The Stovebolt Site Forums The Parking Lot Big Bolts rebuilding brake system

I am rebuilding the brake system on my 54 2 ton. I have replaced all of the wheel cylinders as most were leaking. The master cylinder is leaking also, so I am in the process of rebuilding / replacing it. The brakes worked great as long as I kept the reservoir full. My question is, how do I tell if my hydrovac needs servicing?It looks dry on the outside, but could it still have problems? Should I just rebuilt the master, bleed everything and see if the reservoir stays full. Is that just being lazy and making more work in the long run or are these thing that tough? Thanks!

You can check the vacuum line to the booster for fluid inside, vacuum will sometimes draw fluid into the engine with no outside traces of leakage. If you find it, the booster needs work. If not, bleed and proceed. They are not tough, but they can be expensive. Some guys make it harder than it needs to be by worrying about the costs involved. Sometimes you have to bite the bullet and spend the cash, sometimes the system is fine.

IF all the wheels and master were leaking, the booster is likely bad too but there is no assurance of that. Old fluid gets corrosive through absorption of moisture from the air. The same fluid is in all the parts of the system and usually damages all. It should be flushed out every 2 or 3 years without fail or you will be back to square one.

Take a pair of needle nose vice grips and pinch off the vacume line to the hydrovac.. if it has a vacume leak your engine will start running rich/change in idle quality a fair amount.. If little to no change, I would say good.

I think it is leaking internally. I see a drip hanging from the vent tube. So I will look for a rebuild one. Will take it off tomorrow and look for a part number. It has a 7" piston according to the book.