Alternator Replacement

[Jon Wehrenberg]

It was too good to be true. At almost 214,000 miles my alternator finally has failed.

It is going to happen to all owners who start adding up miles and it has happened to me on my previous coach so it was not unexpected. This time I am going to break some new ground and I will report some findings. I will also document my replacement process for those who want to arm wrestle with their 50DN alternator (the big one) when the time comes.

I am already learning a lot and based on my previous experience I am not going the conventional route.

I have a 24 volt, 270 amp 50DN alternator with a splined shaft for a pulley. Those with an 8V92 use a geared shaft and I would not wish an alternator failure on anyone with the two cycle motor because those are mounted on the rear of the engine up above the transmission bell housing. To say they are tough to replace is an understatement.

Mine however sits to the right of the engine right behind the door. I checked prices and came up with the following. A local rebuild would run about $750. I have dealt with the shop in the past and know them to be reliable and good. Prevost wants $964 (delivered) for a remanufactured and they have a $550 core charge. You pay the return freight. A new 50DN is just under $1400 with no core required. ( http://www.ronthebusnut.com/detailDisp_1117863.html )

This company quoted on a 50DN and they were in the middle between my local shop and Prevost ( http://www.elreg.com/ )

But they also quoted on a brand new ELREG brand 50DN replacement for $763, and $65 freight. My guess is I have a brand new Chinese alternator heading my way.

Since my tires still hold air, and my replacement for the Briggs and Stratton motor on my log splitter works like a champ, I am not concerned at this time about my new alternator. I did not need to send my old one, so as time permits I am going to replace the defective part(s). I will not rebuild it, but will repair it. The economics dictate that I take a chance because I had a failure of the alternator on my first coach. The rebuilt alternator lasted 2 weeks, the second one never got put on the coach because it was binding when the shaft was rotated. The third one was a charm and lasted until we sold the coach. So as you can see the domestic answer is no assurance of better life or quality.

In the upcoming days I will remove the old alternator and get things ready to mount the new one in its place.

[Tully]

Jon:

I just had both my alternators replaced. I will get you the info on pricing and source.

I have a unique situation with my coach right now. Have a in-law of sorts who is letting me keep my coach inside / heated building. He is a mechanic.

He just replaced both 24 volt & 12 volt. Put a single drive belt that runs both.
I will post more info on this as well when I get some additional time.

I will be seeing him on Wednesday and post all the info.

Tully

[Jon Wehrenberg]

Completely different alternators. The 50DN is about 10" in diameter and weighs somewhere around 105 pounds.

[Tully]

Did not see that 105lbs. It is different...

Tully

[lonesome george]

Jon,
Just put my 50DN alternator back on the engine this afternoon, had it out for a clean-up and repaint. Lifting it back into it's saddle is a test of agilility, the thing is just awkward to handle.
George

[phorner]

Jon,

Sorry to hear of the demise of your 50DN. I thought for sure that I was in the same boat, but luckily a simple regulator replacement did the trick for me.

That rascal looks like a real challenge to lift out of the cradle. Maybe an engine lift would do the job?

Anyway, I'm looking forward to your posts, as this will be an important learning experience for many of us.

Wish I could be there to help.....

[Jon Wehrenberg]

My installation technique is unlikely to set the standard for sanity.

I have a 45 foot coach stuffed in a garage whose length was for the 40 foot coach we intended to keep. Since it has taken up 5 feet of space that was previously used for moving about comfortably with the rear doors open I anticipate only brute force and no finesse will be used for the actual lifting out of the alternator.

To get acclimated to the pain I anticipate, I believe I will spend the nights preceding the actual removal and replacement slamming my fingers in a car door, or listening to rap music.

The good news is I now have the opportunity to clean and polish the rear side of my 12 groove pulley.

[Jon Wehrenberg]

The alternator is out and the bus is ready for the new one. What I thought would be a more difficult job has turned out to be fairly easy. I started by getting things ready for the actual removal. This may vary from coach to coach because access is needed from the side door by the batteries.

The first step was to start removing anything in the way or attached to the alternator.

I removed the pulley first. It requires a 1 5/16 socket (not a common size) and an impact wrench works best. The pulley is splined and once the nut was removed a slight bit of levering on the back made it slide easily. I had used a penetrating oil.

[Jon Wehrenberg]

With the pulley removed I removed the air intake. That made access especially to the wires, cable and oil lines easier.

[Jon Wehrenberg]

The next step was to remove all the wires, the big cable, and the oil supply lines.

