gotta problem with a buck 91

[eujamfh]

So I tried to take the buck 91 apart to check the cat...two screws that hold the housing in the back of the stove are turning without biting which means I can not drop the housing. Called Buck and they are at a loss why the bolts are not dropping into the holes to allow them to bite and allow me to break the nut. They basically said I need to cut them out...since I don't have a torch, am thinking of trying to hit them with a grinder to bust off the nut. I clearly will need new bolts...but anyone out there have any ideas how to get them out? I can not get a hack saw back there (way into the stove) and hiring someone with a torch will certainly cost an arm and a leg.

I am really disappointed and feelinga bit blue not knowing what to do...any thoughts will be apprecaited.

Cheers,
Matt

 

[pen]

Any way you can get a thin chisel pounded behind those heads to put some pressure on it then try turning?

Maybe a pic or two of the trouble spot could help also if someone else hasn't seen the same problem.

pen

 

[eujamfh]

tried putting a screwdriver up against it with no luck...really put some pressure on it but it did not help.

I will take some pics in the next couple days when I get a chance. probably will not get at it again until this weekend.

 

[Ashful]

I had a private conversation with member pgmr about the Buck 80, and he mentioned something about the catalyst chamber being a PITA. You may want to PM ("Start a conversation" with) him before doing anything drastic. Not that he'd know anything that Buck tech support doesn't...

 

[eujamfh]

thanks - will do!

 

[Woody Stover]

Can you post a pic?

They have a small handle that holds a hack saw blade; Maybe you can get that in there.
(broken link removed)

 

[pgmr]

If you can get a Dremel tool, cutoff tool or grinder with thin wheel in there (or possibly even a small hacksaw), you could cut a slot on the bottom of the bolt, then hold it with a screwdriver while turning the nut. Wire brush the nut and bolt and soak with penetrating oil a couple times before trying to turn it. If it won't break loose, try heating the nut with a propane torch.

This is a pretty poor design and the thing I dislike most about our model 80.

Btw, the posts that the flame shield fasten to are actually threaded studs. If the shield is a bit warped and won't go on far enough to put the cotter pin back in place, simply turn the stud out until you can easily get the cotter through the hole. I'd spray the stud with penetrating oil as well if you need to move it.

 

[eujamfh]

looked at the hacksaw route but don't think it viable to cut it off. I will try slotting the bottom...will try hack saw first and if that does not work...maybe its my excuse for a Dremel. I have a multi-tool but nothing that would slot the bolt.

 

[pgmr]

Any luck getting that cat chamber out?

 

[eujamfh]

Indeed I did tonight. Used a dremel to cut the bolt on the left of the housing off and then went up through the nut cutting it in half. Used a couple wheels but was easy work. With the only one remaining being the one in the back, I was able to angle the cast housing down which allowed the existing bolt to bite enough to actually take it off with a ratchet set. Attached is a pic of the cat...looks like it needs to be replace.

Also, the heat shied bolts which go into the cast piece are completely frozen into the cast housing. No way to get them out except tapping them out...and since I do not have the tools to do that I would have to bring the housing to a shop (thinking at least $50). So, I am planning on buying a new cast housing ($90 from Buck) as well as a new heat shield ($30) and cat ($300). Yikes...this year this stove is running me a little money...

I am replacing the heat shield since it is warped.

What I found was that the two bolts that were spinning were due to sloppy tack welds that kept the original bolts in place (lots of weld on top interfering with the bolts seating). While I was in Afganistan my wife had a guy come drop the cat and check it and he must have replace the two bolts that were the ones that spun...problem was even though he used correct carriage bolts, they could not seat into the square holes in the housing because the old tack welds prevented the bolts from dropping into the square holes.

So I am now in the process of trying to grind down the tack welds up in the stove so when I put new bolts in they will drop into the square holes which means the next time I drop the cat I will not have to cut them out...still have some work ahead of me but it is doable.

