Brake Problems?? or something else? please help

[NeatOman]

Remember to jack up the front a bit because some air tends to get stuck in the ABS unit if level.

FYI Bleed the furthest from the ABS unit... i know they say from the master cylinder but really the one furthest from the ABS unit is the longest. So start with the rear driver side first then rear passenger then front driver side and last front passenger.

 

[bobiseverywhere]

Ok i will try and bleed the lines again.

This is what the pedal is like the start of the line would be if i could push the pedal to the floor

--------------------{} not pushed
----------{} Pushed the first time and hit the invisible wall
-----------------{} Pushed the second or third time and brakes super hard (Wheels lock up if pedal is pushed any further)

 

[ATL88Supra]

Ok i will try and bleed the lines again.

This is what the pedal is like the start of the line would be if i could push the pedal to the floor

--------------------{} not pushed
----------{} Pushed the first time and hit the invisible wall
-----------------{} Pushed the second or third time and brakes super hard (Wheels lock up if pedal is pushed any further)

:aigo: shrug i dunno do the flush and get back with us

 

[twinturbozs]

Try shutting the motor off.
Do not step on brake.
Open hood and release vaccuum from the booster diaphram.
Then step on brakes,

-is there any travel?
-is it rock hard?

When you installed the used MC, did you bench bleed it?

If you need to pump your brakes, with excessive pedal travel, it points to air in the system.
A rock hard pedal requiring excessive force to brake, points to brake booster.
I find it hard to believe that changing both units along would produce the same exact results. Maybe there's a leak in your proportioning valve or its going bad.

 

[3p141592654]

I would think that air in the system would cause a soft pedal, not what you describe.

If it were me, I would take it to the dealer and have them run the actuator diagnostics described here. Or by a used actuator and replace it if the dealer is too horrible a thought to entertain. I've seen them parted out for not much money.

http://www.cygnusx1.net/Supra/Library/TSRM/MK3/manual.aspx?S=BR&P=61

 

[89turbotoy]

replace the abs modulator assembly i am a tech and just had the problem you are describing with the same code and it was the abs mod.

 

[thedave925]

From the intake manifold to the brake booster runs a firm vacuum line. Supported on the firewall is a little metal device that the vacuum line runs to before continuing to the booster.
That is a check valve to make sure positive pressure doesn't get to your brake booster.

If that valve is sticking, I would imagine that upon cold start up you don't have enough vacuum forcing it open to raise vacuum for the brake booster to properly operate, making it hard to depress the pedal just like when the engine dies and your still moving. And as your engine slows enough to be pulling enough vaccum, like when you leave it in gear or downshift as you slow, that valve suddenly actuates and ABS kicks in. Pretty farfetched but presumably possible.

When you pulled the vacuum line to the booster, was it the manifold side of that check valve?

Try pulling the hose off the brake booster itself and see if it still sucks.

-Dave

 

[bobiseverywhere]

thedave925: i checked the hose from the Booster side and it had Vaccum

89turbotoy: i guess i have to go down that road? is there any easy way to just eliminate the ABS instead

twinturbozs: I will check that out at lunch and give you some results.

 

[bobiseverywhere]

ok so here is where things are at,

doind what twinturbozs said to do, the brakes were not rock hard there was travel to them. and thats about it. i verified again that the booster had vaccum to it.

Also i did bench blled it as described in the TSRM , thankfully there was still fluid in it and we did not really get any air in the system.

I do have half i mind to take it somewhere and say here fix it, but my budget says i should fix it myself....lol So i will try and bleed the brakes again. I think this time i will Get a Vaccum hand Pump to help bleed the lines that way i am not

 

[3p141592654]

Post #46.

 

[Aspec]

I think this time i will Get a Vaccum hand Pump to help bleed the lines that way i am not

Are you trying to bleed the brakes yourself or do you have someone who can help? The "one man show" thing does not work well for bleeding brakes properly.

 

[bobiseverywhere]

I do have someone who can help, that what i did last time but i did just try breeding the lines again put almost a whole liter through the lines in total and still the same problem, Using a Vaccum pump. The only thing it leaves is the ABS, my only question is how hard is it to remove the ABS system? and do i need any extra part besides brake lines?

 

[ATL88Supra]

I do have someone who can help, that what i did last time but i did just try breeding the lines again put almost a whole liter through the lines in total and still the same problem, Using a Vaccum pump. The only thing it leaves is the ABS, my only question is how hard is it to remove the ABS system? and do i need any extra part besides brake lines?

http://www.cygnusx1.net/Supra/Library/TSRM/MK3/manual.aspx?Section=BR&P=46

there ya go:biglaugh:

and http://www.cygnusx1.net/Supra/Library/TSRM/MK3/manual.aspx?S=BR&P=61

 

[bobiseverywhere]

So Basicly i need just one thing to sptil the line for the front into two lines and i can romove the ABS all together