'88 RABS valve question
 

Had a neighbor tell me my issue sounded like my RABS valve and wanted to confirm / ask advise on replacing

basically have soft pedal when truck is running (will almost go to floor before slows). when not running can pump and get firm, so don't believe is the Master cylinder.

I have bleed all wheels with some air removed... no leaks anywhere... still squishy when running.

does this sound like a RABS valve? or could be something else? is there anyway to test the valve to see if is bad or needs to be replaced?

I will try bleeding the valve specifcally tonight... but would think this is a common problem is this is in fact what it is. thanks!

You said 'some' air came out when you bled the brakes....question is if you didn't change the valve yet, how did air get in there?
If there is a logical answer, fine.....but you need to find that out before going further.
Also, be sure you are bleeding the brakes properly. Sometimes with rear anit-lock, there is a very specific way to bleed the brakes.
Is the anti-lock working?
Does the system self check and the light go out?
Did you change tire size or anything else than can affect the system?

Bad sensors are a far more common problem than the valve itself.

sorry so long to answer... some background... I just bought the truck so the question on the valve came about as when I bought the truck the brakes were like this. I figured could bleed was all that was needed. I did as typically would (PR, DR, PF, DF) and did get some air bubbles and did get a little better. I have never dealt with a Rear ABS valve or the like in the past so didn't honestly know about it until the neighbor (who has other F250's) mentioned it. then went looking etc.

as far as the anti-lock - not sure if working or not as I haven't done the good ol slamola and check type routine... Also - lets just say the truck isn't necessarily in perfect condition (i.e. doesn't have all the bulbs in the dash etc.) so the indicator lights and whatnot I don't fully trust. I have been spending lots of time recently replacing and jsut getting around to cracking into the dash to start on that kinda stuff... but wanted to get the mechanical working first - and obviously the brakes are top of the priority list...

the truck does have new tires and a more modern / newer wheel on it as well... so I do believe the guy I bought it from put his $$ there... so am assuming that was a change and is related.

you mention the sensor and is something to check rather simply. is there advise on where that might be located or called so I can look it up? I actually have been looking around at other posts as well and looks like is more difficult that simply bleeding (i.e. should really just take to a brake shop and have them bleed as might take a special tool or whatnot to do)... so might be into that this weekend looks like as a 1st option / next step..

thanks again