Monday, October 15, 2012

Brake line repair and other surprises

I spent a lot of time this weekend not accomplishing much on the Mercedes. I knew I wanted to clean out the interior and the bottom of the floors before starting body work, but I knew I had a brake fluid leak to deal with. As I've been driving the Mercedes in and out of the garage only to work on it, I just kept topping off the fluid as necessary. The car never moved more than one car length at a time anyway.

So, I backed the car onto ramps Saturday. I'd localized the leak last month, and finally got a better look at it:

The line was snaked around a corner and not easy to access, so I disconnected it at the rearmost junction and cut the end off with my tubing cutter so I could take it to the store for matching.

What I hadn't counted on was the metal diesel lines being rotted in the exact same place. As soon as I disturbed the lines, diesel started leaking everywhere... fast. So, I put a couple of empty coffee cans underneath it:

...and disconnected the fuel supply line from the tank, draining it into an empty 5-gallon bucket.

I was able to get some correct bubble-flare brake line at the store, but they only had a double flare loaner tool. Thankfully, I found a clever Youtube video on how to create a bubble flare with a double flare tool. I practiced on some scrap line I had before cutting the line under the car and making a new bubble flare.

But, I'm getting ahead of myself. It got late on Saturday and it was cold, so I got back to work on Sunday. First, I cut out the rotted section of the metal fuel lines and bridged the gaps with new sections of fuel injection hose:

The zip ties are just to keep everything in place. I didn't have time yesterday to reinstall the line-to-body clamps. After all, I also had a lasagna in the oven and the season 3 premiere of The Walking Dead to contend with last night (a man has to set priorities sometimes). Also, one section of line is temporarily bridged between hoses with the hollow tube of a ball point pen. I'll replace that with a proper junction piece in the future (before driving the car).

Quick tip - if you ever need to temporarily bridge a section of 5/16" fuel line, a ball point pen tube matches up exactly.

Anyway, I'm not bothering to solidify any of this yet. The car is just moving in and out of the garage, and I want to replace the fuel tank first (I have a better one, but didn't have time to swap it yesterday). Once the new tank is in, I'll do a more permanent install of these lines. I'm not worried about the fuel injection hose, as there were rubber hoses underneath the car anyway. These are just longer than the old pieces they're replacing to bridge the gap between the tank and where I cut the metal lines.

Once the fuel lines were patched up, I cut off the rotted section of brake line, flared the end of the cut piece, and installed the new section of line.

So far, so good, though I still need to properly bleed the brake lines and double check for brake fluid and diesel leaks. Next week, I'll resume cleaning the car. It's been a hell of a job, but I REALLY want to wrench on a clean machine for once.

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