Prebuy "deal killers" and big items

[goalstop]

Hi all, I'm a first time aircraft buyer and have my eyes set on a 1964 M20E.  The aircraft has had a bit of an incident in the past (hit a wing and nosed into a ditch in 1990's) but has flown since then.  In the pre-buy inspection, I'm having my mechanic be overly meticulous about the wing spar, overall wings, corrosion, and front-end damage inspection.  So far, he's come back with a report of:

+ Seeping fuel tanks (blue, green and brown under wings)

+ "cracking and wrinkling" in the lower firewall

+ Crack in paint on the engine mount - want to do further inspection to make sure it's just a surface crack

Plane is a "good deal" but I'm afraid of maintenance adding up so quickly that it soon becomes a lemon. 

+ How much of an airworthiness issue is a firewall wrinkle?

+ When is it time to reseal the fuel tanks? Do all of you have some leakage, or is it something that should be fixed as soon as a seep is identified?

Will have more detail tomorrow...

[carusoam]

Welcome aboard Goal!

All planes are a good deal… until they aren’t…

Leaks are not normal…. They do happen from time to time… All can be repaired.

When it comes to fuel leaks… find the service manual for the plane… some small things are allowable.  Which gets you home…

Flying with a known fuel leak is one thing… but there may be an unknown one to go with that… depending on where it is of course…

The color is a subtle hint… light blue… a new, small drip…  dark blue… a bigger drip that isn’t new any longer…. Dark brown… is a lot of fuel to get that color…

First thing you want to do… take some pics.

Post them here…

Some fire wall wrinkles or dents in the foot well… aren’t that big of a deal…. But what you have is hard to tell without a pic…

The firewall could be an important structural device… expect actual wrinkles in an actual fire wall to be put in front of an actual Mooney familiar mechanic…

The engine mount is held to the firewall, but the actual structure probably comes from the steel tube frame behind it…

If you read up on PPIs PrePurchase inspections… you will find lists of things to consider… including who, what, where…. Etc…

Good luck getting through this challenge…  (this doesn’t sound as nice as it is intended… )

PP thoughts only, not a mechanic…

Best regards,

-a-

[Mooney Dog]

 

 

I would say if the tanks are leaking, its time to seal them, otherwise how would you know how much fuel you have. I wouldn't wait on that at all. However, the fact the firewall has wrinkles sounds like a deal breaker to me. How good of a "deal" is this airplane. If its like $10,000 then sure, its probably a great deal. But if its $40k+ then you're probably going to spend somewhere around 60-80k minimum. Granted, it depends on how/if it was repaired. 

 

For a reference. I got my E after it had been sitting for 15 years. I got a VERY good deal on it and still had many things to fix. $20G + some over what i paid for it, its now flyable. The major things with mine where paint and avionics, as well as a new prop. 

[goalstop]

Thanks for the advice guys.  Pictures forthcoming later today... also will update with the initial report from my mechanic - will then need to decide whether to go forward with the detailed inspection for corrosion.

Not fun, but way better than finding this after signing :/

[LANCECASPER]

@goalstop The Mooney maintenance manual tells you about the leaks.

[steingar]

Leaks are expensive to deal with permanently.  Expensive to patch temporarily too.  I'd not buy an airplane with firewall damage.  That means it wasn't repaired correctly after an incident.

Edited September 30, 2021 by steingar

[rbridges]

I know wrinkles in the firewall are not too uncommon in 182s.  I guess people have had a tendency to hit hard on the nose gear.  I don't know how that translates to a mooney though.

[Culver LFA]

I believe most ‘wrinkles’ in a Mooney firewall are the result of previous repairs and tools.  I’ve heard many mechanics point out wrinkles on a Mooney firewall like it’s a Cessna that had a hard landing, but that’s not how a Mooney is built.

I’d like to see the pictures of this

[EricJ]

Any cracks in the firewall may be more problematic than wrinkles if they'd let stuff through.    The only thing I can find in the J MM for firewall inspection is to look for "damage".

 

[Yetti]

There are some "wrinkles" around the lip of the firewall.   But the firewall main body should be wrinkle free.  Sounds like it was not repaired after the nose over.   Sounds like the engine mount was not repaired.  There is a firewall inspection/repair SB that should be reviewed.

Edited September 30, 2021 by Yetti

[RobertGary1]

15 hours ago, Mooney Dog said:

 

 

I would say if the tanks are leaking, its time to seal them, otherwise how would you know how much fuel you have. I wouldn't wait on that at all. However, the fact the firewall has wrinkles sounds like a deal breaker to me. How good of a "deal" is this airplane. If its like $10,000 then sure, its probably a great deal. But if its $40k+ then you're probably going to spend somewhere around 60-80k minimum. Granted, it depends on how/if it was repaired. 

 

For a reference. I got my E after it had been sitting for 15 years. I got a VERY good deal on it and still had many things to fix. $20G + some over what i paid for it, its now flyable. The major things with mine where paint and avionics, as well as a new prop. 

Repairing a fuel tank is normal for wet wings. A full reseal each time you get a small leak isn’t necessary at all. 

