MC-1 Drive Dog failure?

[alldodge]

I'm not the best guy for how to weld a nut on stainless studs, I've only done steel. Machine shop should know how

So far as shimming, it needs to be measured and shimming determined even with using same

 

[Pmt133]

I've used flux core on stainless. Works fine, just run hot. If its a 110 unit you'll probably have to run near max for those studs. Make a large puddle and don't stop otherwise you have to deal with the slag.

 

[ratdude747]

I have the shop working on it... no luck welding, it's going to the mill. They weren't comfortable trying to free the trim cylinder pin (without machining it out, more trouble than I think it's worth), so it's just going to be a captive part (makes installation a bit harder, but whatever). Based on how the bolts are going I'm sure it's pretty frozen!

Pulled it apart before I went to bed so the shop could get it today. Some notes:

• The bearing races seem to be more of a press fit in the cap/case. Couldn't get out with a mini slide hammer, but since I'm reusing the races, no big deal.
• The bearings are confirmed to be stained but not pitted. A couple spots of surface rust on bearing cage or two, but the hard parts all seem to be reusable
• The u-joint gear had a small amount of pitting on a couple teeth. Still way better than the other two.
• The driveshaft gear had some black dirt (looked like staining but wiped off) and other than some light wear, looks immaculate.

Even if I have to spend some minor $$$ getting the case fixed, I still think I did OK. For $120 in gas and a fun day trip with the wife...

Edit- forgot to mention that the yoke will need a sleeve. not leaking but does have a tiny groove worn.

 

[ratdude747]

Got the drive back... they did have to helicoil it.

But... more broken bolts, this time in the water pocket:


I used my impact on its lowest setting. The two that didn't break I used a 1/2" drive 11mm shallow with an extension (my SAE impact selection isn't too hot). The two that did I had to swap to a deep non-impact 3/8 socket (bad ratdude!) and an adapter... which may have contributed to the different result.

I removed the pocket because I was having trouble getting the pipe seal off in-place.

I'll see what the shop can and can't do next week if I don't try welding it myself this weekend. Given that I did get two of them to come out, there may be hope? Edit: Nope... I'm going to be down until sometime next week waiting on the speedisleeve, so no need to rush and make it worse. As satisfying as DIY'ing is, if this case gets trashed, then I'm done for a while.

As clean as the outside was, this drive is proving to be one corroded mess... seriously! Maybe something's different with the metallurgy of older cases? Neither of the newer 888's had this problem.

 

[ratdude747]

Against my better judgement I tried to weld some nuts to remove the broken bolts... nope, the bolts just kept breaking internally. Once it got below flush I stopped. My nuts messed the surface up a bit, so that may need to be decked while it's in the mill.

The things I do to try to get out of having to shim...

Edit: it seems the pinion depth tool is avialble for not super expensive in the aftermarket... maybe I am wasting my time and money? I already have the preload torque wrench...