98 silverado brake issue

[Albert]

So im having a little bit of a tough time trying to figure this brake situation for some reason i have soft brakes and i have to push my brake pedal almost all the way to the floor replaced master cylinder and bleed front and rear brakes. Also when the truck is off the brakes are stiff when the truck is on they go back to being soft anyone have any ideas what could possibly be going wrong?

 

[Fuzzy]

Did you bleed the ABS system?

 

[Albert]

No is that what i should bleed next?

 

[Fuzzy]

Yes, as far as I know most people just go out on a back road and lock up the ABS a couple times and then bleed the brakes as you normally would. Otherwise you'll need a scan tool to activate the ABS.

 

[Ironhead]

I want to second what fuzzy said. I did basically the same thing, but did it on a snowy road. Used a Mityvac to suck the old fluid out of the master cylinder, then used it to bleed the wheel calipers/cylinders. Got all the od and cruddy fluid out, and the pedal firmed up nicely. I guess there was some air in the system, and probably some water, because brake fluid absorbs water over time.

 

[Albert]

Thanks for the replies gonna try it with snow on the ground in md we got a good 30 inches lol

 

[rcb1]

You can get one of the vacuum testers that can also pull breaker fluid through the brakes.

 

[Ironhead]

Probably the most common of those vacuum testers/pumps is the Mityvac. Cheap and easy to use. They have a website so you can see what accessories you need to bleed the brakes. If you do go this route, there is a good YouTube video on how to use it. Be sure to use the teflon tape as advised in the video.

 

[rcb1]

Ahaha... breaker fluid. That's what I get for typing on a phone.

 

[Albert]

Had a buddy of mine bleed the brakes an had to replace a rear brake line that runs along the rear axle also had to adjust rear drums. There was definitely a good amount of air in the system thanks guys for all the help!