Mushy pedal ???
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4wd Low
Joined: Apr 2025
Posts: 12
Likes: 3
Mushy pedal ???
1980 F250 4wd, and my brake pedal has always been mushy, yet I’ve been able to stop just fine, everything seems normal I just need to push the pedal about half way down before I start to feel the brakes doing anything. Now that I’ve gotten other projects done I’d like to solve this issue as it is pretty annoying. So far I’ve replaced the master cylinder, booster, all new front brakes and lines, and I’m not exactly what’s been done to the drums as I was on vacation while my grandpa “went through them” and said he checked them and they looked good, not sure what he did to them, and that was over a year ago now. Today I tried to adjust the drums, which didn’t seem like it did very much, almost made it worse but I just can’t tell. I’m puzzled. Should I start by pulling the drums off and getting a rebuild kit (or so I think that’s what it’s called) is it a Vaccuum leak? I have no idea. Any help is much appreciated.
Last edited by 1994F150351w; Jul 9, 2025 at 01:23 AM.
Lead Driver
Joined: Nov 2013
Posts: 7,173
Likes: 1,173
Here you go:
https://www.ford-trucks.com/forums/1...-bleeding.html
Edit: Conventional or vacuum bleeding doesn't work very well on these trucks if the system has been disturbed upstream of the proportioning valve, e.g. a new master cylinder. You'll drive yourself crazy bleeding over and over with no improvement. The link above explains the situation and why pressure bleeding will take care of it.
https://www.ford-trucks.com/forums/1...-bleeding.html
Edit: Conventional or vacuum bleeding doesn't work very well on these trucks if the system has been disturbed upstream of the proportioning valve, e.g. a new master cylinder. You'll drive yourself crazy bleeding over and over with no improvement. The link above explains the situation and why pressure bleeding will take care of it.
Lead Driver
Joined: Jun 2013
Posts: 5,667
Likes: 1,159
From: Tolland, CT
You can get DOT3 fluid from many discount stores for less $$ than the auto parts stores.
You are going to want to inspect the rear wheel cylinders so you know they are not leaking. Check all the 40+y/o brake lines too.
You are going to want to inspect the rear wheel cylinders so you know they are not leaking. Check all the 40+y/o brake lines too.
Moderator
Joined: Jan 2001
Posts: 56,983
Likes: 2,736
From: Virginia
Mushy pedal sounds like air. A low pedal usually means the brake shoes in the rear are not adjust out enough. You need to make sure your adjuster is lubed and free, and then put the drum back on and turn it while moving the adjuster, till the drum locks up. Then turn the adjuster back the other way till you can turn the drum, and there is still some rubbing. Do both sides, and see where the pedal is at.
I had one other thing happen years ago that caused this on a truck I had. No matter what I did, I had a mushy pedal. Found out the rear drums had been turned to thin, and would flex when the shoes made contact. Bought new drums, problem solved. Some shops do not check the drums before they turn them. They do have a spec and when you go beyond that spec, you throw them away.
I had one other thing happen years ago that caused this on a truck I had. No matter what I did, I had a mushy pedal. Found out the rear drums had been turned to thin, and would flex when the shoes made contact. Bought new drums, problem solved. Some shops do not check the drums before they turn them. They do have a spec and when you go beyond that spec, you throw them away.
FTE Legend
Joined: Nov 2015
Posts: 30,904
Likes: 4,122
From: Angier, NC
I had a rebuilt master that never gave me a good pedal no matter how much I blead the brakes even with a pressure bleeder.
1 day I was swapping out the wrong ebrake cables and when I hit the pedal it went to the floor, again no bleeding would get it to get good again.
I replaced the little over a year-old master with a new one, not a rebuilt master, and been good now for 4 years.
So if the rear shoes have been adjusted, they should drag a little, half a turn of the wheel when you spin it, and not getting any air out when you bleed them that master may be bad.
BTW how are you bleeding the system? If using 2 people, 1 pumping the outer bleeding, make sure the pumper is not pumping too fast or fluid will not have time to refill the piston area.
They should pump 3 to 5 times slowly and tell you when holding and hold the pedal to the floor when you open the bleeder till you close it and tell them to pump again.
Dave ----
1 day I was swapping out the wrong ebrake cables and when I hit the pedal it went to the floor, again no bleeding would get it to get good again.
I replaced the little over a year-old master with a new one, not a rebuilt master, and been good now for 4 years.
So if the rear shoes have been adjusted, they should drag a little, half a turn of the wheel when you spin it, and not getting any air out when you bleed them that master may be bad.
BTW how are you bleeding the system? If using 2 people, 1 pumping the outer bleeding, make sure the pumper is not pumping too fast or fluid will not have time to refill the piston area.
They should pump 3 to 5 times slowly and tell you when holding and hold the pedal to the floor when you open the bleeder till you close it and tell them to pump again.
Dave ----
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