TargetDriver

Hey guys, another one back from a rapid deployment issue. I finally get to work on my M20K tanks tomorrow morning ! Before i left I managed to get the two top outer small panels removed. Not too difficult, but the two larger in board ones wouldn't even budge or let me get anything started between the panels. While I was away I got the shipment of PolyGone Gel .. yea that bucket isn't very big for 3 bills ! I got a ship notice for all my sealant and should be in any day... way ahead of being ready for it for sure. After talking with a few guys I've given up on the internal tank sprayer for now and opted for just trying the gel and some hand labor. Has anyone used a heat gun (careful with the paint) to help soften the access panel sealant? I dont have elcetricity in my hanger and was wondering if it would be worth the effort to get it strung up for that?

Phil, Wow, that's good to know. From what I can see in my tanks, there isn't much beyond factory or minimal sealant...not like someone sloshed the tank or similar. Maybe the gel is the way to go. Did it stick to the upper joints/walls alright? Perhaps I don't even need a spray system. How much should I buy for one tank, considering it's a complete strip and reseal?

Ah yep, true. That's sounds right.

They are one-way check valves. Haven't seen those in this application before but they were there when I cracked her open. You can barely see it, but there's one on the right side of the picture that goes between the electric standby vac pump as well. It's mounted vertically on the extreme right side of the firewall (Left seat side).

24J, You're very welcome and it's still an honor to support the warfighter effort when I can. Ya gotta love Clint ! I see what you mean about the light pressure may not be enough to force so many areas into those crevices. The tanks we're doing that on are carbon composite and can take much more pressure if need be, whereas our aluminum skin structure could not. It'll be a real time call when I see the consistency of the sealant and how it all flows. I may do a quick 3 psi test piece to check it. I've met an A&P/IA at my new airport that allows me some of the same freedoms thankfully. Having built several planes, race cars, etc. helps with my knowledge base, but he wants to see my work which I'll gladly do to get his blessing. I like a challenge and as much as everyone curses the fuel tank reseal, I'm looking forward to doing it. I'm kind of dense that way... tell me I can't do it or no one does that because... I'm all over it just to prove I can do it. Had to laugh about your crankshaft wear story... I work with a company of aerospace engineers and use that all the time... I call it the "old person nod". They'll go off in some other language of engineereese and I'll just nod, smile and say...yeaaaa... no clue what they're saying sometimes. Ha ha. Turbo, Have you used that air gun yet? Do you use a long nozzle and leave the gun out of the tank or do you actually get the gun in the tank and use a hard nozzle. How is it for maneuvering it around in the tank if you do? I like that idea. I've seen the 6 oz kits. Do those "kit" tubes just fit in that gun and mix as its leaving the nozzle or do you mix externally and load a disposable tube? At work we sometimes use a ClickBond structural adhesive that comes in a dual tube with a plastic nozzle that has "zig zag path" molded into it. One squeeze and they both mix as they go down the tube.. exits as mixed and ready to lay. It's fantastic for gluing nutplates in position.

Turbo, I've been in the Depot a couple times... but where exactly is that "aviation" isle ? I'm fixing to spend me some money there ! .. like they don't get enough of it now ! ha !

Great observations guys. Yes the cable passing close to the vacuum pump is the throttle (RPM) cable. The photo is somewhat deceptive in that there is actually 1/2" between both vacuum pump tubes and the cable. I had to leave early Sunday before finishing up the "detailing" so didn't get to some of it. The rubber abrasion sleeve with a single tie wrap was originally closer to the intake tube of the vacuum pump, most likely as a precaution for contact. I still have to move it back, clean it and re-tie. I'll end up detailing the entire engine compartment as I get to it. I like things very clean and organized. Makes it so much easier to spot leaks or trace any issues. Attached is a picture of my Top Dragster E bay with the body off showing my wiring. It's okay in that world to tie-to-tubes since they are only on like that for usually a season or two before redoing. I just lightly wiped the firewall down but the pane is that clean most everywhere. (except the underside near the fuel tank leaks, but starting to work on that project now with a fuel tank cleaner system and reseal) The tie wrap (we call 'em zip ties) on the engine mount tube was there to hold that wire bunch in place while tying them. I have it on my No-Fly card to remove before buttoning up. It is amazing what a small piece of plastic can do to a steel tube when enough vibration is given over time.

