Brake Fluid missing from resivour

[plainvanilla]

About 2 months ago, while on vacation in Colorado we were coming down Wolf Creek Pass and stopped half way down to sight see. I smelled a hot burning smell and it seemed like I had a leaking wheel cylinder and it was dripping on the shoes and when the brakes got hot it smelled. I was low in the resivour by about one inch. I filled it back full and drove home with no problems. I bought a wheel cylinder with the intentions of replacing it today. When I jacked up the rear wheels I expected to see evidence of fluid leak on the backing plate or wheels. They were dry. I inspected both sides and the seals were dry. I only found very minor seapage around the RR axle seal.

Where did the fluid go that disapeared?

 

I suspect it got sucked into the intake through the booster, but can't proove it.

I have not had to add any since I returned home in 2500 miles of driving.

 

Could I have a bad check valve?

 

1997 Burb 5.7 ltr

[asepgrad98]

the fluid could be in your front calipers. the level will drop when the pads wear.

[plainvanilla]

I know what you mean, but this was way more fluid than needed for the calipers to refill the pistons.

I am leaning to a bad checkvalve on the booster.