Brake pedal goes to floor after I start the engine

[rockola1971]

Air is likely trapped in the ABS manifold. You will need a bidirectional scanner to run the automatic brake bleed ABS feature. No way to get the solenoids to actuate without a bidirectional scanner or locking up the brakes and causing the ABS to engage which wont happen since your pedal goes to floor when you start the engine.

 

[Wiggybaby67]

Maybe a bad master cylinder ? assume it did not do that before you replaced it ?

You may be right. It did not do that. I hate when you buy a new part and it still doesn't work right. Seems to be more common the last couple of years.

 

[Wiggybaby67]

Air is likely trapped in the ABS manifold. You will need a bidirectional scanner to run the automatic brake bleed ABS feature. No way to get the solenoids to actuate without a bidirectional scanner or locking up the brakes and causing the ABS to engage which wont happen since your pedal goes to floor when you start the engine.

i got the Innova 5510 which is supposed to support that feature on this vehicle, but it says not supported when I try to use it.

 

[rockola1971]

i got the Innova 5510 which is supposed to support that feature on this vehicle, but it says not supported when I try to use it.

I know the tech II will not connect to the ABS system for the automatic bleed if you have an active ABS code/fault. Try a clear AFTER you connect to the ABS system and run diagnostics on it to record codes.

 

[Larryjb]

I came across this article on removing trapped air from the master cylinder: https://www.brakebleeder.com/removing-trapped-air-angled-master-cylinder/ The angle of the master cylinder may make it difficult or impossible to remove all the trapped air if it is bled in vehicle. Also, even if it is bend bled, could some air enter the master cylinder when installing it?

I don't see this causing the pedal to go to the floor though.

 

[Alex_M]

Air is likely trapped in the ABS manifold. You will need a bidirectional scanner to run the automatic brake bleed ABS feature. No way to get the solenoids to actuate without a bidirectional scanner or locking up the brakes and causing the ABS to engage which wont happen since your pedal goes to floor when you start the engine.

You can jump the ABS relay to bleed thru the module on some vehicles. Have actually never tried on my Tahoe, but certainly worth a shot.

 

[MassHoe04]

I figured I would ask the obvious just to be 100% sure of one thing.

Is the level in the reservoir still up where it should be when the pedal has gone to the floor or did the fluid go down?
Maybe it just needs to be topped off...

 

[Wiggybaby67]

I figured I would ask the obvious just to be 100% sure of one thing.

Is the level in the reservoir still up where it should be when the pedal has gone to the floor or did the fluid go down?
Maybe it just needs to be topped off...

Fluid level is good. Got the power bleeder and will try to use that. otherwise, I will either need to find a bi-directional scanner that supports that vehicle or let a shop do it.