CJ7 Heater Duct Modification

Purchased a new heat duct designed to spread the heat in a wider pattern, but it basically sends all the heat out the door openings...

Crown Automotive 55035618 Floor Heater Duct

Modified it to send the heat toward the seats.  Marked and cut 1/4" wide slots with a band saw and capped the side openings with Kydex and some J-B Plastic Bonder.

Jeep CJ7 Fresh Air Box Restoration

PART 2 of 2

Lower Heater Restoration Link

• Spring: Hillman #543210 (shortened to 3 1/4")
• Push Nuts (for damper pivots): Dorman 961-345D - found at O'Reilly's
• Foam: McMaster #86225K57 1" w/adhesive (24" square)
• Eastwood Flexible Strip Caulk 13524
• Damper Paint: Rustoleum Satin Black Professional
• Linkage Paint: Dupli-Color low gloss engine enamel

Removal

• There is no need to remove the dash.  I did loosen the right side dash bolts to provide a little extra room and the glove box was removed.
• Tilt the windshield forward and remove the defroster duct.
• Unscrew the speedometer cable and slide it all the way into the engine compartment.
• Remove the heater cables from the air box and the dash.
• Remove the resistor wire (the red terminal on the passenger end of the air box).
• On the engine side of the firewall, remove the drain vent.
• Remove the cowl vent screws and then the four screws attaching the air box to the cowl.
• The top of the air box can then be rotated away from the firewall allowing the drain vent to come out of the hole.
• Once the drain hole is free, drop and slide the air box to the right and out the passenger side door.

Disassembly

Disassembly: Front

Disassembly: Top

Disassembly: Back

Disassembly: Passenger side damper pin.

Disassembly: Driver side recirculation damper linkage.

Disassembly: Driver side recirculation damper linkage.

Disassembly: Driver side recirculation damper linkage.

Disassembly: Main damper linkage.

Disassembly: Main damper linkage.

Disassembly: Main damper linkage. Note: Missing Spring

Disassembly: Main damper linkage.

Disassembly: Resistor

Disassembly: Interior dampers.

Disassembly: Upper heater unit parts.

Assembly

Parts dunked in Evapo-Rust, cleaned, and painted.  Used Rustoleum satin black on the dampers and Dupli-color low gloss black ceramic engine enamel on the hardware... also rubbed on some Min-Wax wiping poly on the springs and washer nuts and lubed the cable.

Separated box halves, cleaned and treated with Protect-All vinyl preservative.

Inside view.

Using 1/8" diameter, 5/16"grip aluminum pop rivets and aluminum washers to rejoin the halves.

Using 1/8" diameter, 1/4" grip steel pop rivets and steel washers on the two brackets.

Got a chance to use the Craftsman hydraulic pop riveter that my Dad bought to help me turn my 1969 VW into a Baja Bug.

Brackets riveted on using the steel pop rivets (inside).

Brackets riveted on using the steel pop rivets (outside).

Passenger side damper reinstalled.  Note that the damper shafts are flat on one side and only go in one way.

Driver side damper reinstalled.  The damper was sticking so I trimmed a little rubber all the way around.

Box reassembled (front).  Laid a bead of the strip caulk between the halves (encircling the rivet locations).  Used aluminum rivets with an aluminum washer on both sides.  Worked well.

Box reassembled (rear).  Note the new gasket cut from the 1" foam.  The original thicker gasket was 1/2", so cut the thickness on the new one to 3/4"  to allow for greater compression.

Here is the main damper mechanism reassembled.  I painted all the parts, but the paint will ultimately scrape off in contact areas.  The idea was to protect the rest of the areas from rust.  This is the new spring (trimmed to 3 1/4" overall).

Driver side damper mechanism reassembled.

Originally, I laid a double row of the strip caulk as a waterseal.  It got ruined in the process of reinstalling the air box into the Jeep.

Instead, I laid about four rows of strip caulk on the underside of the cowl opening making sure to surround all of the screw holes.  This worked perfectly.

The air box did not go in as easily as it came out.  I had to disconnect the speedometer cable (sliding it all the way back into the engine compartment) and remove all of the heater cables.

All that is needed now is to hook up the resistor connector and install the lower heater unit.

Hope you enjoyed this post!

Mike

Lower Heater Restoration Link

Jeep CJ7 Heater Restoration

These are the final photos of the finished lower heater rebuild using the "Blazer Motor Upgrade".

Following is a description of the disassembly and reassembly and a list of parts used in the process.

