killrickykill

Ok, so I have an 89 4WD V6 pickup...

got it not too long ago and it was having erratic idling at when braking, so I figured ok brake booster has a vacuum leak, replaced it. The reman. one I got didn't work at all, really stiff pedal no braking power etc. So i put the original one back on. After that I had almost NO pedal pressure, however the brakes work great. You just can't feel it, the pedal will go all the way to the floor with little to no resistance, it's just at one point while pressing the pedal down the car just stops, so I don't suffer any loss of braking power at all, there just is NO pedal pressure so I have to be careful when stopping so that I don't lock up the brakes and get rear ended. I bled them more than once trying to get some pedal pressure, nothing, I replaced the m/c, bled them again, still nothing. I am at a loss I have NO idea what the problem could be, if any of you have encountered anything like this and found a culprit and/or a solution please please let me know cause I am at my wits end.

ps. I only joined and am posting today but I have spent months searching this site and the entirety of the internet looking for an answer and have found nothing.

Co_94_PU

iTrader: (-1)

You'll have to work the trouble shooting check list HERE, also do the check and adjustments.

Two things that stick out you don't mention, pads and shoes and rotor thickness.

When you bleed the system do you get air bubbles, could be worn out bleeder valves or bad calipers/pistons. There is also the LSPV as a likely source of air.

PS. erratic idle usually just means you're hitting the fuel cut off and need to adjust the idle down to spec. Diagnose by the book don't throw parts at problems it's a waste of time and money, if you were that lucky you'd be winning lotto on a regular basis.

killrickykill

i bleed until i get new fluid (when there was old fluid), and no air bubbles, LSPV is removed.

LuczOr

I wish I had your problem. You're pretty much describing my dream setup for brakes...

Co_94_PU

iTrader: (-1)

If you're not getting air that's a good sign the system is fully sealed.

Next easy thing is to inspect the pad and rotor thickness, and that the rears are adjusted.

Do you get any pressure/resistance when you pump the pedal?

If the adjustment is good and the rotors aren't too thin the next check is to hook it up for a pressure test. HF doesn't carry one one those, can maybe try the loan a tool at the local parts store. So you'll have to take it to a brake shop to have the pressure test done or price swapping out the soft lines.

That pretty much coveres everything I can think of currently.