Brakes locking while driving

Recently I had a CV axle boot bust and it gummed up my wheel bearing so I replaced both. I made it a mile down the road and my passenger front brake caliber locked down and nearly threw me in the windshield when I let off the gas. Driving home I was running about 4000 RPMs and felt like I was towing a tank. I then ordered an upgraded brake kit (powerstop brakes, rotors, and calipers) and swapped everything out on both sides. I also flushed and replace the brake fluid using DOT 3 as specified. I drove around for 10 miles or so, came home and parked it thinking all was good. I went to pick up my kid from school about 2 hours later and once again my brakes locked up but this time on both sides. I barely made it to a parking lot and the entire time it felt like I was riding with my e-brake on (it wasnt, I promise I checked...) Im lost here and apparently so is every other Google user. Surely I am not the only person to experience this? Brake booster seems to be functioning like normal, there are no lights on the dash, ABS sensors are good. Please world, help me out. 2008 TOYOTA TACOMA SR5 4.0 4X4- 135,000 miles with regular service

 

Almost sounds like an ABS issue

 

Probably not ABS if it happens without you hitting the brakes (and after letting off them successfully), AFAIK the normal ABS system (not the electrohydraulic actuator system in some TRDOR years) is only capable of holding or dumping existing pressure, created by your leg. They can't create their own hydraulic pressure.

If you haven't replaced your hoses... replace your hoses. I chased my tail on my wife's car a few years back replacing calipers every year that'd start dragging on the highway, cuz I swore I'd replaced hoses... turns out I'd only done one hose, the side that didn't keep failing.... durrrrrr me. Hoses can swell shut, or develop a failed flap that acts like a check valve. Usually starts with an intermittent dragging/pulsation that goes away cold, because the pressure they hold makes the caliper drag, then the piston heats up & sticks, then there's more heat, then the fluid expands & clamps harder, etc.

 

When it locks, does the brake pedal still move up and down? If no, maybe there’s an adjustment that can be done to the master cylinder push rod.

 

Maybe a bad vacuum booster?

 

I’ll guess broken rr parking brake cable.

 

Do the wheels spin freely?

 

He said the front calipers are locking up.
I can’t see it being a parking brake cable if that’s the case?

 

That’s a good question.
Can we confirm it’s just the front or all 4 wheels?
Do the brakes “release” after the truck sits for awhile?
When pulling the hose from the vacuum booster? What happens?

We need more information.

 

Oopsy

 

X2

 

thanks for all the input so far. It is just the front wheels. Wheels do not free spin because the calipers are locked down. The first time it happened the passenger front brakes were nearly on fire from me driving it in that condition just trying to get it back to the house. I just changed every thing mentioned before hand when the issue persisted. I have let it sit since it last locked up on me and will be trying once more today before calling the wrecker to get it home.

 

Brake pedal still moves up and down, but when this happens you don't need them. Simply letting off the gas will almost stop the vehicle, first time this occurred it nearly threw me in the dash.

 

UPDATE: after sitting the brakes are now free (for the moment)
Will be replacing soft brake lines and testing brake booster.

 

The booster has a check valve, it may not be functioning correctly.
Or it could be the booster as a whole. These truck are not too when it comes to self adjusting the rear brakes. So, it could make sense that it’s the front locking and not the rears. I guess it depends on how far out of adjustment the rears are.

 

The only thing the check valve does is keep vacuum in the booster so you have brake booster (for ~one pump anyway) without manifold vacuum. You can test it by pressing the brake pedal 2-3 times after shutting off the engine, pump 1 should feel normal, by pump 3 the pedal should feel rock hard, since your leg would be doing all the pressing.

Either way the check valve fails shouldn't make brakes lock... stuck shut you'd get no assist, and stuck open you'd have no assist as soon as you shut the engine off.

 

Had a similar issues years ago with a bad booster. My brakes would apply themselves and lock up but only on the highway. When it happens I would disconnect the booster vacuum line and they would free up and it would last a day or a week before locking up again. I replaced everything up front before realizing it was a booster issue.

 

Update: brake booster was good, master cylinder was good, replaced the brake lines in addition to the before mentioned, and after all that the mechanic had a hell of a time troubleshooting this issue also. Brake pedal rod was loose so they made adjustments then bled the brakes. Did this a couple of times and issue seems to be resolved for now. Will post if any changes....

 

Awesome news man! I went through similar issues and replaced everything. I still get a weird shudder on the highway sometimes where my wheel shakes, pedals vibrate and if I try and apply the brakes the pedal is hard like I barely tap it to stop the truck then after a while it goes away and the pedal is back to normal. I think I have air in my lines.

 

Hopefully it's all fixed now.

I had an issue with my stupid drums. Long story short, the springs inside drums would rust up (launching boat) and the shoe would brake it's self kind of like your front end was doing.