The International Cessna^® 170 Association

Well I suppose it is true confession time After dragging this thing out for 6 weeks or so I put the dye in the oil and used a black light and guess what-----the leak isn't at the alternator flange after all That is the only place I could see oil, but the dye tells all. The oil was leaking by the lower left side of the tach drive housing by the stud. IA told me it might be warped and to sand the mating surface flat, which I did. Changed the oil filter, new oil, fired it up and d---, it leaked worse than before Thought I would pull the tach drive housing off without draining the oil (again!), but NO, alternator wouldn't let the tach drive housing go back far enough to come off. (OK George, you can rag on me for having an alternator--I probably deserve it.) Drained the oil one more time and loosened the 3 bolts on the alternator enough to let the tach housing come off. Checked it close (this time) and, you guessed it------the housing by the bolt hole was cracked. I should have seen it sooner, but didn't. So now I am awaiting a loner tach housing from member Steve Grimsley, who is overnighting me one. With a bit of good luck (I think maybe I'm due a little ) I hope to get Ole Pokey buttoned up Tuesday evening so Paul Wood and I can leave early Wed for Kelowna. Thanks to Steve I didn't have to order the needed part from a vendor. Yes the 170 assn has come to my aid multiple times. Those who don't feel they get anything from being a member better not try to convince me of that Steve is sending me a new garlock seal to put in the tach drive housing. Anyone know the 1-2-3 steps to remove the old garlock seal and install the new one

Don't feel too bad, after my B&C starter conversion I have now picked up a rather bad generator seal leak. I clean the floor each night but the next day there is a puddle of oil like you would expect from a radial. I can look up under the generator and see the oil drip hanging from the internal portion of the generator, dropping down on the oil filter adapter and then on to the floor. Don't know why the seal could not have failed BEFORE I had everything off for the starter work...would have been an easy fix then. But anyway, I see that there are two seals, one a traditional lip seal #352068 and a smaller O ring #AN123864. George, can you confirm these numbers? The generator seal was replaced (supposedly) by a shop in SAT in 2003, but I guess it just failed again. What is your best recommendation for a source for these seals or are there CR or National replacements that I can get at NAPA? One more thing....if I remember correctly, I can avoid draining the oil by raising the tail during the generator work

wa4jr wrote:... One more thing....if I remember correctly, I can avoid draining the oil by raising the tail during the generator work

A friend of mine did that recently, and proved it doesn't work. Ask someone with an O300-powered 172. You might have to raise the tail quite a bit above level. I keep an empty 2-1/2 gallon kerosene jug labeled "clean oil" for this purpose.

Best Regards,

John

John,
make sure the gen. seal was instlled corectly! I have seen them instlled backwards from reputible shops!
brad

Thanks for the info fellas I'll probably just fly another 15 hours to oil change and then do the work. I don't think the gen oil seal is known for catastrophic failure. I guess I'll call Niagra Air Parts...or the place down in KY that did the generator overhaul for the seals. Will be interesting to see the condition and orientation of the seal when I get it out. When I put lipped seals in, I always check three times before taking the block of wood and mallet in hand as it is easy indeed to get them in backwards of you rush things too much

Take the seal out and take it to NAPA or a bearing house and ask for a replacement by comparison. About 1/8th the cost!

blueldr wrote:Take the seal out and take it to NAPA or a bearing house and ask for a replacement by comparison. About 1/8th the cost!

I know you, Dick, and I know you are a clever and frugal guy... but the official AIRCRAFT part is only a couple of bucks and it's a lot of trouble to remove the generator, replace the seal, and re-install the generator (and the owner will have to order a real aircraft gasket anyway while he/she's at it,...so WHAT EXACTLY will they save when the cheap little NAPA part doesn't WORK??? Will it save the hourly fees of the anger-management counselor? No. Will it save the dog from a good kicking? No. Will it save the owner from losing their temper if NAPA gets it wrong and the automotive part does't work and completely stop the leak? No.
Hey, Friends..... save yourself a lot of time, trouble, and lost tempers and buy the OFFICIAL AIRCRAFT PART NUMBER FOR REPLACEMENT PARTS! (Not to mention the peace-of-mind of having done the RIGHT THING.)

George,
Chicago Rawhide and about two other manufacturers make all of the Garlock type seals in the US. Aint nobody making garlock seals for ancient aircraft generators for old airplanes exclusively. If they did, the damn things would cost a couple of hundred bucks each.

George

FYI NAPA will supply the SAME seal by manufactor name and number as you will get from an aircraft supply. Been there done that. I've also gotten them from a local bearing house.

The key is getting the right seal number. Once you have that it doen't matter where it comes from.

You most likely will have to order it from NAPA as I recall it's not one they usually stock.

BlueEldr and Bruce: My point is that if you use the TCM part number, NAPA won't know diddely about that, and will not have a cross-reference to that TCM number. Even if they did, the price difference is merely a couple of bucks.
Versus, simply contacting Aircraft Spruce with the correct part number and it arriving speedily, and being CORRECT with regards not only to fitment and purpose, but also with legality. Why go out of your way to be illegal for only a couple of bucks? (The genuine PN 352068 seal is only $6.60 from Spruce, and most O-rings are less than one-dollar. Those parts may be even less money from other genuine aircraft suppliers.)

