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TonyG

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Hey Guys, Well more grief. Went down to the last night to prep the boat for a tuna trip. After starting, and waiting for it to come up to temp, I got off the boat and around to the stern and when I did I notice a noise. One I hadn't heard before, kinda like gears meshing, low volume and no grinding. I shut it down.

After the hurricane haul out I had some gear oil in my bellows. Made some calls and determined I couldn't make this repair easily on my own. Called the local volvo penta guys they checked it out did a pressure test ( no sure about vacuum test ) and it held for three days filled gear oil and gave it back. (when I drained the drive for transport there was very little oil and no metal on magnet).

This morning ready with a funnel and some oil (or so I thought). Found out, little to no oil on dip stick (with drive tilted enough to keep hole out of the water) and I had grabed a quart that had waste oil not fresh oil. so I pulled the plug on the trip. (bummer) But just could risk damaging the drive for a fish.

How is it possible to have a air tight drive that still leaks. BTW, when I loosened in the fill nut you could hear air getting sucked in. WTF.


Any thoughts.


Thanks Tony G.
 
TonyG said:
How is it possible to have a air tight drive that still leaks. BTW, when I loosened in the fill nut you could hear air getting sucked in.

Thanks Tony G.
Click to expand...
Good call on not using the drive until you find out what's going on.
A complete lower unit over-haul can run upwards of $3k alone....... and this does not include any transmission work!

Tony, not sure where to start here.
In order for the Pressure leak-down test to be of value, all oil must be drained. Otherwise, the seal lip will be hydraulically held against the seal surface.
With the Vacuum leak-down test, it makes little difference.

As the boat is being used, the drive will undergo both a mild pressure and negative pressure increase as it warms/cools. If a seal has been compromised, this may be when we may loose oil, and when we may see water being pulled back in it's place as the drive cools down again.
This is also what may have caused the "hiss" that you mentioned.
However, we may also see the white milky hydrogenated oil... and apparently you are not seeing this....... Correct?

Your DP A uses a double lip seal in all areas but two.... (i.e., the main drive gear seal, and the original eccentric piston seal (later seal is a double lip)).
The main drive gear seal will not allow water in (if the drive shaft bellows are OK), but will allow oil out if not holding the intended pressure value.
IOW, if bad....., upon cooling (mild Neg Pres), there is no water nor oil to pull back in.
This may.... (key word "MAY")....., be part of what is happening. Hard to say without pulling your drive down myself.

There are also 4 Intermediate Housing O-rings that are NOT visible while the drive is still assembled. One of these could be suspect as well.


I'd pull the boat and perform the leak-down test again.
I'd also remove the prop shaft bearing carrier and take a look inside of the DP lower unit. Simple to do.... and will only cost you two new O-rings.
See this thread, and scroll down to "Special tool for removing prop shaft bearing carrier".

If the drive has not been re-sealed in the last 8-10 years, it may be over-due.



Tony, just an FYI: I would not pull the transmission dip stick while the boat is in the water.
 
Thanks Rick for the response. The drive is a 2007 and I was lead to believe it may have been caused by overfilling drive. There is no water (at least the last time) and the oil ended up in the drive shaft bellows.

This all came about while trying to remedy my belt slipping problem. after replacing quite a few parts and realigning the power steering pulley we ran the boat on a very calm day under heavy throttle, and high rpm. Which I never do, but to gain confidence that the problem was fixed we ran WOT for 3 or 4 mins under 4500 rpm. we did this for 5 or 6 short run till we certain the belt issue was corrected.

After that a couple of weeks later I hauled for the hurricane and had a few surprises. My tilt/trim motor gave out and when I pulled the leg I found the oil in the bellows. This drive has the external trim pump.

Thanks again.

Tony G.
 
OK... something with your drive model or year model is not correct.
The DP-A is an AQ series drive.
This drive would not have been OEM in a 2007 boat, unless special ordered.

We'd best go back to the year of the boat and the actual drive designation.

Pictures?
More info?

