I have a 1987 dodge dakota v6 w/ 350000 miles . When I use my brakes I hear a hissing sound. It doesn't stop unless I take my foot off the brake, other than that it is non stop. I am not losing any fluid. The brakes don't seem spongy or anything so far, but this just started 2 nights ago. I was told that the brake booster could be the problem, does this sound right?

sounds like brake booster to me-hissing sound would be vacuum leak

could be the booster. does the engine run any different during the hissing? the booster runs on vacum and if there is a leak it will hiss and could cause the engine to run a little off just like if a vacum line is missing. this is just a thought and if anyone else has a better idea then use it but I would spray just a little eather around the booster when the truck is running . have someone
pump the brakes while doing this and theoreticly if it is leaking it will draw the eather in and the engine will surge a little. dont go nuts with the stuff and try to keep it away from the breather. if the booster is leaking then you will have to replace it i dont know if they can be refurbished. good luck. hwystar.

It's the booster, I am going to replace it this coming weekend once I find one. SEems to be kind of a hard part to get, everyone has to order it... What happens if I don't replace it? I've been driving the truck for the past week with no problems other than the hissing. Not been driving it far, but isit posible for me to completely loose my brakes or anything?

No you won`t loose your brakes. The effort to press the pedal will increase as it gets worse since youe will be loosing the assitance of the vacum booster. How ever I would think before you got to this stage the engine would start to run like crap with a vacum leak that big. At this point you would have less problem stopping then you would have getting going. Hwystar