Replacing Bladex Waste Valves

[Roland62]

The 3” Bladex waste valve on my black water tank developed a stem seal leak and also started leaking through. Since there was no “window” cut in the pan I assume this was the original valve on my ten year old Safari. I read enough posts on this job to face up to the fact I needed to cut a big hole in the pan.

I want to pass on two things I learned doing this job that I had not read about.

The Bladex waste valve seals could be put on either the existing flanged fittings or on the valve. There were no instructions included in the package containing the new valve, two new seals and four new nuts and bolts. Just as a back-up, I also bought a set of Bladex waste valve seals. The seal package had instructions printed on the back directing: “Place new seals over lip of existing flanged fittings”. And, “Re-install valve being careful not to dislodge seals”. Two very important instructions.

The next thing I learned was, no matter what it takes, the flange faces must be pulled far enough apart so the valve can be slid in without dislodging the seals. The seals are flimsy things and if they are bumped sliding in the valve they may come partly off the seat. Then when the bolts are tightened, the seal is pinched and the valve will leak.

Every size and model of trailer probably has a different piping arrangement so there will not be one answer on how to spread the flanges apart. On my trailer one valve flange is attached the black water tank and the other flange is attached the waste piping. I was able to get a ¼” dia rope tied around the joint between the flange and the waste piping. Then I used a Spanish windlass tied to the trailer axel to pull the flanges apart. I had to cut some metal out of the side of the pan to give the waste pipe room to move and then crank the living s… out of the rope to get the flanges far enough apart.

Once the new valve and seals were in place I inserted two extra-long bolts to force the flanges to line up. Then I slowly backed off the Spanish windlass, bringing the flange faces back together while keeping everything lined up.
This was truly a crappy job.