Brake pedal feeling spongy after car warms up

[jambo101]

. First half hour driving the car no problem but after that there seems to be more play in the brake pedal than normal ,front pads were changed last summer and rear shoes were changed last month,
Any ideas?
Thanks

[bronsin]

I would suspect the recent work done on the rear brakes.

How's the parking brake travel before it locks up?

[invader166]

Rear brake adjustment tends to have a big impact on brake pedal feel. I've tried a lot of things from new pads and rotors, to new brake lines. It wasn't until I re-adjusted the rear drums (3 clicks on the hand brake) that the pedal felt nice and hard.

[dogsridewith]

Might be something different going on with Yaris rear drum brake automatic adjusters, which are supposed to tighten adjustment as needed when brakes are applied while backing up. Mine were both quite loose at 135k miles. Real high handle. Lots of clicks.

[jambo101]

my mechanic says i need a new handbrake cable as the one on there now is evidently binding.

[tmontague]

Did you try adjusting your rear breaks first? The auto adjusters tend to never work properly in any car that I've owned.

I always adjust them 2x per year and I make them tight enough where the rear drum barely spins a full circle on it own. That's fairly tight but they wear in to a comfortable point and it make the pedal feel nice and tight and I only have to lift the e brake up 2 clicks to lock the car from rolling.

That said, make sure you're using the e brake when parked even if you have an auto trans. This will stop the e brake from seizing in its cable housing.

[SirDigby]

Originally Posted by dogsridewith

Might be something different going on with Yaris rear drum brake automatic adjusters, which are supposed to tighten adjustment as needed when brakes are applied while backing up. Mine were both quite loose at 135k miles. Real high handle. Lots of clicks.

yea, those things never self-adjust. it's good to adjust them anyway so you can clean them and check for issues.

[Kaotic Lazagna]

How old is your brake fluid?

[Motzking1]

Like the others I agree adjustment of the rear shoes by hand is the place to start. you mentioned when its cold there is no problem?? Strange? There is a simple test to diagnose where the problem lies.
1) drive the car until the problem is present(more than the half hour)
2) in a safe place drive about 30 mph and slowly engage the parking brake until you feel it drag. Hold it to where it's slightly but steadily slowing the car and step on the brake pedal.
If the problem is no longer there and the brake pedal feels high and hard the problem is in the rear brake adjustment, adjusters or as janbo101 alluded to could be a binding parking brake cable in combination with a rear brake adjustment problem.
if you use this diagnostic method and the pedal is still spongy and or low. Your problem is most likely in the front brakes and not the rear.(unless the parking brake cable is completely frozen [not at all likely so let's ignore for now]) if this is the case inspect the front brakes.
Inspecting the front brakes for this problem should be very easy.
1) jack up the front wheel and remove the tire.
2) use a strong flat blade screwdriver and insert it in between the rotor and caliper housing and pry. It takes some force but gentile and patience works best.
3) once you have pried a few millimeters of space remove the flat blade screwdriver and get a new bite in between the rotor and the brake pad. Again pry gently being careful not to damage the brake pad until you push the Piston fully back into the caliper. You're pushing fluid back into the system so be patient it may take 20 seconds for to fully retract the piston.
4) with the Piston fully retracted into the caliper grab the caliper main hydraulic housing. It should be loose and be able to rock it back and forth from the inboard pad to the outboard pad against the rotor. On both sides of the caliper there should be rubber boots where the caliper sliders are located. Watch these while you're moving the brake caliper back and forth they should be compressing and expanding evenly if the caliper is only moving on one side and his difficult to move or does not move freely back and forth something is wrong with your brake caliper sliders.
5) after inspection replace the tire tighten lug nuts and repeat the procedure on the other side.

If you follow these directions you should be able to accurately diagnose the problem you're having with your brakes. Now there are some super weird things that can happen but super unlikely. Seward buy some very odd reason you check all these things and you're still having a problem let us know.


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[Motzking1]

Oh yeah an important safety message. After checking both front brakes and before moving the car at all make sure to depress the brake pedal several times until it feels high and hard. If you forget this step when you go put it in reverse or forward to drive out of where you're working on the car the brake pedal go to the floor and the car will not stop. So this is a really important part. Sorry I missed that part

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