Soft Brake Pedal...STILL - Ford Truck Enthusiasts Forums



Pre-Power Stroke Diesel (7.3L IDI & 6.9L) Diesel Topics Only

Soft Brake Pedal...STILL

Reply
 
 
 
LinkBack Thread Tools Search this Thread
  #1  
Old 08-12-2011, 04:43 AM
WEST AUSSIE 94 250's Avatar
WEST AUSSIE 94 250 WEST AUSSIE 94 250 is offline
Senior User
Thread Starter
 
Join Date: Nov 2008
Location: Western Australia
Posts: 319
WEST AUSSIE 94 250 is starting off with a positive reputation.
Soft Brake Pedal...STILL

Hey guys, long time no chat. Still having trouble with my brakes, seems to be a common story around here.
Just finished replacing both rear brake assemblies. New drums, shoes all springs and clips and new slave cylinders on both rears. Replaced RABS unit with a rebuilt one from Rockauto. Vacuum pump seems to be fine. Used a vacuum bleeder to remove all old fluid and air from system, adjusted rear shoes up good and still really soft pedal. Goes right to the floor if you push on it for a few seconds. Master cylinder is only 4-5 years old according to the previous owner but brakes have never been good since I've owned the truck. No visable leaks in the system or around the master cylinder. Will bench bleeding the master help even though its been in the truck for awhile? Should I just replace the master and make it a whole new system?
Any advice will be greatly appreciated as this has been ongoing for a while now and is really starting to be a pain.
Cheers, Frank
<!-- / message --><!-- sig -->
Reply With Quote
  #2  
Old 08-12-2011, 05:07 AM
Lazy K Lazy K is offline
Post Fiend
 
Join Date: Jan 2005
Posts: 8,402
Lazy K is a name known to allLazy K is a name known to allLazy K is a name known to allLazy K is a name known to allLazy K is a name known to allLazy K is a name known to all
Try bleeding the brakes the conventional way with a helper.
Get the helper to pump up the brakes and hold pressure on the pedal while right rear bleed screw is opened and pedal is pressed to the floor. Hold pedal to floor while bleed screw is closed. Release pedal, open bleed screw and repeat until all air is out. Do the same with left rear, RABS module, right front, left front and see if that helps.
Reply With Quote
  #3  
Old 08-12-2011, 06:23 AM
mistakenID mistakenID is offline
Posting Guru
 
Join Date: Jul 2004
Location: West Valley Utah
Posts: 1,627
mistakenID is gaining momentum as a positive member of FTE.mistakenID is gaining momentum as a positive member of FTE.
I'd say the master cylinder is leaking internally past the seals. You "may" still have a bit of air in the system but that would not account for the brake pedal slowly sinking to the floor.
Reply With Quote
  #4  
Old 08-12-2011, 09:55 AM
mechmagcn's Avatar
mechmagcn mechmagcn is offline
Diesel Junky
 
Join Date: Dec 2005
Location: Moro Bay, AR
Posts: 4,067
mechmagcn has a very good reputation on FTE.mechmagcn has a very good reputation on FTE.mechmagcn has a very good reputation on FTE.
Does it slowly go to the floor if you hold a lot of pressure on the pedal or does it go down quickly? A friend bought a F350 new in 94 that the pedal slowly sank if holding a lot of pressure on it, Ford said it was normal for the RABS system. My 95 F250 has done it for the 5 years I have been driving it. The Ford rep I talked to said to try to move the truck when the pedal is all the way to the floor, I tried this with both trucks and can't move them with the throttle at WOT and the brake pedal down.
Reply With Quote
  #5  
Old 08-12-2011, 11:25 AM
'94IDITurbo7.3's Avatar
'94IDITurbo7.3 '94IDITurbo7.3 is offline
Postmaster
 
Join Date: Jul 2011
Posts: 3,061
'94IDITurbo7.3 is gaining momentum as a positive member of FTE.
Quote:
Originally Posted by Lazy K View Post
Try bleeding the brakes the conventional way with a helper.
x2^^

I hate vacumm bleeders. i think they pump more air in than they do out.
Reply With Quote
  #6  
Old 08-12-2011, 01:20 PM
WEST AUSSIE 94 250's Avatar
WEST AUSSIE 94 250 WEST AUSSIE 94 250 is offline
Senior User
Thread Starter
 
Join Date: Nov 2008
Location: Western Australia
Posts: 319
WEST AUSSIE 94 250 is starting off with a positive reputation.
I will try re-bleeding tomorrow. The conventional way is how my father and I always did our racecars as a kid but as I live alone a ways out of town getting a helper can be hard. I have a mate coming tomorrow so will get him to give me a hand. I am fairly sure the pedal goes down slowly under heavy pressure but the fact still remains that it goes most of the way to the floor before it gets any pressure. If I stamp on the brakes it does stop but just seems like it should have more feel.
Will see how I go in the morning.
Cheers guys.
Reply With Quote
  #7  
Old 08-13-2011, 09:15 PM
Onus's Avatar
Onus Onus is offline
Posting Guru
 