[Jon Wehrenberg]

Even though I had turned off the chassis battery switches and verified there was no power to the wires and cable I still insulated them just to prevent surprises.

[Jon Wehrenberg]

The oil return line under the alternator has to be removed. It takes a 1 1/2 inch wrench, but the fitting loosens easily. I should have also removed the fitting under the alternator because it is easier to do when the alternator is fixed in place rather than when it is loose sitting on a workbench. That fitting requires a 1 3/8 wrench, and it also is easy to remove.

Not shown are the four 1/2" bolts (3/4" socket) that secure the alternator to it's base. They were removed and the alternator was loose, ready to be removed.

[Jon Wehrenberg]

With the removal of the four mounting bolts the alternator is loose and ready to remove. The actual job took about 1.5 hours and now that I know which tools to grab, and I won't have to take photos, I can easily beat that time.

[Jon Wehrenberg]

To recap, I am now awaiting my new replacement alternator. The old one is removed and I will clean up and repaint everything that is greasy and unpainted so it will look good and be easier to work on the next time.

After the removal I now know if I have to service the air compressor or the sensors covered up by the alternator I will not hesitate to pull the alternator and probably the heavy cast iron alternator cradle. Doing that will just make access to the components covered up by the alternator and alternator cradle much easier. Before doing the job it seemed daunting, but in reality is is fairly easy with common tools except for that 1 5/16 socket to remove the pulley nut. (That happens to be the size I used to access and replace the differential seal on a Corvette)

I will document the installation, but I seriously doubt there will be any surprises. I intend to run oil through the new one before cranking the engine, and I am going to wire brush some of the areas with corrosion, but other than that I expect the re-installation to be the reverse of the removal process.

[phorner]

Great job with the posting, Jon.

You sure make it look easy. I'm making lots of notes....:)

[Joe Cannarozzi]

I did not know that there is 3 places oil enters. The fitting with the feed line up towards the pully must be specific to the pully driven ones. The gear driven one on our 8-V is getting oil to that point directly from the gear case.

I was still unaware of that other seperate additional fitting???????

[JIM CHALOUPKA]

Jon, nice picture posts on your project.

While your on it, and waiting around for the new one, if you don't already know, you might want to see where you stand on the larger oil return out of the alternator. I was told of such by the Prevo mechanic that installed my DDEC IV. He said on looking over my bus "oh good you have the upgraded oil return. They have found that the old way was retaining too much oil in the alternator." That's all I know about it.

JIM

[jack14r]

Jon,I have a question,is the oil for cooling the alternator or for lubricating the shaft bearings?

[Gary & Peggy Stevens]

Di, did a great job of taking these pictures? :)

Cause Jon, I know you wouldn't be able to handle a digital camera with all the oil, grease and what not on your hands while doing this kind of a job? :p :D

Great post, I hope I never need to refer to it! ;)

Gary S.

[Jon Wehrenberg]

Jack, I think the oil is both acting as lubricant and coolant, especially when the electrical loads are high which ramps up the temps. In the plane the oil also acts as a coolant. That is a guess.

Joe, I am almost certain the top oil line is a vent as I mentioned in the summary. The oil feeds from a single line which tees to feed the front and rear of the alternator.

Jim, I am not getting a Delco replacement. I am getting one to match my tires, likely made in China, just like my new log splitter engine which has the old Briggs and Stratton beat by a mile for both power and noise. I think my 1" ID hose is ample for return oil.

[rfoster]

Man oh Man Jon, I can't believe all the dirt I see on that engine.

[Jon Wehrenberg]

That's about 214,000 miles of dirt in a place impossible to see until the alternator comes out. Now that I know it collects there I have added periodic removal of the alternator to my maintenance schedule so I can clean and polish those inaccessible areas.

I also made note of the poor quality of the finish on the alternator and I will keep an eye on that as well, possibly copper plating the entire outer case so it will shine up and look pretty.

I'm going to check everyone else's engine now using a borescope and mirrors to see how well all of the POG members are doing at general housekeeping. I'm starting with yours, Roger.

[truk4u]

Good post Jon, I assume you will be rebuilding the old one for stock!;)

[Jon Wehrenberg]

Truk,

This is strictly a guess and will be confirmed when I open it up, but I suspect one of the diodes has puked or a brush has gone bad.

The way the gauges were fluctuating and the fact it was putting out around 25 to 27 volts depending on the load tells me it is going to be a simple repair. I will not rebuild it. I added up the prices of parts to restore it to new condition and they approach the cost of a rebuilt one, or the new one I have coming. The bearings are perfect with no noise or play.

