Intermittant brake problem please help!!

[Boywonder629]

I have a 98 Mountaineer and recently have been having brake problems, first i noticed in panic stop situations it wont lock up the brakes and upon inspection found it need front rotors so i did rotors and padsup front. Now this improved brakeing power somewhat but it still wont lock up the wheels and i have a soft pedal when i first start and it progressivly gets better as the brakes warm up for driving... Now here is the scary part today on my way to school a car pulled in front of me when i slamed the brakes it went to the floor and it felt like only 50% braking power. I have no leaks that i can see anywhere and i have no clue where to start,
Thanks for any help!!

 

[Dave 1955]

Well the master cylinder sounds suspect.
Did the pedal pump up afterwards?
If you are sitting still and push considerably on the brake pedal does it slowly sink to the floor?

 

[crunchie_frog]

Check for leaks on your master cylinder, they may show up as an wet residue on the vacuum booster where the master cylinder is mounted. Are you losing any fluid? You can tell if the level in the reservoir drops in a short period of time like a few days. If so, and not at the master cylinder, check all brake lines, fitting and calipers. If you are from up north, check the rear line that goes over the differential, it can sometimes rust out. Of course, if you find a leak, you need to repair it. After your are 100% sure you do not have any leaks you may want to consider bleeding all the way around. I find this best with an assistant or a vacuum pump, Not knowing your experience level, how experienced are you in bleeding your brakes? If not too experienced, try bleeding again, this time all the way around starting with the left rear, right rear, left front right front, get about a quart of brake fluid and do not let the fluid level drop out of the reservoir, simple stuff I know, but just checking. You don't want to play around with your brakes, if you cannot get a firm pedal, take it to a shop or better, tow it to a shop.

 

[koda2000]

sounds like you have a bad master cylinder if the pedal is soft and is going to the floor. no point in checking for leaks around the master, as they tend to leak internally. check your brake lines for leaks especially the metal line that goes across the rear diff. also check all four calipers for any signs of leaking. you may air in the system now, and because you have ABS brakes, it requires special tools to get it out. I suggest you take it to a professional to get it fixed.

 

[Boywonder629]

Thanks guys i will check the master cylinder today in my Auto class at school (highschool). I am up in michigan so brake lines could be a possiblity too, Dave 1955 yes if i push on it it will sink to the floor but comes right back up which to me i was thinking brake hoses? On another note this morning i pumped the brakes till they were hard before starting the truck this morning and with pressure still on them turned it on and it sunk but very slowly then seemed firmer the whole drive to school then they have been all week,

 

[koda2000]

Thanks guys i will check the master cylinder today in my Auto class at school (highschool). I am up in michigan so brake lines could be a possiblity too, Dave 1955 yes if i push on it it will sink to the floor but comes right back up which to me i was thinking brake hoses? On another note this morning i pumped the brakes till they were hard before starting the truck this morning and with pressure still on them turned it on and it sunk but very slowly then seemed firmer the whole drive to school then they have been all week,

have everything checked in your class ASAP. personally, I wouldn't drive it the way it is because you're an accident looking for a place to happen.

FYI: don't pump the pedal with the engine off. not good for the ABS system. for that matter, don't pump the pedal with the engine on either.

 

[Boywonder629]

Ya i was planing on getting it in today, its weird because when i first start it the brakes are soft and i feel like im pushing the pedal at to much to stop but it gets better as i drive im really hoping this is a cheap fix as prom is next week and i work minimum wage...i swear this truck only breaks when i baby it

 

[koda2000]

Ya i was planing on getting it in today, its weird because when i first start it the brakes are soft and i feel like im pushing the pedal at to much to stop but it gets better as i drive im really hoping this is a cheap fix as prom is next week and i work minimum wage...i swear this truck only breaks when i baby it

I'd plan on needing a new/reman master cylinder based on your symptoms. a reman will run you around $40 at AutoZone. a new one will be closer to $60. personally, I have no problem with reman. the fact that the pedal gets firmer when you pump it isn't strange at all if the seals in the m/c are leaking internally. if you had an external leak you fluid level would be dropping.

 

[Boywonder629]

Well dident get it in the shop today and on the way home locked up the front passenger side tire $55 later and a massive skid mark in my drive way its back in my garage

 

[koda2000]

Well dident get it in the shop today and on the way home locked up the front passenger side tire $55 later and a massive skid mark in my drive way its back in my garage

a bad M/C wouldn't cause a wheel to lock up. that sounds more like a bad wheel bearing. that would also explain the low pedal as the rotor wobbling around pushes the pucks back into the brake caliper. is your truck 2WD?

 

[Boywonder629]

No its Awd, im leaning towards it being a collapsed brake line as that would explain the lock up and soft pedal

 

[Boywonder629]

That and i could get it to unlock but it would lock back up with even slight braking

 

[koda2000]

That and i could get it to unlock but it would lock back up with even slight braking

if it's 2WD (you didn't say) and a bad wheel, bearing you could be looking at a new spindle/knuckle, inner/outer bearings w/races & seals and maybe a new rotor. if it's 4WD/AWD you don't have spindles or individual wheel bearings. the 4WD/AWD's use a hub bearing assembly.

have you noticed that your ABS light has been on lately, or heard a roaring noise?

 

[Boywonder629]

No its Awd, im leaning towards it being a collapsed brake line as that would explain the lock up and soft pedal

Yeah i did lol, hubs are fine really hoping its a brake hose, i will look at it later tonight as im at church right now

 

[Boywonder629]

Well pulled it apart and a calipe bracket bolt had broke an the calier slamed itself into the rim