350turbo411

hey guys..just replaced my master cylinder.....the prob is ..i have good brakes when the car isnt running.. .as soon as i start the car the peddle goes to the floor.....with a swoosh......i can kindof pump them up but it sinks fast ......................i've had MANY people tell me it isnt the booster..because the peddle would be hard...............is it possible that i picked up a bad rebuilt m/c....anyone have experience with a bad m/c....

i bought it from napa....it was the ONLY parts store that carried them....

from hutchins
pepboys
carquest
autozone
and other locals....

thanx.... frustrated.. out 42 dollars...

rob

wuter

I would double check that there is no air in the system. then if the problem is still there i would suspect the rubber brake lines are expanding under the high pressure with the vacuum assist from the booster.

cfabe

I think the problem IS your booster... It's leaking air into the front side, which is normally what happens when you step on the brakes. Sounds like yours is doing it all the time because the brakes go down whenever there is vacuum applied to the booster. A booster can fail either way, make the brakes hard (no boost) or pull the pedal (boost all the time), It just depends which side of the diaphragm is leaking.

TomP

Dude, why are you going to chain stores (Napa, Autozone, Pep Boys, etc)??? Go to a "real" parts store, the kind mechanics go to. They can get the m/c for you usually the next day. And $42? Geez! I paid $20 for my master cylinders, with a year warranty.

And yes, I got a bad m/c. Bled the ever-loving sht out of it, and I'd get the same thing you do- no pedal when I turned the car on. I brought it back, got another master cylinder, and it solved the problem.

Did you get rid of your old master cylinder already? You can buy a rebuild kit for 'em, and I tend to think rebuilding your own is better than buying one that's been rebuilt already. My theory is that they rebuild these things, then they sit for months untouched in a hot/dry warehouse, where the seals dry out. You come along, try to bleed the thing, and the seals rip because they're dry.

I had the same "Swoosh" noise, no pedal, and I'd get the "BRAKE" warning light popping up. If you can find the plugs, you can disconnect your m/c from the rest of the car, and put plugs into the m/c ports. This will seal the system off from the rest of the car. If the pedal suddenly becomes firm, you've got a problem elsewhere in the car (as in, air in the rest of the lines). This way you can eliminate the m/c as a problem.

The bleeding procedure is a bit of a pain in the ***, too. When you bench bleed, you need to wait 15 seconds between strokes to allow the quick-take-up-valve to fill with fluid. The QTUV is why the bottom of the m/c body bulges out right before the bolts for the booster. What kind of bench bleeding kit did you get? For my master cylinders, the "free" kit included did not match my m/c outlet ports. Your '83 should have standard-threads, my 84-up system has metric. The free kit I got seemed to have standard threads. What happend was, when I bench bled it, since the free plastic fittings didn't fit the m/c, air would get sucked in past the threads. I solved it by using the m/c-to-prop-valve lines in the master cylinder to get a good seal, then slipping clear vinyl tubing (home depot) over the other end of the lines, and looping them back into the m/c reservoirs.

If you get really pissed, you can buy the Phoenix Injector! http://www.brakebleeder.com I bought the V12 model, and it is beautiful. I waste much less fluid now, and know the job is done right. You can actually do a pressure bleed (like the pro's do) right on the master cylinder using the "universal port adapter". They even show you how to bleed the GM quick-take-up 2-port master cylinder. It's worth the cash.

If you have any questions, let me know (not thru private message, though, let me know here). I fought air in my brake system forever when I swapped to rear discs. (Course, I just blew the posi, and I'm back with a drum axle, DAMMIT!)

350turbo411

THANK YOU !!....you've provided me with a whole day of work...im going to try to isolate the m/c first and go from there.. ill let you know the results...i cant thank you guys enough..

i'm going crazy....

rob

350turbo411

ok..i plugged the m/c...and the peddle was firm when the car was off....and when i started ..it went to the floor........

the brakes work without the booster hooked up..but i have to push them SUPER HARD..and even then the peddle kinda travels...

soo...

would this be the booster>>???

normal when not started
when started, peddle goes to the floor with a "swoosh" sound...

should i try a new m/c first..???? but if it was the m/c...it would sink when the car wasnt running right??????????????


rob

350turbo411

jeez i keep thinking of things...


with the cap to the master cylinder off..i should see fluid rising from the front and rear bowls right..>>???when i push the brakes.....SLOWLY....

