Here is the heater just taken out of the truck. Where to start? We have a few issues to consider. The two main issues are making it look like new and making it work like new. In this case it will be better than new since we will also use a 12 volt motor to run it. In addition, the unit must look 100% original.

This one will help us figure out the relationship of the parts during re-assembly. Once you have it apart, it becomes apparent how important the before pictures can be. Since this article was published, I have done many more of these so I decided to add more pictures and content.

This is how the small duct housing is attached to the motor housing. In this picture and inside the main housing is a small rubber bumper. This picture shows the direction that bumper needs to be reinstalled in. There are two of these bumpers in the heater assembly. They are usually very brittle and not serviceable once you get them out. Fortunately, they are available in two places that I have found so far. They are:

Marshall's Hardware has them for about 69 cents each. The part number is 0505510.

Steel Rubber Products has them for about $1.00 each. The part number is 33-0127-41.

You want to take great care and use unusual finesse in removing these bumpers if you have any hope of keeping them. They will need to be removed for the re-painting process. I realize this picture is too small to see them (Click on the picture for a larger one), but trust me, they are there.

Here is the rest of the core housing removed from the motor housing. There are no gaskets in between the two.

This is the entire heater disassembled. Not a lot to it, but these pics should help in getting it all correctly back together. In case you can't see enough detail, you can click on these pictures to make them much larger. They are in 1200x1600 high resolution.

The picture on the left is all of the parts fresh out of the Blast Cabinet. No old paint or rust is left after blasting. This reveals rust pits that we couldn't see prior to blasting. Rather than painting over it and calling it a day, let's address these problems further. The picture on the right is to show what can happen when there is a leak in the cab over time. We will repair this damage as well before going further.

Repairs also included adding the defroster cable clamp that had broken off. This is the exact same one that is used on a carburetor, so I fashioned this piece so it could be welded on to the old broken mount. After all of the metal work is done, it is important to smooth out the rust pits and welded areas to get the pieces to come out perfect. To do this, I use a premium quality Filler, then sand everything down. This is a painstaking process but when completed, the metal will look just like it came out of the factory.

The one on the left is the 6 volt original and the one on the right is a 12 volt replacement. This difference would be noticeable under the hood thus unacceptable. It so happens that Chevs of the 40's sells a replacement 12 volt motor that is small enough to fit IN the 6 volt motor housing! It takes a little work to remove the 6 volt guts, but once you have done this, you have a perfectly original looking 12 volt motor. If the motor you get doesn't appear to fit (front to back), it may be because you are not done gutting the 6v motor. Clear inside the back of the motor housings is another small piece that's spot welded in. Remove that, and it should all make perfect sense. You will have to elongate the mounting holes and ensure all air holes are not obstructed, but it turned out to be easier than I had expected. More...

The 6 volt motor disassembles pretty easily. I use a 1/8" drill bit to drill out the rivets holding the brush block to the case, then tap the outside core out with a screwdriver lightly tapping all the way around until it pops out. We will use no packing or anything to keep our 12 volt motor centered, nor will we remove anything from the 12 volt motor. The motor just like it comes out of the box will go right into our new case. I sandblast the case parts inside and out then using a Dremel Tool with a light wire brush, clean everything. This shines up the brass and metal quite nicely. Once everything is complete, I will take it apart for the last time and clean the case inside and out with PPG's DX330, then primer and paint inside and out to prevent rust. Don't forget, this is just a shell. The motor inside is 100% protected against any damage or anything since it is sealed from the factory.

As you can see, the motor just sits right inside the case as if it belongs there! The motor shaft is centered in the cases shaft hole and nothing can move around because it is bolted in from the bottom and from the top. Aligning the top and bottom halves are no problem whatsoever. After this step, I will put a piece of 1/4" shrink tubing about 10 inches long over the wires with the shrink tubing going inside the case as far as it will go, then add an 8-32 round terminal to the Negative lead for grounding to the case and a splice on the Positive lead for adding more length later.

These are shots of the completed motor. I opted to close the 4 rivet holes on the bottom of the motor that were there to hold the brush block in with Permatex Black Gasket Sealer. By using masking tape to form a mold around the holes I was able to make it look like the contour belongs that way. Other than the stainless nuts and washers, this motor looks like it's factory new.

This is the paint I finally decided on. You can get heater paint from any of the vendors, but this product is a name brand and is a perfect factory fresh match. The best part is that it is in aerosol cans so its very easy to use. Use a swirling motion and be sure to shake the can extra well. Two cans is more than enough to do an entire heater. The paint is made by the Kilz corporation and its called Hammerite Rust Cap Bronze. Eastwood sells it.

This is just a close-up of the work so you can see the hammered finish. It looks so original. The colors in these pictures don't do the work justice. My digital camera and the color of the fluorescent lights in the shop change its appearance.

