Failed vacuum test and crunched magnet... next step?

Okay, after fighting with my shift shaft and spending days getting the paint off my "new" mercruiser R drive lower half to get it ready to paint, I put my old upper and new lower together, took it apart a couple times to get the allen bolt in and fix the shift lever, and finally it's all together. New water pump housing, impeller, and all.

So I did a vacuum test with a hand pump. It leaked around the screw attachment point on the upper half, so I moved it to the lower hole.

When I took the screw out of the lower hole, I noticed the magnet on the tip had been sheared/ground off, and it was shorter. I had installed the screw with the magnet on my replacement lower once I cleaned off the shavings from my old gears... I figured it would fit just as well as on the old one and I would have it there to grab shavings again, since the original screw that came with the used lower half didn't have a magnet. Maybe that was part of my problem with shifting after my original assembly...

So now I'm worried about having magnet bits in the front of the "bulb" for the gear case near the drain hole. I was thinking I'd do a partial fill with lube and let it drain out in hopes of getting any bits out. Suggestions welcome.

I noticed the only leak during the vacuum test was at the input shaft. Annoying since the upper half had been fine before the lower gears went. I guess the seals up there were going bad. I did replace the static seal (O ring) with a spare I had, but it looks like I need to replace the seals on the input shaft assembly.

Is there a way to narrow down where the leak is further, or should I just get the whole seal kit for the upper half? I've read some things about multiple revisions of seals, do I need to measure/check the existing one to figure out what to order?

As long as I don't count my labor this is still cheaper than an SEI drive... if I do count my labor up... ouch. At least I'm learning a lot.

Erik

Re: Failed vacuum test and crunched magnet... next step?

vacuum test or pressure test

Re: Failed vacuum test and crunched magnet... next step?

Since most of the seals are designed to keep the oil in a pressure test is a little better. As the oil heats up it will expand causing pressure.

Re: Failed vacuum test and crunched magnet... next step?

cr2k said:

Since most of the seals are designed to keep the oil in a pressure test is a little better. As the oil heats up it will expand causing pressure.

Click to expand...

I would actually be more concerned about water getting in than oil getting out...I guess that is just me.

Both ways are good tests in fact Volvo Penta actually says to do both in their service manual.

Re: Failed vacuum test and crunched magnet... next step?

Okay... I'll do both, certainly, but I think if it leaks on the vacuum test it'll leak on the pressure test too. So it seems there's no way to really narrow this down, and I just need to buy the whole seal kit for the upper half.

On the magnet, I haven't come up with any more ideas, except to remove the gears and everything else from the lower half... which I can't do without buying or making a pile of tools. I'm still planning on flushing it carefully and hoping I get any major pieces out of there.

/sigh

Erik

Re: Failed vacuum test and crunched magnet... next step?

That really sucks about that piece of magnet in the lower. Best hope is that it stayed in one piece when it broke off and you can get it out by flushing the lower. Maybe flush it several times with something thinner than gear oil (diesel maybe?) and hope it washes out.

Edit:

Of course (just realized this - duh ......) being a magnet, it's going to stick to the gears and flushing will not be likely to do much about it. That's a bummer, not sure what I'd do in this case.

Re: Failed vacuum test and crunched magnet... next step?

I had the same thing (magnet) happen to me once........I was lucky enough to be able to see it stuck to one of the gears and remove it with tweezers.....

Re: Failed vacuum test and crunched magnet... next step?

First...Bubba is right.

Second...the magnet is usually too long on some earlier mercs and have to be ground down, otherwise it interferes with and can get broken off.


Third...like Bruce said, oil escaping isn't a problem(unless it's a lot)...it's water getting in. Vacuum test is the main concern. You'll have to check but I think the vacuum was only about 3-7 or so inches.

Early manuals said to install prop shaft seals (2)with the inner seal facing in and the outer seal facing out. Now you install with both facing out to double the seal against water intrusion.


...and check that the old gaskets have been removed from the vent/fill plugs.

Re: Failed vacuum test and crunched magnet... next step?

My vent/fill plugs seem to be bare... is there supposed to be an o-ring on 'em? As far as I know they've never had one, weirdly.

The leak I have happens from about 1 inch of Hg to about 5.. I don't get near 7 ever. I'm going to pick up a seal kit today.

I'll try to flush out the magnet pieces... if they're sitting on the casing I'll be ok, if they're stuck to the shift shaft there I'm still ok. It's only if they're in the gears or bearings that I'm SOL. I guess the only way to find out is to try to use the thing.

Like I said I don't have the tools to pull the lower apart, so my only option is to try to flush some bits out. Maybe I'll get lucky...

Erik

Re: Failed vacuum test and crunched magnet... next step?

The newer shift shafts are stainless so I don't think the magnet will be there unless you have an older shaft.

Good luck.

Re: Failed vacuum test and crunched magnet... next step?

Did you try looking in the hole while turning the shaft?
You might get lucky and see it on the gear like I did........

Re: Failed vacuum test and crunched magnet... next step?

Not yet, I'll give it a shot tonight.

I'm also counting up the tools I'd need to open it up and make sure it's clean... I can make tools to do this with some difficulty, but I probably wouldn't want to use them long term.

Erik