Heater AC duct seals

[K10-Kansas]

Hi. Today I am going to disassemble my ducts on the engine side, cab side, clean then out and look at the seals. LMC sells a seal kit but I haven't seen them yet. I imagine its an OEM replacement but is OEM the best way to go? What's the best material to use for duct seals?

If it's OEM that's fine but I know sometimes with these trucks, newer and different products are sometimes better.

Here the LMC duct seals https://www.lmctruck.com/1967-72-che...r-conditioning

[jumpsoffrock]

Original seals are made out of neoprene. I have found many uses on vintage and new vehicles of similar-thickness neoprene, and decided to buy myself a general purpose roll for very cheap.
https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1
Neoprene Sponge Foam Rubber Sheet Roll - 15in x 60in (1/4in Thick) $17

I crudely cut out my own A/C/heater box gaskets for my truck last year(uncompleted project). They should seal fine but I'd like to admit the truck is not currently in service.

Many different kinds of roof-marker-lamps use neoprene gaskets when new(Ford). I understand many use rubber pads, but many use neoprene too. So I'm gonna try that when I install my roof lamps.

Taillight lenses use neoprene gaskets. As do they use neoprene on my 1997 Honda, which I've made new gaskets for with my roll I bought.

I've used it for cushion for slamming house doors.



It's a cheap roll that goes a long way, is what I'm sayin'.

[dmjlambert]

I like buying the set. I got mine from Outback Truck Parts instead of LMC, but they may be the same manufacturer that LMC offers. The set comes with the large rubber ring that goes around the fan opening, and I would not want to try to form my own seal around there. It would take more patience than what I have, and the set of seals was not very expensive. It was easy to just put the seals in place and re-mount the boxes and I was done. If you take your A/C apart and find you have a metal fan that is excessively rusted and you want to stay with metal, Manes Truck Parts has metal fans. Pretty much everybody else has plastic fans. And National Parts Depot has Brass/copper heater cores if you would rather not have aluminum that is offered by pretty much everybody else.

[K10-Kansas]

Originally Posted by dmjlambert

I like buying the set. I got mine from Outback Truck Parts instead of LMC, but they may be the same manufacturer that LMC offers. The set comes with the large rubber ring that goes around the fan opening, and I would not want to try to form my own seal around there. It would take more patience than what I have, and the set of seals was not very expensive. It was easy to just put the seals in place and re-mount the boxes and I was done. If you take your A/C apart and find you have a metal fan that is excessively rusted and you want to stay with metal, Manes Truck Parts has metal fans. Pretty much everybody else has plastic fans. And National Parts Depot has Brass/copper heater cores if you would rather not have aluminum that is offered by pretty much everybody else.

Mine are plastic. LMC's is plastic also. Thanks for the info. Do you have to remove the hood hinge to get to replace the seals?

[dmjlambert]

I don't remember removing the hinge, but it is so easy that I probably didn't think twice about it. I have had the hinge off numerous times to do various things, so I have 2 pieces of board cut just the right size to prop the hood up. I do remember the most time-consuming part of the job by far was removing the inner fender, because I had a bunch of rusted through U-nuts that would just spin when I try to loosen the bolts. One you've had the inner fender off once and have replaced bad U-nuts, it is easy to take off and put back on all you want.
If you haven't had the A/C box off yet for the first time in 50 years, don't be discouraged if you find work to do with the box before you put it back on. It's all quite do-able. Here is my journey and there's info packed in here: https://www.67-72chevytrucks.com/vbo...d.php?t=790246

I have in my old notes the heater core box in the cab and the A/C evaporator box under the hood share 4 bolts that sandwich them together, and the heater core box additionally has 2 screws to secure it to the cab and a couple screws to secure the diverter box.

[dmjlambert]

When you go put the hood hinge back on again, leave the 2 rear-most bolts that hold it to the fender a little bit loose, then push the front of the hood up while you tighten them. That is the adjustment that keeps the hood from sitting too high at the cowl.

[K10-Kansas]

Originally Posted by dmjlambert

When you go put the hood hinge back on again, leave the 2 rear-most bolts that hold it to the fender a little bit loose, then push the front of the hood up while you tighten them. That is the adjustment that keeps the hood from sitting too high at the cowl.

Perfect, thanks for the info