Brakes and siting

dr deuce · Post by **dr deuce** » Mon May 21, 2007 7:43 pm

I think I may have discovered another brake problem that has gotten me concerned:

Annie the CCKW-Schield-Bantam-crane has the same more modern booster as my cargo CCKW. It is about 4 years old and was a fresh rebuilt unit same as the cargo CCKW. Turns out it is junk inside. All rusted out in the vacume-air area. I mention this because they all work the same way, the old ones and the new ones. This was rusted so badly I think the activation rod was completely non-existant!

Two things are different about Annie: She does not get driven much and she must unfortunately stay outside due to her bulk and space requirements. So the question is, where did all of this moisture come from that really rot out the inside of the vacume-air control parts of the booster. I would think that it would have done serious damage to the engine too with that much moisture. It will cost about $250 to replace it.

armydriver · Post by **armydriver** » Tue May 22, 2007 8:13 am

Moisture is a big problem when any vehicle sits outside. Differences in temps can creat condensation inside engines, gasoline tanks and apparantly tthe hydrovac also. it is tough fighting Mother Nature.
Thanks foir the heads up Doc

Karoshi · Post by **Karoshi** » Tue May 22, 2007 1:37 pm

I'll go with Armydriver, here in Europe with our "moderate" climate condensation can be real problem. I make a living from diesel fuel tanks and Cladosporium resinae, in the marine sector.

The wise guys FILL their fuel tanks for the winter stand to minimise the condensation build up.

I can see how a hot / cold cycle on a hydrovac, it could fall victim to the same problem. Best to just keep em in service, the year thro.

awg · Post by **awg** » Thu May 24, 2007 8:47 pm

I just went thru the rebuild process on my booster. It is a modern pancake style, but works the same way.

When I drained the pancake I got at least 1 litre of fluid.
It had a puzzling composition, there was obviously water, but also
seemed to be light oil, like maybe water, petrol, oil and brake fluid
all homogenized.

I assumed the water would be mainly as a result of the air pressure continually fluctuating within the vacuum cannister. When air pressure
fluctuates, moisture in the air is expelled.

I assumed petrol and oil fumes are drawn in via the manifold.
The check valve had been absent from my vacuum line for a while.

The good news is evrything was still serviceable, and a real bonus, someone had been in there before me and brass-sleeved the relay valve and hydraulic cylinder.

I think it would be desirable to have a drain cock fitted to the cannister,
as I have seen fluid in boosters before. Usually they are ruined.
They dont give much warning. They work fine, then fail quickly.

Mine did so on a recent traffic trip, the failed booster would rob the manifold of air so that the motor would want to stall when braking at low revs. So unboosted brakes and traffic lights are not so fun

I have seen a booster with such a fitting, it would probably be possible to fit a small drain tap, I have seen this done with auto trannies and fuel tanks

regards tony