Master Cylinder going out?? Pedal gets softer while stopped.

Okay, I've had a similar problem before in a VW. But in that one the brakes just almost failed, and were really soft and slow to engage.

What I have on the Tacoma, is the pedal gets softer while I'm sitting at a light or just stopped. At first I thought maybe it was normal, but It seems more frequent. No leaks at any wheel, so I can rule that out. With brakes if the system is closed then the problem is usually the cylinder.

Also I noticed when the pedal does this, it seems like the torque converter engages or disengages giving the truck a small surge.

Wondering if any one else had master cylinder issues or a pedal that gets soft when stopped, but is not spongy under normal use.

 

Similar issue for me in my 08 DCSB Prerunner... the sponginess is very gradual, nothing like when my old integra's master cylinder blew out and I lost my brakes. This happens infrequently and I also get that lurch in the truck.

Don't have any answers for you, but at least you know you aren't alone!

 

The lurch at a stop is your ac compressor kicking on.

 

damn its crazy, every weekend I think I have some major problem, then I come on here and find everything is normal.

I'm going to price master cylinders, probably not a bad idea to change them. I was going to rotate my tires anyway, so I'll do a brake inspection while I'm at it. Damn that is a big surge to be "normal"