Author Topic: 69 Heater Box / Heater Core replacement with AIR  (Read 539 times)

Offline 69FORD

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69 Heater Box / Heater Core replacement with AIR
« on: June 08, 2018, 06:51:37 AM »
Hi to everyone out there.
I have a 69 Mach 1  Marti report 351 4v optioned with Air con. power steering, disc brakes  all the spoilers optioned with a 4 speed wide ratio now running a 5speed tremec.

Heater Core with Air Con

Now I have read many comments about Heater boxes, core replacements etc  so here goes... I've done it...My heater core hoses were sealed off implyiong a leaky core  so okay, replace it.
Step one. You need to get the gas out of the air con system first  then disconnect the hoses in the engine bay. In the Cabib you have to take the top of dash out, the clock facia and dash cluster out, the radio out, the heater control mechanism out, the bottom off the dash, black metal out and then undo a nut in engine bay and one in cabin near you  that hold the heater box,   disconnect associated cables 2 off, and it will slide out.
Being air con its bloody heavy as it has the air con unit , ?? evaporator thingie in there as well.

The unit is made of fibreglass so be gentle. the clips are easy to remove  flat screw driver in bend of clip and pry out.. there are 12  and some are near fire Wall 
  so you cannot do this without complete removal.

Things the buy   Heater core  Brass recommended,     foam filter kit, adjustable thermostat    new globes for dash 5W spade type and new globes for clock .

Split the heater  box   remove all the slide out parts   ie the swivel control pieces  and the heater core.   clean it all and lubricate swivel parts  and silicone on all new foam parts , The kit comes with a schematic were to place me  picture  all great.

I must point out that BEFORE you remove heater box  there is a drain through firewall   its located under heater box  be careful  as easy to break.. this drain is to drain excess condensation from air con to ground through firewall   you know  car sits with air con running  a puddle under it  a good sign its working and not blocked.

After all cleaned   new core  replaced    degassed  etc   and with car running  about 2000rpm  watch the air con temp drop.. put a temp probe in centre vent  doors shut   it should drop to say 5.5 C  and air con cuts out   then cuts back in at around 6 C   this is so the unit will not freeze up   I installed a adjustable thermostat on mine which is accessable with glove box installed but remove side screw and it drops free..

So I adjusted mine to freeze down to 5.5  cut out   temp rises to 6C  then cuts back in. 

It is a major job  probably bigger than engine removal..   but I hate things not working and as for originality  well after 50 years any original car's FOAM  would be cactus..
 
any questions please ask... I have also fitted a retro radio  GRRRRRRRRRRRRRRRRRRRRRRR

 will write about that soon, upgraded the headlights to look standard. Fun...Oh and for those with OLD cars that have had No master Cylinder work  REMOVE It  and get it checked. Mine had corrosion  a piece came loose and blocked the return pressure line  locking the brakes on.. another story  to follow  but now all good.

So to conclude.. If you have AIR CON  you need to remove  just about all the dash  .. without air  maybe just the top and the glove box  a sit is a lot smaller.
By for now  69FORD   John


Offline cobrajet_carl

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Re: 69 Heater Box / Heater Core replacement with AIR
« Reply #1 on: June 08, 2018, 02:40:42 PM »
The unit is made of fibreglass so be gentle. the clips are easy to remove  flat screw driver in bend of clip and pry out.. there are 12  and some are near fire Wall 
  so you cannot do this without complete removal.

I would not remove the clips this way. Use snap ring type pliers to expand the clip and then lift off. It is very easy to damage the housing by prying the clips off. Ask me how I know...
Carl
70 and 71 Dearborn mach Is

Offline 69FORD

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Re: 69 Heater Box / Heater Core replacement with AIR
« Reply #2 on: June 08, 2018, 08:07:03 PM »
Hi Carl
I have completed the job with no issues removing the metal clips  I may need to clarify  you dont put the screw driver between the clip and the heater box  you will break the heater box   the clip has a half round each end  you put the blade in there  pry back and they slip off   very easy and no damage at all..