[hobobimmer]

I also made note of the poor quality of the finish on the alternator and I will keep an eye on that as well, possibly copper plating the entire outer case so it will shine up and look pretty.

I'm going to check everyone else's engine now using a borescope and mirrors to see how well all of the POG members are doing at general housekeeping. I'm starting with yours, Roger.

Removal of and refinishing of the alternator was one of the first things Deb and I did to our bus when we got it from Loc. I gather from your post that others have not done this most important task. I greased the bearings, if it had any, and polished the alternator's ever important slack adjusters. I think you will find that, upon inspecting our unit, if we in fact have an alternator, it will be in very good condition, considering the conditions it is in.

eric faires
huntsville, TN

[rfoster]

Eric: I saw your alternator once, it looked good to me., or was it a compressor? Well anyway Deb sure is a good manager.

[JIM CHALOUPKA]

Jon, don't be too critical of the old alternator, at its end it was performing free of charge :rolleyes:


:DJIM

[phorner]

It must be 50DN alternator season :mad:

I noticed that mine has developed an oil leak......looks like the back cover is leaking. Is there a gasket behind the cover that can be replaced?

Does the alternator drain close to empty after engine shut down?

Comments/suggestions would be appreciated :)

[Kevin Erion]

Paul, if you are talking about behind the groved pulley, that is kind of common. Prevost has a kit that replaces the seal. the seal is attached to the outer casting the bolts to the end of the alternator with the small 10mm bolts.
The key to a successful job is to make sure when you install the new one that it is centered on the splined shaft. There is some float with the holes being a little larger than the bolts. There is no tool to center it, you just have to eyeball it when you tighten the bolts.
They sell a special tool but it is not for centering the seal. You might wonder how I know this, yes I have the special tool and I have done 2 of these seals on my 01. The second one is holding OK, I think about 10K miles now, the first one went about 4K before it started leaking again.
Have fun!

[Jon Wehrenberg]

If the leak is the back cover I think that has a seal. I will know when I take it apart. One thing I can answer is that it does not fully drain. I got quite a bit of oil from mine when I removed it, not from the bottom drain, but from the oil supply lines when the alternator was tipped sitting on the cart.

[phorner]

Thanks, guys. It's the small cover on the back, near the electrical connections.

I'll try snugging up the bolts, but I had considered removing the cover and replacing the gasket, if there was one.

If not, can simply I use a sealant between the cover and the base ?

[Joe Cannarozzi]

I replaced ours Paul. It is a CHEEP THIN cork gasket and if overtightened will crush the cork be careful.

My suggestion would be to buy a sheet of good gasket paper, not cork. and make one yourself.

A good shot or so of oil came out when I opened it up, beware.

[phorner]

Thanks, Joe.

I had a very slight weep of oil and I tried snugging up the bolts a while ago.

I probably damaged that cork gasket in the process, so it looks like a replacement is in my future since the leak is now more substantial.

If I just let it keep leaking, and just add oil when ncessary, does this count as an oil change ?:eek:?

[Jon Wehrenberg]

Paul, the gasket on my old one is not a gasket at all but a round seal. The cover is die cast.

If you do remove the cover to replace the gasket or seal there will be somewhere between a pint and a quart of oil so be prepared to catch it.

[Jon Wehrenberg]

When I opened the box with my new new alternator in it I was impressed with the quality. The fittings, the oil lines, the oil line cover all looked exactly like what was on my old alternator. When I got it out of the box and looked closely I could see why.

The iron end casting had the exact same number cast into it as the Delco I removed. Looking further I saw the word Delco on the rear cover. The sheet metal oil tube cover stamping is identical to the one on my old Delco. This new alternator which is as cheap as a rebuilt one is a Delco. Made in Canada, not China. Apparently someone owns the tooling and is now manufacturing these alternators.

[Jon Wehrenberg]

The installation went easy, and I did a few things that I hope make the installation more successful.

I installed the pulley initially without running the 1 5/16 nut down hard. It is a lock nut and will not loosen so it does not have to be driven home. When I ran the engine I let the pulley find its own position. The one I removed had the nut driven down hard. That pushed the pulley against the front alterator seal and made a slight dragging noise.

When I ran the engine and let the pulley slide along the splined shaft to its aligned position I then tightened the nut only until the nut and washer made contact with the pulley. That did not ram the pulley against the face of the seal, and it resulted in the pulley being true with respect to the path of the grooved belt.

