Page 21 - Summer 2018 GMC Vintage RVing

For additional technical session presentations and papers, go to gmcmi.com/technical-presentations-papers/Overhaul of Jabsco MaceratorEmery Stora | 1977 Kingsley | Frederick, ColoradoI had a macerator stop pumping due to hair clogging the chopper blade. When I removed the macerator I found that two of the bolts holding it together were loose. Further inspection revealed that they were brass studs that had corroded and broken just above where they screwed into the middle section of the pump. I was able to remove the broken pieces by drilling them from the bottom of the studs with a 7/64" drill bit which caught into the studs and spun them out.impeller and sells for $52.31 on Amazon. Part no: 18598-1000. However, I did not need this kit.The bolt kit has stainless steel bolt replacements for the brass studs. Kit 17288- 100 and sells for $16.52 on Amazon. This kit has two long and two short bolts that replace the brass studs and acorn nuts. You just put medium strength Loctite (blue) on the threads and screw them in from the inlet end. They will not corrode and break like the brass parts did.Removing the pump can be a messy job and you must drain the tank first. I decided to put a 1-1/2" Valterra valve between the pump and the connection to the 3" sewage pipe.The valve and the screw on connector and the 3" adapter were ordered from etrailer.com part number T1001A valve $10.11, D50- 2866 $2.35 and T1041 $3.93.Here is the final assembly:Note that the eccentric (offset) 3" to 1-1/2" adapter must have the 1-1/2" connection at the bottom in order to pump the tank dry. The pump must have the inlet opening at the bottom and the hose outlet at the top.I suspended the pump by the bottom of the pump in order to have maximum clearance from the road. This required me to rotate the inlet and midsection of the pump 180 degrees from its original position when I purchased the pump.I use a 3/4" commercial quality garden hose to drain the tank. I cut a 50-foot hose in half and used a 1" x 3/4" hose adapter to fasten the half with the female hose connection to the pump. I store the other half of the hose under my propane tank and I can screw it onto the end of my pump hose if I need more length to reach a drain. I mounted a 20" length of ABS pipe along my frame to store the hose. Pictures of this can be seen on the GMCMHphotos.com site. http://www. gmcmhphotos.com/photos/macerator-and- storage-for-hose/p3554.htmlNow with a valve between the pump andthe tank I can easily shut off the tank without having to empty it which will make it much easier to remove the pump for service or replacement. The use of rubber couplings instead of PVC cement means that any component can easily be replaced by loosening the rubber couplings.The most common pump used by GMCers is a Jabsco Mfg. ID: 18590-2092. If you read reviews of this pump you will find that purchasers have complained of corrosionof the brass studs and they recommend replacement with the stainless steel bolt kit.This pump is held together by four brass studs. Two shorter ones hold the inlet section to the middle section. Two longer ones hold the inlet and middle section to the motor.I used a Valterra T1001A 1-1/2" diameter valve spigot to spigot. This has fittings the same OD as 1-1/2" PVC pipe. I used a Valterra Eccentric Tank Reducer T1041-1 which has a 3" spigot to a 1-1/2" hub. The hub has an OD the same as a 2" PVC pipe. The part that screws onto the pumpis a Valterra D50-2866 which has 1-1/2" FTP pipe tread to a 1-1/2" hub. To connect the valve to the 3" adapter I used a no-hub rubber connector which has a stainless-steel cover with two band clamps. This type of coupling has a rigid cover which gives more support than just a rubber coupling. I could not find the connector at Home Depot soI ordered two from supplyhouse.com at a price of $2.25 each. Part number NHC200- 150. This is a 2" x 1-1/2" reducer coupling which fits over the 1-1/2" spigot on the valve and the 1-1/2" hub on the 3" adapter and on the hub of the fitting that screws onto the pump.Pictured above shows where the two shorter ones in my pump corroded and broke.Jabsco makes two service kits. The full-service kit has the plastic pump body, gaskets, andSUMMER 2018 GMC MOTORHOMES INTERNATIONAL 21