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Old 10-17-2010
Bob Johannesen Bob Johannesen is offline
Resident Rookie
Join Date: Apr 2009
Location: Argyle, Texas
Posts: 1,099
Default Coolant tank filler neck replacement

Blue Bird Radiator filler neck replacement project, 1991 WLWB

After discovering the rusted out radiator filler neck (Thanks to a warning by one of our members), I set out to repair the problem with a solution that would at least out-live me! (Let my kids worry about it!) The factory made the reservoir tanks out of stainless steel, but welded a mild steel pipe to the tank and soldered the filler neck to that pipe. It is mounted from above the engine with four ¼ X 20 studs probably welded to plates above the fiberglass. Be sure and soak these in penetrating oil because they are usually rusty. (I broke one with a short wrench and had to drill and tap another next to it.) Once the tank was installed in the coach, they sprayed urethane foam around the filler neck about 2-3 inches thick (probably to reduce the heat in the rear closet) under the small compartment for the radiator cap. That allowed the rust to build up without being seen.

I encourage every owner of a pusher to check this area by cutting out the foam around the neck. Mine was painted to match the interior of the compartment but was very soft when I cut it out with a pocket knife. The rust was several layers deep and I was able to push a fingernail thru the tube in one spot. Even with a heavy duty radiator cap, it would have started leaking soon. Probably where ever Murphy felt it would cause the greatest logistical problems, domestic distress and heated dialogue!

Now for the fix: I was determined to use stainless steel for the filler neck and tube to reduce future corrosion. On the internet, I located sources in Delhi, China, and Chicago at the Equinox Group, Inc. with a nice website. I called and got the name of their local distributor who had none in stock. I then called back to Equinox and Joe was very helpful. He sent me four for $25.00 each and the UPS COD charge for a total of $113.00. Being in the weIding and machine business and knowing that set up takes longer than the machining and welding, I figured I might as well set up for several as cheaply as just one. Then I ordered the stainless pipe fittings and made the parts required.

I decided to weld an angled coupling (about 123 degrees up from the rear vertical face of the tank) and screw in a short pipe fitting which I had brazed (with high silver content brazing rods $$$ OMG!) to the stainless filler neck. This would give me some latitude about where the overflow line would aimed and the ultimate position of the safety lever on the cap (2 choices 180 degrees apart), not to mention any future repair requirements. Before I sanded and repainted the tank, I installed another larger sight glass off to the right side so it was more visible thru the engine hatch vents and viewed the coolant level an inch higher than the small sight gage (where it seems to want to stay). .
So if any of Ya’ll find this rust, let me know and I will send you one of the other three filler necks along with the angle cut coupling so your local welder can replace it. I probably have $45.00 in material in them at this point.
Otherwise they go in the spare parts locker in the Bird.
Looks like it may be time to think about replacing a lot of heater hoses…..looking at 20 years old!
I’ll do that when I work on the Primus system… never ends!
Drive safely!
Bob & Judy Johannesen
1991 WLWB "Seldom Blue"
1978 FC "Smell The Roses Now" SOLD...Costa Rica
Argyle, Texas

FMCA #72567, WL #1986, Vintage Birds # 345,
IBA #11205
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