.
 
IMG_0095.jpg


OK sorry. The boat is a 1986 Grady White 24 offshore. Originally powered with a 230 OMC w/cobra outdrive.

I was completely redoing the boat in 06,07 & 08. But was forced to buy the motor drive pkg a year early because Volvo had redesigned the drive and was very slow about releasing the specs. (in fact even after 08 when the boat was completed they still showed the old drive and it's specs on their website). I was concerned that the transom cutout might change and since I was awlgriping, the time to address this was during the refinshing stage.

So the motor is a 5.7 GXI-H with a DPS-A drive. I can get serial numbers if that helps but I'm pretty certain of these facts. This drive has 8 bolts as opposed to the 6 on earlier drives that bolt the transom shield through the transom to the rear engine mount & transom Assembly. And the externally mounted tilt/trim pump ( on the transom shield ).

Sorry for the confusion

Tony G.
 
Last edited:
TonyG said:
View attachment 3323

I was concerned that the transom cutout might change and since I was awlgriping, the time to address this was during the refinshing stage.
Click to expand...
OK..... I now understand.
Bummer.... wish I could have spoken with you first.
Volvo has been fighting main drive gear seals on this type drive.

The DP C or C1 would have been a better option, IMO.

You still need to sort out the issue here. The drive should not be loosing gear oil.

.
 
Yah me Too!!... Although a little frustrated with having to put up with the inconvience and expence, I'm not all that unhappy with the performance of the pkg.

Here are two other posts of mine and the reason I joined this forum.

http://www.marineengine.com/boat-forum/showthread.php?394120-It-s-always-something

http://www.marineengine.com/boat-forum/showthread.php?391394-Throwing-Belts

The motor and drive seem to work well, but now the doubt is setting in. The reason I spent the big dollars on this pkg was to have peace of mind and a few years of worry free and problem free boating. Not so much.... Wishfull thinking, I guess.


Thank you for your help.

I think I going to give the drive to my Volvo penta auth repair shop and get an estimate. I was hoping to get an idea of what the problem was so I could direct them in that area. I like to do as much work as I can myself so that I know it was done correctly and nothing that may show up is overlooked for the schedule's sake. But I don't have faith in my ability to trouble shoot or complete this repair myself.

Rick, have you ever replaced the seal or seal around the drive shaft of this model drive? and if you have whats the difficulty factor?

Thanks

Tony G.
 
Tony, the performance of the DPS-A is not in question.
Both the AQ series Duo Prop and the later Gimbal system Duo Prop drives use a very similar Duo Prop technology.


Of course the later is Thru Prop exhaust, and the drive suspension and steering geometry are considerably different.
images




It's the geometry, the upper unit Bearing Box design, and the added service work required for the Gimbal system drives, that separate the two in terms of the issues that have come up over the years.


Your authorized Volvo Penta shop will be aware of the concerns, and will make the proper recommendations.

Here is a link to a page that will show you the Bearing Carrier (aka Bearing Box) and main seal.

Here is a link to a page that will show your upper unit eccentric piston seal area.


You have a good drive.... no question about it.........., but given a choice, I'll take the AQ series!


.
 
Hey Rick, Thanks for the info and related links, any thoughts where my particular problems may be. It looks like there only one seal in that area. Would there happen to be any service bulletins about this problem?

Thank You

Tony G.
 
Tony.... if the drive shaft bellows are not leaking, a failing main gear seal will not cause water intrusion..... however, it may explain the loss of gear oil, and the tell tale will be oil inside of the bellows.

The eccentric piston seal is a very likely suspect. These are often not changed routinely enough, IMO.
You can put drain and dip stick sealing rings on that list also.
The other areas may perhaps be the prop shaft seals.

The best way to determine this, would be to once again drain all oil, and perform the Pressure/Vacuum leak down tests.
While under press/vac, rotate all shafts, operate the eccentric piston, and watch the gauge.
This should be protocol.
See if this causes any change to the reading during both Press/Vac tests.


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