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Cummins ISM02 oil leak

June 16, 2015, 01:14:31 am

When we arrived in Orlando, I noticed a very small oil leak. A few stains were on the Jeep and there were a few stains on rear hatch fins.  Opened the rear hatch and it appears on of the accessory drive shaft seals are leaking.  The leak is minimal.  Has anyone had these seals replaced?

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Re: Cummins ISM02 oil leak

Reply #1 – June 16, 2015, 06:58:50 am

The alternator / water pump accessory drive shaft on my M11 is leaking a small amount also.  The local Cummins expert says that changing the seal is not a problem, but that the bushing behind the seal is probably worn and will need replacing as well.  He says the wear is normally caused by the alternator belt being over tight.  He also said to leave it alone until it starts to slobber bad enough to warrant doing it.  I haven't gotten the price yet for the work, but will take several hours.

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Re: Cummins ISM02 oil leak

Reply #2 – June 16, 2015, 07:37:58 am

Might have them do the water pump when they open it up too. 

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Re: Cummins ISM02 oil leak

Reply #3 – June 18, 2015, 08:16:45 pm

Keep in mind that 99.999% of the ISM Cummins engines are in trucks that (typically) have many Xs the miles of a MH.
As for that bushing needing to be replaced.. I doubt it. 

A seal that runs without being a touch wet is not going to last. 
One that isn't dribbling too much lube, would be better off being ignored.
Wipe the area down and enjoy.  pc

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Re: Cummins ISM02 oil leak

Reply #4 – June 19, 2015, 12:44:45 am

I replaced mine. It's an easy job if you follow the service manual procedure and have a decent puller. I paid the one time fee to Cummins years ago for access to QuickServe which gives you access to service manuals and lots of info. Seems like it was $100 but that was 6-7 years ago, money well spent if you work on your engine.

The bolt was really tight, I used an impact to remove it. I didn't have the pulley install tool but was able to lightly tap the pulley on far enough for the bolt threads to grab, without the washer. Once the pulley was pulled on far enough I removed the bolt and installed the washer. I read about this on a truck site and it worked just fine. I had no way to properly torque it so I used an impact that is supposed to have around the right amount of torque, don't pound away with an impact it can do damage. Torque was 398 ft lbs.

There are two types of pulley/shaft fits. One is a slip fit (no puller required) the other is an interference fit. Mine was interference and I bet your's is also.

----Shop Manual
Do not use lubricant to install the seal. The oil seal must be installed with the lip of the seal and the shaft clean and dry.

The yellow dust lip of the seal must be facing out.
Apply a coating of thread sealant, Part Number 3823494, to the mounting capscrews.

Install the clamping ring and five capscrews.

Tighten the capscrews in a star pattern in two steps.

Torque Value:
7 n.m    [62 in-lb]
20 n.m    [177 in-lb]
NOTE: The accessory drive pulley has a dust seal on the engine side of the pulley.
--- End

Use the installation sleeve provided with the new seal to install the new seal.
I don't remember the term they used for the seal, something like integrated seal. If it gets messed up in any way, during the install, trash it and get another. The seal has a plastic liner that helps guide it on the shaft. This installation sleeve (plastic) stays in the seal until it's in place on the shaft then pull the sleeve off the shaft. The crank seal is similar. If you're replaced seals before it shouldn't be a problem.

There is no oil pressure in the gear case, the oil just splashes around. The seals shouldn't leak.

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Re: Cummins ISM02 oil leak

Reply #5 – June 19, 2015, 02:12:47 am

I am not overly surprised I have a leak.  This coach only had 27,000 miles in 10 years when I bought it.  I think it sat in a garage for the last several years.  Now that I am using it, it starts leaking. I likely will have all the seals changed when I get back to Houston.

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