[goalstop]

The pics! Crack is in the lower copilot side, very tiny, by the edge of the firewall near the cowling

dent is in the engine side of the copilot foot well

Fuel leak pics are obvious

 

[Guest]

Mooney firewall material is very thin and as a result frequently have small cracks.  However this damage looks like leftovers from the mentioned accident.  The good thing is it looks like it’s below the floor level and is accessible by removing the exhaust fairing.

On the fuel leaks, acetone removes much of the old staining from the paint.  Clean it up well, refill the tanks to the brim and look for fuel leaking out after letting it sit over night.  A Lance pointed out from the manual page some leaks are allowed, but leaks in confined or closed areas are not.  That being said the price should reflect this maintenance expense.

From the last picture, the tailpipe support clamp and strap are missing.

Clarence

[toto]

18 hours ago, Mooney Dog said:

For a reference. I got my E after it had been sitting for 15 years. I got a VERY good deal on it and still had many things to fix. $20G + some over what i paid for it, its now flyable. The major things with mine where paint and avionics, as well as a new prop. 

 New paint, new avionics, and a new prop for 20k? Sign me up

 

[goalstop]

26 minutes ago, M20Doc said:

Mooney firewall material is very thin and as a result frequently have small cracks.  However this damage looks like leftovers from the mentioned accident.  The good thing is it looks like it’s below the floor level and is accessible by removing the exhaust fairing.

On the fuel leaks, acetone removes much of the old staining from the paint.  Clean it up well, refill the tanks to the brim and look for fuel leaking out after letting it sit over night.  A Lance pointed out from the manual page some leaks are allowed, but leaks in confined or closed areas are not.  That being said the price should reflect this maintenance expense.

From the last picture, the tailpipe support clamp and strap are missing.

Clarence

When you say "the good thing is it's below the floor and accessible by removing the exhaust faring" does that imply it should be removed?  Or just that it needs to be monitored and if anything happens the firewall can be replaced?

 

Good catch on the tailpipe support clamp / strap!!!

[skydvrboy]

FYI... Clarence owns and operates a Mooney Service Center.  It's REALLY hard to get better advice on the internet than what he provides.

19 hours ago, carusoam said:

The color is a subtle hint… light blue… a new, small drip…  dark blue… a bigger drip that isn’t new any longer…. Dark brown… is a lot of fuel to get that color…

With all due respect to Anthony (another great Mooney resource), I don't believe the color is a good indication to the size of the leak, but rather how long it's been since the leak has been cleaned up.  The page from the manual indicates that the size of the stain is a better indication of the severity, and personally having tanks that seep, that has been my experience as well.

From your picture of the leak, the bad news is you don't have a seep, you have a leak and a pretty bad one.  The good news it looks like it's just the drain port that is leaking, which is inexpensive to repair.  It may be worth paying your inspection mechanic to fix it just to make sure.

[Guest]

Below the floor is reasonably accessible for a repair, above the floor is behind the copilot rudder pedals and behind the firewall insulation blanket, making access to repair a bit more challenging.

Clarence

[EricJ]

3 hours ago, M20Doc said:

Mooney firewall material is very thin and as a result frequently have small cracks.  However this damage looks like leftovers from the mentioned accident.  The good thing is it looks like it’s below the floor level and is accessible by removing the exhaust fairing.

On the fuel leaks, acetone removes much of the old staining from the paint.  Clean it up well, refill the tanks to the brim and look for fuel leaking out after letting it sit over night.  A Lance pointed out from the manual page some leaks are allowed, but leaks in confined or closed areas are not.  That being said the price should reflect this maintenance expense.

From the last picture, the tailpipe support clamp and strap are missing.

Clarence

+1 on all of that.   And even if it does turn out that there's a significant leak in the tank, that's not highly unusual and many people have done successful patch repairs.   I don't know what part of the country you're in, but resources are likely not too far away.

If it is the sump drain that is leaking, that would be good news, but you won't know until you clean it all up and get a better idea of the location(s) and severity of any leaks.   FWIW, knowing how to clean up the stains and get a reasonable idea of the leak status is a pretty normal task for Mooney owners (or any airplane with wet wings).   It's not that big of a deal for the most part, but, again, you wont' know the severity of the leaks until you do some cleanup and more observations.    Absolute worst case is that the tank needs resealed, which is roughly $5k/tank and the few shop that are the ususal go-to places seem to be about six+ months out on booking.   I'd make a wag that based solely on the pics you likely don't need a reseal, just a patch or two, or, hopefully, some love around the sump.

 

[Mooney Dog]

4 hours ago, toto said:

 New paint, new avionics, and a new prop for 20k? Sign me up

 

More like touch up paint, 30k in avionics that was planned, and an overhaul of the prop that turned into a new prop, plus an additional 20k. 

 

7 hours ago, RobertGary1 said:

Repairing a fuel tank is normal for wet wings. A full reseal each time you get a small leak isn’t necessary at all. 

When i hear leak on airplane that hasnt flown since the 90s after an accident, i think big leak. 

