For the last couple of weeks I've had a brake issue involving a soft petal at first,then brakes engage and slow the vehicle down,then a very hard petal for a few feet then a stop so quick it'll break your kneck! If I slowly come to a stop the problem isn't really existent except for a soft petal at first, It kind of resembles a wheel cylinder going out,but stops like it should with ease. The major problem is when I need to stop suddenly. I'm kind of at a loss and have exhausted everything I know how to do. I've checked both wheel cylinders and they're fine,I'm not loosing any break fluid and all the break lines seem to be fine. Any suggestions on this issue is greatly appreciated.

 

It diffently sounds like the "Master Cylinder" is your culprit.At times your break pedal will go to the floor, sometimes it won`t.You will have to pre bake each time you come to a complete stop.If you have the funds,purchase a new master cylinder.In my past experience buying used master cylinders,I wasn`t happy,they would last about 2 yrs tops, then that`s it.Like my quote says.."You get what you pay for!"

 

I was afraid of that. It is 27 years old so I can't really be upset. It's not that it necessarily goes to the floor as much as its just really soft at first. It acts very similar to a malfunctioning wheel cylinder. The hard petal is only here and there but in all my 12 years of driving the truck that's never happened before. I can get a knew one between 30-50 bucks depending on the brand and with or with out reservoir. Time is really the issue as I don't have much to replace it until after Christmas

 

one thing you can try to eliminate your back brakes out of the scenario is take a brake line clamp, they sell them anywhere, harbor freight has a nice set, and pinch off your rear rubber brake hose to eliminate your rear brakes all together. if the pedal is very firm and the truck stops great the problem is your bake brakes. if the pedal is spongy and brakes still suck then the problem is the master.

its pretty much safe to drive like that for a little while as most your braking is done in the front, though might not be a good idea to test drive it like that in the rain or snow.