ArdWrknTrk Posted June 22, 2020 Share Posted June 22, 2020 I'm not a huge fan of RTV so I would try to make a gasket for the firewall. But now that you've encased the plenum halves in foil wrap I might be tempted to use it there. Perhaps spray one side with WD-40 or even PAM and apply the silicone to the other. Then it should remain adhered to A or B side and release from the other. Haven't I read recently that someone is making complete sets of climate control gaskets? If I were facing this job, I think I'd try to patronize and support him, given that he is a good resource for ALL Bullnose owners. But I'd have to go back, searching for that contact info. Link to comment Share on other sites More sharing options...
Gary Lewis Posted June 22, 2020 Author Share Posted June 22, 2020 I'm not a huge fan of RTV so I would try to make a gasket for the firewall. But now that you've encased the plenum halves in foil wrap I might be tempted to use it there. Perhaps spray one side with WD-40 or even PAM and apply the silicone to the other. Then it should remain adhered to A or B side and release from the other. It won't be difficult to make a gasket for the driver's side hole in the firewall. I have a roll of adhesive-faced closed-cell foam that should make it easy, assuming it is thick enough, and I'll have to experiment a bit on that. But I like the PAM idea. That would make it fit tightly but still come apart. Link to comment Share on other sites More sharing options...
85lebaront2 Posted June 22, 2020 Share Posted June 22, 2020 Thanks, Jim. Yes, I think heat is going to have a hard time getting in there. Now I need to figure out how to get the recirculation door out so I can put new foam on it. I really want to ensure that I don't have outside air coming in since I expect to be on many dirt roads. And the foam needs to be replaced. Anyone know how to get it off? Also, I'm considering how to seal all of this back together. On the cover Ford appears to have used rope caulk, which is really sticky and might pull the aluminum tape if the cover has to be removed. So I'm wondering about placing lubrication on the two halves and then using The Right Stuff to seal it. Thoughts? Similarly, I'm thinking of using The Right Stuff to put the whole HVAC plenum on the firewall. I do have a good gasket for the passenger's side but will have to make one for the driver's side opening. Again, thoughts? Gary, this is the 1995 F450 inlet housing. If you notice there appear to be screws holding the two halves together. The gray lever I would imagine snaps into the fresh air recirc door during assembly. If you separate the blower from the inlet housing then you can probably remove the door. Maybe you can figure out a way to make a replaceable air filter like newer trucks and cars have. Link to comment Share on other sites More sharing options...
Gary Lewis Posted June 22, 2020 Author Share Posted June 22, 2020 Gary, this is the 1995 F450 inlet housing. If you notice there appear to be screws holding the two halves together. The gray lever I would imagine snaps into the fresh air recirc door during assembly. If you separate the blower from the inlet housing then you can probably remove the door. Maybe you can figure out a way to make a replaceable air filter like newer trucks and cars have. Jim - That was Scott, and I just sent him a text to see if I can get the contact info for the guy. Bill - That looks exactly like the '90 plenum. But it doesn't have screws holding the two pieces together. Instead there are little pins with catches, and even when you pull the pins back the two halves don't want to come apart. It acts like the sealant is actually a glue and the pins were just there to hold things together while the glue dried. Nevertheless, the arm has to come off the door's pivot somehow as it doesn't go in at the interface between the two parts. So I'll take a closer look tomorrow to see how to get it out. There has to be a way. Link to comment Share on other sites More sharing options...
salans7 Posted June 22, 2020 Share Posted June 22, 2020 Jim - That was Scott, and I just sent him a text to see if I can get the contact info for the guy. Bill - That looks exactly like the '90 plenum. But it doesn't have screws holding the two pieces together. Instead there are little pins with catches, and even when you pull the pins back the two halves don't want to come apart. It acts like the sealant is actually a glue and the pins were just there to hold things together while the glue dried. Nevertheless, the arm has to come off the door's pivot somehow as it doesn't go in at the interface between the two parts. So I'll take a closer look tomorrow to see how to get it out. There has to be a way. I find it interesting how Bill's plenum has a bolt-on vacuum motor, where the one on my 1990 housing was sitting on two studs that were melted over at the top in order to hold it down. In fact, I think the whole assembly was different in that area. Link to comment Share on other sites More sharing options...
85lebaront2 Posted June 23, 2020 Share Posted June 23, 2020 I find it interesting how Bill's plenum has a bolt-on vacuum motor, where the one on my 1990 housing was sitting on two studs that were melted over at the top in order to hold it down. In fact, I think the whole assembly was different in that area. Shaun, that is a 1995 plenum from an F450 Jim dismantled. Link to comment Share on other sites More sharing options...
salans7 Posted June 23, 2020 Share Posted June 23, 2020 Shaun, that is a 1995 plenum from an F450 Jim dismantled. Interesting. I wish I still had the bricknose A/C box because I'd love to know why it was different than what you guys have. Link to comment Share on other sites More sharing options...
ArdWrknTrk Posted June 23, 2020 Share Posted June 23, 2020 Interesting. I wish I still had the bricknose A/C box because I'd love to know why it was different than what you guys have. Shaun, you can see my '87 has a bolt on vacuum motor. I need to correct that my relay is making ground in the 'high' position, not bringing power to the blower motor. I'll try to get a picture where the halves are joined. Link to comment Share on other sites More sharing options...
Gary Lewis Posted June 23, 2020 Author Share Posted June 23, 2020 Shaun, you can see my '87 has a bolt on vacuum motor. I need to correct that my relay is making ground in the 'high' position, not bringing power to the blower motor. I'll try to get a picture where the halves are joined. The 1990 plenum from Huck has a bolt/screw-in vacuum motor. I'll have pics later today, but I have the motor off now so I know it was screwed on. Link to comment Share on other sites More sharing options...
ArdWrknTrk Posted June 23, 2020 Share Posted June 23, 2020 Shaun, you can see my '87 has a bolt on vacuum motor. I need to correct that my relay is making ground in the 'high' position, not bringing power to the blower motor. I'll try to get a picture where the halves are joined. My truck may not have AC but it does seem to have the same snap together case as Huck. Link to comment Share on other sites More sharing options...
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