Front brakes stuck after fitting new pads

Try renewing, is that the correct term for you, the brake fluid first.

 

Have a dealership flush the brake lines, and alert them to your issue?

I appreciate it (brake fluid change) can be a DIY, but at this juncture it might be better to get them on it, and troubleshooting. I know on third gen you need to put the car in special mode while bleeding, if you don't have Techstream.

Has the brake fluid ever been changed? Tri-yearly is a good rule of thumb.

 

Could be a failure in the sensor for the brake pedal. Only the front?

Tires all the same size, about the same wear/tread depth?

 

Mendel,

Don't the caliper rotors have to be turned to a particular position to align with the back of the brake pads?

Could this be part of his problem?

 

2nd gen rears in Britain are disc not drum? But still, OP's saying it's front brakes he's done.

 

There's a recommendation I've frequently seen online, for any car that has elaborate ABS valving upstream, to never replace pads by forcing fluid from the caliper back up into the valving. The recommendation instead is to open the bleeder at the caliper before pushing back the piston, so any gunky fluid from the caliper simply leaves the system, then button it all back up and make up the reservoir level with fresh new fluid.

The concern is to avoid pushing any gunk back up into the delicate ABS valves that might stop one of them from completely re-seating. If one can't completely close, it could be allowing some amount of pressurized fluid to the caliper even when you're not trying to brake. This is the sort of rare thing you could do 99 brake jobs and get away with, but run into as an expensive headache one time in a hundred (which is always most annoying if that one time happens to be the first one you do!).

If that might have happened, then it's also possible a good fluid flush, exercising all the ABS valves, might help, before making any harder decisions.

For what it's worth, I was once in what I thought might be that situation, and it turned out I just had a caliper with inadequate return, which is pretty easy to measure and easy to fix, so that's worth checking. It's especially worth checking since you report the pads so much more worn on that side than the other side to begin with.

-Chap

 

Yeah missed that.

 

I would rebuild/re-hone, or replace calipers first.

 

Would be better to find out where the problem is before just changing parts.

First maybe you should make sure that pads can move freely in their shims.

If that’s not the problem:
Put the brakes to manual mode (only front brakes with no ABS or power assist) by pulling the two relays and using all the pressure: Brake service
If you can then get it to bind (you need to use lot more force) then it really can’t be the brake actuator. Then once it’s still binging (in manual brake mode) you can loosen the brake bleeder. If it then loosens immediately you know it’s not the problem with brake caliber. That pretty much just leaves the brake hose.

 

Toyota US replaced the Gen 3 Brake Booster Pump under warranty and supposedly tested the rest of the braking system.

 

No, utter hogwash perpetrated by those wanting to upsell services or parts.

 

There are THREE possibilities:
1) Binding caliper slides - if you take the pads OUT and refit the calipers, the caliper(s) should move FREELY in-out on the pins
2) Hydraulic issues - if you open the bleeder screw(s) *slightly* and pressurized fluid escapes, it's the HCU
3) Sticking caliper piston - this is the most difficult to dis/prove, but if other causes are ruled out, a reasonable conclusion

While service manuals commonly list a damaged hose as a possible cause, in 40 years of doing brake work, I have never once seen it.

 

Would opening bleed valve cause the car to throw a code? On third gen there is "invalid mode" to circumvent this, if you don't have techstream.

 

If it were me I think I'd definitely check the calipers for return—if only because it's not too hard to check, and it did turn out to be the problem the last time I was having hot-rotor-after-driving issues, and there's a bit of cargo-cultist in us all.

I was testing with the caliper off the car, just using puffs of compressed air. I think it wouldn't be very hard to adapt that to an on-car test, if you had a longish hose to fit over the bleed screw and route upward. If you let some fluid bleed out, part way up the hose, it should then be possible to puff air in at the hose end just enough to nudge the piston outward and measure its return, without getting any air in the caliper. (The rest of the setup would be as I described in the earlier post, just blocks of some hard material about the same thickness as rotor+pads, and a dial indicator.)

The key is using only a puff, enough to lightly bonk the piston out against the block, then measure the return. It might be tempting to try to do the same test using only the brake pedal, but the hydraulic system is so powerful you end up measuring the elasticity of aluminum and steel and not the piston-seal return if you do it that way.

If the ECU sets codes while you're playing, just clear 'em later, no biggie. You could view them as reassurance that it's paying attention.

But you probably want it in Invalid Mode (or the battery disconnected) while having the bleeders open, just so it doesn't happen to schedule one of its occasional self-tests, and squirt you.

-Chap