Periodic noise with clunk

[nizzoball]

I've been having an issue with my '01 'runner for a few months and I was wondering if anyone might be able to shed some light.

The noise is similar to a fuel pump initializing when you first turn the key on but at the end there is a very audible clunk. It seems to be coming from the passenger side of the engine compartment. It always happens when I first start the truck up in the morning and it seems to do it a lot while braking. It's always the same noise, it's like a fuel pump initializing with a clunk when it shuts off.

Other than this noise the truck seems to run and drive just fine. ('01 with ~70k miles). Any ideas?

 

[opie74]

Mine does the same thing. Best I can come up with is the braking system is not run off vacuum from the engine. Pressures appears to be kept up by means of a pump. At least on mine. There is no vacuum booster nor are there any vacuum lines running from the engine to anything the master cylinder is attached to.

With the key on, engine off, pump the brakes and you will hear the motor cycle.