Steps to test the lower unit for leak & lower unit removal

[Karla45]

I have some questions on testing lower unit for leaks by spraying soap and water on seals. First, I do not think the leak is coming from prop area since I am seeing the oil coming from weep holes only. So my question is do I have to take the prop off to remove the lower case? I will be spraying soap on seals to see if I can find the leak. When I first take the lower unit off do I need to spray the soap somehere before removing the water pump? Once I remove the water pump will I be able to see the other seals below it enough so that when I spray I can see the bubbles? Are there other areas that I should spray that have seals besides under the water pump? Also since I am not doing a pressure test do I still need to put in 10psi?

Jerry, you had mentioned that you would give me some tips on what to do. I have never removed the lower case so any advice or warnings would be appreciated. I decided against going in and replacing all of the seals since I have never taken a whole lower unit apart before. RIght now I just want to find where the leak is coming from and replace the seal or oring and maybe inspect and replace any bad seals I see.(What do i look for in order to know seal is bad besides cracking and tearing) I will also replace impeller but have not purchased yet. I plan on starting this weekend. I have a 1989 Force 85HP.

 

[fucawi]

Re: Steps to test the lower unit for leak & lower unit removal

Stop ..get more advice you have some very funny ideas about this job...weep holes ?? you do not have any in a lower unit what you are seeing is just unburnt oil from the silencer......when you take off the lower unit you will expose the water pump ...you dismantle it ..no lub ...you will not see any seals for the gearbox.

When you pressure test you pump it up ,lock it off and see if the gauge drops ..if it does then put in a bucket and look for bubbles. if there is no water in the oil (milky) then leave it alone .

 

[Karla45]

Re: Steps to test the lower unit for leak & lower unit removal

There is water in the oil have already verified. I called them weep holes because someone else told me that is what they are called, these holes are right next to the two different screws under the cavatation plate and there a 4 of these holes under cavitation plate. I have drained the oil and refilled. Wiped the case clean on several occasions and let time pass by then there will be two streams coming down the lower unit coming from these weep holes. I have used a white napkin to verify the color and what oil is coming out and it looks like the lower unit gear oil. The idea of soapy water came as a suggestion from a member of this forum. I reailize alot of info was left out here but I have already discussed the issue of the oil in another thread. I did not see the point in the pressure test since I can already see oil coming out from the weep holes. I do not know if it would be better to submerge the lower unit in water or do as someone suggested with spraying soapy water on seals. Seems like it would be easier for me to narrow it down by using the soapy water and see if it bubbles.

 

[pnwboat]

Re: Steps to test the lower unit for leak & lower unit removal

If you're getting lower unit oil out of the "weep holes" on your 1989 85HP, it's probably the seals under or in the gear housing cover item 53. The water pump is mounted on top of it. The suspect seals are # 51 driveshaft bearing cage seal, # 49 gear housing cover seal or # 56 shift rod seal. NOTE, the water pump bolts have to be removed to take off the gear housing cover. The cover is thin and easily broken if you pry up too hard on either end. Best to pry in the middle where it is thicker.

http://www.boats.net/parts/search/Merc2/Force/85%20H.P.%20%281989%29/858F9C/GEAR%20HOUSING/parts.html

 

[Karla45]

Re: Steps to test the lower unit for leak & lower unit removal

see below post

 

[Karla45]

Re: Steps to test the lower unit for leak & lower unit removal

Hey Pnwboat or anybody,
That diagram you show is a different from my actual lower unit here is mine http://www.boats.net/parts/search/Merc2/Force/85 H.P. (1989)/856X9G/GEAR HOUSING/parts.html My number is 856X9G year 1989 85HP and this is what I have used in the past.

For instance #56 is snout exhaust on mine not shift rod seal. I am not sure where the shift rod seal is on my diagram.

I could not find driveshaft bearing cage seal on my diagram that you refer too either. COuld you please look at the diagram for my motor I have posted the link and give me the numbers as it corresponds to my lower unit?. Thanks on the heads up on gearcasee cover

 

[Karla45]

Re: Steps to test the lower unit for leak & lower unit removal

anybody?

