Where'd My Fluid Go?

[1987 GMC Jimmy]

One compartment of the master cylinder is empty. No leaks on the ground so where could it have gone?

 

[Jrgunn5150]

Any number of places, that's the rear reservoir, so maybe it's going out the wheel cylinders or something.

Fill it back up and get someone to work the brakes while you look for leaks.

 

[kdo58]

Probably in your brake booster. Do you hear a whooshing sound when you apply the brakes.

 

[1987 GMC Jimmy]

Yes, a very loud whoosh.

 

[kdo58]

Your brake booster needs replaced and your master cylinder

 

[HotRodPC]

Yep, that mystery is solved. Brake Booster sucked the fluid out of the master. The fluid is in the booster.

 

[1987 GMC Jimmy]

Thanks, guys.