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My O'Keefe & Merritt Stove Restoration - 2

On Nov 2, 2013, I purchased an O'Keefe & Merritt gas stove (model # 500-2V) from a neighbor. She wanted to find a good home for it because she'd grown very fond of the stove. It was my very first gas stove, an appliance I'd been anxious to acquire for several decades. I happily moved my electric stove out of the kitchen, moved the OKM in. Thus began an unanticipated yet tremendous educational adventure for me; my first do-it-yourself antique stove restoration. Hats off to Parkie O'Keefe and Bob Merritt.


I'm trying to document nearly everything I saw, did, bought, etc., during this process. So it may take some time before this publication is complete. Check back every few weeks to see more descriptions and photos.

The Adventure Continues

Main, simmer burners and burner supply tubes

The burners looked their age, but there were no cracks or problem holes.

I noticed the screws at the base of the heads and figured that indicated a joining where gas could leak. So I decided to remove the burner heads. Each of those puppies are impressively heavy.

After removing the burner head, I assumed there would be a gasket to help seal the burner heads to the joining to prevent leaks. But nothing was obvious, at first. With a putty knife I started poking and scraping, discovering there were gasket remnants. Sorry looking things that had given their life long ago.

I scraped at and removed all gasket remains, sanded the metal surfaces and ordered four new burner gaskets. I even vacuumed the burner gas tubes - only because at the time I didn't know how easy it was to remove them from stove.

Now to the burner heads. With dental tools, I poked into the dozens of holes and scraped out the ash and debris. Banging them with a rubber mallet loosened other debris trapped inside.

The new gaskets arrived and I was about ready to reattach the burner heads to the burner gas tubes when I discovered something amazing, something I could find anywhere on the web.

 

While trying to reattach the burner heads I noticed the burner tube set moved a little! With a little play, it moved more. Eventually I realized it wasn't hard to lift the whole thing out!

No screws or bolts were securing it to the stove. There was a small hole in the brace bar where a pin on the left burner tube set would fit, but otherwise it was stabilized by its own weight.

The burner simmer cap can sometimes be removed. I could unscrew two out of the four.
While they looked bad, they worked, so I scrubbed and cleaned off as much of the corrosion as possible and buffed them to bring back a little of the shine.

 

Gas leak detecting

I had been smelling raw gas in the heated air rising from the oven chimney ever since I hooked up the stove.

So a couple of days before Thanksgiving I got a gas leak detector (UEi Test Instruments CD100A Combustible Gas Leak Detector ) to help pinpoint gas leaks.

It's really cool. It claims to detect gases from the following:

Acetone, Alcohol, Ammonia, Benzene, Butane, Ethylene Oxide, Gasoline, Halon, Hydrogen Sulfide, Industrial Solvents, Jet Fuel, Lacquer, Thinners, Methane, Naphtha Natural Gas, Propane, Toluene.

I first tested it by opening the fuel cap on my car. It worked! So I put it to work on my stove.

The detector confirmed there was a high concentration coming from the stove's chimney. The entire area under the hood was clear - no leaks. But it detected high amounts of gas just above the oven and broiler pilot lights.

Sadly, the unit's power and setting dial broke only after three months - not a good outcome for such a pricey item. Apparently, it's not constructed for serious use.

 

Oven pilots and thermocouples

Figuring there was something wrong with the oven pilot, I ordered a relacement, hoping the replacement would reduce or eliminate the enormous gas leak coming from the area near the pilot.

The trick was uninstalling the existing pilot. What a complete and total PITB. It took me hours and finally I had to nearly crawl inside the oven to reach and loosen the upside down machine screw on the bracket that held the oven pilot and thermocouple.

Once I got the pilot and bracket free, I closely inspected the pilot. It seemed to be in good condition. The pilot caps were fine - no burned away spots - which can cause combustion problems. Just inside the caps were 4 holes.

I also noticed a band at the base of the pilot. I spun around the base and had two holes. When aligned the holes in the band revealed two holes underneath. I figured the band controlled the air/gas mix.

I noticed the bracket had a small bar which appeared to pair to a notch in the pilot. When viewing the photos I took before messin' with the thing, I noticed the pilot was sitting too far forward; the pilot itself was way too close to the oven burner.

Even though I was completely inexperienced with these gas stoves, I figured the gas leak problem was mostly related to the pilot's positioning and the position of the band.

That's one of the design features of these stoves that's so appealing to me. Compared to a lot of appliances made today, this antique stove is relatively simple, not to mention it will probably outlast anything made today.

So I reassembled and installed the existing pilot, making sure the pilot was locked into it's proper position. I relit the pilot, then I adjusted the band's position using my gas detector to help me determine the best air/gas mix.

It seemed to work! The detector wasn't going nuts any longer.

 

 

 

Time to tackle the broiler pilot, which I had learned after reading a few online discussions, even from afar, looked to be in bad shape. The upper cap was missing a section, so proper combustion would be expected to be a problem.
Close-up of the stove's current Grillevator broiler pilot. Pretty bad condition. I'm not sure how it got like this but it's got to go!

A burner pilot, showing its age.

I decided to pull out the entire burner pilot assemly to see if I could clear anything that might be clogging those tiny little holes.

Upon closer inspection, it seemed a good idea to remove some of the corrosion/rust.

After pulling out the entire assembly, I noticed a few black flecks falling from the tube. When I blew air through the pilot end, more flecks came out.

So I snaked a brass wire inside, pulled it out. Lots of debris fell out. Consequently I banged the tube and re-inserted the wire several times to get rid of as much debris as possible.

Seeing all that debris in a fairly closed tube made me think about all the stove's gas lines and what junk they might contain. Note to self: clean or replace all the pilot lines.

