New brake rotors, pads & steel braided lines - pedal needs tapping to be firm...

[sniper_x]

On my 2013 Tahoe LT, I installed new brake rotors, pads, and steel braided lines.
I also flushed the fluid and bled the system.

For several days now, I have had to lightly pre-press or tap/ short-press the brake pedal before I get a solid/firm pedal as I should.

I even took the Tahoe to a brake specialist, and they verified it was bled well and there was no air in the system.
The tech stated that it could be any of several things like the master cylinder, sluggish calipers, etc.

However, this only started after I did the rotors, pads, lines, and flush.

My 2007 Yukon brakes are rock solid - fully stock and have replaced the pads on that one too.
Never had this issue before.

Thoughts?

 

[OR VietVet]

On the 07 you said, "replaced the pads" and that does not require opening the lines. IMO, the brake specialist could be wrong and there is still air in the system. When you had the calipers off, did you clean and lube all contact points and pins? With all tires/wheels off, pump up brakes and apply and then remove foot from brake pedal. Inspect the rest position of each caliper. The relaxed gap between the pad surface and the rotor surface, should be almost nothing that you can see.

 

[sniper_x]

On the 07 you said, "replaced the pads" and that does not require opening the lines. IMO, the brake specialist could be wrong and there is still air in the system. When you had the calipers off, did you clean and lube all contact points and pins? With all tires/wheels off, pump up brakes and apply and then remove foot from brake pedal. Inspect the rest position of each caliper. The relaxed gap between the pad surface and the rotor surface, should be almost nothing that you can see.

"The brake specialist could be wrong and there is still air in the system."

Agreed. I have the GM dealership scan tool and try to bleed the brakes using the built-in ABS bleed process.

"When you had the calipers off, did you clean and lube all contact points and pins?"

Yes.

"With all tires/wheels off, pump up brakes and apply and then remove foot from brake pedal. Inspect the rest position of each caliper. The relaxed gap between the pad surface and the rotor surface, should be almost nothing that you can see."

I am replacing the engine mounts today.
I will check this as I do that work since the front wheels have to be removed and the truck is already on jack stands.

 

[Dustin Jackson]

I don't have a lot of experience with bleeding brakes but I did replace my rubber brake hoses in the front and it took quite a bit to get all of the air out and it didn't seem like I could get all the air in 1 try. I would bleed until no more air bubbles came out, then I would take it for a drive and come back and try to bleed it some more and sure enough more air would come out.

 

[sniper_x]

I don't have a lot of experience with bleeding brakes but I did replace my rubber brake hoses in the front and it took quite a bit to get all of the air out and it didn't seem like I could get all the air in 1 try. I would bleed until no more air bubbles came out, then I would take it for a drive and come back and try to bleed it some more and sure enough more air would come out.

Yes, this is precisely what I did.

What I’m gonna do now is I’m gonna hook up the GM tech2 to the car and let it run the ABS purge program.

We’ll see if that does anything

 

[Geotrash]

Yes, this is precisely what I did.

What I’m gonna do now is I’m gonna hook up the GM tech2 to the car and let it run the ABS purge program.

We’ll see if that does anything

One mistake I see people often make is not closing the bleeder screw when their assistant has the pedal to the floor, allowing a tiny bit of air to sneak back in when they release the pedal.

And I agree with the others that the shop doesn't know what they're doing and it's possible (probable?) that they wanted to materialize a problem requiring further diagnosis and replacement of parts.

 

[sniper_x]

One mistake I see people often make is not closing the bleeder screw when their assistant has the pedal to the floor, allowing a tiny bit of air to sneak back in when they release the pedal.

And I agree with the others that the shop doesn't know what they're doing and it's possible (probable?) that they wanted to materialize a problem requiring further diagnosis and replacement of parts.

Regarding the shop and the possibility they wanted to materialize a problem...

I never take my cars to the shop because I do my all own work (from oil changes to engine rebuilds), but this shop is run by a friend.
He maybe didn't perform the ABS purge program (I know that I didn't) and that is likely the issue.

I'll know more after I finish changing my motor and transmission mounts today and can get to the brakes.
I'll set up the hoses and bottle and then grab the TECH2 tool and run the ABS purge process.

 

[wjburken]

What was your bleeding method and bleed sequence?

Vacuum bleeder? Pump the pedal? Etc?
If pedal pump, did you put anything behind the pedal to keep it from going in too far and damaging the MC?

RR, LR, RF, LF?

 

[Foggy]

Gotta run the abs pump when doing calipers and hoses. Almost the only way to get
all the air out

 

[sniper_x]

F@#K!

Tech 2 ABS automated bleed tried twice

Brake pedal is still worse than my Yukon.

What the hell can I do to absolutely and definitely FIX THIS?!