Mysteries of the Oberdorfer - Seal Replacement - REBUILDING A PUMP w/Flix

[Clay Greene]

So, I managed to get the old seals out and now am looking at getting the new seals in.  Looks like a very tight fit (not surprisingly, given that it is a seal).  Any trick to doing so without damaging them in the process other than a good coating of oil and an attempt to apply even pressure?  Thanks.  

[added Seal Replacement & w/Flix to title - Stu  1/19/12]

[Ken Juul]

The key is even pressure all the way around the seal.  Set the seal in the bore, using a piece of wood bigger than the seal as a "punch" tap it in with a hammer.  Once it is flush with the case, if it needs to go in further, use a socket or piece of pipe that just fits into the bore to finish the job.  You want the pressure to be near the outside edge of the seal not the center so you don't dish the seal which might make it less effective.

[Clay Greene]

Many thanks, Ken.  I'll give it a go. 

[Ron Hill]

Clay : I've written a couple of Mainsheet articles on your very question.

Anyway, take some grease and coat it on the inside of the pump.  Then make sure that the seal is set in correctly (I believe that the writing goes toward the center = weep holes). Then take a deep well socket just slightly smaller than the inside of the pump and start pressing or tapping it in.  The first seal is the oil seal so it goes in first and just past the weep holes and as Ken said make sure it's even and not cocked.
Then take the water seal and do the same, stopping just before the weep holes (again make sure the seal is not backwards).

Hope this helps. 

[Tom Soko]

Clay,
Rather than using a hammer to tap in the seals, you might try using a bench vice.  You can apply even, controlled pressure.  Using a socket as others have mentioned will allow you to precisely position the seal where you want it.

[Stu Jackson]

Thanks to you, Ron Hill and his May 2002 rebuild article, the Sailnet discussion, and a fine Sunday afternoon.

In 1999, when our new-to-us boat's raw water pump started leaking, I went to the local Universal dealer, who said: "It'll cost more to rebuild your pump than to buy a new one."

Being A NEWBIE, I did.  Actually, it was a pretty neat deal:  $176 + tax in 1999 $$s, and all it took was four nuts on the studs to remove the pump and replace it.

Recently, I've seen evidence of leaks (see the Critical Upgrades sticky topic for "checking your engine").

Time for a costly new pump?  

Wait!!!  I'd read about rebuilding a pump.  I read Ron's Tech Notes article, and then literally stumbled across the linked Sailnet discussion.

I bought the Allen wrench, and with the help of a neighbor's grinder, cut it down and got to work.

It was SCARY at first, whacking the pump's innards, but once I realized that the pump is like a tank and the seals are simple replacement parts that can get knocked out, removed and replaced, it became much easier.

Using a pair of needle nosed vice grips makes holding the wrench pretty easy, if not necessary.

The idea from Sailnet about the 12P nail worked, too, 'cuz the Ron Hill tool may be too thick to get between the carbon bushing and the water seal.

Sweet feeling when the old ones came out.

Easy to get the new ones back in with a piece of wood and a socket.

Another helpful link that links back here:  http://www.sailnet.com/forums/diesel-engine-forum/60992-rebuilding-oberdorfer-pump.html

This link is important because it shows the tool that Ron Hill built to get the old seals out (1/4 inch hex head Allen wrench ground down to fit).  second picture, link to Ron's article:  http://www.c34.org/mainsheet/pdf/May_2002.pdf

The C34 Tech wiki also has that article:  http://www.c34.org/wiki/index.php?title=Raw_water_pump,_impellers_and_cooling_system

[Stu Jackson]

Cleaner - planned to use on engine, but too messy - good to learn on a small piece

This is the impeller on the shaft with the MALE end.  This end fits easily into the engine end, unlike the older female end fitting on the shaft.  The trick is to continue to rotate the new shaft until it sits firmly inside the engine and the impeller blades go all the way into the pump.

The two different sides of the new seals.  Writing faces IN.

[Stu Jackson]

The first seal going in, writing facing up, next one writing faces down.

Added to Tech wiki, Engines

There's also a Tech wiki on this, link added there, too

http://www.c34.org/wiki/index.php?title=Raw_water_pump,_impellers_and_cooling_system

[prh77]

Just bought a new Oberdorfer from Depco for $230. Do not know what rebuild parts add up to, but if you have to replace the shaft or cam,$ might be close to new. New style cover plate has an O ring, no more overpriced gaskets. Now I carry the old pump as a spare.

[Stu Jackson]

Peyton, you're right, parts cost.