Pilot light tube & housing assembly, a little cleaner inside and out.

 

Robert Shaw Oven Valve/Thermometer
Ah, the famous Robert Shaw units. Nice, purely mechanical oven temperature regulators - no electricity needed.

In my stove's case, a Robert Shaw BJ model oven valve and thermometer; surprisingly still available and at a 'sit up and notice' price span of $150 - $450.

Mine leaked from the front stem since the day the stove was hooked up. Before learning their costs, I had planned to replace it.

Hmmm... lemme see if there's something I could do, since it did at least work well enough to turn on the gas, in spite of leaking.

Lots of online information warn civilians that they should NEVER touch the things; never try to adjust or tweak them. Naturally, I was intrigued. I love that kind of invitation. :)

Besides, even though the oven valve part worked - gas to the oven burner flowed - tests for temperature control always failed. This indicated the other critical function - the thermostat - wasn't doing squat. That meant the oven would simply get hotter until something either failed or melted.

China Syndrome!

Well, not quite.

But I had nothing to lose by exploring the thing.

Like most other threaded pieces on the stove, the screws had almost seized. With lots of PB Blaster applied with q-tips and a wrench, the mounting screws (the two that secure the main unit to the manifold) loosened. First step done.

I stopped, held my breath, the screwdrivers and wrenches in my hands; waiting for the Robert Shaw police to descend with bolts of lightning to condemn me for violating their laws. Since they didn't appear, I felt like nothing could stop me. I was about to uncover the insides of a sacred relic; perhaps even fix it!

Next, the four screws whose heads were on the back of the main unit. They weren't as stubborn to unscrew, just a lot more difficult to reach because of the gas pipe coming out the back and the burner valve just to the right of the oven valve. I tried to remove the aluminum tube, but the nut wouldn't budge.

After removing the 4 back screws, the Robert Shaw valve mysteries therein began to reveal themselves!

Front portion showing back end of the dial and a large copper washer.

Back portion with a spring and the mounting plate on the manifold. There didn't appear to be a gasket, but there should have been. Any place where two flat metal surfaces are joined there should be a gasket to help seal the join.

The mounting plate looked rather rusty, so I blocked the opening with a wad of paper and sanded the surface to remove the rust.

Underneath the big spring was a thick disk with a screw out the back, and a second smaller spring.

This was as far as I could get without damaging something. Here lay some kind of gimbal. While fascinating, I could not figure how this gimbal thing factored into the operation of the whole unit.

There was a very viscous collection of goo in the bottom area of the ridged base. It was easiest to scoop it out with a toothpick. I had hopes that with that goo gone, maybe the thermostat might work. Just a hope.

The information online about capillary thermostats stated there were very sensitive. The copper wire coming out the back was actually a tube with a fluid inside. When heated the fluid inside the tube expands and somehow mechanically regulates the oven temperature by controlling the gas flow.

Whatev.

The screws I did remove were badly rusted so I replaced them with new machine screws. The replacement screws were a bit too long, so I cut them with my Dremel.

The washers were so rusted, they easily broke. I had washers with the right outer diameter, but the inner ID was too small, so I drilled larger holes.

Handmade gasket; 1st attempt.

Handmade gaskets, 2nd attempt. The tabs really helped when trying to keep them in place. I only had two hands, you know.

Fully reassembled, with lubed valve, new gaskets and machine screws.

Leak test was a success. The valve no longer leaked gas!

Sadly, my victory was short lived. The delicate, fragile thermostat still didn't work. :(

Gotta go shopping for a newer or rebuilt Robert Shaw BJ (4500). But as I mentioned earlier, that brand still exists, BJs are still being rebuilt today, and updated versions of this model are all over the place in residential and commercial kitchens!

   
   

 

Controlling pilot gas flow

According to my nose and my leak detector, both the oven and broiler pilots were still incredibly leaky; even though each had a nice blue flame, indicating proper combustion. These required further investigation and work, but I wanted to at least use the stovetop for cooking.

Eventually I learned I could isolate the pilot gas flow for the oven and broiler to turn each one off by turning their individual pilot light adjustment valves. That meant I could turn the main gas line back on to the stove and not worry about the leaks from the oven/broiler pilots, but I could still use the stovetop burners.

Later, I realized without the overwhelming gas leaks from the oven and broiler pilots, smaller leaks would be easier to find with the detector.

That's when I discovered a couple of the pilot valves were tiny bit leaky as well. The sealant between the manifold and the threads for the valve may have failed, or the rust/corrosion may have damaged the required tight seal. I'll need to remove them and check. Hopefully applying some pipe dope or teflon tape will be sufficient to correct the leak.

 

Oven Clock & Timer

Even though it was superficial, the face plate for the clock and timer was something I absolutely had to address. It looked diseased.

The trick was finding out how to remove it. Again, there were no instructions online, so I had to figure it out on my own.

One important initial step was to remove the back panel to see if and what might be securing the faceplate from behind. Hmm... nothing obvious.
Turns out a single little piece on the front of the faceplate was one of the key parts securing the faceplate. It was easy to unscrew it with needle nose pliers.
I returned to the backside and unscrewed the brackets that held the two white plugs, then pulled them out from the front.
That's all it took. The faceplate was easy to remove. I degreased and sanded it with steel wool and abrasive buffs to remove layers of corroded, oxidized chrome and the copper layer underneath.

Re-chroming was certainly an option, but I didn't want to deal with that process just yet. I didn't know the costs. Plus, I was more focused on getting the stove to function safely. So as long as the panel didn't look diseased, I'd be happy.

I used Dupli-Color engine block enamel spray paint. It is rated to 500 degrees F.


 

 

Last update to this page: 27 Jan 2014. Send comments, questions or suggestions to Desiree McCrorey.