• Welcome Visitor! Please take a few seconds and Register for our forum. Even if you don't want to post, you can still 'Like' and react to posts.

Brakes grabbing after startup

The_Epsicle

New Member
Joined
Mar 2, 2015
Messages
387
Reaction score
1
Points
0
Location
State of Boredom (Nebraska)
Vehicle Year
1994
Make / Model
Ford
Engine Size
4.0 Pushrod V6
Transmission
Automatic
My credo
All hail the mighty ziptie!
I drive a 1994 4.0 Extended Cab Ranger, auto 4x4, auto tranny, Dana 35 front Ranger 8.8 rear, 3.73 gears. This is a problem I've had since I've owned the truck but it just now is starting to annoy me. Right after startup my brake pedal will travel very easily without operating the brakes at all, until a certain point when it will grab and stop the car very roughly, this is at low speeds I haven't tried it at high speeds. After pumping the brakes a few times the problem disappears so I've just taken to pumping the brakes in the driveway before I leave. I have no brake light. I replaced the brake hoses on the front in December after they both exploded, I've repacked the wheel bearings, replaced all the ball joints, the front shocks, the rear shocks need to be replaced, the fluid level in the master cylinder has not gone down, and there is some rust on my power brake booster but it still has a vacuum.

EDIT: I'm pulling left under braking, and until the pedal hardens up a little the left rear tire locks but only the left rear tire. That's why I've been stopping rough at slow speeds.
 
Last edited:


Rock Auto 5% Discount Code: BD8D9A3814E19D Expires July 5th, 2022

The_Epsicle

New Member
Joined
Mar 2, 2015
Messages
387
Reaction score
1
Points
0
Location
State of Boredom (Nebraska)
Vehicle Year
1994
Make / Model
Ford
Engine Size
4.0 Pushrod V6
Transmission
Automatic
My credo
All hail the mighty ziptie!
I've done some searching and found out that Ford put out a TSB(Service Bulletin 985A36) for this. Unfortunately that TSB does nothing to tell me how to fix it or even what's wrong, when I find time I'll inspect the brakes and see what I find. In the mean time if anybody has more information about that TSB let me know.
 
Last edited:

Mark_88

New Member
Joined
Aug 11, 2007
Messages
18,550
Reaction score
228
Points
0
Age
66
Location
Ontario, Canada
Vehicle Year
2007
Make / Model
Dordge
Engine Size
3.3 Fuel Injected
Transmission
Automatic
My credo
Love Thy Neighbor
Have you ever bled the brakes yourself? What colour is the brake fluid or has it been changed since you've owned the truck (completely changed, not just bled when the lines were replaced)?

Even if you have bled them till they bleed...it sounds like either there is air in the lines or the fluid is degraded to the point of needing changing.
 

RonD

Well-Known Member
Joined
Jun 2, 2012
Messages
21,591
Reaction score
5,023
Points
113
Location
canada
Vehicle Year
1994
Make / Model
Ford
Transmission
Manual
Vacuum assisted Power brake booster works like this:

Inside the booster there is a rubber diaphragm, on the front side of this diaphragm is the check valve and the vacuum hose to the intake manifold.
Check valve holds vacuum at highest level regardless of current intake vacuum.
So the front side has a constant negative pressure while engine is running.

On the back side of the diaphragm, where the brake pedal push rod goes into the booster, there is the Atmosphere valve.
When you press on the brake pedal the Atmosphere valve is opened a little and the 15psi air pressure(at sea level) comes in, since the other side of the diaphragm has 18" vacuum(-9psi) the outside air pressure "assists" you in pushing down the brake pedal.
If your Atmosphere valve was failing it could be over assisting you, lol, before it starts working again.

You could also have a failing return spring so the resistance is less than normal, but I would think this would be an all the time thing, not just on start up.
 
Last edited:

Mark_88

New Member
Joined
Aug 11, 2007
Messages
18,550
Reaction score
228
Points
0
Age
66
Location
Ontario, Canada
Vehicle Year
2007
Make / Model
Dordge
Engine Size
3.3 Fuel Injected
Transmission
Automatic
My credo
Love Thy Neighbor
Vacuum assisted Power brake booster works like this:

Inside the booster there is a rubber diaphragm, on the front side of this diaphragm is the check valve and the vacuum hose to the intake manifold.
Check valve holds vacuum at highest level regardless of current intake vacuum.
So the front side has a constant negative pressure while engine is running.

On the back side of the diaphragm, where the brake pedal push rod goes into the booster, there is the Atmosphere valve.
When you press on the brake pedal the Atmosphere valve is opened a little and the 15psi air pressure(at sea level) comes in, since the other side of the diaphragm has 18" vacuum(-9psi) the outside air pressure "assists" you in pushing down the brake pedal.
If your Atmosphere valve was failing it could be over assisting you, lol, before it starts working again.