 

[pnwboat]

Re: Steps to test the lower unit for leak & lower unit removal

OK...Lets look at your lower end now that we have the correct one. Problem areas are item 31 O-ring seal, items 27, 28 and 29, and also item 23...bellows. Cost for the bellows seems outta line though. Take a very close look at your bellows to see if it is OK. Everything else is pretty cheap.


http://www.boats.net/parts/search/Merc2/Force/85%20H.P.%20%281989%29/856X9G/GEAR%20HOUSING/parts.html

 

[Karla45]

Re: Steps to test the lower unit for leak & lower unit removal

Which one is the shift rod seal? Okay now my next question is if I am going to remove lower unit for first time and do the work myself, is this a very difficult thing to do? I am considering replacing all of the seals since I will have it off the motor since the boat is so old. I would not be doing the lower gear case right now. Do I have to remove the driveshaft at any point in order to get these seals? By the way thanks.

 

[jerryjerry05]

Re: Steps to test the lower unit for leak & lower unit removal

Leak points:
Do the leak test.Don't change anything unless you need to.
Re-sealing might be more than you can handle.The bearing carrier needs a puller.
You don't need to remove the shaft.The seals on the top under the water pump and the shift shaft seal.The cover will need to come off and it can be a B to reseal.
I woudn't do any more than needed.Unless you can afford to have a mechanic do it at a set price.

 

[pnwboat]

Re: Steps to test the lower unit for leak & lower unit removal

It's hard to tell which one is the shift rod seal, but I suspect that it may be the bellows which is the expensive piece. The second picture that Jerry posted shows the shift rod and the seal that the rod comes through. Yours may not look exactly like it. All of the seals that I referenced are on the top of the lower unit and are easy to get access to and replace after removing the water pump housing and top plate. Like Jerry said, the seals on the propeller shaft bearing carrier may require a puller, but from what you are describing it appears that the leak is not in that area, but the best thing to do is to remove the lower unit and pressure test to locate the leak to be 100% sure.

At the top of the Forum there is a "Sticky" labeled "Force and Chrysler FAQ and other great information" Open that up and you'll see a post called "Step by step impeller change" by Frank A. It outlines the lower unit and water pump housing removal.

 

[LarsMN89]

Re: Steps to test the lower unit for leak & lower unit removal

Just to throw out a different possibility.....
I had a similar issue this spring. Gear lube appeared to be mixed with water, foaming, expanding through the the drive shaft seals, and dripping down through the weep holes. I took it to my shop and they pressure tested it for 2 days, out and in water, and could not find a leak. They drained the lube and put in fresh 100% synthetic and gave it back to me - and I've not had a problem since. I had put in fresh lube this spring and it seems the lube was of low quality and foamed.

 

[Karla45]

Re: Steps to test the lower unit for leak & lower unit removal

Okay I am really glad I asked. I was not planning on doing the whole lower unit, just the upper part but I see it might be too much. When I look at the diagram it appears to me that 3 of the seals you are referring to are under the cover. I think you are right about the shift rod seal being the bellows on my lower unit because if you compare the two they are in the same place but just different names. I will do the leak test and go from there. I do have something now I can use to test the pressure. My question is would it be better to submerge the lower unit in water to identify where the leak is coming from or spray the seals with soap and water? Thanks for the pictures Jerry.

 

[pnwboat]

Re: Steps to test the lower unit for leak & lower unit removal

Either way works. I prefer the soapy water, but you have to know where to spray. If you submerge it, no need to know exactly where the seals are and it will be obvious.

 

[Karla45]

Re: Steps to test the lower unit for leak & lower unit removal

So I submerge the whole lower unit to where water goes into the case? How does the water drain out? I know there is a drain plug at the bottom but I thought that was encased. If you look at the second picture Jerry posted in the opening where the leaf is is what I am talking about if water gets in there how does it drain out or do I have to lean the case over to to side to dump the water back out?

 

[pnwboat]

Re: Steps to test the lower unit for leak & lower unit removal

The lower unit is completely sealed. No water will go inside of the gear case if the seals are good. Those openings do not go into the internal part of the lower unit where the gears and the oil is located. There are some small "weep holes" on the outside of the case below the cavitation plate that allow the water to drain out from those openings.

 

[Karla45]

Re: Steps to test the lower unit for leak & lower unit removal

Hey thanks for answering my question.