[nothin-but-mud]

Something all of a sudden went wrong with my breaks and they are barely working now. when I push the break petal it will break a little then just let loose and go to the floor. I cheked the brake fluid level and it was ok and I know I dont have a leak in the lines because when I pump the breaks without the truck running it they will build up pressure. I dont think I need to replace the pads because the breaks were fine before, they justy all of a sudden were not working very well. It almost feels like just the rear drums are working. Is it posible that there is a clog somewhere in the line leading to the front?

Thanks for any help.

 

[OhPinions]

Check the fluid level in the reservoir, and closely inspect each wheel for ANY leakage from the wheel cylinder/calipers. If any leakage from any wheel and has contaminated the pads/shoes, those pads/shoes MUST be replaced after repairing the leaking part and bleeding the system.
If the fluid is very low or worse, empty in one of the reservoir cups then air might have entered the brake system, bleed the front or rear system (whichever one was low/empty), and road test.
If all checked systems are fine then suspect the master cylinder has failed. Inspect the brake booster and vacuum line to ensure mechanical soundness as this too will affect braking performance.

Let us know how this turns out.

Rich

 

[Mala-Sangre]

With a full master cylinder resevoir, I'd say it's time for a new master cylinder...................Los

 

[doug3968]

sounds like an internal leak in the master cylinder--replace it, they're cheap

 

[IntenseImages]

same thing happened to me, one minute i had breaks, next minute nothing. the magic word here is master cylinder. cost me $34.00.

 

[TaZMaNiaK]

Most likely the master cylinder, but check the brake booster too. (That big black disc-looking thing with a vacuum hose coming out of it behind the MC) With the engine off, pump the pedal repeatedly. Each time it should get firmer and firmer. If not, the booster is bad - Replace it and the MC. If it firms up, press the pedal down halfway and start the engine. If the pedal goes to the floor, then the MC is probably the culprit. I'm not sure, but I believe moisture in the hydraulic lines can make it mushy too, since it's "Squishy" like air, compared to hydraulic fluid, which is very dense. Easiest way to get rid of it is to flush a gallon of DOT3 from a sealed bottle through the system using standard bleeding techniques.

Just my $.02, hope it helps!

Peace,
Matt {peace}

 

[nothin-but-mud]

Thanks Taz, with what you just said I now know that it is the master cylender. When I pump them with engine off it will firm up and then when I start it up the pedal goes to the floor. I will get to the parts store tomarow morning to pick up a new MC.

Thanks to everyone for the help.

 

[ramdodger]

put the new master cylinder on the truck and bleed it before you hook the lines up to it...
Tony

 

[RAMMAN4]

This same thing happened on my dad's reliant. We couldn't figure out what was wrong with it. The pads were all good and there was plenty of fluid in it. We would bleed the system but that didn't change it. We pulled the master cyclinder and ripped it apart. The o ring inside was busted and the MC pretty much just fell apart.

 

[nothin-but-mud]

Hey, I got the new MC on but now my breaks are locking shut, I tryed opening a bleeder valve on the front break, pushing the pedal down, tightning the bleeder valve, then releasing the petal. This got the breaks loose, but then when I tested them in my driveway they locked up again .What can I do to stop them from locking up

 

[OhPinions]

Hey, I got the new MC on but now my breaks are locking shut, I tryed opening a bleeder valve on the front break, pushing the pedal down, tightning the bleeder valve, then releasing the petal. This got the breaks loose, but then when I tested them in my driveway they locked up again .What can I do to stop them from locking up

Are you getting a Brake Warning light or does the dash brake light remain lit?
Look under the truck on the left frame rail near the drivers door and inspect the proportioning/hold-off valve assembly. When your brakes are released does the little stem retract?