You are right George and that is exactly what I did. Bought one from an aircraft supply house using the part number. I then bought 4 more of the exact same seal brand and brand part number. Two from NAPA and two from a local bearing house.

I know you not saying that a brand x seal, part number x bought at an aircraft supplier is more legal than one bought at NAPA or a bearing house.

The extra seals where given to a friend who placed them in his LARGE inventory of stuff. If he marked them as being specifically for the generator, in other words I can identify them with out question as being the right seals when I find them, I'll post the numbers here. It might take me a while to visit with him and find the seals so don't anybody wait for the info.

What were the price differences?
And while not trying to be argumentative,...and without knowing if any apply to these particular parts (other than O-rings which almost always have limits),... it's worth knowing that many gaskets/O-rings, etc, have shelf-life limitations when used for aviation purposes. I don't know any automotive suppliers of those parts that record or observe such limitations.

Indian err Uncle

What do you Texan's say when you give up

There was no big price difference unless you have to pay shipping and the seal is the only thing your buying.

As you say George to do the job your going to need a gasket so order one and the seal by part number from the aviation supplier. If you happen to mess up the seal or loose it while installing it you may be able to get one locally. It may be a little old though.

Wish I new how old the seals in the gasket set where that I rebuilt by C-145 and more recently my C-85 where. I'm going to loose sleep over this tonight I can tell

[quote]

Screw the price differance! Does the auto zone garlock, o-ring, bearing, ect, come with a 8130-3 form! I won't put them in an aircraft! I can get the same part number from federated (my local auto store) for voltage reglators, If any one still uses them, but they don't come with the paper work. So I don't install! You Know what you are talking about George!
I don't Know but the preview didn't show my quote's but I'm sending anway! can't think of a way to fix it!
brad

Careful there, Brad! The NAPA seal might be good for "ground test" purposes...

I truly don't mean to seem so disagreeable... I just usually need to keep my airplane operational until I have the part "in hand", then I can remove the leaking seal and install the correct one. I don't usually have the luxury of time, to down the airplane or bother with removal, take it to NAPA, let the auto parts guy "guess" which autopart might be comparable, ...then go back home and hope the auto part will perform better than a genuine aircraft part that was failed and leaking. (An unlikely scenario at best.)
Usually the reason most folks are endeared to auto parts that can mimic aircraft parts is their pleasure at a $aving$ that is meaningful. I don't agree with that when there is a legality/traceability problem AND there's no real savings!
There are certainly comparable materials in automotive/marine/aviation common useage. Some examples might be bulk gasket materials made of cork, or fibre... Or gasket sealing compound such as Permatex (which although the packaging states "Aviation Permatex"...actually carries no other indication that it meets any aviation grading system whatsoever.)
These are the sort of things that involve a smidgeon of good ol' common sense. I'd never worry about using an automotive Shrader valve in an inner tube on my Cessna 170 .... but I'd certainly never do it on a high performance aircraft, or on a high-pressure application such as an oleo nitrogen-fitting.
But the standard I try to make and support is the one that, even tho' we might not like the price.... aviation parts are better manufacturing quality, better identification, and better storage (which keeps them in better condition for installation and recordkeeping) than the local autoparts store ever thought of.
I can be easiliy criticized for violating my own public high-standards in my private world of ownership of N146YS. Anyone who knows me and my airplane knows it has an automotive back-up lightbulb in it's aft nav light fixture. (It's a GE-5606.) Not because it's cheaper, because it's not. It costs about the same as the Cessna-specified GE-93 (which also happens to be automotive.) The reason I violate my own rule about this matter is because the 5606 bulb puts out more light due to it's higher candlepower. (But it is well below the amperage rating of the wiring and CB in that circuit.)
I also use automotive (well, marine actually) grease in my wheel bearings....rather than aviation Mil-spec Aeroshell 7, etc. ... because the boat-trailer wheel bearing grease is designed for a more challenging purpose, and the Cessna Service manual allows "any high-quality, brand-name" grease for the purpose. I'm absolutely positive that the green, waterproof marine wheelbearing grease that has kept my boat trailer wheels smoothly running since 1986 without a re-packing or cleaning, despite those wheels/bearings being subjected regularly to being plunged below the water and then run at highway speeds for hundreds of miles without a single failure,... makes that grease quite serviceable for Cessna 170 aviation purposes.
I'm at risk for being intransigent on this subject of recommending aircraft parts for aircraft, while publicly admitting that I violate that rule myself from time to time in certain situations. I like to believe those particular situations are especially non-threatening to safety.
However, running the risk of publicly endorsing the use of automotive parts to another person, who might subsequently run the risk of dumping all his/her engine oil out the generator during flight (at night? ifr? over the lake?) in unknown conditions.... makes me pause and think about whether saving only a buck or two merits the risk of offering what is technically illegal and unsound advice to a fellow member who comes here seeking the best advice he can find...not necessarily the most expedient or that which puts a devious smile on his lips merely because it saves him two or three dollars by purchasing it from an unconventional source.
Philosophically...I endorse the use of only aviation products on airplanes.