HELP!!!! Brake problem!
Thread Starter
|
New User
Joined: Mar 2017
Posts: 23
Likes: 0
From: Arkansas
HELP!!!! Brake problem!
So I bled the brakes this afternoon on my 77 f100 because the pedal was sinking to the floor before I'd get any stopping or slow down...so I followed procedure I had read on here starting on the back right brake drum...loosened the nut had a buddy pump the brakes till fluid shot out then re tightened the nut. Did the same procedure on both back brakes...and she is still dropping to the floor!!!!
Is the vacuum booster bad?
Is the vacuum booster bad?
Senior User
Joined: Jul 2014
Posts: 328
Likes: 1
Re
from your post it is not clear on a few things
are you loosing any fluid when pumping and all nuts closed
are you keeping nuts closed during pumping except for the last pump where you open nut only when driver is pushing down pressure and you tighten nut before driver lets peddle up
are you loosing any fluid when pumping and all nuts closed
are you keeping nuts closed during pumping except for the last pump where you open nut only when driver is pushing down pressure and you tighten nut before driver lets peddle up
Thread Starter
|
New User
Joined: Mar 2017
Posts: 23
Likes: 0
From: Arkansas
No fluid loss from the lines while pumping and nuts closed...
I loosened the nuts...buddy pumped brakes till fluid shot out then he held brake pedal down and I retightened the nuts...did each rear wheel independently the same way...pedal still goes to the floor....
Checked master cylinder have slight seepage around front of cylinder with lid on and locked...
There is fluid in the main reservoir (bigger reservoir in the back) no fluid in the front smaller reservoir...
I loosened the nuts...buddy pumped brakes till fluid shot out then he held brake pedal down and I retightened the nuts...did each rear wheel independently the same way...pedal still goes to the floor....
Checked master cylinder have slight seepage around front of cylinder with lid on and locked...
There is fluid in the main reservoir (bigger reservoir in the back) no fluid in the front smaller reservoir...
Tuned
Joined: May 2016
Posts: 448
Likes: 13
If you are having your buddy pump the brakes keep the bleeder closed while pumping. Then when the brake pedal is being held down open the bleeder. Let the air out then close the bleeder. Then let the pedal up. Pumping the brake pedal with the bleeder open you are just sucking air into the brake lines. As a rule I follow have a helper push the brake pedal to the floor. Then open the bleeder let all the fluid and air stop flowing then close the bleeder. I usually have the engine off so my deaf ears can hear what the helper is saying
Senior User
Joined: Jul 2014
Posts: 328
Likes: 1
Pumping with nut open was my concern
You are trying to push the air out of the line
If nut is open and the brake pedle is traveling from down to up position you are filling line with air
You open nut only when pedle is moving from up to down position
So
With nut closed pump
Then apply pressure to pedle and hold pressure
Open nut and pedle will travel to floor pushing out air
Tighten nut
Let pedle up from floor pulling fresh fluid into line
Repeat pumping
Repeat the other steps until just a steady stream of fluid is all that comes out when you open nut as pedle is traveling to floor
You are trying to push the air out of the line
If nut is open and the brake pedle is traveling from down to up position you are filling line with air
You open nut only when pedle is moving from up to down position
So
With nut closed pump
Then apply pressure to pedle and hold pressure
Open nut and pedle will travel to floor pushing out air
Tighten nut
Let pedle up from floor pulling fresh fluid into line
Repeat pumping
Repeat the other steps until just a steady stream of fluid is all that comes out when you open nut as pedle is traveling to floor
Elder User
Joined: Sep 2015
Posts: 794
Likes: 19
From: between lost and found
and a lot of the new aftermarket Master cylinders tops/lids don't fit tightly to achieve maximum seal, I recall a fellow FTE'r shimming his to get his master cylinder to stop leaking
Trending Topics
Thread Starter
|
New User
Joined: Mar 2017
Posts: 23
Likes: 0
From: Arkansas
Pumping with nut open was my concern
You are trying to push the air out of the line
If nut is open and the brake pedle is traveling from down to up position you are filling line with air
You open nut only when pedle is moving from up to down position
So
With nut closed pump
Then apply pressure to pedle and hold pressure
Open nut and pedle will travel to floor pushing out air
Tighten nut
Let pedle up from floor pulling fresh fluid into line
Repeat pumping
Repeat the other steps until just a steady stream of fluid is all that comes out when you open nut as pedle is traveling to floor
You are trying to push the air out of the line
If nut is open and the brake pedle is traveling from down to up position you are filling line with air
You open nut only when pedle is moving from up to down position
So
With nut closed pump
Then apply pressure to pedle and hold pressure
Open nut and pedle will travel to floor pushing out air
Tighten nut
Let pedle up from floor pulling fresh fluid into line
Repeat pumping
Repeat the other steps until just a steady stream of fluid is all that comes out when you open nut as pedle is traveling to floor
I just thought that a simple brake bleed might fix the issue...boy I guess I was wrong! Lol!
