Smiths heater assembly restoration

After some days off, I am back again. Another mayor component I wanted to restore was the heater matrix assembly. Removing the assembly will also let me rust treat and paint all the battery shelf and surroundings.

Removing the 4 bolts that hold the assembly was a mayor task…. Not because it´s a difficult task it´s self, but because the bolts where very rusty. Using different tip sizes, ended up with a useless bolt head, and there was not human method to remove them. Parting off the bolt heads could have been an option, but because this bolts are screwed to soldered nuts on the body, it was my last option. Finally I figured out how to remove them….. using my trusty Dremel tool and the cut off wheel, I flattened 2 faces of the bolt, and pushing a spanner cup, I was finally able to remove them. That was about 2 hours just for 4 bolts….

Once I had the assembly off the car, It could be clearly seen that situation was very sorry  as all the bottom part was badly corroded and surface rust was severe. The heater matrix was not leaking, so why was there so much rust??? I tend to think it had to do with acid from the battery that some time had come in contact with the battery tray and the heater assembly

Disassembly is straight forward, just removing 5 clips reveals the inside. The assembly is made out of 2 metal sides, 1 main body case, and the matrix. The assembly has inside several foam pads to force air trough the matrix, and some seals on the outside where is rests against the car body. All of them where of course nearly destroyed…..

I first cleaned the matrix from all the dirt, bugs, and old foam. I connected both matrix tubes to the tap and force high pressure hot water for several minutes, until only clean water come out. At the beginning brown water come out, with all the rust deposits. Not flushing a refrigeration circuit every 2 years, leads to rust and scale that will surely make trouble in the future. Once I was very sure the matrix was in good condition, I could pass to the body case restoration. This was the original situation…… no comments….. first step: remove the id plate. The id plate paint has seen better days, and although I could buy new reproduction plates (to which I will need to stamp new ID numbers), I will clean it and use it again.

Restoring the case was an easy job, now that I have my sand blast machine available. You can see the difference between a side plate in original condition, and the other recently sand blasted. The metal surface was pitted on the lower part, but not enough to make complete holes.

On this occasion, I used a different approach to the paint procedure. Other parts on the engine bay, where just painted with por15, as they are not going to receive direct sun light. Por15 will fade with sun light and the colour can become grey… So it's necessary to apply a final coat of paint in case the part is going to be exposed to direct sun light. I just wanted to experiment a little bit, and I had two possibilities to apply the final paint coat: 1-apply final coat when por15 is not fully dry, or 2- wait until por15 is fully dry, scrub all the surface with fine sand paper and apply final coat. Searching on internet, revealed most people will apply final coat before por15 is fully dry, so I made the same.

I first gave a por15 coat to all parts using the sponge brush which will leave a very uniform coat, and some hours later (about 5 hours because there is a very low humidity level in sunny Spain and por15 will cure faster on humid climates), when it was tacky (just enough to leave the finger print but not to get paint on my finger), I applied 2 fine coats of normal enamel spray paint (in this case from the Spanish brand Titanlux)

After letting it fully dry overnight, I was very impressed with final result. The finish is superb, taking in mind that the por15 was not prayed, very glossy, and looks very hard.

Assembly was straightforward: fit the ID plate with new pop rivets and fitting the foam pads to the heater matrix. I could have just got locally some foam and cut it to my needs, but well, I was lazy and when I made my huge MOSS order, I included the 2 foams I would need.

I was so impressed and happy to see the final result, a nearly brand new heater matrix assembly, that new one cost a fortune, and that will look gorgeous one fitted.

Final touch, apart from the 4 new bolts, will be fitting the warning vinyl plate on the case that once was fitted and sometime in the past was lost.

Just another weekend project!!!