Alternator Seal 50DN

[mikedee]

I arrived at the Winter Rally in Vegas only to find a coat of oil in my engine compartment from a faulty alternator seal. Thank to Kevin Erion and his parts truck we got it fixed.

I talked with the group and found that the alternator seal was repaired buy a pretty large percentage of members, some more than once. This put me on the path for a better solution and I may have found one,

http://cgi.ebay.com/ebaymotors/Kirks-50DN-Alternator-Oil-Seal-Plate-Kit-K-5015_W0QQcmdZViewItemQQhashZitem2557210190QQitemZ1 60375570832QQptZMotorsQ5fCarQ5fTruckQ5fPartsQ5fAcc essories#ht_731wt_941

I ordered a couple seals form this company and sent one to Kevin for review, we both think they are quality and might be a better solution. Best of all they are $24 cheaper.

[GDeen]

Looks like a good part to have in stock on the buss....how big a deal is changing the plate and seal out?

[Jon Wehrenberg]

Don't overlook this company. I bought the entire alternator from them thinking I was buying a knock-off because the entire alternator was as cheap as the cost to rebuild my old one. It not only was not a knockoff, but the real deal with the Delco castings, they did not even want my old core.

I haven't priced their repair parts or kits, but if they are proportional to their new alternator cost they will be very inexpensive.

http://www.elreg.com/category/83.aspx

[Kevin Erion]

The seal kit that Mike sent is a better than stock part. To add to Jon's story I ended up with a brand new 50DN from Elreg. I found that when I was almost done with the order, the salesman pointed out the updated version. What was the change........the front seal area! I now have the updated 50DN on the bus, the original 50DN that I took apart, installed new o-rings and the improved front seal kit I got from Mike, in the back of the parts truck it is! Maybe now I will never have another oil leak, from that area of the motor anyway. I did have fun taking the old one apart and would not think twice about taking one apart again. It's nice when you know if you don't like the way it goes back together, just chuck it!

[mikedee]

I have a year on the aftermarket seal and not a drop of oil. I was installing a front new seal every year. If you have the original seal I would upgrade when it goes bad. The aftermarket is $40, OEM is over $60.

[AmeriStar]

Our company has searched for a solution for the 50dn seal problem for a long time. We have found that the Kirks Automotive replacement is by far the best available. Check their website = www.kirksauto.com for many bus related electrical parts.

[Jerry Winchester]

Kevin,

That is exactly the seal I got from Kevin Erion. I think he bought several of them from Kirk's. It was easy to install and finally ended my oil leak on the alternator.

[phorner]

An interesting note.... my alternator leaks very slightly from the rear, not the front. I thought that perhaps it was the oil tube leaking but it isn't. Apparently this is normally addressed as part of an alternator re-build and is not commonly repaired alone.

It really is more of an oil weep than a leak and is more a nuisance than anything else.

So far, it's easier to clean up a little oil staining than pull the alternator.....

[treedoc]

Paul Could it be that your alternator is trying to tell you something.......like a water pump does?

[joelselman]

Paul: 50DN on my sister Liberty began leaking at about 125K from one of the bolts on the center perimeter and failed totally shortly thereafter both electrically and severe oil leak. Replaced it with a unit with the updated front end cover and seal which started leaking within 6 months from the end seal and was then replaced with an old style end plate reman. At the same time, we upgraded the upper oil return line to larger diameter as on later applications. Still ok but only about 5K on this one. If I have problems soon, I'm inclined to go the air cooled conversion route.

[Charles Spera]

I've a leak back there. Is this the alternator I have on my bus? If so, I probably have a repair job coming up. Thx

[mike kerley]

Chuck, do you have an 8V92?

[GDeen]

So my question is does a small leak or seep as Paul described mean that one just needs to change the seal as described with the new kit or, does it indicate a bigger potential problem with the alternator?

[Kevin Erion]

Gordon, if you are talking about just behind the pully, just replace the seal.

[Charles Spera]

Chuck, do you have an 8V92?

Yes, Mike, I do.

Since my posting I went down to Kirk's (they're here in Detroit) and picked up a new cover for the off-drive end. It is a die cast part that uses an o-ring instead of the stock plate with a paper gasket. Although is was a bit of a reach to get to it, the install was easy and so far it doesn't seem to be leaking.

[GDeen]

Gordon, if you are talking about just behind the pully, just replace the seal.

Thanks Kevin. Have one on order.

[BrianE]

Our pulley seal had been damp for about a year. Recently the alt. started leaking from the rear and shortly after that the voltage started to spike. Ordered and installed a new Elreg unit for $975 including freight. Spoke at length with Mark, tech support guy at Elreg, he indicated that if leaks continue there is a chance of internal oil damage causing shorts, etc. He suggested replacing seals at the first sign of leakage. He also said that the latest "improved" seals have started leaking leading to a recent Delco Remy upgrade. Upgrades are on extended back-order status.

[Jon Wehrenberg]

Brian,

The reason the alternator leaks oil is because it is full of oil when the engine is running. Maybe not exactly full, but it getting oil pumped into it under pressure and the oil is essential for cooling as well as lubricating the bearings. It drains via gravity through the big hose on the bottom back into the oil pan on the engine.

So I question what exactly is meant by internal oil damage causing shorts. If the seals leak at the driven shaft end or the back plate to me it just means the end result is a dirty alternator. The oil internally is engine oil which is circulated through the alternator and none of the internal alternator components are adversely affected by leaks at the seals.

Is Mark sure of what he is saying?

[GDeen]

I spoke with Mark this morning. He was the tech I got when I called Elreg about the alternator and my options.

What he told me was that if the voltage wasn't spiking, he wouldn't worry about it. Said they have many fleets with the oil cooled 50DN's which leak all the time. The operators have problems with their own regs, or on the over the road coaches, the DOT who doesn't like oil leaking. He said many of the city fleets don't worry about it. For the others, they are chasing the best seal(s) system possible, or choking up the 50% premium for the air cooled version.

I pressed him for evidence that any oil leaks could be symptomatic of impending failure and he wouldn't bite. Just said to figure out where it is coming from and fix it (shaft seals, back cover seal, relay terminals, etc). For a guy who sells them, I gave him every opportunity to sell me a new one.

That is the story I got from Mark. Now, Brian (and you) know way more about these things than I ever will, so I still worry about impending doom with my alternator - particularly after reading Brian's story above. But for now, I am going to cure the leak and roll with it.

[Jon Wehrenberg]

Gordon.

Our alternators like anything mechanical can fail partially or wholly at any time. It could be caused by bad diodes, windings, etc. There is no preventive maintenance for an alternator that I know of that can prevent a failure or extend the alternator life other than making sure oil is circulated.

The biggest enemy of our alternators is heat which is why oil circulates through it.

Heat is generated by increasing the output which is why I am a strong advocate of running AC units powered by the generator rather than through inverters. A 270 amp 50DN alternator is being pushed to the limits on output when two AC units are run through the inverters and other normal loads such as the refrigerator and TV are also drawing power while driving. Turn on the lights on the coach along with driver's air and try to charge a set of marginal chassis betteries and the alternator is screaming for relief.

Curing leaks is not going to make the alternator work better, but it will make your bus nicer to service and make it look a whole lot better. I have an Elrig alternator (I think I was the first POG member to buy one) and so far except for a bit of smudge behind the pulley the alternator is clean and dry. The back plate with the O ring type seal is a vast improvement over the old style flat gasket.