2003 Tacoma Brakes randomly very sensitive

Good morning all,

Im trying to diagnose a peculiar issue, and searches result in nothing.

We've got a 2003 Tacoma RWD, at random times the brake are overly sensitive. For example the first 10%-20% of the brake travel is normal then 25% and on is like you pressed the brakes to the floor. Yes, it will even lock up a wheel if the road has any dirt or is wet. Any some times its just the opposite, the brakes are very dull and not grabby at all. It makes it very tricky to drive sometimes and is definitely not normal.
Fluid, brake booster is normal or operates as normal, and the front and rear brakes are relatively new (pads,rotors, drums)

Im hoping someone has experienced a similar issue and can help me out.

Thanks!

 

I’d start by checking adjustment on the drums...

 

Got ya, I'll open them up and check the shoe adjustment and for normal travel.

Thanks!!

 

I would look at the flex lines to the calipers and the line coming off the load sensing valve in the rear. The flex lines may or may not have an internal issue that is not apparent from an external examination. Without being there to see the whole system these are just guesses. When was the last time the brake fluid was flushed/replaced?

I am assuming no ABS as you said a wheel will lock up.

 

Ok. I am going to inspect the lines. It is my younger sister's truck so I'm not sure if it is equipped with ABS, but it should have kicked in when I test drove it, if it did. And yes I agree with you that the lines could have an internal tear, possibly keeping the caliper partially compressed then when hitting the breaks it is far more sensitive?

And the truck was purchased within the last year so I cant tell when the fluid was flushed. I might go ahead and do that while inspecting all four corners.

Thanks.

 

You might want to spray the brake shoes and drums with Brake Cleaner. I take some sandpaper (held with a block of wood against the rotor) to score the surface a little too.
Also, lube the caliper slides so the pads can move in & out.

 

it is not so much a tear as it is internal sweeling that restricts the passage of pressure and then holds it shortly after you release the pedal.