What scrap metal is this in my lower unit?

[Bsparks923]

1999 Volvo penta 5.0gl with sx-m outdrive. My prop kept catching on something and killing the motor. I removed the lower unit bearing carrier and found this behind the carrier! I noticed the internal set screw for the bearing carrier was sheared because there is still a small piece of the bolt in the bolt hole that i cant get out(arrow is pointing to it). Also, i circled an area where it almost looks like the lower unit body is scalded. It is supposed to be like that right there behind the internal set screw? Do I have to have this internal set screw installed? What does it do and what scrap metal is this? Oh also, when i drained the oil there were tons of tiny metal flakes and about 2 or 3 shavings about 1/4" long which i believe is from these two scrap pieces i found. Other than this, this lower unit looks almost brand new, gears in lower unit look ok.

Thanks in advance for any info. I wanna get on the water.

 

[Bsparks923]

After removing lower unit and prop shaft, it appears the rear big gear is rubbing the aluminum housing right where the arrow is pointing, what is causing this gear to rub the housing? All of the flakes i saw in the oil were aluminum which was caused by this gear rubbing the housing.

 

[Grub54891]

Get it to a shop for rebuilding, or get a new lower. Any parts floating around in there is not good. hopefully if it gets rebuilt, they can save the case.

 

[Bsparks923]

Yea, but I think the internal set screw and keeper just came loose.

 

[muc]

I'm not sure what the piece in your hand that's on the left is, maybe a bolt?
But the piece on the right is the inner propshaft bearing housing retainer. This part is "external" to the drive. So I have no idea how it got inside, unless somebody put it there. When was this drive last apart?

What service manual are you using?

 

[Bsparks923]

The other piece is a bolt, most likely to the housing retainer. I just bought this boat so i don't know the history. I can tell that the lower unit has never been taken off the upper unit though. I also have no idea how this retainer and bolt got in the case. Really weird. Maybe someone put it in there and forgot to take it out last time they removed the bearing housing? I'm going to have to take the vertical pinion out so i can take a look at the prop shaft gear and its bearing. I think the bearing might be going out causing it to grind against the aluminum case. Also not 100% sure what holds the prop shaft gear in place, other than the prop shaft itself. I'm using the 270 page service manual from boatinfo, which is also a sticky on this forum.

 

[harringtondav]

I'm going to have to take the vertical pinion out so i can take a look at the prop shaft gear and its bearing. I think the bearing might be going out causing it to grind against the aluminum case.

That's my guess. I don't know VP, but I've rebuilt one Cobra and several Alpha 11s. One way or another there is either a caged needle bearing or a tapered roller bearing that centers up you FWD gear. The front of the prop shaft rides in a second needle bearing in the gear. Get it fixed. Gear alignment is very critical. Yours don't appear to be in bad shape, but this won't last long with the FWD gear loose as shown.

 

[Bsparks923]

Correct me if I'm wrong, but when reading the service manual, it appears that when you torque the bearing housing down on the prop shaft, the prop shaft itself centers the gear in the case. When I stick my hand in the case and put pressure on the gear, there is no play and it feels like the bearing is ok. Does the prop shaft hold the gear centered, or should the bearing/gear feel nice and tight without the prop shaft installed? I know i should take the pinion out but i sure don't want to until i get a little smarter on this.

 

[Bsparks923]

Also, would anyone happen to know what the pinion gear nut size is? I know it's larger then 1" and smaller than 1-1/4". Not sure if its metric or not.

 

[harringtondav]

Does the prop shaft hold the gear centered, or should the bearing/gear feel nice and tight without the prop shaft installed?

I looked up your SM-X assembly shown in the snip below. It shows the front of the prop shaft splined into the FWD gear. The bearing roller assembly is pressed onto the FWD gear. Forward thrust on the prop shaft centers the gear in the bearing's race which is likely pressed into the housing. The second tapered bearing set at the aft end of the prop shaft centers the rear of the prop shaft. I suspect there is a torque spec on the carrier to control preload or end play on the shaft's bearings.

You pinion should be centered in the housing bore. If the carrier lost preload and had enough play in the bearings, the FWD gear could move off center and contact the hsg. You need to remove the vertical pinion, pull the prop shaft assembly and see what is going on. Hopefully just looseness, but that FWD gear bearing set could be shot, or the race may have spun in the housing and wallowed out it's bore. That will require a new housing.

 

[Bsparks923]

Thanks

 

[harringtondav]

Also, would anyone happen to know what the pinion gear nut size is? I know it's larger then 1" and smaller than 1-1/4". Not sure if its metric or not.

You are likely getting to special tool territory here. Check the Boatinfo process. You may be able to slip a std. OE or box end wrench over the nut. But you may need a special pinion shaft retainer to remove the nut, and more important torque it back up correctly.

 

[muc]

With that much metal floating around in there, I highly recommend that you disassemble and clean the upper drive also. Volvo has a really good lube circulation system in these drives and I’m pretty sure you will find metal in the upper.

I’ve rebuilt quite a few of these drives and I wouldn’t attempt it without the special tools.

 

[GeorgeDes]

The special tool to loosen the pinion gear makes the job a snap. In order to complete the job you will also need a special tool to pull the vertical shaft off the pinion. I am sure you can fabricate tools to do this, but the special tools make things so much easier. Check out ebay for used ones. They often show up there.

 

[Bsparks923]

I’m trying to find the drive shaft adapter VP# 3850598 so I can take off the pinion nut and VP wants $100. That is absolutely crazy. Does anyone know where I can find one for cheaper? I don’t even see that Sierra makes an aftermarket one. eBay no luck. These “special tools” must be gold plated.

 

[GeorgeDes]

If you can find an old splined sleeve that connects the lower to the upper drove unit you may be able to fabricate the 3850598. That tool is basically a splined sleeve with a half inch socket slot so you can turn the vertical drive shaft to either loosen or tighten the pinion gear nut.

 

[Bsparks923]

I went ahead and bought another splined sleeve off eBay for $20. I’ll weld a nut on top of it and make my own special tool. Hopefully it gets delivered by the weekend.

 

[Bsparks923]

I got the pinion out and everything looks good. Gears, bearing, everything. I think the steel bolt and retainer just caused havoc in the gear case, or the bearing carrier loosened up causing the fwd gear to rub case. Wish me luck.