DP-A with oil inside the u-joint bellows

[greener14519]

Hello folks. Thank you for posting some great and helpful information on this forum! Here's a question to anyone who can offer help. I have a '90 Chap with twin Volvo 431 powerheads. The outdrives are DP-A's and on the ID tag each unit says 2-30 and the S/N's are 3102102214 Port and 3102102218 Starboard.
Back in the fall, when I pulled the oil drain plugs, the port side lower unit had nothing in it. There was a small bit of greasy residue that might have drooled out, but nothing more than that. The starboard side ran about a pint of pure water before the oil came out. I knew I would have my work cut out for me this spring. Incidentally, neither of these drives made any noise, and both ran and shifted fine as I went from my marina to the launch area.
So I was surprised in the fall to find no oil in the lower gear housing on the port side unit. I was even more surprised this spring when I pulled the upper gear housing cover and it was full right up with oil. And also the u-joint bellows was full of oil. Does anyone know what causes this to occur?

 

[greener14519]

Re: DP-A with oil inside the u-joint bellows

I have both drives in my shop and I'm focusing on the port drive first. I have all new seals and o-rings and I'm almost ready to start re-assembling the drive. But I would like to solve the mystery before I put it back together. I assumed that the answer would be fairly obvious once I disassembled the unit. I thought maybe a plugged oil screen or something that was not allowing the oil to return to the lower unit. I have found no such evidence. And the sealing ring on the input shaft looks like new. There are two microscopic grooves on the shoulder ring that nestles into the sealing ring. I have seen grooves much deeper on an harmonic balancer from a front oil seal that didn't leak a drop. It's almost as if this oil were pushed out under pressure. The hollow bolt seems to be clean and clear.

 

[greener14519]

Re: DP-A with oil inside the u-joint bellows

A picture of the input shaft seal.

 

[greener14519]

Re: DP-A with oil inside the u-joint bellows

Have you ever seen this much corrosion on a freshwater outdrive before? PO swears it never saw salt water.
The second picture is after sandblasting and applying a coat of primer.

 

[greener14519]

Re: DP-A with oil inside the u-joint bellows

Wow! 55 views so far and not one person has ventured an opinion. Now I'm stuck wondering if that's because it's such a strange situation, or because it's so basic that nobody thinks it is worth their time to reply. I have used the "advaned search" feature to see if there are other similar threads, but nothing pops out yet. Hope someone has some suggestions that might help. I spoke with the tech at my local Volvo Penta dealer and he says he's never seen anything like this.

 

[billbayliner]

Re: DP-A with oil inside the u-joint bellows

Well here is a shot: I had to read the post a few times before understanding what was stated.

You say that the upper of the outdrive had oil in it and the lower had none?

Well I am guessing 1 of a few things...... Plugged strainer .... Debris blocking ports.... Drain plugged....

I say crack the lower unit and intermediate and give her a look.

I seen in the picture you dis-assembled the upper double bearing box. I hope you know how to reset the drive gear bearing's rolling torque value or the units will not last long.

As for your local Volvo dealer I would guess it is the guy behind the counter. The only one to get advice from is the mechanic that works on the drives.

I rebuilt a couple of DP-C uppers last spring that had ran on water and had no oil at all left. I was amazed this thing held together. If it would have been re-commissioned in the spring and not tore down they would have been toast.

It was just another example of the bullet proof / resiliency of the Volvo AQ series drives.

 

[greener14519]

Re: DP-A with oil inside the u-joint bellows

Well here is a shot: I had to read the post a few times before understanding what was stated.

You say that the upper of the outdrive had oil in it and the lower had none?

Well I am guessing 1 of a few things...... Plugged strainer .... Debris blocking ports.... Drain plugged....

I say crack the lower unit and intermediate and give her a look.

I seen in the picture you dis-assembled the upper double bearing box. I hope you know how to reset the drive gear bearing's rolling torque value or the units will not last long.

As for your local Volvo dealer I would guess it is the guy behind the counter. The only one to get advice from is the mechanic that works on the drives.

