Tuesday, April 2, 2013

A different kind of motor

With my 351W out of my garage, it was finally time to start thinking about reassembly...or at least getting the rest of the car ready for reassembly, which is obviously something quite different. I'm pretty sure it's a requirement of any worthwhile Mustang restoration that you "do the heater box" while the motor is at the machine shop. If not, it should be! My version started with liberating the heater box from its packing crate. I've moved house garage twice since the heater was put to bed, so it was fortunate that I packed it well.

The last time I saw my heater box was in early 2010, so I was actually a little bit shocked to find out how crusty it was. But then again it will be 45 years old in August. Unfortunately, I forgot to break down the unit....which meant all the metal parts missed out on my batch refurb/painting process. Oh well...

Started by removing everything from the heater case. Ford did not design the heater unit to come apart, so the tear down involved drilling out plenty of pop rivets. The blower housing was a bit rusty: especially in the places where it wasn't originally painted (like the whole car!).


There were a few cracks in both halves of the case...but nothing a bit of superglue couldn't take care of.

The first major positive of this mini-project was the chance to once again fire up my favorite dewalt angle grinder and its knotted wire wheel. All the metal parts got a good going over before you could say "rust removal". Well not quite that fast, but you get the idea.

The flapper unit was a challenge too far for the wire wheel though, so I legged it over to Mostly Mustangs in Oakland and swapped a six-pack for twenty minutes fun in their blast cabinet. Lovely.

The cleaned up metal parts were wiped down and painted with primer, and then I laid down several coats of the same black paint I used on everything else.

I painted the exterior brackets and some of the other parts with my favorite Eastwood brake gray. This is an old BAMA trick that is designed to make sure everyone knows you took the entire unit apart...and it's use is most definitely not restricted to the heater box.

Initially I wasn't going to paint the heater box, but it didn't look right next to the cleaned up parts....so I hit it with two coats of black fusion-for-plastic paint. I even painted the inside...

All the Mustang supply places sell a kit for replacing the foam and rubber heater parts. There were a couple of extra bits in mine, so it's worth figuring out exactly where you're going to stick each piece before you start gluing up the foam.

Speaking of glue, I used the 3M "Yellow Weatherstrip & Gasket adhesive." (Part #3M8001 if you order from NPD).

You want to apply the adhesive to both surfaces, and it helps if you've got a spreader. I had to improvise with a bit of folded over card board from the packet the glue came in. It wasn't ideal.

Wait five minutes or so, and then slap the two surfaces together. The opportunity for repositioning/lining up is minimal once the two surfaces are in contact.

I used a bunch of different sized pop rivets to get it all back together.

When it came to the heater core I was tempted to put the old one back...but ultimately I decided to replace it. I also bought a pair or reproduction end caps, which were missing from my unit.

All back together....and back into the box. I'm more than three years into the project now and the pile of boxes of parts finally includes more stuff that is finished than still "to-do!"

The driver side ventilation duct was in similar shape to the heater unit (and it was packed in the same box), so I took care of that at the same time.

The seal for the duct does not come with the heater kit, so you need to buy that separately. It goes on the same way though, and I used a few bulldog clips to hold it in place while the adhesive cured.

Onto the heater motor. The part# clearly starts with C5 (65), so it's reasonable to assume that it's original.

It looked in poor enough shape to to be original too....plus I accidentally chopped the terminals off when I removed the motor from the car. Oops.

After the wire wheel did it's work and the case had been re-painted, I soldered on two replacement wires and reattached the original terminals.

I also added the (almost) correct colored plastic sleeves which I got front my new heat-shirk tubing kit. The bolts which hold the two halves of the motor case together were zinc plated long ago.

Finally I sourced a replacement plastic plenum chamber from NPD. There wasn't strictly anything wrong with the original cardboard one.....but I decided a while back that I'm not going to put anything back which smells like "old car," so the original cardboard chamber had to go.

The ducting for the defrost vents went the same way....


  1. WOW! You put my heater box restore to shame! Excellent attention to detail. It looks simply awesome.

  2. Awesome work! Even though it's a shame those parts will never been seen for the beauties they are, it sure must feel good knowing what goes back in your car will be so tidy. Glad to see you've been busy! Cheers!

  3. That is a very clean and tidy looking refurb. Glad to see some progress on the old girl.

  4. Joy - at least WE know you painted the inside of the heater box :) Nice bit of restoration on a non-glamorous part.


  5. Great work! I am in the process of restoring mine and will use your post as a go by. Do you still have the cardboard diffuser? I would be interested to use on my car if it is complete.

    1. Thanks for your comments. I do not have the diffuser...and to be honest I think you'd be better off with a new one for about 15 bucks. Good luck :)

  6. Nice! Funny how we'll spend time on a piece like this that not many people will see. But at least there's the satisfaction of a job well done...and that is what you've done!