[SilverStreak] Re: Dupree Products grey and black water valves

["waymark1@xxxxxxxx" <waymark1@xxxxxxxx>]

Our '79 SS is equipped with Dupree Products (successor to the original manufacturer) 
Twis-Loc manual gate valves:
http://www.rvnetlinx.com/dba/dba.php3?id=4290 I don't recall the name that is molded 
on the valve core - our trailer is 3,000 miles from here so I can't go out and look.

You will find that Dupree will sell parts and subassemblies for these valves, so if 
the valve housing (which is solvent-bonded to the holding tank drain pipe and to the 
outlet manifold) is not damaged all you have to do is take out a few screws and 
replace whatever parts you need to.
If the seals have not been renewed since 1977 I suggest you replace the rubber seals, 
either alone or by replacing the complete valve assembly (entire valve except the 
outer housing). The seals are a bear to change - vegetable shortening helps and won't 
damage the rubber. I have done it but my fingers were sore afterward.

Next time we won't let those tires go until they are old and cracking, will we? (I 
know, tires, even brand new ones, can fail, either from a defect or from a road hazard. :))

Many of us don't put enough miles on our trailers to wear the treads out by the time 
the tires need to be replaced due to old age. Even though they are (most likely) nylon 
cord they still deteriorate with age. Ten years is certainly the outer limit for tires, 
seven years is recommended. If the tires have been stored exposed to the sun and outside 
air, sitting on the ground, they need replacement even sooner. If they have been stored 
indoors near electric motors they may also been damaged - it's the ozone. Cool, dry, 
indoors, away from ozone producers is the way to help tires last longer.

A tire failure on a car going straight down the road is not usually an extreme crisis. 
With trailers it is different. You usually don't know you have a flat until the tire is 
completely flat and then it will likely shred before you can pull over and stop. You may 
lose not only the tire but the wheel. If the trailer stability was marginal to start with 
you may lose the trailer also, and maybe even your tow vehicle...and whoever is riding in 
it. Not good. 

Two axle trailers are more stable if one tire goes flat. Nevertheless if the tire comes 
apart it may beat the trailer body up, and as you found, if it is the left rear tire that 
goes, the dump valves go too, perhaps the fresh water connection with them.

Al