Brake HELP

I installed a electric line lock and in the process ran my master dry...refilled it and bled forever till no bubbles and the pedal feels like shit...goes all the way to floor but the truck stops fine...tried a vacuum bleeder and everything...there are NO leaks. Air keeps coming up from the master like this

 

There is still air in the MC. Time or a Bench Bleed will fix that, tho bench bleeds are a PITA.

 

You don't think it's a bad mc? It will still drop to the floor with the truck off...althouth it is much firmer

 

Air bubbles are visible at the bottom of the master res

 

19yo truck, master cyl has traveld only so far in the bore for the install of line lock and bleeding of the system. now the seals are traveling past a possible ridge of crud and wear that builds up inside the bore ( right where the seals stopped previously)

I agree there is probably still air in the system, but be aware the seals are worn too. might be good money to replace the master, bench bleed then rebelled the system. I've had this issue when replacing caliper(s)

 

I was thinking of purchasing a new master....when bench bleeding how far do you push the piston?

If the truck is off the pedal is much firmer but will still drop to the floor

 

new master cyl shouldn't matter how far, bore should be smooth with no crud or wear.

with your existing master, you're pushing past possible wear, pitting or crud in the aged bore which damages the seals

 

So even though I've bled my brakes (manually) many times before you still think it could be the master?

 

I don't see any fluid leaking

 

its always possible, unless you removed another part of the system, the only way for air to get in the master is running it dry or coming from an opening down stream, you're working right at the master with the line lock.

the master cal is a dual piston ( one for front one for rear ) if one seal goes, the other can pressurize the other system, which is possibly why you're getting a firm pedal, but it never stays off the floor.

brake fluid is an alcohol, it absorbs water by nature, this happens ALWAYS, the master cyl is NOT sealed in the cap, to there is always some air movement and always moisture in the air. the moisture accumulates and can cause pitting and a crust of debris in the master cal bore ( calipers brake lines and wheel cyls too ) this is why it is recommended to flush the brake fluid every other year ( very few ever do )

to be sure you get there air out of the master you should (need) to bench bleed, then carefully install and bleed the system, a new master your chances of having redo the job multiple time are reduced.

I can only go on what you're telling me, though given your location ( if its accurate, you're not far off the ocean), so you have humidity to an extent. your truck is 19yrs old, so age isn't in your favor for not having issues as described.

 

you could try running tubes from every bleeder screw into the cylinder reservoir and just pumping the $h!t out of the brake pedal. either all at once or 1 at a time. probably 1 at a time. i mean, how much would 15 feet (if that!) of clear tubing cost?

 

Picking up a new master right now...I did bench bled my current one this morning...zero change

 

what's an electric line lock?

 

Locks the wheels (I don't have a e brake)

 

did you have to remove any lines in the process? or perhaps did you disassemble part of the e-brake components that held the shoes in place and thereby allows immediate pressure to buildup rather than float around loosely?

 

Yes I removed a line and ran the master dry in the process...truck has never had a e brake...it has a tundra rear axle

 

and this line lock is for use when ?

 

When I want to leave the truck running and in neutral (manual )

 

what line lock is it and where did you place it?

 

Biondo and it's by where the sway bar mounts to frMe