Very soft brake pedal!
Logistics Pro
Joined: Sep 2010
Posts: 4,411
Likes: 4
From: Victor, MT
its a goofy looking manifold with all the brake lines coming out of it, my brakes are great....i step on them and I dont get a sinking or anything, but my RABS light is on....what causes this lol?
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Laughing Gas
Joined: Apr 2011
Posts: 1,002
Likes: 7
From: London, KY
I don't know but after bleeding all the brake lines today, my park brake light is staying on now! WTF?? Oh well, at least the truck stops when I want it to! I've got the truck and a 16' trailer loaded down with scrap metal right now so I'll see how it does when I haul it off tomorrow.
Senior User
Joined: Dec 2011
Posts: 484
Likes: 0
From: Rockland Ontario
I don't know but after bleeding all the brake lines today, my park brake light is staying on now! WTF?? Oh well, at least the truck stops when I want it to! I've got the truck and a 16' trailer loaded down with scrap metal right now so I'll see how it does when I haul it off tomorrow.
Why it's on now, I believe, is your master ran out of fluid while you were bleeding it.
Here's an Excellent thread on the subject at hand.
Read the whole thread for how this problem was solved.
https://www.ford-trucks.com/forums/5...e-dilemma.html
Last edited by hookedondiesel; May 15, 2012 at 05:49 AM. Reason: added thread
Mountain Pass
Joined: Oct 2000
Posts: 180
Likes: 0
From: Backwoods Massachusetts
What I'm hearing here is:
- booster works (difference running vs not)
- master cylinder is bad (leaking down)
One other thing to check with the age of these trucks is the rubber lines. When they degrade they can swell with pressure.
Just my humble opinion!
Good luck,
- Jeff
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Laughing Gas
Joined: Apr 2011
Posts: 1,002
Likes: 7
From: London, KY
I'm setting in the truck right now. With it not running, with both feet and all of my 180 pounds, I cannot make the pedal sink down to the floor. With it running, the pedal will stop up off of the floor then gradually sink on down.
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More Turbo
Joined: Nov 2010
Posts: 521
Likes: 6
From: Cincinnati, OH
If the pedal sinks under light pressure, that can indicate a bad master cyl. It is leaking back and usually shows up as brake fluid leaking down the back where it bolts on. Check carefully for fluid, it might be going into your booster instead of leaking down.
Even new master cyl could be bad, unfortunately. Easy enough to unbolt it and pull it away a slight amount to see if any fluid.
The brake light being on could be your proportioning valve is uncentered. There is apiston the floats between the sides and if it gets too far off center, it will set the light. See the small wire connected to it? That is what causes the light.
Even new master cyl could be bad, unfortunately. Easy enough to unbolt it and pull it away a slight amount to see if any fluid.
The brake light being on could be your proportioning valve is uncentered. There is apiston the floats between the sides and if it gets too far off center, it will set the light. See the small wire connected to it? That is what causes the light.
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Laughing Gas
Joined: Apr 2011
Posts: 1,002
Likes: 7
From: London, KY
The brake light issue is fixed, me being the retard that I am forgot to add more brake fluid after I got done bleeding the lines. It wasn't empty but it was down to the sensor. It went off when I filled it back up. If it was the master cylinder leaking off, wouldn't it do it just the same without the truck running? I have a new booster and I'm gonna put it on tomorrow and see if that fixes the problem. I'll report back.
Senior User
Joined: Dec 2011
Posts: 484
Likes: 0
From: Rockland Ontario
LSO, I just recently did my brake's....
The pedal was good but the reason I did them was, (and this is a newly purchased truck that the guy told me the brakes were just done, crap)
when I stopped, my rear wheel was smoking. The wheel cylinder had a small leak, from inside the rubber cup, nothing major, but had to be fixed.
I installed.....
All new hose's,x3
Two new rear wheel cylinder's.
Two new rear drum's.
New shoes for the back, front were 3/4 and working properly.
New brake lines, front to back.
Adjusted rear brakes.
Bled and re-bled the system.
Pedal would go to the floor.
when running.
Pedal was hard when it wasn't running.
Re-bled, again
Still the same issue.
Re-adjusted the rear shoes, one more time, until the wheels had a drag on them.
Now, the brakes are almost back to normal.
I personally don't think it's your booster.
"IF" the rear's are adjusted properly and your absolutely sure there is no more air in the system, then I would do one of two things.....
Bypass the ABS, as was suggested, or replace the master, it may have been damaged if it went dry in "your" bleeding process.
In any case, you'll have to bleed again.
The pedal was good but the reason I did them was, (and this is a newly purchased truck that the guy told me the brakes were just done, crap)
when I stopped, my rear wheel was smoking. The wheel cylinder had a small leak, from inside the rubber cup, nothing major, but had to be fixed.
I installed.....
All new hose's,x3
Two new rear wheel cylinder's.
Two new rear drum's.
New shoes for the back, front were 3/4 and working properly.
New brake lines, front to back.
Adjusted rear brakes.
Bled and re-bled the system.
Pedal would go to the floor.
when running.Pedal was hard when it wasn't running.
Re-bled, again
Still the same issue.
Re-adjusted the rear shoes, one more time, until the wheels had a drag on them.
Now, the brakes are almost back to normal.
I personally don't think it's your booster.
"IF" the rear's are adjusted properly and your absolutely sure there is no more air in the system, then I would do one of two things.....
Bypass the ABS, as was suggested, or replace the master, it may have been damaged if it went dry in "your" bleeding process.
In any case, you'll have to bleed again.
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