VN 12 gearbox disassembly question.

Steve Steven said:

I definately recommend you match-mark and record number of turns for each ring you have to loosen to get the hold down out that holds the sight glass in. I had to replace mine, it was covered with a rubber gasket due to the cleas plastic (which had to be a replacement) was broken. When I restored it, I had a very hard time getting the preload and clearances set correctly, Cal had to help me get it close. It is still not right, but I think it is close.

I have several flashlight lenses, glass, about .050 thick I used to replace mine with, I also have several rubber gaskets I got from McMaster-Carr which are too big and have to be cut down, and the opening cut out, but they work. On mine, I had to use only one gasket (on the inside) since two were too thick.

I will be happy to send you some of these if you want.

One thing, on my early VN#12 there was NO SEAL on the shaft, I cut the housing for a seal and installed it, it does not leak any more.

Steve

Click to expand...

stoneaxe said:

...
The gearbox oil level viewport is leaking and I want to fix it. - but the threaded retainer is trapped under another large threaded ring-

There is the shaft, a collar it goes through, and what look like two adjustment or lock rings on the collar, one of which traps the oil port retainer. It looks like there MIGHT be clearance to loosen the biggest ring, and get the oil port ring out from under?

I would sure like some advice here, or a drawing- my drawing for this is not the clearest of drawings-and does not show the shaft /bearing lock rings. I am a bit reluctant to dive in willy-nilly , these lock rings and collar look like they adjust bearing pre load on the shaft.
Pus I am sure that one of these parts is the lock ring holding the bearing the entire universe spins on, and if I screw up that one we are all in the deep doo doo!

Thank you!

Click to expand...

Cal Haines said:

The big ring on the outside, the one that's in your way, is just a lock ring. The large piece with the external threads for the outer lock ring is the body of the right bearing cartridge; it has a pair of holes for a face spanner. The smaller ring with face spanner holes, the one that the shaft comes out of, is the cap for the bearing cartridge. The output shaft uses double row ball bearings and I believe that the pre-load is automatically handled by the bearing assembly. However, the right bearing cartridge appears to control the position of the cutter-head pinion gear, so you want to take pains to keep it exactly where it is.

I would make a sheet metal gage that you can use to transfer witness marks from the ram casting to the rim of the bearing cartridge. It’s not so important where the outer lock ring winds up as long as the bearing cartridge stays (or winds up back) in the same place. It can’t hurt to put witness marks on the outer lock ring, as Steve suggests, but if there is some question on reassembly you want to maintain the position of the bearing cartridge. You should be able to back off the outer lock ring enough to replace the sight glass without moving the bearing cartridge.

You may want to make up a custom spanner for the cartridge as a typical face spanner may not give you enough leverage. A plate or disk with a large nut welded to it should do the trick. Bore the plate/disk to be a close fit to the shaft. I haven’t had much luck using bolt circle estimates to get the locations of the pins; use transfer pins to mark the locations for pins.

This reminds me that I owe Steve a set of gaskets for the sight glass...

Cal

Click to expand...

Cal Haines said:

From the drawing it appears that if you rotate the right bearing cartridge it moves the pinion gear in and out...

You probably have a drawing for a roller bearing gearbox. Send me an e-mail or PM with your e-mail address and I'll send you the right manual.

Cal

Click to expand...