Notices
1973 - 1979 F-100 & Larger F-Series Trucks Discuss the Dentsides Ford Truck
Sponsored by:
Sponsored by: Moser

Bake problems

Thread Tools
 
Search this Thread
 
Old Sep 13, 2021 | 08:54 PM
  #1  
Davis f250's Avatar
Davis f250
Thread Starter
|
5th Wheeling
Joined: May 2021
Posts: 30
Likes: 10
Bake problems

OK guys. My son posted a question regarding his brakes on his 78 F250. Front brakes were tighting after a little while of driving to the point that the truck wouldn't move. We changed both flex lines and crossed our fingers. No luck! We bought the truck from an original owner that said that booster, master cylinder and calipers were original. (They looked it!). Truck has 107,000 original miles. Booster has given no assistance since we bought the truck. I went ahead and decided to replace all original parts. Booster, master cylinder, flex lines, and calipers. The problem still exists. Is it possible that the booster somehow is building pressure and applying plunger pressure to the master cylinder? What about proportioning valve? I'd welcome any advise
 
Reply
Old Sep 13, 2021 | 09:27 PM
  #2  
440 sixpack's Avatar
440 sixpack
Lead Driver
5 Year Member
Photogenic
Photoriffic
Community Builder
Joined: Oct 2018
Posts: 7,847
Likes: 2,353
Are you saying the new booster isn't doing anything ? do you have good vacuum to it ?

Did you check the rod length between the booster and master ?
 
Reply
Old Sep 13, 2021 | 09:30 PM
  #3  
arnegrant's Avatar
arnegrant
Tuned
Joined: May 2006
Posts: 304
Likes: 77
From: St Paul MN
In my experience, grabbing brakes are from air in the lines.

Bleeding without equipment takes two people, some hose, excess container, and a container of new brake fluid.

Work your way around the truck one tire at a time. You know there is air in the line if you open the bleeder and fluid comes out without pushing down the pedal.

I will see if there is a good video on it

Watch out, the fluid eats paint and shouldn't get on your skin
 
Reply
Old Sep 13, 2021 | 09:35 PM
  #4  
440 sixpack's Avatar
440 sixpack
Lead Driver
5 Year Member
Photogenic
Photoriffic
Community Builder
Joined: Oct 2018
Posts: 7,847
Likes: 2,353
I've never had brake fluid DOT 3 bother me but it is hard on paint. that's why I use DOT 5 fluid.
 
Reply
Old Sep 13, 2021 | 09:37 PM
  #5  
buckin69bronco's Avatar
buckin69bronco
Laughing Gas
15 Year Member
Photogenic
Joined: Aug 2010
Posts: 896
Likes: 55
From: Bothell
Did you replace the proportioning valve? A sticking prop valve can keep holding pressure every time you hit the brakes and cause your issue.
 
Reply
Old Sep 13, 2021 | 09:39 PM
  #6  
arnegrant's Avatar
arnegrant
Tuned
Joined: May 2006
Posts: 304
Likes: 77
From: St Paul MN

3:00 to 5:00 gets you the idea

I put a hose on the bleeder so it isnt so messy.

If you pump the brakes a few times, stop, and open the bleeder with no force on the pedal and fluid shoots out there is still air in it.

Sometimes helps to let it sit overnight (air gets stuck in pockets)

good luck
 
Reply
Old Sep 13, 2021 | 10:23 PM
  #7  
440 sixpack's Avatar
440 sixpack
Lead Driver
5 Year Member
Photogenic
Photoriffic
Community Builder
Joined: Oct 2018
Posts: 7,847
Likes: 2,353
The OP says to the point the vehicle won't move. that's not air.
 
Reply
Old Sep 14, 2021 | 12:23 AM
  #8  
Christmas's Avatar
Christmas
Logistics Pro
5 Year Member
Liked
Loved
Community Favorite
Joined: Jun 2018
Posts: 3,550
Likes: 441
No it has to do with the master cylinder rod adjustment not releasing. Power brakes or not the rod is not coming back to a reset the master cylinder and holding pressure.
 
Reply
FTE Stories

Ford Trucks for Ford Truck Enthusiasts

story-0

Top 10 Ford Truck Tragedies

 Joe Kucinski
story-1

AEV FXL Super Duty - the Super Duty Raptor Ford Doesn't Make

 Brett Foote
story-2

Lobo Vs Lobo: Proof the F-150 Lobo Should Be Even Lower!

