Soft Brake Pedal
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More Turbo
Joined: Apr 2003
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Soft Brake Pedal
Hi guys i have been trying to search and read up on the soft brake pedal issues on our trucks. Mine is a 94 F350 7.5 cclb 4x4. So I am going to try to fix mine tomorrow. I bought this truck several months back and had a mechanic put a new master, booster and new rear pads, drums and rear slaves on. Brakes work fine and I can stop decent, but the pedal is really soft. I also have a 95 F250 7.3 and the brakes work awesome in it. its like a night and and day difference. Anyway, I keep reading about the RABS valve. Is that the valve almost directly below the booster on the frame rail? Also, is there a load proportioning valve, if so where is this I can't seem to locate it. I think I am going to start with taking the RABS valve out and trying to go through it. Then re-blead everything. I have a feeling that this is my issue.
Cargo Master
Joined: Jan 2004
Posts: 3,118
Likes: 149
From: South Dakota
You say the pedal is really soft. Do you mean it pushes down too far before the brakes start to work? If you pump the brake pedal and then hold it down, will the brake pedal stay up until you push really hard and then it slowly goes down?
The most common problem seems to be most people don't get the rear brake shoes adjusted up tight enough. I would look into that possibility first thing.
The most common problem seems to be most people don't get the rear brake shoes adjusted up tight enough. I would look into that possibility first thing.
Tuned
Joined: Aug 2014
Posts: 305
Likes: 2
Proportioning valve is located on the master cylinder, the rear brake line screws into it. Yes, the RABS valve is located on the drivers side frame rail. You can bypass it by connecting the two lines via a small line with fittings.
Don't rule out collapsing rubber brake lines, rear brake shoes that are not adjusted out far enough and/or, air in the system.
I'd start with the latter. Also, a master cylinder from a 97 F350 will have a larger bore and provide better braking power.
Don't rule out collapsing rubber brake lines, rear brake shoes that are not adjusted out far enough and/or, air in the system.
I'd start with the latter. Also, a master cylinder from a 97 F350 will have a larger bore and provide better braking power.
Tuned
Joined: Aug 2014
Posts: 305
Likes: 2
Sizes: 1-1/16", 1-1/8", 1-1/4". You want the 1-1/4", it was found on the 97 F350's. Ask Napa for the specs, they should be able to look up the bore size. When you pick it up, inspect it, the bore size will be in raised numbers on the cylinder along with the number 79 on the other side.
Example from Advance: https://shop.advanceautoparts.com/p/...9i9VqfCro%2FFg
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More Turbo
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Mine says 1-1/8 on it. I eliminated the RABS valve on it and I have been bleeding for almost an hour. Have the rear tightened up with drag on the drums. Im about done with this POS. I have done lots of brakes and never have I had issues like this. Like I said my 95 7.3 has a pedal twice what this one feels like. I just don't get it.
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More Turbo
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Well i finally got it. I bled and bled and bled it, and finally all of a sudden the pedal came up!!!!! Now it feels very similar to my other pickup and i won't be nervous about my 5'2" wife driving it.
Now I need to figure out how to get rid of the OBS light and get cruise control working.
Now I need to figure out how to get rid of the OBS light and get cruise control working.
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Hotshot
Joined: Jun 2015
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I replaced the master and then the booster on my '89 because of the spongy pedal. When the booster didn't change anything I put the old booster back on. I learned that the RABS valve could cause this issue so I replaced it and the pedal was normal once again. I'm not sure why you bypassed the RABS valve instead of just replacing it unless you were trying to save a couple bucks. I'll admit it isn't the best ABS system but it does work on my truck. Pull the bulb to get rid of the ABS light? Just don't pull the red brake light.
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More Turbo
Joined: Jun 2003
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To get the light to go off and get the CC back, you could try replacing the speed sensor that is mounted on top of the differential. It fixed mine. But read this story first.
https://www.ford-trucks.com/forums/1...ed-sensor.html
https://www.ford-trucks.com/forums/1...ed-sensor.html
Fleet Owner
Joined: Oct 2005
Posts: 20,785
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From: Kentucky
Pull the RABS codes.....quit guessing at the root cause for the ABS light.
RABS Flashout Codes
courtesy of Steve83
RABS Flashout Codes
courtesy of Steve83
Hotshot
Joined: Jun 2015
Posts: 12,788
Likes: 2,425
Pull the RABS codes.....quit guessing at the root cause for the ABS light.
RABS Flashout Codes
courtesy of Steve83
RABS Flashout Codes
courtesy of Steve83
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More Turbo
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Abs light was on before I removed it. I coundnt care less about the ABS. I am more concerned about the brakes and the cruise control than the ABS. We all drove for how many hears with no ABS vehicles?
Fleet Owner
Joined: Oct 2005
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From: Kentucky
That would answer the reason for the ABS light being on. Missed the OP has already removed rhe hydraulic module.
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