HELP! W126 Brake Questions

[jcantor]

On my very short drive into work this morning, the brakes on my '87 560SEL went from a little spongy to almost nothing. The fluid reservoir is empty and I can smell the fluid so obviously there is a leak somewhere. I'm going to take the car in to have someone else deal with the issue since its below 20 deg out there and only getting colder.

I'm assuming that this is probably just a blown seal or a rusted steel line but I wanted to know if there are any common failure points on these cars that I should be aware of when I get to the shop. Are there any pitfalls or areas where shops have a tendency to make errors - intentional or otherwise - on these systems? Is there something with the ABS system that could be part of the issue?

Thanks
jlc