Buying Advice Need advice on a Jinma 284

[double hunter]

Finally got a chance to drive my new toy (just had to go fishing this morning, it's a tuff job but somebody has to do it), I don't think the clutch is bad, I put in low range and one of the lower gears and drove it up the back of my pond dam with rotary cutter behind it and it climbed the dam just find, no hesitation in low gear, shifted it into high range and 3rd gear when I let out on the clutch it just sat there for a few seconds then it went on, just hesitated for a few secondsl I think if the clutch was bad it would not have climbed the dam, there is a dealer who used to sell Jinma and he told me the other day that he would check the clutch adj for a couple hrs. labor charge, this may be my best option, what do you all think.

 

[greg_g]

No, you're describing a clutch that's has a worn out main drive friction disc. If it was out of adjustment, it's out of adjustment in both ranges and all gears. But to hold in low gears and slip in high gears is the classic sign of a worn friction disc. The only reason it started moving in high gear, was heat. It slipped long enough to expand just enough to engage. That won't last long.

The good news is that friction discs only cost about $50. But it requires splitting the tractor and essentially rebuilding the clutchpack to install.

//greg//

 

[double hunter]

Couple of squirts of PB Blaster and the 4 wd is working like a champ, now I've got to do something with the clutch.

 

[double hunter]

Went by the shop this afternoona nd picked up my Jinma and they had the clutch adjusted and working like achamp.

 

[Rich Waugh]

That's good news! Were they able to give you a measurement on how much friction material is left, so you can plan ahead?

 

[greg_g]

Went by the shop this afternoona nd picked up my Jinma and they had the clutch adjusted and working like achamp.

Rich has a good point. Reminds me of used car dealer that put sawdust in the tranny to muffle the clanking. This is said not to impugn the guy that sold you the tractor. But there is an adjustment that can be made to take up the slack on a worn friction disc. That's the good news. The bad news is that it's only good as long as there's material left on the disc. You now have no idea at all how soon the rivets will start hitting the pressure plate. When that happens, rebuilding/replacing a clutchpack can turn into an expensive proposition.

FYI, there's about 9mm of friction material on a new 200 series friction disc. But of that, only ~75% is wear material. After that, you risk hitting rivets.

//greg//

 

[erj]

Rich and Greg,
For my education-
What tool do you use to go through the small access hole and measure mm on disc?
Thank you,
RonJ

 

[greg_g]

None that I know of. The measurements I provided were done with a caliper when the disc was in hand. For mounted discs, I insert a slim object of a known width. Personally I use a 6" digital caliper ($20 from Harbor Freight). If you don't have an accurate caliper, use something of a known width - like nails. Metric nails are perfect for the job, but they're not very common in this country. Here's a "penny nail" chart. Simply convert the diameter or head width to millimeters. Select the closest size nail, grind the point off to gauge small gaps. Use the head for wider ones

//greg//

 

[Rich Waugh]

That's pretty much the same method I use, Ron. Find/make something that will get into the area and can be used for visual comparison with the object being "measured." Nope, it's not really accurate, but it is good enough to estimate available clutch material, tread depth, clearances, etc. If you have a caliper and a grinder, you can make progressively more "accurate" comparator pieces until you can arrive at a surprisingly close reading - just takes patience, so I generally get close enough for the purpose and let it go at that..