Funky brakes

Hi All,
I just installed new UCAs and got an alignment done. The only thing they adjusted was the toe. Driving to work this morning one minute the brakes were firm and then the next time I go to hit the brakes the pedal was kind of soft. After briefly letting off and pressing them again they were firm. Happened maybe three times over the course of a 25 mile drive. The temperature here recently went from 60-70F degree days to 0F this morning. Could the brake pads be catching on something after the alignment? Or does this sound like a master cylinder issue or something else? Thanks in advance for any advice!

 

how many miles on the truck?

do you use your e brake?

Reason i ask is typically something like you describe is caused by brakes getting pushed back into the caliper / clearancing further than necessary due to either bad hubs / warped stuff / non adjusted rear brakes due to not using the ebrake.

 

Only about 40,000 mi on the truck. It is an auto so no e brake.

 

always use your ebrake.... even if its an auto... your auto will THANK YOU as the parking paw wont get bound up.

This is also likely one of the reasons you are expierencing this issue. When you set the Ebrake it actually adjusts the rear drum brakes... without it you have to push the pedal down further n further for any pad contact.

 

Good to know. If that doesn't clear up the problem do you have any other suggestions?

 

zero degrees and brakes have some initial weirdness ?

welcome to the club. My 1999 4runner has done this from year 3, to now (that is 12 years)

when it is 5 deg F or lower, and I roll out in morning, my brakes require 2 or 3 pumps to get them normal. never happens above 5 deg F.

either I have moisture inside the calipers, around the pistons, or the minor amount of water that is dissolved inside the brake fluid (all of us have 'some' amount, it should be negligible and only micrograms) makes the fluid 'slow' when super cold

if you want to chase this problem down....first thing to do is strip all brakes apart and flush entire system, and also clean out the disc brake pistons

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also, about using the e-brake. yes use it often. the #1 killer of rear drum brakes is never using the e-brake, and what happens is the bellcrank pivots will eventually rust up and seize, then the day you do use the ebrake, they won't return...or otherwise they will cause the rear brakes to stick and wear out and overheat the rear drums. nasty. all you gotta do is use the ebrake regularly and it will remain free and loose. and yes using ebrake helps click the adjustment pawls so the rears remain adjusted. on my 4runner rolling in reverse and yanking the ebrake will notch-up the adjuster so i don't have to reach in there manually and poke it with a screwdriver to tighten up ebrake slop. it can do 1-3 clicks per yank

 

Almost sounds like they just need to be bled with them going from firm to soft but back to firm when you pump them.