[carusoam]

Oops…

My mind turned off when writing about the brown stains…. They are time telling…

This plane has been unloved for some time….

A pilot can change out a fuel sump in about a minute…. The fuel sump in this plane has been leaking a lot, for some time… enough to turn it brown…

But…  a leaking fuel sump is an external leak… an easy clean and replace kind of activity… why did it not get replaced?

Big question… what’s inside the fuel sump keeping it from closing…?  It’s a spring loaded plunger with a rubber seal… does it have dirt or rust inside of it?

If you look at the wing drain holes… that’s fuel leaking inside the wing and getting to the drain hole… much tougher to find and fix…  much more important from a safety point of view…

The missing exhaust hanger is just another disappointment…. They are low cost bits and pieces that didn’t get replaced when it broke… the unsupported exhaust system can get expensive to fix because it simply wasn’t supported properly…

Old planes are great to have…. Their maintenance costs are very similar to new planes…

Keep up with the detailed search… write down each observation… they are easier to discuss when they belong to the other guy…. 

Looks like an oil drip on the exhaust pipe…  see where that is coming from…  it might be asking for new seals just above it…

Looks like there may be some fresh paint in there as well…  did it get loved once?

PP thoughts only…

Best regards,

-a-

[ZuluZulu]

5 hours ago, M20Doc said:

Mooney firewall material is very thin and as a result frequently have small cracks.  However this damage looks like leftovers from the mentioned accident.  The good thing is it looks like it’s below the floor level and is accessible by removing the exhaust fairing.

On the fuel leaks, acetone removes much of the old staining from the paint.  Clean it up well, refill the tanks to the brim and look for fuel leaking out after letting it sit over night.  A Lance pointed out from the manual page some leaks are allowed, but leaks in confined or closed areas are not.  That being said the price should reflect this maintenance expense.

From the last picture, the tailpipe support clamp and strap are missing.

Clarence

Related question: how frequently should a slow leak be cleaned off?  Can fuel damage the body and/or the paint?

[carusoam]

Looks like a project that might not be finished yet…(?)

1) Look close at the pics of the trailing edge… those are remnants of the fuel leak getting that far before evaporating… each rivet is working like a wick to evaporate fuel around it…

2) Have a look inside the cowl… the engine mount has been repainted from the original black it probably was born with… but there is some missing paint there as well…

3) Nice pics… very clear….  

4) Find a similar Mooney and see what the differences are to this one….

5) Check the logs to see what they say was done…

6) Is this a new ground wire? Did the old one wear the paint off the engine mount? Is that drill shavings? 

7) See if you recognize what I, II, III, IV are referring to… V would be the missing clamp… VI, the oil drip…

I most likely have exaggerated what is going on in the pics… my observation and writing skills are a bit limited… I’m working on them still.

Best regards,

-a-

[EricJ]

1 hour ago, ZuluZulu said:

Related question: how frequently should a slow leak be cleaned off?  Can fuel damage the body and/or the paint?

The longer it gets left on the harder it can be to clean off.   The more aggressive the chemical used to take it off, if it's been on a long time, the more damage it may do to the top finish (polish, wax), but unlikely to damage the base paint and finish unless one gets overly aggressive.   Moderate application of mineral spirits will usually get recent blue stains off, but if it gets too crusty you might need acetone or MEK, which is more aggressive on the finish as well especially if it stays on too long or too much is applied. 

So I think staying ahead of it and not letting it go too long is a good idea, imho.

[Yetti]

Who ever repaired this sucks at fixing things.  A hammer and dolly would straighten up the firewall Doc mentioned that is easy to access.   There is a fuel hose without a fire sleeve.   The exhaust is way too close to the bend in the firewall which is why they left the clamp off.  That clamp is really important.

I normally say to have 10K in the bank after the purchase.   I would say have 20K in the bank for this one.   There is going to be lots of things to fix.   If you know how to wrench on things that might be fun for you.   If you want a turn key flying machine, might was to move along.

There is supposed to be a grounding strap up top of the firewall there.  Someone is trying to solve some electrical issues with that throwdown ground wire.

[chriscalandro]

17 minutes ago, Yetti said:

Who ever repaired this sucks at fixing things.  A hammer and dolly would straighten up the firewall Doc mentioned that is easy to access.   There is a fuel hose without a fire sleeve.   The exhaust is way too close to the bend in the firewall which is why they left the clamp off.  That clamp is really important.

I normally say to have 10K in the bank after the purchase.   I would say have 20K in the bank for this one.   There is going to be lots of things to fix.   If you know how to wrench on things that might be fun for you.   If you want a turn key flying machine, might was to move along.

There is supposed to be a grounding strap up top of the firewall there.  Someone is trying to solve some electrical issues with that throwdown ground wire.

Fire sleeve isn’t required (although it’s nice to have)

 

that ground wire could be a number of things but looks alternator ground sized, not a problem. 
 

there is a missing piece of scat (maybe 100$ worth) that is secured using “1 ,2 and 3”. Not a big deal and a 10 minute fix.