TomP

Yeah, you should. I seemed to get more of a geyser from the frontmost reservoir (which controls the rear brakes), and a smaller geyser from the reservoir closest to the firewall (for front brakes). When I had the m/c bled at it's best, the geyser from the reservoir closest to the firewall grew a bit.

I also originally had little air bubbles from the reservoir against the firewall; if I pumped the brakes repeatedly with the car off and the m/c cap on, when I removed the cap, the fluid in that rear reservoir would be foamy.

You could also reconnect the m/c to the rest of the system, and see if you get a BRAKE light (have your e-brake handle down). If you get the BRAKE light, that means uneven pressure is present. If you've got no BRAKE warning light, maybe it is the booster!

350turbo411

ok. .sorry to keep bugging you but i've never worked on brakes before ...and i'm going CRAZY...

today i found a plug that would work..

i plugged off the rear bowl started the car ...AND THE PEDAL WAS FIRM AND DID NOT SINK...it was like it was originally....

i removed the plug and hooked the steel line back up.....started the car....and the pedal went to the floor..instantly....the "fountian"in the rear bowl was amazing.. it was like it was just pushing fluid UP...not sucking any in....

so..

i think i can eliminate the booster.....thats good..

since the back port(front brakes?) was the problem...


its a problem with the front brakes, and its not the booster...

now what......just keep bleeding the front brakes???

i checked the pads....they are both touching the rotor......inside and outside....is this normal???


rob

350turbo411

nope...not the m/c...put on another..and it does the same thing...

with the car in the air..and someone pushing on the pedal with the car off......i cannot spin the front tires.soo i know the calipers are ok....

now with the new master..i can kinda pump them up a bit...and get "some braking power" but..the pedal sinks....

ahhhhhhhhhhhhhh i dont possibly see what the problem could be....

Rob

cfabe

Like i said earlier, you need a new booster. The fact that you disconnected the vacuum line and it stopped pulling the pedal doing it is screaming leaky booster.

Go here http://www.howstuffworks.com/power-brake.htm for a nice overview of how the booster works, you should be able to see why the booster could cause this. There is a vacuum leak on the cabin side of the booster that is allowing atmosphere pressure to get in on the front of the diaphragm all the time (this usually only happens when you push on the brakes)

cfabe

Actually I just re-read and i think you were talking about disconnecting a brake line not the vacuum line. Try disconnecting and plugging the vacuum line to the booster, I'll bet it doesnt sink.

350turbo411

i blocked off the hose from the booster..and the carb

and it didnt sink.. and was hard...

but BUT.. when i installed a plug into the front brake line connection to the master cylinder...THE PEDAL WAS FIRM.. WITH THE BOOSTER HOOKED UP........

SOO..without front brakes ....connected ..the pedal was normal with the car running ..thats why i wasnt thinking it was the booster..

very informative site......

350turbo411

I'm an idiot.. i'm sorry for wasting your time... when i say that the pedal goes to the floor.. i mean.....when i push on it....it doesnt suck to the floor....extremely spongy...

TomP

Here's something you can try, that was recommended to me by the guy at the Phoenix Injector Company...

Ever see those little clamps, that look like little pliers, or little vise-grips, at Pep Boys (or similar auto parts store) that are meant to "safely" crimp a hose shut? They're for hoses like fuel lines, and heater hoses, and trans cooler lines, and etc. He told me a million ways to chase down a bubble in the lines; one of which was to buy those hose crimpers, and put 'em on all the soft brake lines on the car. (I guess you just need to put them on the front brakes, since that m/c reservoir closest to the firewall is for the front brakes.) Then he said to try the pedal. If the pedal's hard, you know it's a problem with a caliper, or a leaking brake hose. If it sinks, it's a problem between the caliper hose and the m/c. You could go a step or two further; you could find plugs for the prop valve, and block off the front lines "after" the prop valve, and try the pedal. Etc, etc. Or, you could plug one of the lines at the prop valve, so you would just have one front caliper, and see how the pedal is. Keep in mind everytime you open a fitting, you're getting air in there...

You might fix your problem as soon as you can get those damn bleeder screws un-stuck. I hear that you can buy a rebuilt front rotor for $10 from Autozone; maybe you want to try that? Oh, and yeah, the pads should be almost touching the rotor- they should look like they're on it. They're really only a few hundredths of an inch off. That's why we have a "quick take up valve" on the master cylinder- it gives a "quick" shot of fluid to "take up" that little difference between the pad and rotor.

If you've got the equipment, you can do what I did, and make a homemade pressure bleeder that acts on the brake lines coming out of the master cylinder. I even tried to fabricate a plate across the top of the master cylinder, but it couldn't hold the pressure, and brake fluid went everywhere- what a mess.