You could also have a failing return spring so the resistance is less than normal, but I would think this would be an all the time thing, not just on start up.
AhA~! I was right...I just gave the booster advice to the wrong person...it should have been here...and the other guy gets to bleed brakes...:icon_thumby:
 

RonD

Well-Known Member
Joined
Jun 2, 2012
Messages
21,591
Reaction score
5,023
Points
113
Location
canada
Vehicle Year
1994
Make / Model
Ford
Transmission
Manual
After re-reading OP I no longer think it's power booster, I think you have a bad slave or spring on left rear drum.
It is leaking but you may not see where, it is returning to closed all the way when it sits.
So when you first start off it has to refill and that causes the long pedal push, it has to re-expand so shoes are touching drum again, which is also causing the lock up on the left rear.

Can't explain the pulling though, that's front brake issue, and the front and rear brakes should be separate.
The reason hydraulics are used for brakes is because the pressure will be equal at both front wheels, pulling is generally the sign of a bad caliper.
If vehicle pulls to the left then the right caliper is not transferring enough/equal braking
 

adsm08

Senior Master Grease Monkey
Supporting Member
Article Contributor
Ford Technician
TRS 20th Anniversary
Joined
Sep 20, 2009
Messages
34,623
Reaction score
3,578
Points
113
Location
Dillsburg PA
Vehicle Year
1987
Make / Model
Ford
Engine Type
4.0 V6
Engine Size
4.0
Transmission
Manual
2WD / 4WD
4WD
Tire Size
31X10.50X15
Ron, I have seen rear brakes cause a pull too. It's not as common because the difference in performance has to be drastically different, but it can happen.

I agree, it seems to sound like an issue in the hydraulics is causing your problem. Check the rear brakes for leakage.
 

The_Epsicle

New Member
Joined
Mar 2, 2015
Messages
387
Reaction score
1
Points
0
Location
State of Boredom (Nebraska)
Vehicle Year
1994
Make / Model
Ford
Engine Size
4.0 Pushrod V6
Transmission
Automatic
My credo
All hail the mighty ziptie!
Thanks for the help everyone, the steering pull is hardly noticeable but that is also because my steering is loose because of a sloppy gearbox and I've associated weird steering issues to that for awhile. The front brakes ought to be good since the pads and rotors are wearing evenly. When I replaced the hoses I bled the front but not the rear and the fluid looked new, so far I haven't looked at the rear brake system and I wouldn't be surprised if those hoses were about to go as well, I've been in my chiltons a lot since I don't have a lot of experience with drum brakes and the spring would make sense too. I'll check both, thanks!
 

96firephoenix

New Member
Joined
Aug 20, 2014
Messages
194
Reaction score
0
Points
0
Location
Indianapolis, IN
Vehicle Year
1997
Make / Model
Ford
Transmission
Manual
I experienced this same issue the other day, and was surprised to find this very recent thread on the topic...

I can attest to the "pull". Mine pulls the ass end out like it's going into an oversteer condition, and then the wheel locks up. I'm thinking that there has to be some differential pressure between the rear brake drums.

I did notice that with about 300 lbs (fridge) in the bed, the problem did not appear. I did a deliberate test to see if this would occur, rather than find out suddenly with extra weight in the mix... I'm wondering if perhaps it is originating in the suspension, or if that is merely a coincidence (leaning towards the latter).
 

scrapper

Active Member
Supporting Member
U.S. Military - Veteran
Joined
Nov 27, 2008
Messages
468
Reaction score
39
Points
28
Location
central IL
Vehicle Year
1994
Make / Model
ford
Engine Type
2.3 (4 Cylinder)
Engine Size
2.3
Transmission
Manual
2WD / 4WD
2WD
Total Lift
6+3
Tire Size
33/12.50/15
Mine does that but only once. It seems to do it after it rains, heavy dew. I remember somewhere reading a lot of rangers have this problem.
 

ranger1997

New Member
Joined
Apr 9, 2015
Messages
14
Reaction score
0
Points
0
Transmission
Automatic
Front pads could have brake fluid on them from the blown hoses, will cause grabbing and uneven braking. Moisture will exaggerate the problem.

Cheap pads and shoes can also cause grabbing. I had a set of cheap pads on my 97 ranger from auto zone that just plain sucked and would lock up easy when cold or wet until they warmed up a bit.
They almost got me in a wreck in the rain.

Possible the rear also. You need to do a good inspection of your brakes front and rear.

Me personally would replace rear wheel cylinders and shoes, springs as needed, turn the drums. If the drums have fluid on them replace them. If the front calipers are old replace them also.
Flush the brake fluid and bleed.
It will cost a lot more if you hit something.

If you have anti lock special procedures apply for proper bleeding.

Anti lock can cause strange issue also if the module has air in it.

My 97 only has rear anti lock and there is a valve under the truck that must be held open to properly bleed the rear brakes.

I use bendix thermoquiet brakes and very pleased with them. No fade or rapid wear or grabbing.

There was a TSB on the ranger brakes for grabbing and a believe replace of pads or shoes was the fix, don't remember front back or both.

I would think a booster problem would be all the time. Usually the diaphragm goes bad and they would be hard to push be cause it doesn't hold vacuum.


Sent from my iPhone using Tapatalk
 

Sponsored Ad


Sponsored Ad

Top