I have inherited a 1993 Yamaha Big Bear. It is basically a bit of a rehab project.
It is running much better after a thorough tune up and cleaning.
Next I started working on the brakes or lack thereof and wobbly wheels. I would like to point out that prior to this point all wheels turned freely- with the full time four wheel drive.
I replaced the wheel bearings / seals, brake shoes / springs and wheel cylinders.I put in new brake fluid and bled out air.
I reassembled everything completely as it was. After noticing the wheels would not spin, i backed the brakes off, eventually completely. The wheels still would not spin - at all.
Thinking that I had done somethiing wrong, I disassembled, and after trial and error and much troubleshooting , I have removed the CV axles and cannot see any gear movement at all inside the differential. I removed the yoke cover and can see movement at the yoke as it tries to turn with the drive shaft- but simply cannot turn. I thought I had jacked up the splash pan against the yoke but removed it to no success.
What in the h*ll have I done? Somebody besides me has got to have had this problem...surely?

 

By your reference to CV shafts I assume you are referring to front wheels? If all four wheels are off the ground, handbrake off, and it is out of gear, the wheels will turn. If they are not, and just the front end is in the air, the front wheels will spin in opposite directions as the diff spider turns, but Quads have a limited slip diff and, if this decides to lock, the wheels won't move. Always set brakes with all four wheels in the air on a permanent 4wd machine.

 

So let me say the front wheels are in the air, and locked- will not turn in either direction.
With that said, what can I do to remedy my situation?
During troubleshooting, I had all 4 wheels off the ground and started it with the same result. Back wheels turn, front wheels locked
Can I undo this? Or is this a major repair?]]]]]]]]]]]]]]]]]]]]]]]]]]]

 

This is a puzzle, I would double check by lifting all four wheels up, out of gear, and handbrake off, as I wrote above. Try to turn each front wheel by hand. If you can't there must be something wrong with the diff but, even if the crown wheel jammed, the driveshafts can turn against the spider inside, though as I wrote before, the limited slip mechanism makes this very stiff. The only other thing I can think of is a front wheel bearing seized.

 

Just noticed you recon the back wheels turn without the front ones moving, this is impossible on a permanent 4WD machine unless the transmission is broken.

 

Wow- I feared that but it was running good right before I put a jack under it to repair the brakes and bearings..Thanks merryman- I am still going to try your other suggestions..with hope

 

Just tried your suggestions- and everything seems to be okay. My guess is that I put the tranny in a bind by working with just the front end up in the air. I put all four in the air and all four turned.
Geez that's a relief!
It's not completely back together, but I am checking it every time I reassemble something.
I really appreciate your advice Merryman !

 

Yessir! Runs like a champ! ol' Chap

 

Man, that's such a relief when scary stuff like that works itself out, isn't it? As mechanical guys, I think that we're always expecting the worst!

 

Yep, I was sure I had screwed it up. But the forum is a great place to hash things out and make sense of it. Merryman made me think at it from a different angle and thus when I followed his ideas it all made sense. Made my 3 boys happy too! More rehab to do on it, but at least for now it is ride-able and safe.