You need a shop air compressor (or possibly a bike pump), an air fitting (or possibly a tire's valve stem with core), a bottle of brake fluid, a length of clear tubing with a grommet, and little "cone" adapters that usually come in a $5 "one man brake bleeder kit". By making this "tool", I was able to ensure air-free lines after the master cylinder, and didn't have to touch a brake pedal. Let me know if you're interested, it's a lot to type up... and it doesn't really matter until you get those bleeder screws open!

If you do replace the calipers, it's more cash, but think about replacing the caliper hoses. If they're the original '83 hoses, they're probably deteriorating on the inside, and might be close to being clogged. If you replace the hoses, remember, you'll need two copper crush washers for each caliper. The copper washers might even come with rebuilt calipers!

Good luck dude, and keep at it... let me know how it goes. Imagine dealing with this and not having another car to drive! That's how I was fighting it.

Oh and that close header tube might've had something to do with it. You might be able to re-bend the offending brake line to get more clearance. I bought my "cheap-o" brake line bender from Strauss Auto in the "cheap-o tools section" for $4, and it does a good job. It's just a pain in the butt to use.

cfabe

oh, that makes alot more sense.

Give what tom just said a try and see what happens. If you can't get the bleed screws open... well thats a problem. If they're just stuck and arent rounded off yet, you can try this method, its worked for me in the past. Disconnect the brake line to the caliper, and then heat with a torch all around the bleed screw, dont get it too hot because you can damage the seal in the caliper, like glowing is definately too hot. Then douse the threads of the bleed screw with a good penetrating oil (PB plaster is my favorite) until it stops smoking. Repeat as necessary. Once you think they might be loosened up, get a socket that fits the screw and work it back and forth to fee it up.

If the screws are rounded over beyond all hope, I'd just bite the bullet and buy new calipers. Theres no way to get all the air out of the lines and caliper without opening the bleed screw.

350turbo411

OK THIS is sounding better...the thing now is.

i cant get a cocket back there....between the strut connection and the caliper....i can only get a wrench on it...but.. i will defanately try some heat..

thanx..

rob sorry about the confusion..

cfabe

if you have to use a wrench i'd only use a 6 point box end. Dont use the open end, you WILL round the bolt off. You can take the caliper off and get a socket on it that way. Also, a 6 point socket would be advisable too.

TomP

I couldn't get to either one of those f'ing bleeder screws, either. I had to remove the caliper mounting bolts, and "slide" the caliper upwards a bit on the rotor to clear the strut. Stupid, stupid design...

Did you have any rubber caps covering the bleeder screws? Those help prevent a frozen bleeder; they tend to rust from the inside-out... if you put a cap over that center hole, they won't rust (or at least, rust as hard). If you get 'em out, you can also put some silicone brake lube on the threads of the bleeder screws, that'll prevent rust, too. I use a silicone dielectric, same as for spark plug boots, since I can't find a tube of "real" silicone brake lube anywhere.

350turbo411

thanks....i think i'm going to do what you said..and remove the caliper...i dont want to round it off......i've got some pb blaster soaking on it...............i hope this works

rob..

thanx..

350turbo411

2 front calipers 12 bucks a piece

2 hoses 17 bucks a piece

set of brake pads 14 bucks

knowing ill be able to stop priceless

TomP

That was the last commercial I heard on my way back from lunch!

Damn, $12, that's cheap! Maybe I should replace my front calipers just "For the hell of it", eh? (230,000 miles on original calipers) Did they come with the copper crush washers for the brake hose?

350turbo411

YEAH... I JUST GOT my income tax check..

soo i decided to do all the front brakes

it was 12 bucks....it came with bushings and 2 copper rings for the hose connectiong

AND I GOT THEM AT PEPBOYS.....

i ended up replacing the front lines too....just about threw my pipe bender through the back window...but i got the hang of it...

the whole job will cost me under 70 bucks......plus i have a new m/c too.... i'm thinking of new shoes and srping kit for the back......i didnt know brakes could be this fun......

but.. tomarrow i have to have my women pump the brakes and stuff..... i have to bench bleed m/c again... yep you guessed it...i let it run dry but....the fluid in the front lines was garbage....

what fluid do you recomend for high heat....i can only move the lines about and inch or two from my headers..??? non coated...

anyone have any luck with header wrap?????

thanx guys... i let you know how this works out....

thanx again..........

