abs brake bleeding instructions from a completely dry system?

[ttocs]

my brakes are working but are much softer then I would like them to be. I have bled them 3 times now the traditional 2 person way, once with a power bleeder and a 3rd time in a one person way I saw a video for. I have heard getting the air out of the lines before the abs can be a bitch but is there any special advice on how to do it?

 

[lutter94]

Did you bench bleed the new master?

 

[07GtS197]

If air is in fact in the abs pump you have to cycle the pump aka activate abs. Go for a drive and make a few panic stops and then bleed it again. Ive personally never done it but have read about it.

 

[ttocs]

I could not find any instructions on what to do when it came time to fill it and start the bleeding so no I did not bench bleed the pump.

 

[lutter94]

Give youtube a search, I'm sure you can still "bench bleed" in the car. Only instructions are have lines feeding back into the fill cap, it just purges the master of air. I didn't do it on mine, but I'm not advocating that, it has a firm pedal so I didn't take it past swapping it out. From reading online, it sounds extremely recommended though.

 

[01yellercobra]

I had a similar issue when I did the calipers and lines on my car. I used a Motive bleeder as well as a vacuum pump. I used the bleeders on the master cylinder to bleed it before moving to the calipers. The pedal was still a little softer than I liked. So after a rain I drove it to a high school by my house. Slammed on the brakes a few times to get the ABS pump to cycle and then did the two person bleed one more time. The pedal firmed up after that.

 

[ttocs]

do I need to get all 4 wheels to lock up? I am just curious how dedicated I need to get to get it to slide...

 

[01yellercobra]

I only got it up to 25 or so then slammed on the brakes. It wasn't a drifting style skid or anything. I did it 3 or 4 times. Although the 4th time was more because I was enjoying scaring the people on the other side of the lot.

 

[ttocs]

with the car still unregistered I do not have a parking lot close to do this. My neighborhood is pretty quiet, so this should be fun although it will be easier now since they just "repaired" the roads here. By "repair" I mean they shoved a bunch of tar/gravel in the pot holes and then finish it off with a nice fine gravel mix on top so it will not be too hard to get it to slide at least in the repaired areas....

 

[ttocs]

I got the car out after some rain and got the wheels to lock up but I could not get the abs to kick in. At that point I figured I had pulled the fuse prior to this when I was having some electrical gremlins and had not put it back and I was right the 60 amp under the hood was gone. After putting it in, I went for another trip but again I could not get the pump to activate with the wheels locked up. I looked to make sure both harnesses were hooked up to the pump and they were but then I noticed another harness that was not being used that fit the smaller 4 pin harness. So I tried that one but it also did not activate. I am going to go through my mustang bible electrical book tonight but was wondering if anyone had an issue like this before and had any insight on it?

 

[evilcw311]

.............lil voice in your head says you should of eliminated the abs..............


Sent from my iPhone using Tapatalk

 

[ttocs]

lookin at my bible there are 4 fuses tied into the abs. I have not looked yet but I am sure one of them is probably missing. hopefully I can figure it out my neighbors have to be wondering what I am doing...

 

[ttocs]

to my surprise I have all the fuses back in the fuse box and they were all good. Looking at the schematic in my electrical book the only part of the system that I still have removed is the abs warning light. From what I read in the manual it looks to be just a warning light, but then after some digging it sounds like that circuit provides power for the relay that when activated, powers the abs pump. This was taken from another forum where they were explaining how to install a line lock but if this is correct it sounds like I need power on that wire with the key on to power the pump. Anyone have any more info? I am curious if I can just tap it to a 12v switched wire or if it needs to read the resistance of the bulp somehow?

