Today the transmission tunnel was more thoroughly cleaned then etched with phosphoric acid and coated with POR15. This was very time consuming due to the many weird angles and hidden areas involved. Prior to cleaning/painting the many dents/dints to the underside of the transmission cradle were fixed.
Tonight I cleaned the transmission and transmission area. This is just a first pass and more cleaning will be required prior to paint. I was again surprised at what good shape everything is in; much of what appeared to be rust was actually just rust-colored mud.
Tonight I pulled out the transmission (it’s surprisingly easy) to allow access to clean and paint the area above/around the transmission. With the transmission out it was easy to see what had been blocking one of the heater channel entry points just above the transmission, a mouse! It was basically mummified so I’m sure it had been there since the bus was stored outside. Also, over the weekend I had cleaned/painted the underside of the belly pans but didn’t post or take any pictures, so I took a picture of the underside tonight.
More patching on the belly pans tonight. With these holes repaired all that’s left is to grind the welds and paint the entire underside.
Tonight more patching was completed on the belly pans. With all of the rust cut out and the insides clean/painted the pans are now making a satisfying thump sound when knocked instead of the previous crinkly rusty sounds. None of the welds to the underside look particularly nice, but they are solid and will look fine once ground flat; welding upside down is extremely tough. All that remains for the underside with regards to metalwork/paint is the following:
– Finish patches to driver side belly pan
– Finish fabricating and install front passenger side belly pan section
– Small frame repair to driver side front frame rail
– Grind all welds
– Wirewheel entire underside
– Clean/etch entire underside
– Paint entire underside with POR15
Today the central belly pan was welded back in place and I began fabricating a replacement belly pan section for the forward passenger side belly pan area. The are a few holes in each of the belly pan areas but the forward passenger side belly pan was beyond salvage; when the bus was parked outside for 25 years it was likely facing downhill and leaning to the right, at least with enough slope for all the water to collect here.
To reproduce the belly pan I created a hardwood form to match the contour of the existing rusty pan and I’m using the hammer forming process to stamp the rib pattern into the new sheet metal. The belly pans were only used as reinforcement on busses with sunroofs or large pop-up campers; because of this, repair sections are not as available as other parts have been.
Today the rest of the spot welds on one side of the center belly pan were drilled to allow access to the heater tube. It appears that the heater tube’s insulating blanket was holding water against the tube, causing it to rust. The tube was replaced and then the entire inside of the center floor compartment was thoroughly cleaned, acid etched, and coated with POR15.
Tonight the other frame rail was repaired and the crossmember welded in place. I had planned on just repairing the end of the center heater tube but I was able to pull the entire tube out. So apparently, and this makes sense now, the water that collected in the crossmember traveled down the heater tube and rusted it out. The center belly pan will have to be fully removed and the center heat tube replaced.
Tonight I fabricated and installed a repair piece for the heater channel and worked on the frame rail holes left by the crossmember. This is going much more easily than I had expected, thanks in part to having the bus lifted extremely high, and in part due to the parts being much heavier gauge steel here, which is much easier to weld. One of the four frame repairs is complete (except for grinding), one has been prepped, and two remain untouched; I should be able to finish all of these tomorrow night.
Tonight the crossmember was removed; It was in extremely bad shape, with all of the bottom missing. Once it was removed though I found that everything around it is solid. It had even blocked rust from spreading to under the floor, for the most part. It’s apparent that the crossmember had been holding water, and because of this there are two rust holes in the frame where the frame met the end of the crossmember. These areas will be cut out and patched along with the hole in the heater tube.
