bleeding brakes

[quickcampbell]

This is my first post. tried to search for the answer and just cant find what I need. I have a 1995 bronco and I recently replaced the ball joints, shocks, driver side rotar and put new calipers on both sides. During this process I broke a sensor on the pass side Im assuming it was abs. I did not replace that sensor. I went on to bleed the brake system and it will build pressure but wont hold it. brakes get spongy after 30 seconds or so. If I crank it up the pedal goes almost all the way to the floor and makes a wooshy sound when I push on the brakes. Ive bled the **** out it, going master, front, back. Im getting clean fluid, no air, and cant find any leaks. Is that sensor causing this, or is there somthing else I need to know to get my monster growling again. its a daily driver for me and Im hoping to get in back on the road asap so any help is really appreciated.

I did put this on another board on here. I figured this was a better spot for my question.

Thanks,

Quick

 

[bigbluebronc]

well as I know a sensor will only take out the abs part of the brakes, when you bled did you might have by mistake put air in the master cylinder, that can make the brakes spongy, check manual for master bleeding can be tough too bleed, just a thought, I could be alll wrong though...The wheel sensor in my blazer and corvette had too do with tracktion control and that could effect brakeing.....

 

[quickcampbell]

that is what I was thinking, the abs should be seprate. But I cant say for sure. I did bleed the master cyl, however not 100% it was done correctly. I just pumped it up and broke the lines loose from the mstr cyl. I didnt remove it though. this just does not make since to me, it was working just fine before. thanks for the reply blue and thats a sharp bronco in your pic.

 

[bigbluebronc]

that is what I was thinking, the abs should be seprate. But I cant say for sure. I did bleed the master cyl, however not 100% it was done correctly. I just pumped it up and broke the lines loose from the mstr cyl. I didnt remove it though. this just does not make since to me, it was working just fine before. thanks for the reply blue and thats a sharp bronco in your pic.

I now on my 92 chevy blazer the wheel sensors only had too do with the first gen abs, not the engine controls

 

[bigbluebronc]

broncos the big ones did at one point go from dfi too efi ,,,...efi on your model might need wheelspeed for the computer, replace sensor , sorry for other posts was not thinking just remembered the research i did on efi conversions

Sorry

 

[Broncobill78]

When you say the pedal makes a whooshy sound and goes to the floor that makes me think either master cylinder or vacuum booster. Is the fluid level changing ? If/when the diaphragm in the booster goes the pedal goes down to the floor, it makes noise & you start pushing fluid from the master cylinder into the booster housing. If you're certain there's no air in the system and you aren't losing fluid somewhere then I'd look at the master cylinder first & then ck the booster.

I would think the broken sensor would only **** the ABS part of the system, I assume the ABS light is on ?

 

[quickcampbell]

okay the thing is that it will gain pressure when the truck is not running, when I crank it up it looses it. when I bleed the brakes it is pushing fluid out and no air. that tells me that the master cyl is working and the system doesnt have air in it... or at least I think, because it seems to be doing its job.

 

[quickcampbell]

okay the thing is that it will gain pressure when the truck is not running, when I crank it up it looses it. when I bleed the brakes it is pushing fluid out and no air. that tells me that the master cyl is working and the system doesnt have air in it... or at least I think, because it seems to be doing its job.

 

[J&SBroncolvrs]

Brake fluid could be leaking past the seals in your master cylinder which means it is shot or maybe you just have to take it off and bench bleed it.

 

[Broncobill78]

okay the thing is that it will gain pressure when the truck is not running, when I crank it up it looses it. when I bleed the brakes it is pushing fluid out and no air. that tells me that the master cyl is working and the system doesnt have air in it... or at least I think, because it seems to be doing its job.

If there are no leaks & no air then it still sounds like the master cylinder, unless the diaphragm of the vacuum booster is torn.

 

[quickcampbell]

okay, thanks for the help. Im gonna try putting a new master cyl on it. I'll let you know how it turns out.

 

[quickcampbell]

I just put a new mastercyl on it and its doing the exact same thing!! any ideas???

 

[Bronc76]

qc- did you ever replace booster? you can check it pumping it several times with engine off. shift tranny into neutral and start engine. if pedal height decreases and it doesnt need a lot of pressure to keep in applied position then its good. if it feels like its in a bind then i think it could be bad. i hope i explained this right.

 

[quickcampbell]

no, not in a bind. I think the booster is okay. I read a similar thread on the 150 forum and that guy was told that there was still air in the system, also just talked to a guy at pep boys that does brakes and said the same thing"air still in the system". Is there a certian way or order that you guys bleed the system? Is it possible that Im just moving air around and just not getting it out?

 

[Krafty]

does your booster have a vacuum line going to it? if so then make sure the line goes to the right place. if it is only effected when the engine is running then that means it has to be either something that is vacuum controlled or electronically.

1. Does it have the problem when the key is on but the engine is not?

2.Or is it only when its running?

1. yes 2. no = something electronic i.e abs system

1.no 2. yes = Vacuum controlled ie booster

give that a try and see if it gets you anywhere