Rob i could not believe the condition of my hoses.. once i pulled them.....and really inspected them...WOW!!!!! thats serious

cfabe

for the heat issue i'd get some header wrap and wrap the lines in it where they go by the headers... or maybe get some of those spark plug boot protectors and put them over the brake line.

350turbo411

i installed all new parts... and new brake lines.......i still have to bleed the system.........TONS of air in the lines...its gonna take awhile...but... hopefully this will do it......


the old calipers where pretty bad...the pass. side i couldnt get the piston out...............

i ll let you know the outcome on sat.....

even with all the air ibn the lines now.. its hard but when i start it ..it does the same thing ..but...i've got to bleed em....


rob...

350turbo411

MAN. i bled the front lines..until there was no more air....


they act EXACTLY like before...i can push it all the way to the floor...

how much air in the lines would cause this..??? little tiny bubbles...or huge pockets of air???

back to the drawing board.....

TomP

Well, at least you got new calipers out of the deal! Hey, did you ever tell me if you get a BRAKE warning light or not? Have your e-brake down, start the car, and press on the brake. When the pedal swooshes down, your brake warning light (unequal pressure) should come on. If not, you might want to replace that booster!

If you want, here's how to make the homemade pressure bleeder. First, find one of those one-man brake-bleeder kits, they have little cone-shaped fittings that connect into clear tubing. Then buy some clear tubing out of either a Pep Boys (by the windsheild washer tubing), or a Home Depot, or similar- something that the cone-shaped fittings will fit into. While you're at pep boys, pick up a tire valvestem (rubber) and valve core, a big 'ol bottle of brake fluid, and a rubber grommet that will fit around the tubing. If you can't find rubber grommets at Pep Boys, then Radio Shack sells a little assortment pack of rubber grommets for $2. You can see the conical fittings I'm talking about in the -center- of this picture, directly to the LEFT of those short pieces of vinyl tubing: http://www.mityvac.com/images/06000.jpg

Hay wait, do you have an air compressor? If so, substitute a male quick-disconnect fitting for the tire valve stem/core.

1. Remove the cap from the big bottle of brake fluid. Remove that paper gasket from inside the cap. Mark the cap for two holes- one to hold the grommet, and one to hold the air valve. Remember not to put the holes right on the edge of the cap; the bottle needs to screw all the way onto the cap... leave 1/8" around the inside of the cap.

2. Put the grommet into the cap, and slide the tubing thru. Slide enough tubing thru so it would touch the bottom of the brake fluid bottle. Attach the tire valve stem (with core) to the other hole in the cap. (If using a shop air compressor, use teflon tape around the threads of the quick-disconnect fitting, just like you would for an air tool.)

3. Screw the cap tightly onto the bottle, submerging the tubing.

4. Get your bike pump (or air compressor!!), and attach it to the cap. Give it a few pumps (or 10-15 psi with compressor). You should hopefully see brake fluid start to travel through the tube. I did this with my air compressor, "supposedly" it'll work with a bike pump, but you'll have to try it.

5. If fluid comes out, great! Attach the conical adapter to the tubing.

6. Disconnect the m/c lines from the m/c, but leave them attached to the prop valve. Somehow plug the m/c ports up. Work the pump until the tool's tubing is filled with brake fluid, and it's dripping out of the conical fitting.

7. Hook your tool up to one of the lines; probably the front line. (This is the prop-valve-to-m/c-line that's more towards the rear of the car.)

8. Crack a bleeder screw open at a caliper, and attach tubing to it, and lead it into some kind of pan. Make sure to make that upside-down "U" shape with the tubing; a clothespin is handy for clipping the line to the existing brake hose. When fluid starts to ooze out due to gravity, have your girl watch the tubing.

9. Work that bike pump like mad. (Or, put your air compressor at 10-15 psi. You can go a bit higher, but don't apply too much pressure to the brake system, you can blow out the seals. You just want to shove fluid thru gently.) It should pressurize the bottle of brake fluid, and push fluid thru the vinyl hose, thru the prop valve, thru the brake lines, thru the brake hose, and out the caliper bleed screw.

10. When your woman says that no more air bubbles are coming out, close the bleeder, and move to the other wheel.

11. This tool helps ensure that you have absolutely NO air in the front lines after the master cylinder. Do your trick again, with the m/c ports plugged up, engine running, and testing the brake pedal- make sure it's firm. If it's firm, and you have no air in the front lines anymore, hook the m/c up to the prop valve again, and see how the brakes work now.

