Hi Jim,
I see nobody has been able to help you out so far but hopefully I can. Those tabs are notorious for failure and you are certainly not able to burn at full efficiency without the damper locked in tight. I replaced a damper tab this summer, same type of problem. To answer your question about access-No, you will need to take off the heat shield, flue collar, and back panel of the stove to do this repair. Note: I have a model 0028 from 1986, but it should be very similar. Also, I recently posted about some issues I've had since the repair. It turns out it is likely the secondary air probe is failing so you may want to consider that while you are accessing the back of the stove. I also recommend cleaning and/or replacing the cat element as well as replacing any gaskets you open up because it's inexpensive and easier while you are working on the tab project. Note the dates of your maintenance.
To to this project you will need the following:
Parts- 3 damper tabs, new stove bolts for tabs. As mentioned, I also recommend all gaskets for the back panel, damper, flue collar, and cat element panel. Replace catalytic element if needed. A pint of Rutland Black Furnace Cement. go to the rutland.com to find your local dealer. Possibly may need 1/4" thrubolts.
Tools- 1/2" & 1/4" Socket set w/ extensions. #2 & #3 Phillips, Hammer, solid steel chisel between 1/4" and 1/2". Helpful is an angle grinder with wire wheel. Possibly needed is a quality drill and pilto and 1/4" bit or set if Titanium coated or equivalent drill bits.
My explanations are given from the perspective of looking at or into the back of the stove as you work on it.
How to do it: Make your stove accessible and remove the pipe. Remove the heat shield on the rear. Remove the flue collar with your #3 phillips. You are now ready to remove the back panel of the stove. Remove the bottom bolts first and work your way up -the panel should not just fall away but no promises. The panel should remove with a tug up and bottom out first--somewhat heavy but is manageable by one person. Do not let refractory fall out and break. Carefully place aside. At this point you can work on the tabs with easy access. Thinking ahead....Once you have the damper removed, switch tasks and replace your damper's fiberglass gasket following tips below. This will make replacing this gasket easy while it is outside the stove.
Very very carefully try to back out the bolts on the left tab first. The right tab is a more difficult project. Here is where the curveballs start. In mine, the left bolt easily sheared off prompting a few bad words, if you are lucky it will come out and you can just replace the tab. With mine sheared, I was forced to either easy out or thru bolt. This is where the drill and bits came into play. I opted to drill the bolt out and then easily thru bolted the new tab. High quality bits will make this easy if required. Thru bolting the right tab is a different story and requires removing more interior panels. Be very careful with the right tab. On the right tab...."If it ain't broke, don't fix it." I also had no problem replacing the damper bar tab and opted to do it while I was in there as the replacement tabs are stronger than the originals. So hopefully your bolts slip right out and you are able to replace the damper tabs easily. Just remember to do the gasket before you replace the tabs and damper. Once done, test motion and then lock damper closed so gasket seals properly. Place a piece of newspaper in between the damper and fireback so any leaky cement does not stick.
Gaskets and putting it all back together:
I recommend doing the project in this order: Take it apart, clean out all gasket channels and prepare new gaskets for install. Service combustor and put someplace safe. Shop vac any ash or junk out of back of stove. Be careful not to damage ceramic refractory ($400). To replace gaskets, gently tap out old gasket cement with chisel at an angle being careful not to crack the iron. For a super clean, use wire wheel on grinder, 4 or 4.5" works best at high RPM. Measure and cut gasket rope being careful not to stretch or cut too short. Apply Hi-Temp gasket cement or Black Furnace Cement and replace gaskets doing the damper last. Now you finish the tabs part of the project and install and lock the damper. You will notice that the bottom of the back panel has no rope gasket. Myself and others think this is odd and have discussed how to properly seal this area. You may want to further research this part. Since there was cement present at that seal prior, I chose to apply copious amount of black furnace cement to the bottom seat and corners just prior to replacing the back panel. Follow cement direction, wiping clean and leaving area damp. Apply bottom seat cement and take back of stove and slide up under top panel and then into position. Position and thread top bolts working your way down. Then tighten bolts alternately as if you were putting a tire on a car. Keep alternating as gasket compresses. No you can put the cat element back in and replace the cover(your model may be different on this). Then replace the flu collar then the heat shield and.....wait. Wait at least one hour or preferably overnight so cement can set up before you move the stove and possibly rattle it. Later.....Put the stove back in place and connect. Remove newspaper from damper and light a fire that will slowly temp up. Either burn up to 500° for an hour or more or just burn and don't let it get much over 500°. After the stove cools, the cements should be cured. Now you can burn normally. Good Luck and let me know if I can be of any help.
-Darren