Gents,
Retired and moved up to New Hampshire a couple of years ago.
During the Winter, I always garage the wife's 2001 W210 wagon to avoid using it on the salt coated roads up here. It sits in an unheated garage for several months waiting for Spring. It has pretty low mileage at having just turned 70K.
Each Spring, when I pull it out of the garage, the pedal is soft and very low. When I bleed the brakes I always get air out of the front calipers. I get more out of the left than the right. After I get the air out, no further problem until the next Winter.
Any ideas on why this is happening? None of my other cars seem to suffer this problem.
How is air getting into the system over the Winter?
Thanks for your ideas.

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KenP

1996 S500 W140 Coupe

I would scrutinize all four rubber brake hoses as they go to the calipers. Actually, I'd scrutinize the entire length of each hose. You may have horizontal hairline cracks in them. Move them around, you'll be surprised at how these hairline cracks can hide. That's the downside to rubber, it ages regardless of mileage.

Thanks, Boston Benz. Much appreciate the idea.

Has anyone actually experienced this issue before?

__________________
KenP

1996 S500 W140 Coupe

Yes, I have. On my 2001 210 wagon, ironically enough. In my case I was traveling overseas for about 3 weeks. The car was parked in my garage, undriven the entire time. That first Monday morning going back into the office, the brake pedal was very soft. The car was driveable, though it certainly wasn't right. A quick fluid flush fixed it right up.

I had the problem only that one time. It did not occur to me to inspect the flexible brake lines, the car was only 7 or 8 years old at the time, and had low miles - 70K or less.