Annual Help (alternator and brake line)

[billsheila]

Guys;
N2131X is in for annual and a few items cropping up. Need some advice.
1) rear alternator. Mechanic says seal is shot. He took it out and is scratching his head on how to change the seal, having never before taken a skymaster alternator apart. Next idea is to send it to a specialist shop to have the seal done and alternator checked and cleaned (of oil) at the same time. He says "brushes don't look good". As far as I know this alt was changed when engine was changed by prior owner (only about 250 hours). What do you think I should do? I was thinking to send it to the shop but make sure they will "repair on condition" the alt and not just do a full rebuild for nothing. What do you think of bad looking brushes at 250 hours? Note my plane is a 1965 will the (only) 30 amp alternators.

2) brake line swivel joints. Seems I may have one bad swivel joint, but he is still diagnosing. I know I have read prior posts on this either here or on CPA website, but I can't seem to find them. My recollection is that they can be rebuilt, but then I also recall some folks saying don't bother...but new ones are Cessna crazy prices. If someone has more information on these or can point me to prior posts, I would really appreciate the help.

Thanks in advance for any help provided.
Bill Taylor

[Ernie Martin]

Some (most?) of the alternators are Ford units used in other non-aircraft applications. I know of someone who simply takes it to the local automotive generator/starter shop and has it rebuilt for a song.

Can't help on the swivel joints, but if Cessna price is high and you have the part number, try surplus suppliers; I list three in the "Purchasing Parts" page of my "backup" website at www.SkymasterUS.com (pink box near the bottom).

Ernie

[jchronic]

Can't offer any advice on the alternator, but my plane had a leaky brake swivel fitting. Not sure they can be rebuilt (i.e. new 'O'rings); a very competent mechanic in my local shop tried to take it apart for a rebuild and destroyed it trying to disassemble the thing. Not his fault; I was watching him and couldn't see anything he could have done differently. Fortunately, I was able to find one on a junker in the area.

Are you sure the leak is internal to the fitting, or could it be where it attaches to the bulkhead? If so, that's an easy fix...happened to me on the other side shortly after replacing that fitting. The brake went flat on landing rollout - just an 'O' ring replacement.

Joe

[John Hoffman]

Bill - There was a post/replies within the last month on the CPA (Cessna Pilots Association) forum. It was a 210 that had leaking swivel joints - sounds like what you are dealing with and hopefully 210s and 337s have the same joints. Search "swivel".There is a series of replies with info re. repair of the joint by removing roll pins and replacing a teflon backing ring which seemed to be reuseable and an O-ring which is the leaker. Being computer challenged I dont know how to forward it to you but hopefully you have some connection someone who loggs in to CPA. The poster of that thread reported that he had "fixed" the problem without going into detail.

[Skymaster337B]

The only thing those swivels need is a new o-ring. Taking it apart is easy too, small drift pin to knock out the roll pins. Then remove and replace the o-ring. But you do have to remove the swivel from the aircraft and put it in a vise to knock out the roll pins. I did this with my 337 7 years ago and it still working just fine.

[billsheila]

Thanks for the replies guys. I spoke to Don Nieser and for $250 he will exchange the swivel. He says they can be difficult to do, but his shop seems to have it figured out. So now the only questions is whether to see if my mechanic wants to try to tackle it or simple buy it from Don. I was considering doing both, because I likely have the same age (46 year old) seals in both of them, so it would seem like the time to do them.

Re the alternator issue, I am getting more confused the more information I get. So please forgive the long drawn out additional questions:
1) The alternator was working before the annual. The issue is an apparent oil leak. A&P thinks it is a seal. I looked up an old (more on that later) exploded view of the ALM5103 alternator...I don't see a seal. Any ideas on the oil leak theory?
2) The accessory repair shops I call are all claiming "no go" on the ALM5103 alternator, they say "obsolete" can't get repair parts any longer. One shop told me it is superceded only by a contintental part number TCM #633962, which is a 38 AMP alternator.
3) Re point #2 above, does this mean I have to buy a new alternator from Continental as the only fix here. I have read the story on the drive couplings and am told to avoid the "new and improved" version that fail easily and are hugely expensive (Cessna Pilots Association have a tech bulletin on that). I am wondering if I do have to buy new from TCM for the alternator if I can still use the older style drive coupling?
4) Lastly, as a pretty high wear item, I am thinking that others must have run into this in the recent past with a bad alternator so am writing to see if other members have any suggestions on this alternator situation.

Many thanks
Bill

[skymstr02]

The alternator shaft seal is number one on the list:

http://www.hartzellenginetech.com/ap...ear_Driven.pdf


Your mechanic should be able to obtain this seal from any one of his regular distributors like Aviall.

[Aeromx]

Bill,

On your brake line swivel.......I'm the mechanic that worked on Jchronic's ship and he had the description of of what we did a bit off. Never having taken the swivel fitting apart before (new or rebuilt from D. Nieser very $$) I did break the fitting. However, after breaking it I studied it and realized that besides the two roll pins there is also a internal circlip "c" retainer ring around the swivel "ball" holding it together. Once I figured that out I got another fitting off a junker 337, disassembled it properly, replaced the swivel O-ring with a new MS29513-010 & reassembled. Leak check & test OK. Has been in service for 100+ hrs on Joe's ship with not leaks. We just did the other fitting in the same matter in Feb. Keep in mind this not an "approved" repair as legally all you can do is replace the whole fitting as no maintenance info or parts breakdown (ie the o-ring #) is given by Cessna.

- Aeromx/Tim

[billsheila]

Thanks very much for this reply. At first my mechanics said they didn't want to get into repair (they gave it a quick try), so I started to head down the path of buying from Don. He actually shipped me two used units he had serviced, but in the meantime my mechanics had gone at mine and replaced the o-rings. Don graciously agreed to take them back from me and put them on the shelf for the next needy buyer! My mechanics did not mention the clip you describe but did say "it was tricky". They leak tested them with brake pressure overnight and no issues, so I seem to be good to go. Many thanks for your reply though. Best regards. Bill Taylor