Spongy/Soft brakes

[36fatfriends]

I have a 2005 f150 FX4. 165k miles.

I just replaced all 4 rotors, 2 calipers, and all pads. I did a full bleed in the proper order to get all the air out after cracking the lines for the calipers (1 has siezed piston, the other a siezed bleeder nipple that I stripped). My brakes were still spongy when done so I took it to the shop to have them bleed with a scanner tool and get any air out of the ABS Module. $130 later and they are still spongy.

No air in the lines at all, what could cause this? Note: they were spongy before as well.

 

[harrycalahan]

They were spongy before as in theyve always been spongy since owning the truck?

 

[DADI03]

Booster or Master Cylinder. I would bet on the Mastercylinder

 

[36fatfriends]

They were spongy before as in theyve always been spongy since owning the truck?

Spongy before this break job. Not spongy always. I’ve had the truck 10 years.

 

[36fatfriends]

Dude at the shop said he thinks the abs module is bad and that he doubts it’s the master cylinder. Never heard of them going bad though.

 

[DADI03]

I had to replace mine on my 92. The fluid would pass by the cylinder. It made it feel spongy. The pedal was slow to recoil as well.

 

[fast306stang]

Dude at the shop said he thinks the abs module is bad and that he doubts it’s the master cylinder. Never heard of them going bad though.

Could be the rubber brake lines. Under pressure they will swell and give a spongy pedal. It's a nasty job, but you could replace the lines with new ones, or upgrade to braided lines.

 

[MRM]

You need to lock the brakes down to cycle the abs.
Maybe the shop did this with a computer.
It should help.
Do the brakes "pump up"?

 

[41mag]

I have seen a vacuum leak make them spongy sometimes, but as fast306stang stated, it probably is old brake lines or a bad master.
It is going to be one of those things you are going to have to try this and that to find it , probably. Good luck!

 

[36fatfriends]

You need to lock the brakes down to cycle the abs.
Maybe the shop did this with a computer.
It should help.
Do the brakes "pump up"?

when the vehicle is off they do. pressure builds as normal.