Hello everyone! I guess I'll make this my first post on volvoforums. Unfortunately it isn't under better circumstances. I recently just bought my first Volvo (1992 Volvo 940 Turbo Auto) and couldn't be happier with the car except for a few things. As I was driving the car the other day completely at random I went to hit the brakes at 60mph and lost brake pressure COMPLETELY. The pedal went strait to the floor and I instantly got concerned thinking I blew a line. However when I let of the pedal and went to depress it again to try and pump up pressure it was back to normal. I stopped a dozen times after that to try and replicate it but the pedal still held semi firm. I should mention that the car was in storage for eight years prior to my ownership and the engine being rebuilt. The brake fluid is almost completely black but it still has the power to lock up the brakes and activate the ABS if I really hit the brakes hard. This has happened on three other occasions and it completely leaves me scratching my head. I've already ordered a new master cylinder and reservoir and will be doing a fluid flush as soon as it comes in. I was just wondering if anyone else might know more about these cars/have another recommendation as to what It could be, I've never experienced something like this before so I'm at a bit of a loss. I need to get the car safe to drive since I have a 30 mile one way commute to work. I appreciate any help in advance and happy to be apart of the community!

 

any sign of brake fluid leakage at any of hte 4 disk brakes? how about at the ABS unit ?

 

No signs of leakage that I can find anywhere and there isnt a loss of brake fluid out of the reservoir. The ABS pump is bone dry, I just checked again at the moment. It looks like the only thing thats leaking on the car is one of the oil filter lines.

 

Failing master cylinder would be my guess... Leaking internally--you pump it up, it builds pressure, lets go now and then. Change it, flush the system, bleed the lines!

 

That's what I figured as well but I wanted to be sure there weren't any other possibilities that I could be ruling out. Do these cars just use regular DOT 3 brake fluid? I'd check my owners manual but the PO was nice enough to not include it with the car.

 

DOT 4 fluid as per the owners manual.

 

Thank you and Lev for all the help/information. I truly do appreciate it! I just wanted to make sure I had eliminated everything else before I kept working on it.