88 Clutch Problem Mystery

My 88 RC has had what I thought was a clutch problem since I purchased it. Whenever the transmission was shifted into neutral and the clutch let out (such as to park tractor with engine running) once I wanted to shift, I could not shift the transmission from neutral to any gear without the gears grinding (clutch pushed in as far as possible). I adjusted the clutch linkage as much as possible, but that did not help the problem. To avoid transmission damage, I just got in the habit of shutting off engine so as to never have to shift out of neutral to a gear after having let clutch out in neutral.

Now that I've finally gotten time to disassemble things and look at the clutch, I don't notice anything wrong with the clutch disc, it's not worn excessively (still a good deal of material above the rivets), and the pressure plate has some wear on the contacts with the throwout bearing, but otherwise appears OK.

The one thing that I have noticed is that the old throwout bearing does not match my new one. I ordered a new bearing from a bearing house (just the bearing, no collar), and got an Aetna A-2262, just as my 88 parts book listed. However, the old one in the tractor is an Aetna A-2469. Physically, the bearings themselves look similar, but I'm wondering if someone has replaced the correct 88 throwout bearing collar with something that's not quite right. I don't have another throwout bearing/collar from an 88 to compare it too. If the throwout collar was too short, the clutch might not be disengaged completely when the pedal is pressed? If the throwout bearing and collar are sitting on a bench, how high should it measure?

I don't think the problem is in the transmission, with the clutch disconnected and the it in neutral I can spin the input shaft without problem. To me the problem has always seemed like I can't get the clutch to disengage completely from the engine.

Sorry for the very long post, but I wanted to explain the situation. Any thoughts? I'm probably overlooking something, so I can provide more info if needed. Thanks for the help!

88 RC Gas. S/N 138---

11" B&B clutch. Approximately 5/32" of total material thickness remaining on each clutch surface. What is thickness of new clutch?

Currently has bushing type pilot bearing, which will be replaced with ball bearing (have hub, new bearing, and different shaft). There is noticeable wear on bushing and current shaft.

Throwout bearing is non-greasable. The bearing assembly (bearing and collar) I removed measures approximately 1.875" tall. I can't find the odd Aetna part number in my parts book for either greasable or non-greasable.

Release levers: With pressure plate flat on bench, approximately 2.625" from bench to top of release levers. Top surfaces of arms appear worn, but I have no reference as to how much is too much.

Transmission is 80-90W. Idle speed is low (I'm guessing) about 400 rpm.

I also failed to mention that, at some point, the clutch release lever had contacted the pressure plate enough to wear into the lever and take the end off of the clutch pedal spring.

Let me know if more info is needed. Thanks for the help (and your patience!).

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