The Stovebolt Site Forums The Shop Area Interiors heater fan

I have a 1952 GMC 3/4 ton truck and when I bought it, it came with two different heaters. The one that was installed was actually a Chevy heater that mounted to the firewall and was kind of shaped vaguely like a turbo scroll or a shell. This one had a donut-shaped heater core with the fan motor in the middle and then a 4-bladed fan. Well, when the heater core blew, I took it out and found out it would cost me $375 to have the heater core rebuilt.

Therefore I dug out the original GMC heater, which mounts in the kick panel on the passenger side of the cab. The truck has factory holes for either style heater in it. This one had a more typical rectangular heater core, about the size of a brick. I had that tested and it is a good heater core. But the motor and squirrel cage fan that goes with it were missing.

I found an old GMC 1/2 ton truck with the same exact heater in it, and was able to buy the rusty old heater from the owner for $20 bucks. I pulled it out with some difficulty, brought it home, cleaned it up, and started taking it apart, with even more difficulty. But with penetrating oil and a torch, I got it mostly apart. The squirrel cage fan is in good shape, but getting it out is a bugger. I got the set screw out and lubed it up for a long time. I was able to get the shaft pushed out about an inch or so, but no further! This is a sheetmetal fan, and I simply cannot pull and tug on it without destroying it.

Does anyone have any tips for how to get that fan off the motor shaft? Looks like it's going to require a hydraulic press.

Oh by the way, I didn't mention it, but the exact same motor is used for either type of heater. So I'm planning to use my old motor, which is good.

I think I know how I'm going to have to free that fan. I'll have to cut through the motor shaft to free the fan, and then take it to a machinist to see if they can get the shaft out.

I'd like to know why I can't find a simple stupid Squirrel cage fan for this thing in the classic truck parts catalogues. I've looked at about a dozen sites and have not found it.

Sounds like a void to be filled Dad. Start manufacturing those squirrel cage fans.

Your problem is just that age old delema that all of us old wrench twisters run
into, i.e., "RUST". Soaking and tapping it apart part are the only solutions
that I could recomend.
DG

Well I did get it tapped out about an inch, but it wasn't going any further.

Finally claimed "Uncle" and turned it in to a local shop to pay them to extract the motor shaft.

The rest of the heater is sanded, primed and repainted and looks brand new. It looks good enough to install in my truck. Just need the fan now.

do that have BFH

I'm sorry, I don't know what you mean by BFH.

Anyway an update. The shop got the motor shaft out of the heater fan and only charged me $26. Now to get it on the wire wheel and get as much of the surface rust off as I can, prime it with rust neutralizing primer and paint it, and the whole thing can go back together this weekend.
Cool.

BFH= Big F***** Hammer

Not sure what kind of heater your trying to repair

American classic truck parts offers a plastic blower wheels
Part number HAC-66
...click...


I believe it's a replacement wheel for a Harrison

It's what I think was called the "Deluxe" heater. The truck is cut for cutouts for either type of heater. The one with the round heater core that costs a fortune to re-core is the one that mounts to the firewall only. That uses the 4-bladed fan that looks like a miniature radiator fan.

The other type mounts to the passenger side kick panel, just below the glove compartment, uses a rectangular heater core and a squirrel cage fan. That's the type I am restoring, since I don't want to spend $375 bucks on the round type of heater core.

Thank you for that part number. That would have saved me a lot of effort. But it's too late, I've already pulled one out of a parts truck and paid to have it separated from the old motor shaft. I guess I'll go with what I already have.

Here are 1954 GMC heaters (four styles). At least one of those heaters are slightly different from the earlier GMC heaters. This price pad shows that there were 6 GMC heaters in 1951 (1952 would be similar/same-as 1951). Four of the GMC heaters are different from the two common GM Chevrolet truck heaters.

GM heater motors would have been the same for similar style and voltage GMC/Chevrolet-truck heaters.

Mine's the first one on the upper left. That's the one I'm restoring.

