I can go but hard to stop

[layedouton22z]

99 f250 7.3 turbo.....just started having brake issues.....brake pedal gets soft and ends up at the floor and the abs light comes on when it seems to bottom out...it stops but not with the authouiry it did earlier in the day...abs light stays on rest of time truck is on...once turned off and restarted light goes away until pedal reaches floor......what is this and how do i fix it? i am new here so please help !!!!!!!!!!!!!

 

[jestersv]

have you tried bleeding the brakes sounds like air in the system or you may have a ruptured hose or master cyl leaking down what happens when you pump the brakes does the petal get harder?

 

[layedouton22z]

when I start to brake it feels normal but the longer my foot is on the pedal the softer it feels and slowly goes to floor !!!!

 

[Tail_Gunner]

Master cylinder??

 

[jestersv]

2x fluid leaking past seals on piston

 

[layedouton22z]

ok, so in turn would that activate the abs light?

 

[arrowstrap]

when mine had this issue it was due to a faulty vacuum pump. replaced the pump and all was well.

 

[Tail_Gunner]

when mine had this issue it was due to a faulty vacuum pump. replaced the pump and all was well.

With the Superduty's, the power assist for braking comes from the power steering pump. IIRC, the OBS had an engine driven vac pump. The Superduty electric vacume pump supplies vacume only for HVAC and those perpetually useless automatic front locking hubs.

If the power steering pump was going bad, I don't think the brake pedal would be going to the floor.

 

[DaveBen]

After all I have read on this thread, it sounds like a Master Cylinder going, or gone, bad. Easy fix and not too costly.

Dave

 

[layedouton22z]

the verdict is in and we have a winner.....Master Cylinder needs to b replaced...took to a shop cause it was gonna end up there anyway......I really do appreciate all of the ueful help..you guys are great......i have a fewmore quirks with this thing I will post later!!! you guys rock.....an i thought i bought the worlds only 2wd diesel!!!