I thought I would show in pictures my AC Gasket change.
Prior to starting I unplugged from the AC power and shut off the inverter (even though I know it doesn't feed the AC's), but I forgot to shut down the DC power, which cost me a blown 12V fuse for the Dometic Control. When I change the other gaskets, I'll pull that fuse which was located in my 1/2 bath fuse panel.
Cover removed. You can see one of the lag bolts. Two more are in the front, and the other side is a bit further back than the one you can see.
These are the wires to disconnect (at least on mine). The yellow connector is the AC power. Remove two screws and pull apart. There were two "telephone" connector boxes. I tagged one of them so I knew what connected to what. There is a small, thin white wire to disconnect. Then there are four bundles of 12 V wires. I tagged three of them. The two blue wires were not connected to anything.
With my SIL's help, the unit was flipped upside down on a blanket. I took a picture zoomed in on the opening. Notice that at every seam in the old gasket there is a noticeable line where contaminate/liquid could be working inside. I do not think they were, but the fact that there is a "dirty" line there shows that these seams are a potential weak point in many of these gasket makes. This is one reason I chose the Steele Rubber Products gaskets which are seamless on the outside gasket. Note another "dirty" line on the left side about 1/3 of the way up. That was my leak point. I didn't have a serious leak and caught it right away, so fortunately, no damage.
Gasket Configuration: The main square. A small gasket at each lag bolt. Pieces in back to balance.
The offending area. I have no idea how or when this happened. Actually, it looked like a sharp cut inside the material. From original installation and with age it finally started to leak? A stick from a branch shoving under it at some point?
While some of the outline of the main gasket had "ridges" in the metal bottom as a guide, I marked around the gasket with a black marker.
I first used a plastic putty knife to take off as much of the gasket as possible, then softened residue with rubbing alcohol and scrapped off the rest with a metal putty knife, a scrungie pad, my finger nails, and a rag...whatever worked. It was interesting that the inside gasket to separate the inbound and outbound air came right off, double sided tape and all, with little effort. The main gasket, exposed to elements over time, was time consuming and the biggest part of this job.
New gasket material installed. Notice that the outside square is seamless. I did have to seam the inside divider, but that is not subject to liquid, just a separation between incoming outgoing airflow. I paid more for the Steele Rubber kit, but the gasket material was exceptional and there's more than enough material in the package to do whatever configuration one may have.
Lag bolt pieces cut. I used a 3/8" hole punch I have to make the lag holes.
The area around the vent hole is all cleaned up. Just before reinstalling the unit, I put clear silicone sealant into each of the lag holes. I had gotten that tip from a tech that has installed, by his own account, over 100 Newmar AC's during his time working for a Newmar dealership.
Again with the help of my SIL, we flipped the unit carefully back into place and I reconnected all the wires while his youth allowed him to hold the front up some for me to have room to work. Per Newmar's specs, I tightened the lags to 60 INCH pounds. A note here....these are lags into a metal plate. Sometimes the wrench was clicking off more than 60 inch pounds just to get the lags in...not tightened down. This is not like putting the usual bolts in from the bottom of the unit with perfect threads going into a perfectly threaded hole! So, I finally ran the lags in until I had the seal evenly compressed to about 5/8" (Newmar says 1/2" if you don't have a torgue wrench.) Then I tightened each to 60 INCH pounds, which did compress the gasket evenly down to 1/2". I also put a dab of clear silicon around each of the bolt heads (as had been done on the original installation).
NOTE: I did not run the AC for 24 hours since I had it sitting upside down for several hours.
In net, this was not a hard job. It takes a couple of people to lift the unit off and flip it over so you can remove the seal and clean it. Then also to flip it back over and set it straight down into position vs sliding it around. If I hadn't screwed up and forgotten to turn off the DC power, I wouldn't have had the issue of my Control Center being shut down because of the fried fuse (glad it wasn't a fried control center!)
I plan to just go ahead and do the other two AC's at my leisure as a preventive measure as time permits in the near future.
I hope these pictures help anyone else looking to change a gasket on their Newmar AC's.
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