Here's the price list from Torreson

http://www.marinedieseldirect.com/catalogs/catalog_group.php?owner=mdd&page_ident=200142-56&model=M-25%20/%20M-25XP%20/%20M-25XPA&manufacturer=Universal&title=Sherwood%20Water%20Pump%20-%20300986&quant_position=&catalog=200142&printparts=200142&printservice=200151&printoperators=200157&comment1=

I had the seals which I'd bought many years ago.  They cost $20 bucks now and the shaft was fine.

[Ron Hill]

Guys : NEVER NEVER buy Oberdorfer parts from any one other than DEPCO (800-445-1656).  

www.depcopump.com

You might as well light your cigars with $20 bills!!

added link to Depco website - Stu

[Stu Jackson]

Here's another good link from Maine Sail

http://www.pbase.com/mainecruising/raw_water_pump

Different kinda pump, but the same concepts.  We don't have to bang out our shafts!   

[Stu Jackson]

In some of the OLD literature for M25 engines, there was a discussion that said, essentially, "If you pull out the shaft, you WILL have to remove the pump to reinsert the shaft."

That was because there was a female end on the shaft and a male end on the engine side.

The "newer" (mine's a 1986) Oberdorfer pumps have male end on the shaft and a female end on the engine side.

This makes pulling the shaft and replacing the impeller a SIMPLE job WITHOUT having to take the pump body off the engine.

Here's a picture of the INSIDE of the engine with the female end.  Match that with the picture of the shaft in the earlier posts and you'll see how easy it is.  Make sure the impeller is ALL THE WAY in the pump, or else you won't be able to put the faceplate on.  How do you know if it's in all the way?  Read the last sentence.     In my case, I wondered about it, then just kept turning the shaft until it slid in all the way.

This picture was taken with the pump off to be able to show the inside end of the engine.

OBERDORFER PUMP MODELS

There are two you can choose from: the N 202M-15, which has an O ring on the faceplate and a reversible faceplate, or the standard 202M-15 which uses a paper gasket for the faceplate with only one "inside" face on the faceplate. We have the 202M-15 in this topic.

"Crud" on the Aluminum Timing Belt Cover Above the Pump

Please note the "giveaway" scaling above and around the pump.  While I don't think the seals were the cause of this, because there was no distinct weeping, it appears that the paper gasket between the pump and the engine had deteriorated and the salt water was "creeping" all around the pump.  I'm going to clean that up and repaint.

For repainting engines, see "Engine Paint" here:  http://c34.org/bbs/index.php/topic,4600.0.html

[KWKloeber]

In some of the OLD literature for M25 engines, there was a discussion that said, essentially, "If you pull out the shaft, you WILL have to remove the pump to reinsert the shaft."

That was because there was a female end on the shaft and a male end on the engine side.

The "newer" (mine's a 1986) Oberdorfer pumps have male end on the shaft and a female end on the engine side.

This makes pulling the shaft and replacing the impeller a SIMPLE job WITHOUT having to take the pump body off the engine.

Let me clarify about the male/female thing.  Some of the early engines had Oberdorfer 202M-07 or 202M-03 pumps, both of which which have a FEMALE (fork-ended) shaft.   The camshaft on the engines were ALL FEMALE (as in Stu's picture below).  Thus, using these pumps, Universal added a female-to-male adapter in order to mate the female pump shaft to the female camshaft.  If one pulls the pump shaft out, the adapter falls off the shaft and remained inside the engine (it won't fit through the pump body.)  When reinserting the shaft,  it's nearly impossible to line up the shaft/adapter inside the engine.

The adapter for the 202M-07/03 pumps is explained here:
http://www.c34.org/wiki/index.php?title=Why_do_some_of_our_engines_have_different_Oberdorfer_sea_water_pumps_than_others,_and_what_about_that_cir-clip_%22holding_the_impeller_on%22%3F

kk

[Stu Jackson]

I'm back at it again.

This time the oil seal let go and splattered the starboard side of the engine.

Got the seals out and cleaned up much of the mess today.

I used this thread and Ron Hill's excellent May 2002 Mainsheet writeup yet again, even found an old 2012 printout of it in my raw water pump collection in the box from my 1999 new pump.

Bought Aquavite in 1998, new pump (mentioned earlier) at, say, 1200 hours.  First rebuild at 2581 which is 1380 hours of use.  I installed the new seals in 2012 and now have 3391 hours or 810 hours on those seals.

That 12P nail is really necessary, not just useful, unless your "Ron Hill Tool" is really short and sharp.  It won't be able to get between the carbon bushing and the inner seal.  The edge of the nail can be wangled against the middle of the seal and you can whack the bottom part of it out first.  The picture shows the inner seal coming out.  I placed the head of the nail between the upper and lower rings of the seal, on the soft spot, and whacked the bottom part first.  The picture was taken after it started coming out and I'd turned the pump engine side up.  The first seal comes out pretty much intact if you use Ron's handy dandy tool.