"I have an '05 SR5 V6. It has 195K miles on it. I've owned it for 2 weeks. Aside from the usual maintenance issues, the big concern for me is that I can hear and feel the brake boost pump come on every 10 seconds, lasting for about a second."

* I would inspect all the brake lines from the booster to the brake calipers looking for any signs of a leak.
* Consider having a brake fluid exchange done on it at the dealer so that they do it per the Factory Service Manual. There could be air in the lines or in the hydraulic assembly itself.

My booster assembly pump started running every 10 seconds or so followed by a sqwelch like noise. I replaced the accumulator and the problem went away for 2 months, then re appeared off roading one day. I unscrewed the accumulator let some brake fluid out and re tightened it. that was two weeks ago and no issues since, so I`m not sure whats happening. My guess was air since I never bled the lines when I first replaced the accumulator.

Hope this helps a bit.