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Discussion Starter #1
Hi,
My name is Guy Chammas, and this is my first discussion here.
I drive a 1972 350 SLC as my daily, but sometimes I travel and it sits for upwards a month. Lately it's been sitting around, I try to drive it as much as I can, and that has only been once each week.
Last week, I went for a drive with no issues whatsoever. Yesterday however, I jumped in the car and the brake pedal feels loose, only around 5% pressure, BOTH with the engine off or on.
The 2 front brake lines were replaced and the master cylinder was refurbished one year ago. I can't see brake fluid spilled anywhere, and the reservoir sits where it sat before, between min and max.
I'm no mechanic but I work on my first car a lot. Taking it to the local mechanic is currently a hard task because of all of the protests here in Lebanon.
What is your opinion on what might have caused the issue here?

Best Regards,
Guy Chammas
2608289
 

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1983 380SL, 2000 S430, 1991 420SEL (retired) - RHD
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5,120 Posts
Could be air in the system. Do you know how to bleed the brakes?:)
Nice looking car!
 

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'79 450SL, '04 CLK200 convertible; former A124, W210, A209.
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1,077 Posts
As Aussie mentioned that should be the first step especially that your brake level is correct.

Indeed, a great looking SLC you got there!
 

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Discussion Starter #4
Thank you! I will try it as my first step. In the meantime, can somebody explain to me how is the brake pedal linked? How is it connected to my system?
 

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1998 C280; 1987 560SL
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431 Posts
Yes I do, but any tips on how to do it as a one man job, on a hill, would be awesome!
There are two methods I know of that one man can use to bleed brakes; 1) vacuum hand pump & 2) pressure bleeder. I use the vacuum hand pump, which in US is available at Harbor Freight for $20. Start at on the rears and go forward. You suck out the fluid through the bleed screw with the vacuum hand pump, making sure the reservoir stays full. You can probably find a youtube video demonstration of both methods.

As far as the hill is concerned, it may be better to have the car headed down hill, since you are pulling the air toward you (easier for air to go uphill).
 

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1984 380SL
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2,264 Posts
Sounds like you need to flush and refill the brake fluid. Only use DOT4 (DOT 3 in a pinch). It's a regular every 2 years process.

As Mr. Frankly mentioned, there are power bleeders and the "Sweetie can you help me". Bleed from the farthest caliper first to the closest caliper in relation to the master cylinder while a tool pressurizes the brake system to move the fluid out.

The bleeder screws on mine are a weird size. I think either 9mm or 11mm. Just make sure. You have the right one. You don't want any otherwise easy job turning into a brake bleeding marathon.

Don't forget that the reservoir is split in two sections. To properly fill it, you need to fill the first chamber up really high, almost like you're going to over fill it.

Put some paper towels underneath the workings so when it will spill, the towels will catch most of it. Wash the rest away when you're done.
 

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Discussion Starter #8
Ok, I dived under the car today on the street, and turns out there is brake fluid everywhere in the the right rear caliper, which i didn't see last time. Going to tackle the job in the next couple of days with new rubber bushings for the caliper, or worst case scenario, if it turns out to be a broken caliper, i will have to replace it. Beginning of 2019, my front right brake caliper had a tiny fracture, and had to search everywhere to find my specific caliper because turns out there are numerous types for different discs, my discs are thick and have the cooling separation in the middle. In the end, I installed the newer US spec calipers with the bigger brake pads. Thank you guys, will post pictures of the repair soon.
 

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Discussion Starter #9
Hi everyone,
Finally did the repair! Had to drive it around 5 km with 5% brakes, thank god it was an uphill drive haha.
Here is a photo of the caliper, all of the rubber was perished. Replaced all of the rubber with new ones, and the brakes are as good as new. Thanks!
 

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