I am considering purchasing a 2008 Tahoe hybrid with 39k miles. After reading a number of posts a have some concerns regarding the braking system and failures. Is this something I should really be worried about or is it just isolated incident? Also is there anything I should be looking for before I purchase? Thanks!

ah the dreaded brake nonsense again! one guy CLAIMED to have this ONE issue and it spread all over the internet in various places so I did some research and found that EVERY POST could be traced back to this web site.
There were no NHSTA reports on this even though I gave the web site out to him. IMHO he bought the car and didn't like it so was trying to get out of it.
quite simply the brakes in our cars, just like in other cars are HYDRAULIC and the only way they could stop working is with a total failure of both the primary and secondary master cyl ports. could it happen, maybe but I bet you could get million to one odds of that happening in Vegas.
could the POWER ASSIST stop working requiring more pressure on the pedal to stop the car? yes but IT WOULD STILL STOP. could the electric brake assist fail YES BUT IT WOULD STILL STOP!
I have a 2008 Yukon with 29K on it and it has had one issue with a faulty crimp in the wiring harness in the trans which caused the engine to shut off. it happened twice BUT THE CAR STILL STOPPED it just took a little more effort.
caveat emptor but this is one of the better new technology cars I have had and I sold a mercedes ml55 AMG and replaced it with this never looking back. I have owned multiple range rovers as well great off road but slow as an old dog on the highway.
good luck with your decision but I am totally pleased with my yukon

actually if you are a porsche man as your s/n says, it feels like a 4 wheel disc brembo brakes. it is easily modulated by your foot. it is very reliable and not grabby.

Really not a problem. They are fantastic brakes, but (yes there is a "but") the engine switching on and off with the electric assist and regen kicking in and out, can give a non-linear feeling very near a standstill. This is very, very minor and not a problem for any sort of aggressive driver. If you ever really need the brakes, they are ALWAYS there.
This past Saturday, I decided I needed to turn right on a road as I was entering the intersection at 45mph, the brakes and Stabilitrak made it uneventful (except the noise generated by the tires and my wife's mouth).

'13 Chevy Silverado Duramax/Allision 2500HD Crew Cab 4wd
'12 Chevy Volt
'08 Tahoe Hybrid 2WD
'97 A-M DB7 Volante
'61 Cadillac Series 62 Convertible, 3.6L LLT V6, VVT, Direct Injection, 6-speed auto, Side Pipes
'56 356 Speedster Replica, 1915cc, Dual 48IDF, hand ported intake/heads, Tiger Mendez exhaust, 120 cam.

[quote=(except the noise generated by the tires and my wife's mouth).[/quote]

I have heard that same sound!

Made the deal just a few min. ago. I apreciate all the replies...this site is great! Purchase price is $31.3k....39kmil. I think I got a great deal on it. Blk/tan...extremely clean.
Thanks again for all of your help!

p.s.- saves me money for new 911!!!

the hybrid demands a really different driving style. your right foot dictates mileage. you need to learn the various instruments that will help you. I think the most important is the instant mileage gauge in the speedo (read the manual) the more you keep it in v4 or under 30 elec mode the better the mileage. I have driven a couple of miles home from my office in elec only during rush hour and have been averaging 19.5 for the last several months in stop and go (no highway at all) traffic.
good luck with your new car

I purchased a used '08 Yukon Hybrid a month ago. This morning I went into the garage, turned the key to start the car and my foot (on the brake pedal) went to the floor. The dashboard lit up with warnings about the Stabilitrack system, ABS, etc. I tried turning it on and off a couple of times but it kept happening.

I put the car in reverse and rolled backward a bit then applied the brakes. They seemed to work given a lot of effort but the pedal sure was lower than normal. I'll be calling the dealer today but wondered if anyone had thoughts of where to start looking for answers?

Thanks,
Peter

just bring it to the dealer to do a diagnostics.

Yes, I'll call them this morning. Probably have to tow it there - I don't think I can drive it.