2002 4Runner - Typical Brake System sounds

[2002_thundercloud]

Hello, New member here, or I should say new to this forum, not new to forums ;-) . My quick T4R history... wife and I bought a new 2000 T4R SR5 4WD and kept it 5+ yrs, BEST vehicle we ever owned. Bought a new 2004Chevy Silverado Z71, actually a sweet truck and I cannot complain about it. Went back to Toyota in 2009 when we bought a new 2009 Taco Double Cab 4x4 TRD Off Road. Nice truck, but somehow just wasn't what the 4Runner was. Anyway, I sold the Taco and just bought a 2002 4Runner Limited 4WD with a mere 78,000 miles. Some might think it's a step back, but I am loving this SUV. It's thundercloud silver with all the typical stuff and so far, I'm really pumped about this rig.

I notice brake system sounds that the 2000 did not make (different hardware, I know) and my 2009 Tacoma was not quite so obvious about (similar hardware). Wanted to get some feeback from some other owners with the VSC equipped brake systems to see if what I hear is typical.

At morning startup, a pump/motor runs for about 5-6 seconds then a relay click is heard and the motor stops. After two firm or three average brake applications, the pump/motor runs for 3-4 seconds and the relay click is heard and the motor stops. 2-3 brake applications will always cause the pump/motor to run and it generally runs for just 3-4 seconds. The brake booster can be depleted (to full hard pedal) with 29 pedal depressions. It takes the pump/motor about 30 seconds to rebuild the boost and it often will pause for less than a second twice during that rebuild cycle. These times can be repeated almost to the second pretty reliably.

I don't recall ever hearing the Tacoma pump/motor running when the engine was running, though you could make it run if you pressed the pedal several times with the key on-engine off. So my question is... am I hearing typical brake pump/motor activity, or is my pump/motor running more frequently than it should? If it is running more frequently than normal, what are some common causes?

Thanks much for any help you can offer.

 

[sawtooth3]

I have a 2001 T4R Ltd, and I know the sound you're referring to. I guess it's normal. In six years with my vehicle I have I just ignored it, don't pump brakes or anything, and everything always works, is fine. It is weird, agreed, but no problem I'm aware of so far. It fires off more when the engine is cold, decreasing as everything warms up (although cuts on occasionally even then). As you can tell, I'm not a mechanic, just a driver.

 

[cfranck1]

Sounds about normal. It's the "hydroboost" brakes (hydraulic brake booster) that the 2001-2002 got because of VSC,ATrac,ABS all in one. You rarely see hydro boost brakes on an gas engine vehicle. You mainly see them on diesels because they don't produce any vacuum like a gas engine does. I guess Toyota figured to run them on a separate pump instead of running the hydro brakes by the PS pump which most do.

As far as I know the TACO has normal Vacuum brakes.

 

[PalmettoRunner]

Yeah I've got the same noise as well, gets pretty darn annoying to be honest. Its a lot better since it has been warm here, can't hear it nearly as much. I've had two mechanics tell me its just normal brake system noises and there is nothing to worry about, still seems a little strange to me.

 

[2002_thundercloud]

Thanks for the feed back. The current Tacoma 4X4 comes with two very different brake boost sytems. The non-TRD Off Road (meaning "Sport" and others) has vacuum assist, where the TRD Off Road has the electric pump assist. The Off Road version has "Active" (what ever that means) traction control, hill descent control, and hill start assist, where the Sport does not. I guess the electric system is part of the magic behind all that stuff. Just don't remember hearing the pump run in the Tacoma, I guess Toyota got better at isolating the pump noise from the passenger compartment in the later designs.

I'm not really bothered by the pump noise or the following relay "click" after every 2-3 brake applications.... just wanted to know that it was normal behavior and that something wasn't wrong.

thanks again.