sudden failures in old brake lines like that. you don't know how far into the hose the crack is extending.

[Vanilla Sky]

Yeah, I'd go ahead and replace the brake lines along with everything else.

[labeledsk8r]

The first time mine went bad it was still under the extended warranty. The second time I replaced it with a new one very similar to what forrest posted. Mine was about $60 also. I bench-bled it and then bled each wheel after installing it - no problem at all. Mine has the rusted area on the booster, too, but yours may have been caused by a previous master cylinder. You really don't have any way of knowing if it has been replaced before, do you? Is the rusted area wet with fluid? If it is I can say with 100% certainty that you need to replace the M/C. If you are even thinking about a rebuilt unit you are far better off getting a kit and doing it yourself, but it is much better to go with a new one for this part.

The rebuild kit is $32.79 at Rock Auto.
If it cost that much to rebuild it the new one sounds even better.

true.. well theres rust and im not sure....its not wet anyware... but it had leaked at some point in its life... so your saying rebuild the break booster?? and get a new master cylinder.... ?? im looking at just doing the entire damn thing so i dont have to think about it and will be fine when i se-i rear brake swap later.... im not really good at bleeding brakes... so im not sure if i want to takle this on my own.... any tools to make this easyer?? most likely will be working alone

[labeledsk8r]

master cyl also check your rear brake cylinders if they go bad you will get air in the system,and they go bad all the time. they are cheap.if your booster is bad you will still have brakes, you probably have an internal leak in the master cyl. if the rear brake lines are cracked replace them now!! i had sudden failures in old brake lines like that. you don't know how far into the hose the crack is extending.

i need to figure out were the problem is... how can i tell if the rear cylinders are bad..... leaking?? i cant start blindly ordering parts....

[labeledsk8r]

i need to buy this stuff tonight so any last ideas of exactly what i should buy?? or anything else to check??

[Ichiban]

Here is how I diagnose brakes:

Problem: Soft pedal.

1. Check master cylinder brake fluid level

Solution: Obvious. Bleed brakes afterwards.

2. Check for leaks, broken/bulging lines or wet areas. Remove wheels/drums and check wheel cylinders for leaks.

Solution: Replace affected part. Bleed your brakes.

3. Pump brake pedal rapidly. Check to see if it builds pressure.

Solution:

If pumping the pedal builds brake pressure (the pedal gets hard), the most likely situation is air. Bleed your brakes. If this doesn't solve the problem, another issue may be poorly adjusted drum brakes. In this case, pumping the pedal is necessary to take up the drum/shoe clearance before the brakes apply. After the brakes are released, return springs force the shoes back to their original position, creating excessive clearance again. Since your E-brake works, this is probably not your problem.

If pumping the pedal DOES NOT build brake pressure, you either; have an external leak (see number 2 above), or you have an internal leak in the master cylinder, or a faulty rear seal on the master cylinder allowing brake fluid into the booster. Remove/replace the master cylinder and bleed your brakes. If a failed rear seal has filled the booster with brake fluid, you "should" replace the booster. At least suction the fluid out. Also, black fluid and chunks of seal material in the reservoir indicate piston cups are in bad shape. Even if brake fluid isn't leaking out of the master cylinder, pressure can bypass the seals and return to the reservoir, instead of going to your brakes like it should.

4. Perform a brake function test. Road test the vehicle in a safe area.

I can also give you detailed instructions on how to properly and easily bleed your brakes if you want. It's simple, but if you do it wrong it'll become a major headache.

Good luck.