Join Date: Jun 2009
Location: Charlotte, NC
Posts: 1,318
Onus is gaining momentum as a positive member of FTE.
I always though these trucks have a bit of a squishy pedal but i like that when you step on it it actually does something. Unlike some cars that have a stiff pedal but it doesn't equal the braking power. Speaking of which i need to bleed the brakes on my plow truck.
Reply With Quote
  #8  
Old 08-16-2011, 09:55 AM
WEST AUSSIE 94 250's Avatar
WEST AUSSIE 94 250 WEST AUSSIE 94 250 is offline
Senior User
Thread Starter
 
Join Date: Nov 2008
Location: Western Australia
Posts: 319
WEST AUSSIE 94 250 is starting off with a positive reputation.
Righto, update time. Removed the master cylinder cleaned and bench bled it. Refited with the plugs still in and tested the pedal with the engine running for vacuum. Was perfect, good hard pedal so master cylinder all good. Reconnected the lines and bled the system and the soft pedal was back. On the suggestion of a mate I clamped the flexible lines to the frontwheels and all of a sudden good pedal again. Drove around the yard with just the rear brakes and pulls up on a dime with good pedal feel. So from this I find that the front calipers are the problem. Clamped the rear flexible line and tried with just the fronts and truck still stopped good but the pedal went right to the floor. Looks like I will be stripping the fronts.
Is there anything I should look out for while removing the front rotors from a 4wd with a ttb axle?
Does it involve stripping the front lock hubs and if so is this something I can do at home or is it a specialist job?
Will measure all the variables on the rotors and checkout the operation ofthe calipers.
Am glad I have narrowed it down to one end of the truck. Gives me something to focus on.
Reply With Quote
  #9  
Old 08-16-2011, 11:43 AM
Lazy K Lazy K is offline
Post Fiend
 
Join Date: Jan 2005
Posts: 8,402
Lazy K is a name known to allLazy K is a name known to allLazy K is a name known to allLazy K is a name known to allLazy K is a name known to allLazy K is a name known to all
the locking hubs should be no problem. Remove the little cap screws and cap. Remove the inner and outer snap rings. The one around the inside of the hub may need a small screwdriver or dental pick to pry it out. The locking mechanism then pulls straight out.
You now have access to the bearing retainer nuts. You might need the pronged wrench to get these out but you could probably make one.
Once the bearing nuts are off and the caliper is out of the way the hub/rotor slides off the spindle. You can then press or pound the lugs out and seperate the rotor from the hub.
Reply With Quote
  #10  
Old 08-17-2011, 03:42 AM
WEST AUSSIE 94 250's Avatar
WEST AUSSIE 94 250 WEST AUSSIE 94 250 is offline
Senior User
Thread Starter
 
Join Date: Nov 2008
Location: Western Australia
Posts: 319
WEST AUSSIE 94 250 is starting off with a positive reputation.
Sounds fairly straight forward. Will give it a go tonight.
Cheers LazyK
Reply With Quote
  #11  
Old 08-11-2014, 10:49 AM
94F-150NEWBIE 94F-150NEWBIE is offline
New User
 
Join Date: Oct 2012
Posts: 2
94F-150NEWBIE is starting off with a positive reputation.
Did you figure out the issue with the soft peddle?
Reply With Quote
  #12  
Old 08-11-2014, 11:15 AM
hairyboxnoogle's Avatar
hairyboxnoogle hairyboxnoogle is offline
Post Fiend
 
Join Date: Apr 2008
Location: Jordan Valley, OR
Posts: 5,983
hairyboxnoogle is gaining momentum as a positive member of FTE.hairyboxnoogle is gaining momentum as a positive member of FTE.
Most likely the flexible rubber brake line was getting soft and expanding. This can make the brakes very soft and unresponsive.
Reply With Quote
 
 
Reply

Related Topics
Thread Thread Starter Forum Replies Last Post
Need help / info on '76 brake please. Nitro901 1973 - 1979 F-100 & Larger F-Series Trucks 38 09-17-2016 07:53 PM
1973 F350 Brakes Spongy After New Master Cylinder jcarrick 1973 - 1979 F-100 & Larger F-Series Trucks 17 04-10-2013 07:00 PM
Overflowing Master Cylinder therealulysses 1973 - 1979 F-100 & Larger F-Series Trucks 14 08-26-2012 08:08 PM
(updated)Replaced [some stuff], brakes still suck. burnout400m 1987 - 1996 F150 & Larger F-Series Trucks 35 03-22-2012 09:46 PM
1997 E-150 Conversion Van Brakes ydaveitsu Brakes, Steering, Suspension, Tires, & Wheels 4 08-05-2011 01:29 PM


Go Back   Ford Truck Enthusiasts Forums >

Tags
1999, 94, brake, bronco, duty, f250, f350, floor, ford, heavy, low, pedal, sinking, soft, superduty, trucks

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

Forum Jump


All times are GMT -5. The time now is 09:37 AM.


This forum is owned and operated by Internet Brands, Inc., a Delaware corporation. It is not authorized or endorsed by the Ford Motor Company and is not affiliated with the Ford Motor Company or its related companies in any way. FordŽ is a registered trademark of the Ford Motor Company.