brake problems.

[96EB351]

Remember flame free zone and i tried the search function but after a good bit of digging i couldnt come up with anything that matched my vehicle. I would be much appreciative of some advice or someone pointing me in towards the threads where this has been covered.

Vehicle: 96 Bronco, 351, e40d, 31's, auto hubs, eddie bauer trim, bone stock best i can tell. I have owned the vehicle for less than 2 wks.

My experience: no mechanic by any means. I can change an alternator or some oil, put in a stereo, and possibly diagnose a simple mechanical prob but thats where my "expertise" ends.

Problem: A few different brake issues:

1) No pressure or varying pressure at the pedal. In the mornings i have to pump them a little to get pressure but they seem to be fine after i get it built up.

2) when slowing to a stop it seems like they are spongy to a point then become stiff and feel like they are about to lock up.

3) One of the first mornings i had it the pedal went 3/4 way to the floor and locked. I had to let it sit a little while then kinda pump them with one foot while pulling back on them with the other. only did this once.


Im thinking prob going to be a master cylinder or brake booster or brake booster but I dont know.

[hizootiemizark]

Sounds like possible air in lines. I would flush the old fluid refill with new and make sure they are bled properly.

[96EB351]

Originally Posted by hizootiemizark

Sounds like possible air in lines. I would flush the old fluid refill with new and make sure they are bled properly.

thanks for answering!

would there be air bubbles in the MC reservoir if that was the case or is there anyway to diagnose for sure?

[V8Ranger]

Does not sound like the booster and no there would not be bubbles in the master cylinder reservoir. Could be air in system but master cylinder is suspect. The pedal "going 3/4 the way to the floor and lock(ing)" sure points that way. I've had air, bad wheel cylinders, stuck calipers, even pads that where melted to rotors from calipers leaking so bad, never made pedal stick.

Carl

[smiggey]

i agree with v8ranger it sounds like a master but it wouldnt hurt to flush/bleed the system. one thing though, with the truck off if you pump the brake pedal like 7 times and then hold it does it slowly sink towards the floor?

[96EB351]

Originally Posted by smiggey

i agree with v8ranger it sounds like a master but it wouldnt hurt to flush/bleed the system. one thing though, with the truck off if you pump the brake pedal like 7 times and then hold it does it slowly sink towards the floor?

Im honestly not sure, but i will check it either at lunch or after work today and respond back.

thanks for responding.

[miesk5]

yo 96EB351
This is the FORD 1996 F-150, F-250, F-350, F-Super Duty Chassis Cab, Motorhome Chassis and Bronco Workshop Manual; partial, on-line for FREESymptom Chart, Brake System Diagnosis
for example;
Feels Spongy When Fully Applied
Rear brakes out of adjustment.
ADJUST rear brakes. REFER to Section 06-02.

Front wheel bearing out of adjustment.
ADJUST front wheel bearings. REFER to Section 04-01A or Section 05-03C.

Brake master cylinder or power brake booster dash unit mounting loose.
TIGHTEN nuts and bolts to specification. REFER to Section 06-06.

Front or rear disc brake caliper attachment loose.
REPLACE or TIGHTEN as required. REFER to Section 06-03 or Section 06-04.

Worn or damaged self-adjusters.
REMOVE brake drum and CHECK rear brake shoe and lining for proper adjustment. REPLACE brake shoe adjusting lever. REFER to Section 06-02.

Brake pedal or support improperly mounted.
REPAIR or REPLACE as necessary. REFER to Section 06-06.

Worn or damaged brake linings.
REPLACE brake shoe and lining. REFER to Section 06-02, Section 06-03 or Section 06-04.

Brake drum out-of-round or front or rear disc brake rotors with excessive runout.
REFINISH or REPLACE if wear exceeds limits. REFER to Section 06-02, Section 06-03 or Section 06-04.

Worn or damaged four wheel ABS hydraulic control unit (Bronco only).
REFER to Section 06-09B, Symptom Diagnosis.

Worn or damaged RABS valve accumulator (F-Series only).
REFER to Section 06-09A, Symptom Diagnosis.

Brake tubing improperly positioned.
CHECK brake tubing for misposition near heat source. Fluid can boil and result in spongy pedal response.

Low brake fluid level.
FILL as required.

Clogged brake master cylinder filler cap hole.
REPAIR or REPLACE brake master cylinder filler cap.

Air in system.
BLEED system.
GO to Pinpoint Test F for spongy brake pedal.
GO to Pinpoint Test H for excessive brake pedal travel

[Yeti_Rescue]

Lots of good advise but I'm a simple man and have to ask the simple questions first. Is the ABS or BRAKE light on? Have you checked the codes if they are ? This to me sounds like an ABS issue. Good Luck

[JKossarides]

I don't see how air can suddenly get into a sealed system, certainly if there was air in the system it would have been noticeable in the begining so it if the pedal is going to the floor it's more then likely you need a new master cylinder that fluid is passing over the piston O ring inside losing air pressure.

Make sure if you replace the MC that you "bench bleed" it before you install it or you'll never get a good bleed out of the sytem. There are MC rebuild kits but I think it's cheaper jsut to buy a complete new MC, check it out either way.

