H3 advice needed

First off I'd like to apologize for the length of this post.  I am currently looking at a H3 with 6 way blade that is for sale.  The engine runs fantastic, the hydraulics work great, however there are 2 problems that I need advice on.  I'm not an expert with dozers but have been studying up online, etc.  Problem 1 is the foot clutch doesn't retrack after you push it in.  The spring isn't broken on the rod, I don't see anything else wrong externally.  Any suggestions as to what could be going on with this?  If the engine clutch needs to be replaced how hard of a job is it on a dozer?  Problem 2, the left brake doesn't work.  How hard and costly is it typically to repair this if I do the labor myself?  I've found brake bands forsale online. Problem 3 is my biggest concern.  The left drive slips.  At first I thought the track was jumping the teeth on the sprocket but something is binding up inside.  After further inspection it seems that the spocket isn't parallel and is out of line.  Thus causing the teeth to hit part of the undercarriage.  What could be the cause of this?  Could a bearing be out on that side?  Again I'm not an expert but would appreciate any advice.  Lastly, how much would an H3 with power director, 6 way blade, no grill guard, with these problems be worth?  Thanks.

I own and HD3-1968 vintage and have removed and installed clutches and final drive bearings and seals. The steering clutches are removed though two openings under the seat. They can be lifted out with the brake bands as a sling. My first advise is buy a service manual if you intend to buy the tractor and do it your self. The clutches had a mod which the 5/16 through bolts were replaced with 3/8  bolts, a must do. The output shaft which the sprocket bolts to gets a special double seal  installed and looking at the  position of the sprocket, the 90W grease has probably drained away already. They are a great little tractor if everything is working. Be prepared to spend some time and money on it if you want it working correctly. 

I'd guess the final has a bearing problem or the casting is junk. Looks like the sprocket is gone so maybe pins and bushings also. Could very easily get expen$ive.
 I wish I had something like that right now for a month or 2 but don't need one to WORK on.

That sprocket out of line is almost a common problem as the axle runs on two timken bearings .. My HD4 has a problem with race working loose in the case then eating into case. I might just be the outboard bearing is shot but bet on case needing work also . Cost me about $500 to have case machined to put in a new welded in steel piece machined to take the timken cup for the axle bearing . 

Coke,  Thanks for the reply.  Sounds like to fix this it could get costly for parts.  Luckily I could do the work myself but sounds like quite a bit of time involved, especially since i've never been into a dozer before.  I'm concerned that the case might need work.  And unfortunately, it's hard to say if it has little damage or if a ton of expensive work will need to be done.

Sounds complicated and pricey.  I'm not sure what a shop would charge to have this done around here.  I never knew that this was a common problem on 2 point bearing machines, but it does make sense.