"[FONT=&quot]The BEST thing for BOTH situations is to FIRST pull the ABS fuse. Again, for MUSTANGS ONLY! A pulled power fuse is "the same" as if the ABS controller detected an error. The internal relay that provides _power_ to the solenoids (that do the ABS) is not activated. That relay is activated ONLY after the ABS computer goes through self test, system test, and does not detect a "problem" (such as 2 wheels going from 0->40 and two other wheels staying at 0). Again, for MUSTANGS ONLY! [/FONT]

 

[ttocs]

ok so after some time researching in my electrical bible I found these two pages.

following that I found I needed to find the red/yellow wire and the dark green. I looked through the harness connector diagram and found the wires and connected my light to them.

With the key on the light lit up and then stayed on showing that there was an error somewhere. Is the diagnostic plug under the glove box? I tried jumping those two wires but I could not get any codes to flash. Makes me wonder if the abs module is bad or....

edit 3 hrs later - Found the diagnostic harness its the by the battery/engine fuse box and of course marked with a big red cap saying something about brake testing. I grounded the wire I needed to and found no difference, the light just stayed lit up. I remembered that there were two harnesses that could plug into the abs pump and the smaller one actually had another harness that it could plug into as well. I was not sure which was right so I just picked one at the time. Tonight I went back and swapped those two and then the light started blinking to indicate the left front wheel speed sensor was reading faulty. I have not had a chance to check it out yet but will later tonight.

 

[ttocs]

last night I checked the wheel speed sensor in the back under the back seat where it comes in and it tested as normal at 2.4k ohms so I knew the sensor was good. That kinda sucks as it means there is a brake or short in the circuit and with neither wire showing continuity to ground it looked like a cut wire. That sucks as you can either trace the wires or run new ones, neither is that much fun but needs to be done. To trace wires all you do is follow them in the harness they go in and test them ever so often. In my case I was testing the pair for the impedance/ohms and the first place I could find them was where they ran under the back seat, towards the front of the car. I was lucky that as soon as I cut the tape they were right on top(tan/green, brown) and the other side is the other pair that has about the same length.

At this point measuring between both pairs shows 2.4k ohms which is perfect. At this point I thought about going forward a few feet and testing them again but I like to try and get all the easy to test spots first so instead I moved up into the drivers side fender where I know they are also. I was amazed when I poked my head in and looked, there was the end of a fairly familiar looking brown wire looking right at me. It was hanging out of the harness and everything, almost calling to me... Tracing wires NEVER is this easy so I figured it was just a mean trick but after testing it and the tan/green right next to it they showed 2.4k ohms! I Found the other end of the brown wire and soldered them together and then confirmed I could measure 2.4k ohms now at the end of the harness, SUCCESS!

The abs system is able to store these codes so that we can check them later even after a problem has corrected itself. To clear them I disconnected the battery for 10 mins, disconnected the ground I put on the abs diagnostic harness and then turned the key back on. It was a happy happy day to see the light turn on for a second and then turn off completely. The road test will be the real test to see if its functioning now but there are two things I will be doing first.

First I am installing a switch hidden somewhere that I can flip to put the abs in diagnostic mode to save me the time digging the harness out, finding a ground. I have plenty of switches and with the wires I already have I can just flip a switch, turn the key and read my codes.

The second part funny enough is I want a way to disable the abs for my when my line lock is being used. After all this research now it wasn't hard, just one relay is needed.

If you can read my chicken scratchings in the schematic in the simplest of terms all I am doing is interrupting the ABS warning light I just installed, normally already in the dash. By doing this the system recognizes there is a fault and shuts down. I have also set it up so that when I do this the same abs light with light up solid to tell me that the line lock has been activated. If your not familiar with relays the pins marked 87a and 30 are common when the relay is not activated so running the circuit through these will allow it to operate as normal with no power on the relay. When the line lock switch is turned on, it will activate the coil which will make the contacts of 87 and 30 are common which will provide the ground portion needed to light up the light.

 

[ttocs]

YES! I have ABS! Took the car around the block and got it to cycle on some loose gravel and no errors. Tomorrow I bleed hopefully for the last time! Another interesting note I learned is that if you parking brake light comes on and stays on it is trying to tell you your brake fluid is low.