 Michael S. Palmer
story-3

Ford's 2001 Explorer Sportsman Concept Looks For a New Home

 Verdad Gallardo
story-4

10 Best Ford Truck Engines We Miss the Most!

 Joe Kucinski
story-5

2026 Shelby F-150 Off-Road: Better Than a Raptor R?

 Brett Foote
story-6

2027 Super Duty Carhartt Package First Look: 12 Things You NEED to Know!

 Michael S. Palmer
story-7

10 Most Surprising 2026 Ford Truck Features!

 Joe Kucinski
story-8

Top 10 Ford Trucks Coming to Mecum Indy 2026

 Brett Foote
story-9

5 Best / 5 Worst Ford Truck Wheels of All Time

 Joe Kucinski
Old Sep 14, 2021 | 06:14 AM
  #9  
Davis f250's Avatar
Davis f250
Thread Starter
|
5th Wheeling
Joined: May 2021
Posts: 30
Likes: 10
Thanks for all the input. To address the first response. The new booster is working great. The rod is adjusted correctly and I have good pedal. I feel pretty certain the brakes are bled completely. I guess I'll look at he proportioning valve. I still welcome any input
 
Reply
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
AZSCAWPION
1961 - 1966 F-100 & Larger F-Series Trucks
0
Mar 27, 2017 10:30 PM
Bowsandovals
1948 - 1956 F1, F100 & Larger F-Series Trucks
43
Jun 13, 2016 06:28 PM
85AustinTucker
1980 - 1986 Bullnose F100, F150 & Larger F-Series Trucks
7
Mar 7, 2014 11:06 AM
chesire17201
1973 - 1979 F-100 & Larger F-Series Trucks
9
Feb 5, 2012 02:38 PM
67lunargreen
1967 - 1972 F-100 & Larger F-Series Trucks
1
Aug 5, 2008 09:24 PM




All times are GMT -5. The time now is 08:03 AM.

story-0
Top 10 Ford Truck Tragedies

Slideshow: Top 10 Ford truck tragedies.

By Joe Kucinski | 2026-05-18 19:34:33


VIEW MORE
story-1
AEV FXL Super Duty - the Super Duty Raptor Ford Doesn't Make

And it might be even better than that.

By Brett Foote | 2026-05-18 19:26:42


VIEW MORE
story-2
Lobo Vs Lobo: Proof the F-150 Lobo Should Be Even Lower!

Slideshow: Does lowering an F-150 Lobo RUIN the ride quality?

By Michael S. Palmer | 2026-05-18 19:20:37


VIEW MORE
story-3
Ford's 2001 Explorer Sportsman Concept Looks For a New Home

Slideshow: Ford's bizarre fishing-themed Explorer concept has resurfaced after spending decades largely forgotten.

By Verdad Gallardo | 2026-05-12 18:07:46


VIEW MORE
story-4
10 Best Ford Truck Engines We Miss the Most!

Slideshow: The 10 best Ford truck engines we miss the most.

By Joe Kucinski | 2026-05-12 13:09:47


VIEW MORE
story-5
2026 Shelby F-150 Off-Road: Better Than a Raptor R?

Slideshow: first look at the 810 hp 2026 Shelby F-150 Off-Road!

By Brett Foote | 2026-05-12 12:50:07


VIEW MORE
story-6
2027 Super Duty Carhartt Package First Look: 12 Things You NEED to Know!

Slideshow: Everything You Need to Know about the 2027 Super Duty Carhartt Package!

By Michael S. Palmer | 2026-05-07 17:51:06


VIEW MORE
story-7
10 Most Surprising 2026 Ford Truck Features!

Slideshow: 10 most surprising Ford truck options/features in 2026.

By Joe Kucinski | 2026-05-05 11:17:22


VIEW MORE
story-8
Top 10 Ford Trucks Coming to Mecum Indy 2026

Slideshow: Here are the top 10 Fords coming to Mecum Indy 2026.

By Brett Foote | 2026-05-04 13:49:49


VIEW MORE
story-9
5 Best / 5 Worst Ford Truck Wheels of All Time

Slideshow: The 5 best and 5 worst Ford truck wheels of all time

By Joe Kucinski | 2026-04-29 16:49:01


VIEW MORE