Harbor Fgreight has a hand help pistol grip self bleeder, combo vaccum guage for around $29.00, I got one and it works great so you can bleed the sytem by yourself...


Good Luck ~

[96EB351]

Originally Posted by FNG

Lots of good advise but I'm a simple man and have to ask the simple questions first. Is the ABS or BRAKE light on? Have you checked the codes if they are ? This to me sounds like an ABS issue. Good Luck

no lights on.

[96EB351]

Originally Posted by JKossarides

I don't see how air can suddenly get into a sealed system, certainly if there was air in the system it would have been noticeable in the begining so it if the pedal is going to the floor it's more then likely you need a new master cylinder

thats just it though, it doesnt go to the floor every time it is pretty variable. I really "feel" like its going to be the MC but i dont want to spend $ and not fix the problem.

[96EB351]

Originally Posted by smiggey

i agree with v8ranger it sounds like a master but it wouldnt hurt to flush/bleed the system. one thing though, with the truck off if you pump the brake pedal like 7 times and then hold it does it slowly sink towards the floor?

Originally Posted by 96EB351

Im honestly not sure, but i will check it either at lunch or after work today and respond back.

thanks for responding.

super busy day at work so i havnt had a chance to ckeck this but i will when i leave work. If it does/doesnt slowly sink to the floor what is the deal with that?

[96EB351]

just 'snuck' outside and to see if it had pressure while off.

with the truck off i cant push the pedal anymore than 1/8 of the way or less.

back to work, will check in later, thanks to everyone for respondiong.

[JKossarides]

It's been my experience in all my years of wrenching my own vechiles that when the brake pedal starts to fade when you press down to stop and goes to the floor either all the way or partialy it's time for a new master cylinder.

The O ring on the piston is fubar allowing fluid to pass over it and you lose pressure.

One quick check by visually inspecting each wheel fitting for brake fluid leaks can give you the answer, perhaps one of the rear wheel cylinders is leaking slowly which would contribute to pedal fade....look for leaks at the bottom of the MC where it's attached to the front of the brake booster which would indicate the booster is going...

The only thing you could try now is bleed the entire system by starting with the farthest wheel away from the MC, next etc. etc. and see if that makes a difference with the pedal otherwise replace the MC because the last thing you want is to drive unsafely and maybe have an accident because you can't stop when the pedal is all the way down to the floor....right?

Good Luck ~

[smiggey]

most of the new master cylinders i have bought in the last 3 years have had bleed kits in them. plastic fittings that little hoses go on , routed back into the resevior. so no vacuuming or vise/bench bleeding. hook up the master to the booster and run the supplied tube from the ports to the res. fill, turn on the radio and slowly pump the pedal. stoopid easy, my kind of easy.

[96EB351]

Originally Posted by JKossarides

It's been my experience in all my years of wrenching my own vechiles that when the brake pedal starts to fade when you press down to stop and goes to the floor either all the way or partialy it's time for a new master cylinder.

The O ring on the piston is fubar allowing fluid to pass over it and you lose pressure.

One quick check by visually inspecting each wheel fitting for brake fluid leaks can give you the answer, perhaps one of the rear wheel cylinders is leaking slowly which would contribute to pedal fade....look for leaks at the bottom of the MC where it's attached to the front of the brake booster which would indicate the booster is going...

The only thing you could try now is bleed the entire system by starting with the farthest wheel away from the MC, next etc. etc. and see if that makes a difference with the pedal otherwise replace the MC because the last thing you want is to drive unsafely and maybe have an accident because you can't stop when the pedal is all the way down to the floor....right?

Good Luck ~

So even though the pedal wont depress with the vehicle off, its prob still the MC?

Will check tomorrow but I parked in fresh snow 3 days this wk and have looked for any "spots" of anything since I've only owned the vehicle for a couple wks and havnt noticed anything. I already checked the inside of the wheel wells for brake fluid that had been "slung" and cant find any.

Thank goodness so far I havnt lost brakes. The most dangerous part of my day is the ice covered parking lot at work, ive done my fair share of "wheelin" i've also driven in a lot of ice and snow, but not having good feel in the pedal can make even simple every day driving a little tricky.

[96EB351]

Originally Posted by smiggey

most of the new master cylinders i have bought in the last 3 years have had bleed kits in them. plastic fittings that little hoses go on , routed back into the resevior. so no vacuuming or vise/bench bleeding. hook up the master to the booster and run the supplied tube from the ports to the res. fill, turn on the radio and slowly pump the pedal. stoopid easy, my kind of easy.

suggest a good brand? any tips i should know? im guessing there is a how to on this site and i may try to dive into it myself if it isnt too complicated.

without getting into big time $$$ i wouldnt mind spending a little more if it will help this thing stop at all, Ive driven an explorer for a long time and the brakes are the only thing i miss.

assuming the MS is my prob.

[bukk]

u can check if its leaking from underneath the dash where the rod touches the pedal or pull top of carpet back and feel for fluid on carpet right at the top .

[V8Ranger]

Master cylinders are not all that expensive, Rockauto.com has them listed form $18 to $80 (plus shipping).

Carl

[JKossarides]

Common sense will dictate based on how old the current MC is, nothing lasts forever so what else could it be, it's little money and time to drive safe IMO....


Good Luck ~