PART 1 of 2

Fresh Air Box Restoration Link

Inspired by this guy: Heater Upgrade

• Fan Motor: Napa BK 6551039
• Spring: Ace #102
• Push Nuts (for damper pivots): Dorman 961-345D - found at O'Reilly's
• Foam: McMaster #86225K53 1/4" w/adhesive (24" square)
• Foam: McMaster #86225K57 1" w/adhesive (24" square)
• Eastwood Flexible Strip Caulk 13524
• Rubber firewall spacers: 20Pcs Black Rubber Bumpers J9B4
• or Rubber firewall spacers: 8Pcs Black Rubber Bumpers RH-1606-8-A 1.5"Dx.82"H .25" Hole
• Firewall Hole Saw:  Irwin (mandrel type) 3 5/8" diameter
• Metal Paint: Rustoleum Satin Black Professional
• Plastic Housing Paint: Dupli-Color low gloss engine enamel (wipe with lacquer thinner first to promote bonding)
• Heater Core: Autozone Transpro #846071-399210 (make sure it has the silver L-bracket welded onto the hose side)

Removal: Open glove box door, remove inside box insert. Unplug fan resistor wires, disconnect control cables from door levers (only the ones that come in from the dash). Remove the defroster duct flexible hose from the top of the box. Go under the hood. Disconnect the wire from the blower motor, heater hoses. Remove the nuts from the studs that hold the box to the firewall, don't forget the one behind the valve cover. Go inside the Jeep, pull the box back and may have to tilt it down in the rear a little to clear the firewall. I had mine out in about 15 minutes. 

When I reinstalled mine, I put a self-tapping screw into the blower motor mounting flange and ran a wire from that over to one of the heater mounting studs at the firewall.

Disassembly

Disassembly: Battery tray.

Disassembly: Fender/battery tray brackets.

Disassembly: Fender/battery tray brackets.

Disassembly: Firewall coupling nut ground connections/heater hose connections.

Disassembly: 

Disassembly: Remove glove box.

Disassembly: Remove seats (unless you are a contortionist).

Disassembly: Heater hose connections.

Disassembly: Taped a small bucket to firewall to capture coolant.

Disassembly: Hung heater hoses to hood to prevent further coolant drainage.

Disassembly: Disconnect heater control cable and defroster duct.

Disassembly: Lower heater box; back.  Note: dried and cracked rubber mounting spacers.

Note: Four mounting bolt locations (one is directly behind valve cover).

Disassembly: Fresh air box; top.  Note: gasket.

Disassembly: Fresh air box; top.  Note: gasket.

Disassembly: Defroster duct; top.  Cable brackets.

Disassembly: Defroster duct; top.  Cable bracket.

Disassembly: Heater duct; bottom.  Cable brackets.

Disassembly: Heater duct; bottom; duct speed nut and screw.  Cable bracket.

Disassembly: Interior defroster damper/washer.

Disassembly: Interior heater dampler, cable connection/lock washer.

Disassembly: Cable bracket and cable clamp.

Disassembly: Cable bracket assembly.

Disassembly: Fresh air box; cable connection.

Disassembly: Fresh air box; right side

Disassembly: Fresh air box; left side; metal washer and spring washer.

Disassembly: All lower heater box parts

Utilizing two existing holes in the firewall, secure a piece of plywood to the firewall and mark the center of the existing motor housing hole using a circle template.  Drill a pilot hole for the mandrel hole saw.  Drill new hole with 3 5/8" diameter bit.  I ultimately filed off the sharp points where the two motor and electrical connection holes converge.  Before proceeding, I test mounted the back panel with the motor mounted and the fit was good.  File opening and use black liquid electrical tape to finish the edge of the new hole.

Reassembly

Disassembly:  New fan motor on left, OEM fan motor on right

Lower heater box back panel painted and new motor installed. Used the rubber feet listed above for the firewall spacers.

Lower heater box back panel painted and new squirrel cage mounted.  The Napa motor shaft is a perfect fit.

Painted dampers and cable bracket.

1/4" foam on dampers. Make template before removing old foam. Scratch an awl line on damper before removing to use as a guide in placing new foam.

New 1" foam gasket (bandsaw worked great, coping saw on large inside hole, 3/4" hole punch").

Laying out holes required some drafting skills, and a compass. Laid it out on the paper backing (make sure to lay it out in reverse).

Inside heater box; pre-assembly.

Decided to use Eastwood Flexible Strip Caulk (also known as "dum-dum") instead of RTV to attach the front heater box to the rear panel.  May use it to seal the Upper heater unit to the cowl as well.  Does not harm paint, stays pliable and fills gaps well.

Lay out the strips in the middle of the seam and around each screw then screw the back panel to the front plastic housing.  Fill in with more caulk where there are gaps.  I used a wet finger to smooth out the joint much like household caulking.

Here is the new foam gasket that will fit between the upper and lower heater unit as an air seal.

 Finished front.

Finished rear.

Next will be the upper heater unit.

Fresh Air Box Restoration Link

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