89 f350 brake problems

Reply Subscribe

Thread Tools

Search this Thread

Feb 15, 2018 | 07:27 AM

Gravy train89

Thread Starter

New User

Joined: Feb 2018

Posts: 11

Likes: 0

89 f350 brake problems

I have a 89 f350 7.5L that I've been having rear brakes issues, finally found that the tabs valve was sticking causeing them to drag. When I bypassed the valve even on jack stands the rear brake barely worked. I put a new valve in and that fixed my original problem but it doesn't stop like it used to.Also the pedal goes almost all the way down before anything starts to happen. I bleed them many times no air. I'm kind of thinking my master cylinder has been on it's way out and now that I don't daily it anymore I get in it and realize it used to stop way better than it does. The only thing in the entire system that is original is the master cylinder. Should I just replace it? Any thoughts? Thanks.

Feb 15, 2018 | 10:07 AM

Scott Bowmaster

Senior User

Joined: Dec 2017

Posts: 109

Likes: 0

If they're the "self adjusting" type, like mine has. Drive it in reverse and slam on the brakes a few times, they should tighten up on their own.
I experienced the same thing, and an older guy told me to back it up and jack the brakes a few times and they got a lot better immediately.

Feb 15, 2018 | 11:15 AM

Gravy train89

Thread Starter

New User

Joined: Feb 2018

Posts: 11

Likes: 0

I've never tried that I've always just manually adjusted them in. so I know they're pretty close, but I'll give it a shot.

Feb 15, 2018 | 01:04 PM

Gravy train89

Thread Starter

New User

Joined: Feb 2018

Posts: 11

Likes: 0

Also I meant RABS not TABS.

Feb 15, 2018 | 04:18 PM

madpogue

Lead Driver

Joined: Oct 2003

Posts: 8,476

Likes: 37

From: Madison, WI

Did you bleed the RABS valve? Did you bleed in reverse order of distance from the MC (RR, LR, RABS, RF, LF)?

Feb 15, 2018 | 06:26 PM

Gravy train89

Thread Starter

New User

Joined: Feb 2018

Posts: 11

Likes: 0

Yes 5 times. Stopped getting air after 2 times, I don't understand how some people get rid of the RABS valve but when I bypassed it my rear brakes hardly worked at all with the rear on jack stands. Air or not they should have still worked. Right?

Feb 16, 2018 | 06:28 AM

Scott Bowmaster

Senior User

Joined: Dec 2017

Posts: 109

Likes: 0

I bypassed the RABS valve in my Bronco, and I had to adjust the pushrod out a few turns because I didn't get brakes until the pedal was pretty much on the floor
Maybe adjust out your pushrod a little, see if you get some better braking action higher in the pedal.
I think your first post might be dead on, that master cylinder might just be done.