I rebuilt a couple of DP-C uppers last spring that had ran on water and had no oil at all left. I was amazed this thing held together. If it would have been re-commissioned in the spring and not tore down they would have been toast.

It was just another example of the bullet proof / resiliency of the Volvo AQ series drives.

Thanks for your Thoughts BillBayliner. I was hoping to find a plugged drain or clogged strainer. Unfortunately, not the case. Thing was clean as a whistle inside.
And I agree with you that these drives are pretty tough. I switched from Merc to Volvo years ago because I think they're better made than Mercs.
As for the double-bearing box, yes I had to take it apart. I couldn't trust the input shaft seal after I found all of that oil in the bellows. I'm glad I did tear it apart because the screw that holds the pre-load on the double bearings was not even finger tight. And there was no thread locker on it. I replaced the seal, the shoulder washer, all the o-rings and installed a new pre-tensioning sleeve and torqued it to spec.
It's all back together now, but without an answer. It was almost as if the oil was airlocked and couldn't drain because it was under pressure. And I realize that this can't happen. There are way too many passages down through the gears for it to not allow the oil to drain down.
As for my local dealer, through the power of deductive reasoning, I have ascertained that the parts guy is named Scott and he orders my parts for me. The mechanic is named Jack and he is the guy I asked about this unusual condition.

 

[greener14519]

Re: DP-A with oil inside the u-joint bellows

Here's a little back-story if anyone is interested. I bought this boat late last year, almost on a whim. I was chugging around in an old Bayliner flybridge and was fairly content. A couple of years ago I replaced the transom on the Bayliner and swapped out the very tired 280 for a 275 I picked up that looked like brand new. Well, last August, some friends of ours decided they wanted to buy the Bayliner. Around the same time, I had found this Chaparral on CL and decided to go have a look. The broker selling it had it in the water and so I went and checked it out there. It ran well and it was to be my first twin engine craft.
It also came with a receipt showing that the PO had had both outdrives completely rebuilt at a local VP dealer to the tune of $6K. This pleased me because I really wanted a boat that I could just put gas in (lots of gas) and drive. And that's exactly what I did. My wife and I crossed Lake Ontario and spent a week in the Thousand Islands last Labor Day week. It ran and drove fine.
Shortly after that vacation, the water in our bay got so shallow that we had to pull the boat out a month earlier than normal. It was then that I discovered the oil problems with both units. When I pulled the plug on the port unit nothing came out. When i pulled the starboard plug, I got a bunch of water and then oil. Incidentally, I have found the problem with the starboard drive. See picture below.
I also found all manor of problems with both drives. The previously mentioned loose pre-load screw. Missing washers, missing shims, obvious signs of re-used o-rings. Someone even broke off two jack screws that you use to pry off the pivot pin in the steering helmet. I don't even want to tell you how much work it was to get that pivot pin out without breaking something.
I also found out that I need all four hydraulic trim rams to the tune of over a grand per pair. And they were a nightmare to get out also. It turns out that having a twin engine is nice until you have to actually work in the bilge area. Wow!
Lastly, the level of corrosion on these drives made me think that this must have been used in salt water, even though the broker swore it was fresh water only. I made two discoveries that might indicate that he was telling the truth.
First - the annodes have been painted. Probably by the same rocket-scientist who screwed up the drives when he "rebuilt" them. Second - a couple of the green grounding wires weren't hooked up. I'm learning that those green wires are specifically designed to ground all of the major components together to reduce corrosion. I'm hoping that the combination of these two things may have been the culprit. We'll see because I did a ton of sandblasting and wire-wheel grinding and a good re-paint. Here's hoping that the drives are in better health. I intend to run across the lake again this year and it's no joke. It's a 90 mile cruise, just to get to the mouth of the St. Lawrence River. Being more than 40 miles from shore in any direction, and having 600+ feet of water depth below you makes you want to feel confident in your equipment!
Anyway, check out the stellar job done to the seal on the eccentric shaft.