master cylinder
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master cylinder
i have a 1977 f250 highboy 4x4 with a 351m engine,my brakes were done a few months ago but they have been getting a little mushy then one hard stomp on the brakes and the brake light came on.it seems my master cylinder has a small leak in the rear brake resovoir,is there a seal or a screw onthe bottom of it that could be leaking that i could check? any hints would help....screw , valve whatever? cmon guys you havent let me down yet thanks, mike
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From: Saratoga, NY
I can't remember is the rear resevoir the big one one or little one? the big one is the front brakes and the small is the rear. Whichever, there isn't any seal or screw on the bottom, I would suggest you check the lines to the hose(s) to the brake and look for leaks. If you don't find any you might just need the system bled, I had mine done by somebody(don't ask) and later found them too suck and once in awhile the brake light would come on. The idiots put new hoses and all new lines, and at least never bled the front. If that don't fix the problem you probably have an internal leak in the master cylinder, go get a remaned for like $15.
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From: Saratoga, NY
do you have power or manual brakes? If power just remove the 2 lines on the side and 2 nuts on the booster and slider out. You will have to pre bleed the cylinder but the last one I bought had instructions in the box on how to do this. Oh yeah I remember the rear res is the front brakes, check for leaks at the hoses and calipers first.
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master cylinder
i have power, so sounds easy.just went out and cleaned it all up and refilled it,then pumped the brakes... and it seems tobe a small leak from the front where the top goes on..do you think a new gasket would do it???????????????id like to try before replacing if you think it would work....if i do replace, after i have to bleed the brakes at each wheel right?
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From: OR
yes you will need to bleed the brakes after replacment of the master cylinder. I would recommend replacing it, my truck didn't stop so well anymore so I replaced the master cylinder and it stops on a dime again all for I think 12 bucks (plus some for brake fluid)
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From: Saratoga, NY
you shouldn't have a leak from the cap, it's not there to hold pressure just keep dirt out. Sounds like you have an internal seal gone bad if you got enough fluid turbulence to make it leak out, how old is the MC anyway? yes you will have to bleed the whole system, but at least this way you can purge all that old fluid and start fresh, I would still advise checking for leaks around the wheels
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If it spurts out of the reservoir,you have a problem in the slave cylinder in the M/C.
In other words, Fluid from one section of the reservoir is sent into the other section of the reservoir.
Replacing the M/C besides the bench bleeding should involve evacuating all of the brake fluid in the system.
This is where a power bleeder or vacuum bleeder comes in handy.
This sounds to me that You need to do some basic test first.
Look at every corner for fluid leaks.
with the engine NOT running.... pump the brake 3 times.... HOLD.........
does the pedal go to the floor ?
Now Pump 3 times ...hold...try & start engine >
What happened to the pedal once the engine was running ?
In other words, Fluid from one section of the reservoir is sent into the other section of the reservoir.
Replacing the M/C besides the bench bleeding should involve evacuating all of the brake fluid in the system.
This is where a power bleeder or vacuum bleeder comes in handy.
This sounds to me that You need to do some basic test first.
Look at every corner for fluid leaks.
with the engine NOT running.... pump the brake 3 times.... HOLD.........
does the pedal go to the floor ?
Now Pump 3 times ...hold...try & start engine >
What happened to the pedal once the engine was running ?
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pumped 3times with the engine off builds up pressure doesnt go to the floor,then pumped 3 times and started engine as soon as iy started brake went to the floor.....ps looked like it was seeping very little at the top front lid earlier not spurting and front resovoir goes down very very slowly.. i also tightened front hose a little today to make sure it wasnt leaking and its definetly not leaking from the rear to the front cause the rear is always full