I will verify if this is the best way to insure alignment, but as near as I can tell the belt runs true, and with the belt removed I can hear no signs of dragging or rubbing on the seal face.

[Jon Wehrenberg]

Installation of the oil supply, oil return and vent lines was simple and installing the wires and the cable was equally easy. Re-installation went very fast and there were no issues or surprises. A little over an hour was required and the hardest part was aligning the alternator with the four bottom mounting bolts.

They went in easily after I used a drift pin to align the alternator with the mounting holes. There is virtually no slop in the holes so the alternator is positioned exactly where the old one was.

Here are some more photos of the finished installation. Total cost $828.85 for the alternator, delivered, and a few minutes less than 3 hours of labor, a time I can easily beat the next time.

[Kevin Erion]

Jon, sorry if I missed the Co. that you made the purchase from. Could you pass that info on for future knowledge.
Thanks!

[phorner]

Wow, Jon, that's great!

Thanks for all the pictures. Great post!

[Jon Wehrenberg]

Here is the company I bought the alternator from.

http://www.elreg.com/

I forgot to mention the most important part........It works!

If you are going to do a replacement keep one very important piece of information in mind. The alternator is oil lubricated and cooled. Unless you have flooded the alternator with oil sufficiently before start up (you can jury rig a garden sprayer to push oil through it before connecting the oil supply line) run the engine at idle for at least 15 minutes. The key is to keep the alternator output below 100 amps until oil filled. According to the Delco performance chart the output will be less than 100 amps as long as coach RPM is at idle.

[dalej]

Great post Jon!

I'll bet you enjoyed every minute of it. It looks like a great, I did it myself and saved a bundle of cash jobs.

[Joe Cannarozzi]

Somewhere down the line they figured out the gasket we have on ours was crap and changed it. The rear cover plate in the picture is cast with a rubber seal, very nice.

Mine is a metal plate with a cork gasket, no good.

Dale if yours is original like ours you too have a plate and cork seal.

[rfoster]

Are you sure that is a 200,000 plus mile Liberty you took pictures of? It sure looks like new.

Looks great!

[Jon Wehrenberg]

This has been a good learning process, especially since there are components on the bus that are a bear to get at with the alternator in the way. If I have to remove or service the air compressor for example, or the sensor below the alternator and behind the compressor I know removal of the alternator is not a big deal.

I have not diagnosed the problem with the old alternator yet but I know I could have diagnosed and repaired it on the bus if the problem was a diode. There is a drain plug in the rear of the alternator to drain the diode housing (or to change cover gaskets, Paul). Once drained and with the cover removed the diode checks and replacement are easy.

Since mine was as old as it is I opted for new but if the bus were real low miles I would have popped the cover with it installed on the bus and run the checks. All parts and service kits are available. Here are two places where you can get parts:

http://www.elreg.com/

http://dixie-electric.com/catalog/9801-50DN-003.pdf

I am now seeking a direct replacement for my big Delco Remy regulator. I have found a couple of sources and will replace my old, but still working regulator just to complete the renewal of my charging circuit. The cost should be under $100. The Prevost cost for a new regulator is $272.86 and does not include labor to replace it.

[JIM KELLER]

Jon, Could that be the same Regulator I got in Sevierville that was incorrect for my Bus ? If so I have just what you need !

[phorner]

My replacement regulator came from this company, their part #D699.


http://www.transpo.de/Catalog/Browse.htm

[JIM CHALOUPKA]

Beautiful thing there Jon.

Just wondering, is the new alternator Taiwan China, or Main Land China, and the tires too?


:)JIM

[Jon Wehrenberg]

Jim C. look again at the photos, especially the ones that show the made in Canada label and the Delco name on the components. Even the main casting is the exact same as the old alternator because the same number is cast into it.

Jim K. I know the regulator Prevost is selling is different than the one I have, and it is actually a kit to deal with the extra connections. I am trying to find the original Delco Remy regulator and have two sources I am awaiting prices from.

[JIM CHALOUPKA]

Jon, I have poor internet where I am now and missed a whole page of posts and photos. Sorry for the dumb question! I was just going by what you said you had ordered.

JIM

[Jon Wehrenberg]

Jim C,

Understandible. When I got the quote and had a price that was $200 less for a brand new one, with no core charge compared to the Prevost price for a "remanufactured" one I was sure it would be a knockoff. I was very pleasantly surprised to see the Made In Canada label and the use of the exact same parts and castings that were on my old alternator.