Sometimes all my washers and dryers work perfectly for months and months, then sometimes I get 2 or 3 repairs at once.

My 1951 electric Hamilton wasn't heating, I tested EVERYTHING and jumpered past lots of stuff, have accurately narrowed it down to the motor "throw-out switch" as the schematic calls it.

I have removed the 4 long screws from this heavy cast iron Delco motor, but cannot get it apart. I don't want to damage it, ain't quite ready for a hammer. The large rubber bushing are part of the endcaps, right, I don't remove them seperately? Does it just take tons of strength, or am I foregtting something here?

the other end

The first answer is the best way, tapping with a screw driver and hammer where the cast iron end bells touch the round center section. I would not pound on the motors shaft at all as this could damage the bearings or end shims.

I got it apart with various folks advice, gently tapping right where cast iron end meets the round sheet metal center. Surprisingly clean inside, I cleaned all the contacts at the throw out switch, filed them a small amount, reassembled but still no luck. As I think about it, I don't think I tightened one spring/screw as tight as original when i re-assembled, tonight or tomorrow I'll try that.

Earlier, I strongly believe I proved it's the throw-out switch. First I bypassed the thermostat dial HiMedLo, still no heat. then I bypassed the timer so the power always went to the heater and motor, no heat at all but the motor turned regardless of whether the timer was on or not.. Then I jumpered the thermal fuselink, still no heat. When everything was fully reassembled and no heat, I then took the power going into the throwout switch and instead hooked it directly to the heater and it got hot right away, and the thermo cycled on and off and all was well BUT....  It also did not turn off when I opened the door and thereby shut off the motor! Dangerous excess heat for sure. So in my book, I proved it was the centrifugal throw out motor switch. But cleaning hasn't fixed it yet, so it needs another better attempt. 

The schematic shows thermal link, timer, thermo dial, and motor throwout switch, nothing else, and I followed all wires and checked continuity. It has to be the throw-out centrifugal assembly for sure, I just gotta do a slower better job of inspection, cleaning, maybe new contacts? All pieces/parts/springs look intact, but 2 contacts are relatively worn down to 1/2 height, hmmmm.  All lights work, door switch is proper, etc, simply no heat And prior to no heat at all, for a week or two it was iffy. I'd open and close the door 3x, turn the timer 4x, finally it worked for an entire load, then next load no heat. Intermittent behavior  also tells me it's potentially the throwout more than a thermostat or timer issue or thermal fuse.  The thermal fuse and motor throwout are really the only 2 safety features on this old machine, so I will fix it properly and not even think out ways to monkey rig it, no way.

I'll take any advice, and thanks in advance. I also might not get back to it till Tuesday! And when the Delco motor is soon apart again, I'll do my best for up-close good photography. I never kenw when I started this hobby that I'd need to be a great photographer too, but it surely helps me to get the correct advice.

Thanks again, I'll take another crack at the throwout switch.

1951 GM Delco motor, throwout or centrifugal switch

Here's the pivoting lever when the bell is off the motor. When assembled on the shaft and NOT running, these contacts are apart. Notice the clean contact that is only used as a bolt for 2 wires to junction on the other side of the board.

This spring assembly moves out from center when the motor is running, allows that pivot in the other picture to make contact.

Ugly worn contacts(worst are on the cloth, can't see the heads, sorry.) . It turns out that they are bolts, not soldered or anything, so I simply swapped the 2 best (contacts for lights) with the 2 worst (heavy power for the heater) and now all is well. This pic shows it already mostly apart, sorry, but some of the contacts sitting on the cloth are horridly pitted, 61 years of 4400 watts pulling thru them.

Out of 5 bolt-in contacts that run thru those square holes, 2 were horrid and not making contact, 2 were slightly worn but working, 1 is pristine, was simply used as a junction bolt for 2 ring-end wires, no contact on this side of the board. I just swapped worst for best and versa-vicea.

No more intermittent heat, the heater gets red hot about 20 seconds after the motor starts, and goes out as soon as the door is opened, everything checks out well and is back together drying clothes.

One other slight oddity, this centrifugal switch is silent. I'm quite used to other dryers with that small click after 2 - 5 seconds, modern WP and GE's. And another motor click when you open the door on modern machines.  Whereas this 60 yr old design is silent when that switch goes in or out. Who knows?

Congratulations on a good fix Mark, and a good observation about the quite operation of these centrifugal switches on old Delco Motors. However I do think since this did not have a quick snap action switch is one of the reasons we see so many old er style Delco motor switch problems. But it was quite and at least you can take it apart and fix it.