Ok, so I've been driving my 240 with no brakes (been pulling the handbrake to stop) and I've decided to fix the brakes. I track the problem to the master cylinder and find a hole, although very small, that is causing the master cylinder to lose compression. I tried to take the thing off to clean out and I was going to weld the tiny hole shut, but the master cylinder is bolted into the firewall. Anyone have any advice on how to fix this thing? Taking the entire car apart is not an option - I'd never be able to get it back together. Is there a way to get the front half off and clean from there? Any advice is appreciated.

Welding cast iron is not a very succesful process when it has to maintain pressure. You owe it to yourself and everybody else on the road to go the distance and change your master cylander.

Just one opinion.

:) Don

Yeah I thought about the cast iron thing, but I figure if I buy a new one the old will be trashed, so why not try to weld it? But I understand what you mean, and by driving it, I mean on the dirt road around my house.

Just buy a new one dude. They're like 40 bucks from carquest. Do you have a brake booster?

I probably sound like a retard, but what's a brake booster?

Ha it's alright. It basically boosts your braking power. Manual brakes don't have them and you really have to muscle the pedal to get the car to stop. It's a big metal doughnut like thing that would be mounted on the firewall RIGHT in front of the drivers side. Your master cylinder would be mounted to this if it has one. Although I'm not sure if it does as your car is an 84.

Here is a very good picture of the cylinder and booster.
This isn't from a Volvo though, but it looks almost the same.
http://www.trustmymechanic.com/parts_galle...ake_booster.jpg

I thought the master cylinder was the brake booster lol.yes it has the other thing but is it pointing to the reservoir or the piece below? either way it has both.

Ha. Nope that big thing in the back is the brake booster. The metal piece that is bolted to it is the master cylinder. The reservoir holds the brake fluid. Now you say that there is a hole in your brake booster??

Yes the hole is in the brake booster. Its really tiny and I never would have seen it but i pressed the brakes and just a tiny bubble came up where the hole is.

so booster will cost you more than the master cylinder unfortunately

bit of a gamble getting second hand one, but I paid $250 for one 2 years ago and still going strong [quoted $800 to recon my old one]

BTW is that actually YOU in the aviator thingo, going like :bwekk:

Lol, not me. And she's actually making a kiss. And the hole is where the MC meets the booster, so I don't know which part is bad. I'll post a pic soon.

Well it's most likely not the MC. Those things are made of cast iron and a hole is very hard to put in one. I'd recommend replacing the booster. Like the doctor said it's iffy to go with a second hand one but if you can test it first you might be alright.

Do you have a digital camera? If so take a picture of the hole and we can help you out more.