• NAXJA is having its 18th annual March Membership Drive!!!
    Everyone who joins or renews during March will be entered into a drawing!
    More Information - Join/Renew
  • Welcome to the new NAXJA Forum! If your password does not work, please use "Forgot your password?" link on the log-in page. Please feel free to reach out to [email protected] if we can provide any assistance.

Sudden soft brake pedal

Volatile

NAXJA Forum User
Location
Delaware
The other day leaving for work I noticed my brake pedal is significantly softer than it should be, not grabbing until near the floor. This thing has been a brake nightmare, beginning with replacing the bendix abs with a 96 booster/master setup. Rotors and pads are ~2 months old, shoes and hardware ~1.5 years old.

I don’t see any visible leaks at the master, prop valve, calipers, or lines running underneath, my wife hit the brakes and I didn’t see anything leaking then either. Reservoir hasn’t gone down any noticeable amount. I can’t get the system to build pressure with it running, or off, which still makes me think it’s a leak/air issue rather than vacuum.

The only thing I can think of is a wheel cylinder, as I cheaped out when I did the rears and only did the passenger side since it was visibly leaking. It looks like the back of the drum on the driver side is almost slimy looking around the adjuster hole, compared to the bone dry passenger drum, so I’m thinking my cheap ways are coming back to bite me. I’ve since been buying better parts and replacing things correctly.

I know the solution is probably obvious to most, but before I tear it apart and replace the cylinder, am I going in the right direction? Is there anything else I can test to definitively track this issue down?

Thanks


Sent from my iPhone using Tapatalk
 
Sounds more like the master cylinder internal failure.
 
Sounds more like the master cylinder internal failure.



It very well could be for all I know, but what makes you say that? I forgot to mention that the master is also about 1.5 years old, replaced when tracking down my previous issues which ultimately ended up being the opposite wheel cylinder.


Sent from my iPhone using Tapatalk
 
It very well could be for all I know, but what makes you say that? I forgot to mention that the master is also about 1.5 years old, replaced when tracking down my previous issues which ultimately ended up being the opposite wheel cylinder.


Sent from my iPhone using Tapatalk


Pull the wheel on the rear that you think is leaking and check. If it's suddenly not pumping up, no obvious leaks, and not losing fluid, that's usually a failed seal in the master though.
 
Was definitely the wheel cylinder. Inside one of the caps was a nasty, sludgy mess. Bled the crap out of them afterward and it brakes harder than it ever did before.

I think last time I bled them after my overhaul I didn’t get all the air out. This time I took my time using the one person bottle method, and it brakes like a dream.

Thanks everyone.


Sent from my iPhone using Tapatalk
 
Back
Top