Front Brakes (Both) Locking Up - 07 PreRunner

Picked up a new truck, needed Rotors and both front wheel bearings. Replaced along with pads. Drove it around today for about 10 minutes and the front brakes began grabbing up until the point it wouldn't drive. I pulled the vacuum line to the booster and both calipers released. Plugged it back up and drove home with no issues.. Checked the booster check valve and seems to be functioning just fine. No ABS lights.

My guess is while bleeding the brakes something became hyper extended damaging the booster? $200 part, don't want to throw money at it..

Ideas?

 

Maybe unrelated, if you allowed air into the system, the air gets trapped in the abs. What I’ve heard is it causes low to no pedal. Which is why it’s probably unrelated seeing your issue is not releasing.

Sometimes when putting new pads in, the calipers pistons may have had some smutz on them. Usually when you push the pistons in to accommodate the new pads that crap will be pushed off by the seals. Maybe that stuff is stuck between the pistons and seals causing them to get stuck?

 

I had this same issue happen twice on my 07 2wd auto. While driving on the highway my brakes applied themselves and I had to pull he vacuum off the booster which instantly released them. I bought a rebuilt OEM booster off E-bay and it lasted 5 years until the other day when the issue happened again while waiting in a drive through the pedal got firmer and firmer until the brakes locked and I had to yank the vacuum line off which fixed it until the following day when they locked up again. I have no ABS light, new brake lines for the front calipers and a new master cylinder because I threw the parts cannon at it like an idiot. I'm about to order another booster but this time from AutoZone or RockAuto.