I'll give it another go when I have more daylight out!Cheers! And thanks to all of you!
FTE Stories
Ford Trucks for Ford Truck Enthusiasts
3 Best / 3 Worst Parts of Modern Ford Ownership
Brett Foote
10 Amazing Upgrades That Solve Common Ford Truck Owner Headaches
Pouria Savadkouei
Every 2026 Ford Engine Explained
Brett Foote
10 Ugly Ford Trucks That We Still Kinda Love
Joe Kucinski
10 Things Every Truck Owner NEEDS (2026 Edition)
Michael S. Palmer
Rezvani's Latest Post-Apocalyptic Monster Is a Ford F-150 Raptor Underneath
Verdad Gallardo
Top 10 Most Expensive Ford Trucks Ever Sold on Bring a Trailer
Joe Kucinski
2027 Ford Super Duty Buyer's Guide (Every Model, Engine, & Package)
Brett Foote
Top 10 Ford Truck Tragedies
Joe Kucinski
Fleet Mechanic
Joined: Feb 2010
Posts: 1,742
Likes: 5
From: Near St. Joseph,MO
If small reservoir was empty, that's why it went to floor. By letting it go empty, it's now got air in it. You need to completely rebleed the whole system and keep the reservoirs full
Post Fiend
Joined: Apr 2002
Posts: 19,311
Likes: 97
From: Waterloo, Iowa
If small reservoir was empty (I didn't catch that part) he needs to find the source/cause of the leak.
Bleeding won't help anything. A leak is a leak, the fluid doesn't disappear. 30 year old system ... it needs a lot of work by rights.
Bleeding won't help anything. A leak is a leak, the fluid doesn't disappear. 30 year old system ... it needs a lot of work by rights.
FTE Legend
Joined: Nov 2015
Posts: 30,935
Likes: 4,124
From: Angier, NC
But the pedal is going to the floor without pumping at all...I filled the front reservoir and will re attempt tomorrow or the next day. I went to autozone and ordered a new master cylinder just in case...since they really aren't to expensive....might just swap it out and follow the Haynes manual and recheck the whole system with it up on jack stands.
I just thought that a simple brake bleed might fix the issue...boy I guess I was wrong! Lol! I'll give it another go when I have more daylight out!
Cheers! And thanks to all of you!
I just thought that a simple brake bleed might fix the issue...boy I guess I was wrong! Lol!
I'll give it another go when I have more daylight out!Cheers! And thanks to all of you!
get it to come up I would say bad master.
I think replacing the master to start is the best thing right now being you bought it.
Just make sure you bench bleed it before you install it.
If you find pumping the pedal bring it up you will need to bleed the system as air got in some how.
BTW when I have a helper for bleeding I have them pump 4 time and hold, they yell out "holding", then I open bleeder and have them hold to floor till I close bleeder and I say "pump". I do this maybe 3 time per wheel, check the fluid level and top off and move to the next wheel.
Dave ----
Thread Starter
|
New User
Joined: Mar 2017
Posts: 23
Likes: 0
From: Arkansas
Ok...so I went under and rebled the entire system after filling the small reservoir and followed the steps outlined here by all of y'all. Even after all of that and verifying the small reservoir still has fluid in it...the pedal still goes to the floor.
So now my thoughts are to put her up on jack stands, pull all the tires and do a complete inspection of all the brakes pads and shoes to verify they are all still good working order, and then proceed with replacing the master cylinder and possibly the pressure differential valve and booster.
That is, of course, if someone else has a thought??
I'm all ears.
Thanks and cheers to you all!
So now my thoughts are to put her up on jack stands, pull all the tires and do a complete inspection of all the brakes pads and shoes to verify they are all still good working order, and then proceed with replacing the master cylinder and possibly the pressure differential valve and booster.
That is, of course, if someone else has a thought??
I'm all ears.
Thanks and cheers to you all!
Elder User
Joined: Feb 2014
Posts: 878
Likes: 3
From: british columbia, canada
Ok, I told you in your other post that you need to bleed the master. That's why you aren,t able to build pressure. Go to the store and buy a master bleeding kit. You said the PO put a new master on right? He probably did not bleed it first.