No brake boosting at all!
 

My beautiful 2000 S80 T6 has 168 000 km (105 000 miles) on the clock. At about 130 000 km I started noticing the brake pedal going low when holding the car at rest in traffic. When I released it & re-applied it, the pedal would go high again accompanied by a slight hissing noise. The brakes always worked perfectly, as did the ABS (easily tested on African dirt roads) and no warnings or messages on the screen. All went well till monday when I started the car and discovered that I need Arnold Schwarznegger's right leg to stop 2 tons of Swedish machinery wheras before only my big toe was necessary! I've read a lot of posts in this forum and most indicate a defective brake booster. A small amount talk about a vaccuum pipe. Parts in South Africa for these machines are hugely expensive, so before I have a nervous breakdown at the thought of replacing the booster, could it possibly be anything else? And also, how could I test for the problem? My eternal gratitude in advance for any help in this regard!

Just got some quotes from Volvo Dealers around Johannesburg. Replacement of Brake Booster is $750.00. Replacement of Vacuum pump is $490.00. One nice service advisor told me it may just be the valve (?) that is faulty. Is there any way of finding out beforehand?

Turned out to be the brake booster after all :( That and major service came to $1100.00. Worth it for such a beautiful car though!

wow.. that is amazingly pricey.... mine is definitely on the way out.. it has the hissing and only really bites 1/3 down the brake travel... but, it hasnt seemed to get any worse so I figured I would hold on for now...

Anyway sorry to hear you had to incurr such a cost, but glad you love the s80

PS. Wish I could be in SA for june/july...

Thanks for the nice reply. My advice is to keep on driving it till the booster goes. It gives you plenty of warning so is quite safe. Mine lasted 14 months & 20 000 miles in this condition inlcuding a long family holiday pulling a trailer ( 4 sleeper caravan). I'm not a super rich person who can afford such a vehicle brand new, but if you are prepared to drive them with love and look after them, then these big Volvos are pure pleasure :)