24J, After studying the resealing procedures I think I'm going to use a technique we use in the field on military target fuel tanks (Composite) if there's a leak. .. I know I have to be very careful to prevent any over-pressure due to the structure but we would slosh or paste a tank (that had seams) and then apply no more than 3-5 psi for about 20 min. This forces the still-semi liquid sealant into the same cracks that fuel would be trying to seep into. We don't leave the pressure on too long so not to force it completely through any possible seep ports. I have yet to figure out how much of each type of sealant to get though for a tank. I'm only going to do the left tank completely as the right one only has one small seep showing. After filling it completely and letting it set for two weeks, the left tank has dropped 4-5 gallons. Hard to believe really.

You're right Jetdriven, it is. Thought I might cut it open to inspect for very small particles or an amount of dust. The new pump I have (Rapco) has the wear port as well with a small inspection capscrew ...and the cutest little plastic calipers to check it with. ha So I've replaced the pump and the new filter now. The hoses on both sides were two different types and there were squeeze clamps and screw clamps so I replaced all of it with new hose as well and all new screw type hose clamps. I also cut most of the old tie wraps away, cleaned the wiring and tie wrapped. Picture attached.

Anyone still following this chain? Sure would like to see those pictures. I'm building a flush system now for the K model I just bought. Left tank is the worst, right tank has one small weep. It doesn't look like anyone on MS has mentioned resealing or doing their tanks in some time. I've found the sealant but haven't figured out how much to buy (per tank). I'm going with 3 gal of PolyGone for the stripper. I opted for rotary nozzles for my system with more flow than pressure to keep atomization down and wet-flow up. The intent is to make it somewhat smaller and crate the system and for it to be shippable...just in case someone else wants to use it.

I ordered a new Rapco unit and a new inline filter as well. The warranty seems good as well for this one. I'm certain I'll run out of time before the hours. "3 years, 1300 hours from date of installation or 4 years from date of manufacture whichever comes first.". Being the curious type, I'll cut the inline air filter apart liek we do oil filters, just to see if there is any minute particles that would have made their way to the gyros.

Ha ha R.really liked the Chip Ganassi Target driver reference ! I've driven sand dragsters to alcohol top dragsters and funny cars... but I'd give one of my *** to crawl in one of those Target cars! I fly military targeting aircraft...hence targetdriver. So after weighing the issue I am sure I could have flown the plane w/o the DG or AI and would have been in VFR but not being 100% knowledgeable on the Conti accessory case and its mounting configuration, as to whether or not there could possibly be any passage of debris or FOD into the engine, I decided not to fly it until I put on the new pump. Ordering today. I've got plenty of engine/mechanical experience but just not sure about this particular application. Now I guess my biggest dilemma is to have to pay an A&P to simply R&R that very basic 4 bolt pump. Ha ..time to finish that A&P tag I guess.

I am much more likely to spend the extra money for the new vacuum pump, is there a reliability or lifespan difference in the reman unit versus a new one ?

Guys, Thank you all for your welcome, replies, and the great advice. I thought I was going to have to fly it to have it repaired but it turns out that I will most likely be able to have it repaired at my new home field. I went through the logs today and as best I can tell, the pump is 7 1/2 yrs old and has 456 hours on it... so, yep ...500 hour life! The engine only has 300 hrs on it after a major and the turbo system has less than that. I suppose the accessories obviously have a lifespan of their own. I pulled the top cowling off and its the 215CC pump, so a new one looks like $355... a small price to pay for piece of mind, even if it would only be a sheared shaft. I'll order a new one tomorrow, along with a new filter.

Hello All. I've been quietly soaking up Mooney knowledge from your great site for some time. Last week I finally did it ! I bought a '80 M20K and made the 3.5 hr flight from Minnesota to Missouri, then on to California in a single day of 10.5 hours of fun... that ended with an hour of concern but thanks to my new 231's back up vacuum pump system, we got home safely. While in VFR flight following I lost the vacuum pump over the Sierra's at 10.5K ft in the dark. No other indication than a panel warning light and lost the ADI. We had just did a very detailed pre-buy and annual before leaving but I guess the Vacuum pump just ran out of hours (500 I hear is about the life) . Checking the log books now for some indication of vac pump hours since last. My question is this. I'll tear into the plane next weekend to check the pump, regulator and filter but is the plane safe to fly as is? Obviously not in IFR conditions, but is there a risk to further damage maybe an input shaft, send FOD downstream , etc ? If I switch on the backup, which I presume is electric, the system come right up. Is the backup capable of being ran occasionally, or is it only for short-run backup usage? Thanks all for your info and I'm looking forward to spending many hours making my way into the Mooney club! Thanks