That one would be the same for GMC and Chevrolet. They would have different name plates.

The 53-55 versions are different from the earlier versions. The cases are different and the cable-controls are different.

There were about 4 parts trucks out there, all GMC and Chevy AD's. And you know, every one of them had a different heater style. Some even differ from the ones you showed me, so they must have had some universal units available too sometimes.

There were many non GM units and earlier GM units, sometimes installed by the dealer or by the owner.

The only bummer is, I made a pair of plywood speaker boxes and put a stereo in my AD truck. One of the speaker boxes is in the way of the stock heater assembly. Looks like I'll have to find another home for one of the speakers.

But that's secondary. the primary concern is restoring my original heater.

I'll post pics when I've got it together and when I'm about to go in with it.

Okay the fan cleaned up nicely. It wobbles slightly, but maybe they all did back then. I don't know. Got the rust treated and will paint today. Then everything will go back together and will plan on installing it tomorrow.

Pics to come.

Well, I installed the restored original heater fan and thought I'd better test it on the truck's battery first before going through all that to install it on the truck. I'm glad I did. It is so badly out of balance that it vibrates like crazy, like it's going to come apart. And it probably will, since separating it from the old motor shaft also separated the fan hub from the sheetmetal fan. I had epoxied it back together but the way it's vibrating, that surely won't hold.

Therefore I have put in an order for a new fan from American Classic Truck Parts, part number HAC-66. (Thank you Dads50!)
At $22, it wasn't very expensive. The main thing is they said it could take up to 10 business days to get in. Obviously, my heater installation is going to take a couple more weeks.

But it's not all wasted time and money getting that original fan out of a parts truck. I also got what appears to be another good heater core and a heat valve, which was missing when I bought my truck. I have restored the heat valve and will install that in my truck and move everything out of the way in preparation for the heater installation.

I've got one question though. And I'm including a picture. There appears to be a thermostatic sensor wire coming out of the heat valve. I can't imagine what that's for, other than if there was a temperature gauge attached to the heater system. Does anybody know?

Here's the pic...

[IMG]http://i664.photobucket.com/albums/vv9/axeimen/ADTruckheatervalve.jpg[/IMG]

The tube is the "Control Valve Capillary Tube."
> Figure 99
> Complete installation instructions

BTW -
Don't know if Classic Parts offers different sizes of squirrel cage fans. FYI - the diameter of the fan in a 12v Impala heater is smaller than the fan in an AD AirFlow heater. Same motor shaft diameter. (I scavaged the Impala 12v motor to use in my '54 heater.)

I don't understand what the control valve capillary tube is for. What exactly is its function? The control valve already has a mechanical control for warmer or cooler setting. If it's mechanically controlled, then I don't know what it's for.

Never mind. I found it.

https://www.stovebolt.com/ubbthreads/ubbthreads.php?ubb=showflat&Number=345645&page=1

In short, the manual setting on the control valve sets the temperature that you want, and then the capillary tube has a diaphram inside that can restrict hot water flow further as the water temp changes (as truck warms up?), stabilizing the system and not requiring constant manual adjustment.

In other words, it's an early version of an automatic control system. Interesing.

Okay, the installation went pretty well. A few times, it was a 2 man job, one for the engine side of the firewall and one on the cab side of the firewall. But I got it in. I ended up using the newer plastic fan that was recommended earlier. Runs strong. Just need to connect up the heater hoses, then I'll be done.

Here's a few pics of my restored Deluxe heater.

http://i664.photobucket.com/albums/vv9/axeimen/056.jpg

http://i664.photobucket.com/albums/vv9/axeimen/057.jpg

The heater works good. I did since purchase and affix a new GMC decal in place of the old one. It's so nice to have heat again. It's a very noisy heater, but everything in an AD truck is noisy. Now I find out my fan speed switch has only two settings, full on and off. So I'll need a new switch, but I'm happy with how the rest of it turned out.

I've noticed a lot of other people are restoring their old heaters now. I hope they find info in this thread useful.