Notice the motor. It looks exactly like the 6 volt original. After I shot these pictures, I added the proper defroster decal. The 'Chevrolet' emblem is not a decal. It is a faceplate and you can get that from most of the vendors. I used JBWeld to attach it to the original plate once I polished the sides of it.

There were two slightly different styles of the Ranco Type HF Heater Control Valve. I will point out the differences as we get to them. The first thing I did was sandblast the entire unit. To properly sandblast this unit without doing any damage, use #1 Silica Sand or equivalent, set the air pressure in your blast cabinet to 40psi, and just dust it off for now. This one had cobwebs and lots of dirt and crud all caked inside making it impossible to see the internals. Always be very careful around the copper tube and bellows. If you do not have a blast cabinet, clean it like you would anything else being very careful around the copper tube and bellows. Begin by removing the Spring in the picture shown on the right. I used a pair of needle nose pliers. This is the only part that needs to be removed before we separate the case.

Next let's separate the plate from the rest of the assembly. This needs to be done VERY carefully and extra patience is needed. You do not want to break off these tabs much less make them weaker. There is quite a bit of force on these tabs and you will want them to be strong when you bend them back down later. Start with the easy ones, the three brass tabs holding the bellows in place. Very carefully wedge an Exact-o knife in under the tab and carefully lift it enough to get the next thicker putty knife blade, very small screwdriver, whatever you need to slowly and carefully bend them up just enough to get the bellows loose. Move on to the four corner tabs and do the same thing. The corner ones are under pressure and will want to pop out once they are sufficiently free. Once free, the parts (to the right) should be what you have as well. The larger spring and wire clip are what holds the "Warmer" knob on. Your bellows compressor spring and plate may look different depending on your model. Some of them only have a bellows compressor and no spring. That is normal too. If you do have that kind, remember the orientation for assembly.

Remove the clip with the slots in it (left) by using a very thin blade to pry it apart enough to get the shaft to come loose. This is not an easy task, but take it slow and you can do it. Remove the small copper bell and set it aside. Clean the remaining 'rubber' seal out of its place. Depending on the model of your valve, there may or may not be another copper cap that comes out after this (right). Some Valves came with this piece soldered on. If you have one like the one shown, removing it you will be able to clean the inside of the tube out better. Also, it's nice to ensure the small tines on the far end of the shaft (hard to see) are straight and the far end cap on the shaft seats properly. If it REALLY bothers you that you can't see inside the tube, the end cap is soldered on with regular solder used in plumbing copper pipes. Heat with a propane torch until it comes loose. I didn't find it necessary because of the model I am doing having the removable closure.

With the shaft clamped in place, install the large copper cap if you have one, and then install the rubber seal as shown. I put a little lithium grease inside the rubber hole to slide it in easier. Once you have it down below where the groove is for the crimp-on slotted clip, install the small copper bell over the seal, then crimp on the slotted clip. You can remove the Hemostats now. You want to make sure the tabs on the copper assembly are nicely bent. What I mean by this is, no stress is placed on the base of the tabs, and you can easily slide the copper tube assembly in place. Look at the pictures for the orientation. Be sure to get the tube inlets pointed in the proper direction. Once you have it placed by hand and it seats completely all the way around, insert a thin screwdriver into the slot you are working on as you bend the tabs back by hitting them gently with a small brass hammer. This keeps the base from distorting and causing a leak. Don't jamb the screwdriver into the rubber seal you just replaced! It is merely there to keep the tabs from distorting the underside of the copper assembly. Be slow and deliberate and finesse those tabs into place. Once you are 90% there, you can be just a tad more aggressive with the hammer to set them.

Now for the tricky part. Face the slotted clip as shown and insert the spring in between the slots. Bend the slots just a bit to hold the spring in place. If the spring were to fall out during the next part of this, don't sweat it, you can install it last if you want. To assemble the faceplate to the rest of the assembly, two things have to happen at the same time... the bellows plunger needs to sit perfectly centered on the bellows while on the front part of the assembly, the two slots have to be aligned to go into its holder as shown (next frame left). To keep the bellows plunger and spring from moving, you can always tape it into place. Tape it where you can retrieve all of the tape when done. Some of you do not have this type of plunger. You have one that doesn't use a spring. Install that in the correct orientation and no taping is necessary! That one requires that you keep the tabs on it aligned with the main body so everything fits together properly.

Finish up by putting the adjuster assembly back on in the correct orientation which you marked earlier, then install the clip. The picture on the right is to show how the "warmer" shaft is placed on the end of the assembly. The Clear Coat will keep it from rusting and the assembly is ready for action. To test the system, you can get a can of Freeze Spray from your favorite vendor. Do a search for Freeze Spray on the Internet and you will have no problems purchasing it. To check the assembly, spray the freeze spray over the bellows while looking at the rubber seal assembly. If it works as intended, the plunger will go down magically all by itself! Do not freeze it too much. Just hit it with a few short shots. This mission is complete! If you have questions or suggestions on how to improve this document, please email deve@speedprint.com.