So had a lot of fun playing with my LSPV and master over the summer, but finally got everything properly fixed and bled...I thought. https://www.yotatech.com/forums/f116...l-damn-290882/

Basically had a leaky lspv which drained my master and I had lots of air in the system. This was a few months ago and everything was fine since.

Well I had very little pressure today and checked the reservoir to find it damn near empty. Avg temp right now in the front range of colorado is 10-30F, but I just drove up to the hills for a few days (0-20f)(2 hours both ways) and just came down to find this issue the following day. Still have yet to find any leak.
Should I wait to find the leak first, or is this common problem in cold weather from say....an O-ring...a bad master...or should I be looking for a specific culprit that likes to act up in cold weather?

 

How many miles since you last checked your brake fluid??

As the front pads wear the caliper pistons extend drawing more fluid.

You checked for leaks every where ??

Smell brake fluid in the cab??

Your Emergency Brake is being used to keep the rear shoes adjusted??

 

Fluid going down noticeably is not a common cold weather thing.
I'm surprised it's that cold in Colorado already though!

 

Still haven't found a sign of a leak, but haven't been able to thoroughly examine yet.

Probably only been a few hundred miles since I last checked it. (Just a few commutes to denver and the hills)

Can't smell brake fluid in cab.

When I bled everything last time, we WERE going to change the brakes but the pads were in good condition, though brake squealing has returned. They were making noise even after we replaced them at one point.

Dont understand the part about the emergency brake. The emergency brake light came on when it started getting cold. Had to readjust bake drums to make it turn off last time. Pretty common everytime it gets cold though.

I assumed it definitely got air in the system as there wasn't much fluid. Before I take out the master and bleed everything again, I'd like to find the culprit.

 

Whelp...
Cleaned it, drove it and waited for it to get cold again. It's definitely leaking from the master at the base of the attachment area. Hoping there's a ring in there I can replace instead of the whole thing?

 

Cool that you found it. Probably because of materials shrinking when cold, expanding when hot.
Different area but same principle... I drove my 4Runner between So Cal and Nor Cal for a couple of years after engine rebuild with no issues. Then I drove a shorter distance to las Vegas last TG weekend. After an evening of near freezing temps, I checked and found coolant dripping from top radiator hose where it is clamped to radiator. I retightened, and after driving back to San Diego saw no issue.