How To Repair Cracks And Refinish A Fiberglass A/c Housing Box On 1969 Chevelle

This commodity walks through a heater box rebuild for a GM A Body motorcar. This write-upward was based on our 1972 Cutlass Supreme "The Crusher Cutlass", although the soft goods are very similar for its sister cars, such as the Chevelle. This box includes Air conditioning.

Here's what I was starting with. The system worked, but leaked. Also since I had the fenders and wheel well liners off for the frame off restoration of the machine, the timing made sense.

Shopping List:

I bought a rebuild seal set for the rebuild, however note that I was quite disappointing with the production. Information technology was nothing more than cheap loftier density foam, and I could only use 3 of the seals out of the ten+ included.

Here's what I bought, but I practice not recommend it. CH17468 From OPGI.com.

Here's what you'll really need:

• 3m Strip Caulk – for the Air-conditioning evaporator core to heater box seal.
• Butyl rope seal (1/4″) – For the completed heater box to the firewall. I felt the rope seal was less messy than the wider strip caulk. although strip caulk could be used also.
• Cream or Neoprene Sheet/tile. With this you can cut your own blower motor seal (round) and line seals.
  • Thicker sheets can be used for the seal effectually the AC lines entering the box. Thinner for the gasket around the blower motor. Look at your originals prior to ordering to get an thought.
  • A great source for foam that's exactly like what comes in a kit is the shop foam floor tiles that you can buy at Lowes, Harbor Freight etc. They are big, inexpensive and you tin can cut any shape from them. And they are the correct thickness. Amazon.com sell foam and neoprene sheets equally well.
• Chord/Rope seal for heater box halves. Butyl rope above could exist used as well, merely is messier and stickier, and y'all would desire 1/16″ if you used butyl rope. Example: Neoprene Chord

Rope seal and some of the gasket kit:

Total cost, around 30-50 dollars depending on how much you buy of each of the above.

Procedure

The bad news is that the hood, fender and wheel well liner on the passenger side will demand to be removed to completely remove the heater box. If yous are doing this procedure, chances are you lot probably already take them removed. If not, remove in this order: Hood, wheel well bolts, Fender bolts. You volition need a 2d hand for the hood and fender to foreclose dings. Also, salve the exact location of each of the fender shims. This is critical for gap alignment.

Remove the box from the machine. There are studs attached to the firewall which need the basics removed. There are also smaller screws which thread into the firewall that need to be removed. You lot'll also need to remove the heater cadre and Air conditioning lines. DO NOT allow h2o or contagion to enter the AC lines. Record/Seal them off when disconnected. Remove all wiring. Don't forget the ground and hot to the blower motor.

Once the entire heater box is removed, Intermission apart the halves by removing the screws around the perimeter. Remember which screws/bolts go where for reassembly. If you are missing bolts, or some ignorant prior owner used random parts from the commodities box, now is a good time to lodge the missing/right bolts you need. My car was missing one-half of the necessary bolts, and a few others were cross threaded in which damaged the fiberglass box. Hardware stores have thread checkers that can requite you the thread size of your good bolts.

Remove the Ac evap core, which is probably stuck to the heater box from the factory strip caulk. Remove the air dam/metallic plate. Remove the temp switch and resistor. Remove the blower motor.

Salve all of your former gaskets for dimensions/use to compare to your new gaskets that yous either ordered or will brand.

Pictures of Disassembly

Make clean the box inside and out with soap and water. Clean the evaporator core as well, however be VERY careful around the fins, and don't let water inside. If you lot become water inside the cadre, you'll need to dry it for days to ensure you don't get water into your Ac compressor, which will destroy it.

I also used this opportunity to remove the nasty, terrible, gross, ugly looking manufacturing plant insulation around the thermistor. I basically use a razor blaze and Advisedly remove the material. Cutting a line down the heart and then chip off each half. The AC evaporator core is only aluminum so be conscientious not to damage it.

One time the box is autonomously and make clean, locate or make your new foam gaskets first. Test fit each foam gasket for fit and seal prior to final assembly. Lay out all of your right hardware as well. The butyl steps need to be LAST, because they are permanent.

Now is time to repair whatever stripped or damaged threads. Utilize epoxy to fill up in whatsoever stripped threads. Permit it harden, and and so tap the threads with a self tapping screw. Brand sure to drill the hole out to ane size below the screw prior to trying to thread information technology, or yous'll only damage/cleft the epoxy. DO Not over torque. Inch pounds of torque are required for these bolts, not ft-lbs. Just over finger tight is required for everything threading into fiberglass.

After thread repair, I opted to pigment the box too while it was removed. Lightly sand the suface of the box with 200+ grit paper. I used primer and rattle tin enamel. About 4 or 5 coats of paint were all-time to cover upwardly the fibers of the fiberglass. Primer is recommended on fiberglass and helps fill imperfections. If the box is fully disassembled, at that place is no taping off required. Paint it all.

After Repair and Painting Pictures:

When set up, hither'southward the order of assembly if memory serves, although it's fairly obvious.

1. Fit the round line seals around the ii Air-conditioning lines. They go towards the inside of the box perimeter.
2. Install 3M strip caulk/butyl rope around where the perimeter of the Air conditioning evaporator. Basically install it where you removed the old material. Information technology goes behind the evaporator, and under the metal plate.
3. Install the evaporator core and lightly stick to the strip caulk/butyl record.
4. Install the retaining plate. Make sure the little U department on the retaining plate lines upward with the line from the evaporator core, which holds the core in place.
5. Install the rope seal in the channel effectually the heater box halves.
6. Press the 2 halves of the box together and tighten the bolts.
7. Install the switch and resitor. No gasket is needed here.
8. Install the blower motor cooler. No gasket is needed here. This is the modest plastic square thing near the blower motor.
9. Install the blower motor gasket and blower motor.  Notation the blower motor does have a correct orientation. Look for the little guide hold to line up with the housing. Reference my installed pic below for right orientation.
10. Install blower motor Ground wire.
    1. This is CRITICAL! y'all will not be able to admission this ground connectedness in one case the fender is back on. Make certain the ground has a skilful connection to the metal on the blower motor and will last a lifetime. For some odd reason this ground line is not shown on the assembly line electrical drawing, although trust me the motor volition not piece of work without it.
    2. Make sure the footing wire is long enough to go to where you will put it.
11. Install butyl rope/strip caulk seal effectually the perimeter of the assembled heater box.
12. Line up the heater box with the firewall studs and very lightly stick in place. Do non press hard yet, equally you may demand to remove the box to refit if the bolt threads don't line up well enough.
13. Install heater box bolts and nuts, pressing the box up/downward/left/ride as needed to line up the bolts.
14. Reinstall electrical connections and heater/AC lines.

Assembly Pictures:

There were some signs of heat damage on the bottom of the box near the header. With the upgrade to a stout large block and new larger tube headers going on, I opted to install agglutinative heat shield on the lesser of the box. Information technology can barely exist seen when the box is installed, and should help the AC stay absurd and keep the fiberglass/pigment intact.

Completed Install before and later on!

Cheers for reading! Check out the whole projection in our Projects Articles!

LEFTLANE BRAIN

Source: http://www.leftlanebrain.com/heater-box-rebuild-gm-body/

Posted by: beckerluffird.blogspot.com

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