Hi gentlemen,
I have a leak coming from the driver's side, rear of the engine bay. I confirmed that it is not oil, as my first thought was valve covers. But those are not the culprit when I got in there to have a look.

It looks to me like there could be several possibilities: 1. the air conditioner lines that go to the back of the truck on the driver's side? Or, 2. the brake master cylinder / booster.

I checked all fluid levels (brake, ACE, power steering, coolant, and oil) and all appear to be normal. But overnight, it looks like it loses a good amount of fluid, so I'm not sure where it is coming from.

I also looked through the rave but didn't see anything too helpful, since I honestly don't even know what fluid it is.

Any help or guidance would be greatly appreciated!

Picture looking down, with the master cylinder in the top right of the picture.



Looking up right behind the drivers side wheel. You can see the two coiled hoses are very damp, and the hose directly above those looks like it might be the culprit. Sorry this picture is not a great angle. Since it is sideways.



Slight better picture of those I was referring to in the previous picture. This hose it right above the two coiled hoses in the previous picture. It is connected to the A/C system (I believe it is the "L" hose).



The amount of fluid over a couple days. It is NOT a daily driver, so it was jus sitting there for 3-4 days.



Very difficult to see, but it looks like there is some fluid coming out of the bottom of the mast cylinder.



Slightly better angle, where the master cylinder is sitting at the top of the picture and it looks like fluid has run down the wheel well (center of the picture).

 

So I put a drip pan under there to catch some of the fluid, and it's clear, greasy, and slightly thicker than water.

I'm pretty stumped though.

 

Definitely not engine coolant?

 

Yes, definitely not coolant from what I can tell. Where would coolant be coming from in that part of the engine and I can take a look to confirm?

If it was on the passengers side, I would be thinking it was coolant related for sure.

 

My money would be the seals between the master cylinder reservoir and the master cylinder leaking causing the fluid to run downhill to the booster, then down the frame.

 

Ya that was my thought as well. However, the brake fluid level isn't going down? Not even slightly?

 

That is the reservoir seals. 69.00 for the rebuild kit. My black 02 D2 started out slow and I never saw the fluid level move that much, then when it got cool it leaked like a SOB..

Will have to get the rebuild kit and take care of it.

 

Ya that is the interesting part is it leaks a lot more after it cools down... Thank you for the tips! I'll look into the rebuild kit!

 

Unless you have a massive leak your refrigerant is always under pressure, so it would leak as a vapor.