 

[eujamfh]

pgmw - those threated heat shield studs had nuts not cottor pins on them...so I thin my stove had either been work on or was one of the original from the factory and they changed to cotter pins whe they realized nuts that were in direct flame contact would certainly seize. I am hoping when I call them they tell me the new cast housing and heat shield will come with studs that have cotter pins since I don't want to have to worry about them seizing in the cast in the future. I soaked them in pb blaster, banged and heated the studs with no luck. Sorta sucks since the cast piece is in perfect order...but as noted, since I would have to pay at least $50 for someone to tap them out...it is worth the extra $40 to get a new one sent to me. Shoot...I would pay $15 in gas to and from a machine shop...

 

[eujamfh]

BTW - you can can see on the left side of he cat there is a diagonal crack through the honeycomb. Another reason I figure I might as well replace the cat now that I have it all out. In fact, I would certainly need a new seal since the cat is pretty set into the housing and I am certain more will crumble when I try to get it out. As best I can tll...this cat is about 20 years old. It would last year, but was taking longer to light off. Once it did get going, it worked fine...I bet if I washed and soaked it, I could get a year or two more (assuming I could get it out) but since I am well past the normal life expectancy...I might as well do it all now...

 

[pgmr]

Congrats on getting it out. That's a bit different in design than the 80. It has a deeper chamber that the cat fits into completely - flush with top of chamber. It only has 4 nuts to remove to get the chamber out and appears to have 1/3 less catalyst.

Is that damage to the cat in the upper right of the picture only on the face or does it go all the way through? If it's only on the face, the cat might still be usable. You probably wouldn't be able to move it to a new housing w/o further damage, but if you can free up the heat shield studs with penetrating oil and torch at least you wouldn't have to replace the housing

Edit: Sorry, didn't see your follow up posts prior to the above.

 

[pgmr]

I wonder if you could cut off the existing, rusted on bolts and have a welding shop replace with something like this clevis pin? The multiple holes would give you adjustment as the heat shield warps a bit and you can use cotter pin and washer instead of a nut.

They should weld on a stop (a large nut would work) to give you the standoff room needed for the smoke to enter the cat (or you could just use another cotter pin to keep the shield from sliding up too far). If you can find it in SS, it should last indefinitely. Even mild steel should last a long time.

 

[eujamfh]

UPDATE - I ordered a new cast housing, a new cat and gaskets all around. Also added a new flame shield which has cotter pins vice nuts to keep the heat shield on - much better design.

I had to get a grinder up in the top plate to knock down the tac welds originally placed on the housing bolts. PITA but doable. Same goes for cutting the bolts themselves.

Anyways - it is all ready to go for the year. Not burning it yet since it is too warm to get that beast running. Needs to be below 40 for a while to run the Buck. The Hampton gets us along fine until then...

 

[eujamfh]

BTW - got the cat off ebay for $250...and housing was $90 so not too bad considering the last round lasted 15 plus years with the original owner not burning dry wood nor leaning the cat!

 

[BrotherBart]

Glad ya got the big boy ready to romp before it gets colder.

Do you think design changes will keep this from happening with the newer Bucks?

 

[eujamfh]

not sure since I have not seen the new ones. I can say I love the performance and it is built like a tank....but the fact the cat is not to easy to service would definately be a draw back if I bought new. I had the stove given to me from a neighbor - I moved it, but paid to had a liner run...so it was not free (ran about $1200) but it heats like a champ. In the shoulder season I can get 30 hours of heat...in the cold months, two loads is not a problem at all.

And the firebox is huge - it takes a lot of wood to load it...but then, it takes a long time to burn it.

Long windeed anser to what I should have said which is "I do not know."

 

[BrowningBAR]

In the shoulder season I can get 30 hours of heat...in the cold months, two loads is not a problem at all.

Good to hear! I didn't know Buck cat stoves ran that well.

 

[eujamfh]

well cant speak to others, but I know in the shoulder season I can get those times. Granted, we get 5 degrees of solar gain if it is sunny...but the stove itself will put heat out for those times. If it is cold out, we can not get those times...the it is 8-12 hours...that being below 40 degrees constantly. Regardless, the Buck 91 can burn a long time and takes a lot of wood...and the times are directly proportional to the wood and the ambient temps.