12. You can also use this tool on the rear brakes, but due to the distance, it'll take a while for the tool to push new fluid to the rear- especially if you're using a bicycle pump.

You can do a search thru yahoo.com for "bicycle pump brake bleed", you should find the articles I found.

And if all else fails, there's always http://www.brakebleeder.com

Did you try that trick the guy told me, about crimping off the brake hoses, to check for a firm pedal? He says as you remove a hose crimper one by one, check the pedal; when it sinks, that's the line with the problem.

TomP

Oh and Rob, you actually bent new front lines? Wow, that's a lot of work! I'd never have the patience for that! How'd they come out? What kind of bender did you use? (I have a little cheap sucker, no rollers at all)

350turbo411

HAHA... wow..brake line bending....here's the thing..if you fab it up with all the bending before hand...i found that i could not get it in place because of room in the engine compartment....the pipe bent pretty easy and did not kink like i thought....for the right side i just made a big "L" and connected the top side to the prop valve and bent the bottom end ...like a "J" and hooked it to the new rubber hose...THIS ONLY TOOK ME LIKE 5 MINS....it was WAY easier than i thought....i think i might do the rears too!!...but... the pass side was a little tougher....i bent a big "L" again and from the bottom of the car routed it up near my power steering box...hooked it to the prop valve....then i coiled the other end of the "L" and routed it through the block and the fuel pump...then just bent it to "J" up under to the hose... kindof hard to explain but.....IT WORKED.... i just used the pipe bender for sharp 90 bends....it was a hand held one.. that looked like pliers..


thanx for the suggestion ..i'm going to read it over ....and attempt to do this.....i know its air ....but like i said ...it should not be the booster..because with the rear port of the m/c plugged.....and car running ..i get a good pedal..........

the brake light does not come on............i can push the pedal down..about half way with the engine off....if i really push on it...

350turbo411

i needed about 5 foot of line for the pass side.. and 3 foot for the drivers side....

cfabe

It sounds like you've got alot of air in the back brakes. Bleed em real good and make sure theres NO air in the lines. You should then have nice firm brakes all around. Once you do one or two complete brake jobs, they get real easy. You get a feel for how much you have to bleed them to make sure all the air is out. I just did a rear end swap and it only took me and my buddy like 3 minuted to bleed the brakes.

350turbo411

yeah..lots of bleeding for tomarrow...i've never done this before ..so i think everything is major ....and things like that ..but...you guys have calmed me down....I CANT BELIEVE i put new brakes on at all...this was a major step... i dont have a feel for the pedal..and what the prob is....i can see little air bubbles ..in the fluid.. not just huge pockets....real little bubbles..like it was mixed up

cfabe

You really need to get all of the air out, whether its in a few big bubbles or lots of little ones, it can still compress. I assume you're using the method where you open the bleed valve, have helper put brakes down, close bleed valve, helper bring brakes up. This is what I always do and it has never failed me. You just have to be careful to make sure you close the line fully before helper lets the brakes up or else you'll end up sucking air back into the line. Evnetually you'll see a nice solid stream of brake fluid every time they press on the pedal with absolutely no air in the line. That is what you want. If the lines are totally empty like when you've just replaced them, it can take a while. Make sure you keep the resevoir full enough or else you'll suck air in the top and have to start all over agian.

As for the feel of the brakes, with the engine off if they are bled properly, there should be a little free play and then the pedal should be nice and firm. You can still push it down a little more if you push hard, but it will not go down all that far.

TPI Monte SS

Also, make sure you bleed in the proper sequence....you're supposed to start at the spot furthest from the MC.

So, in order, you should do -

Right Rear - till you have no more air
Left Rear - till you have no more air
Right Front - till you have no more air
Left Front - till you have no more air

Hope that helps!

TomP

Did you buy pre-flared lines, or did you buy the ISO bubble flaring tool? Eastwood has that tool for $70... I want one, but it's not often I flare lines. Maybe one day! But you're saying you bent most of the lines by hand? My bender was $3, and is shaped like an installed timing chain. I want to get one with the rollers...

Cfabe, if you do a lot of brake work, check out http://www.brakebleeder.com ! I bought the V12 w/SmartPak, and man, brake bleeding is actually fun now! No more pedal pushing, and I get air-free lines much much faster! You can even reverse-bleed; force fluid in thru the bleeder lines, since air rises. You can even cross-bleed the rear axle; shoot fluid in one bleeder while you have the opposite side's bleeder open. (2nd day delivery to NJ was $25...)