Terrible Squeeking Sound When Releasing Brake Pedal

Ever since I bought my truck used, it's had a horrible squeeking sound coming from the brake pedal area (could also be inside the engine bay), which sounds like an angry goose. The noise happens even when the truck is parked with the engine on, so it doesn't seem to have to do with the actual brakes.

I've tried to spray the brake pedal nuts and bolts with WD-40, but no relief. Could it be the master cylinder? What are the common reasons for this noise in tacomas?

 

Sounds like a failing/leaking brake booster.

 

Check that the hose is on the booster is tight. The booter is big black thing pictured.




Try this too. Just because you can.

 

Thanks boss. I tried out those tests, and for the most part it seems normal. I did notice just now that the pedal does make the noise with the engine on too (I need to press down really hard), which makes me think that it’s a mechanical issue

 

I sprayed the absolute shit out of the brake pedal with WD40 and the different linkages + joints connected to it, but its still happening. Also, yes the hose to the brake booster is tight-ish

 

If you’re thinking the noise is in fact coming from the pedal, give this a try.

You’ll need a helper. Do the upside down crab walk so your back is on the door sill and your face is pointed up looking at the underside of the steering wheel. Have your helper push the brake pedal while you try locating the noise source. A small flat drop light would be ideal, or a short flashlight. It’ll be cramped with both of you trying to occupy the same space. If you end up using a broom handle or something to push the pedal, take precautions so you don’t get jabbed in the face.