Working on a project truck I bought that I'm about ready to shoot, but regardless running into something I've never dealt with before. Brakes are good and than maybe every 3rd-4th time you use them they start out normal and than get real soft. Not acting like there's air in them. Person before me had just replaced the master cylinder and not seeing any leaks. Flipping bleeders are rusted up, so I'm working on that but again it's not acting like a normal air in the line where it's just soft. Sorry about no paragraphs, my enter key isn't working on here for some reason. Thanks

online swag:
air bubbles somewhere.
if the bleeder screws are rusted
up, then whoever replaced the m/cyl
couldn't have got the air out even
if he did bleed it at the m/cyl.
you'll have to get the bleeder
screws working to even get started
right.

Air in the system is a good bet. Also a binding caliper will allow the fluid to boil after a while and cause a soft pedal, as will play in the wheel bearings. That will allow rotor "tilt" and lick the pads back in the calipers. The last shouldn't be intermittent though.

I don't know what kind of truck or how old, but if it's got any age to it, pressure bleeding/flushing the entire system is a good idea. You can do it the old fashioned way with two guys and pumping the pedal or use a pressure pump.

Also, depending on the truck, there may be a load equalizing valve on the rear axle. If so, it needs to be bled as well. Ditto if it is ABS equipped. Sometimes there is a bleeder on the pump. If equipped with ABS and no bleeder, it is a good idea to find a dirt road and do some hard stops that exercise the actuators in the ABS system. If you have air hung up in there, it will help move it along to where you can bleed it out.

I'm hoping to get back at it this afternoon/evening, soaking the bleeders now with PB.

2000 Ford Ranger XL 4x4


Thanks for the advice so far

does your truck have rear drums? if so adjust up the rears that will cause soft pedal. but most likely its air in front calipers, honestly if it was me and the calipers are original I would just by new and replace them. rock auto has some good prices.

I'd of guessed Master Cylinder. Did he replace with a new unit?

If drum brakes are far enough out of adjustment, the wheel cylinders can leek air into the systems.

Caused me a long and frustrating headache.

It does have drums

Had a HELL of a time getting the passanger side bleeder loose, after heating/cooling it a few times (hopefully didn't cook any seals) I had to pound on a socket and finally got it broken loose.

Ended up getting a good little burp outta the drivers front side. After a test drive it feels much better.


I agree about replacing them, but I'm about ready to take a a hammer to this truck. Picked it up for a fair price with a miss in it. Was hoping new plugs/wires and maybe a coil pack would do it. Ended up being a cracked valve on no.2.

Replaced both heads with new heavier cast heads, replaced the push rods, few of the rockers. Full gasket kit and replaced the cam shaft and crank shaft position sensors just because it was easier to do so at the time.

Idiot I got it from had taken the cats off and I didn't realize that. Exhaust was a mess, but I cobbled one back onto it as the local muffler shop wanted 700.00 as they wouldn't use an aftermarket catalytic converter.

Put new shocks on yesterday and still need to do the power steering pump. I'm into it for about 600-700.00 over what I paid for it and into the thing for about market value as we speak.

Tired of sinking money into it as it's just a hunting/fishing truck but as far as the engine goes it should be good for another 150.

still, cheaper than a new car payment,
higher insurance, property tax, etc.

Here's my two cents. If the bleeders were that corroded, even getting them loose and installing new bleeders doesn't account for the corrosion in the wheel cylinder threads. Hit the brakes hard and out pops the bleeder. This is exact scenario that happened to a buddy of mine years ago that owned a service station with a customer vehicle. After that, if he couldn't bleed the brakes with normal hand tools, it was new or rebuilt caliper / wheel cylinder time.