Clutch disk will not slide on spline (1 Viewer)

[Shyrock]

Replacing the clutch and have tried to test fit the clutch disk on the spline. It goes on about 1/4" and then stops.
1965 FJ40 with small block Chevy conversion. 3 speed manual on the floor.
Info from old clutch indicated it was a Chevy truck clutch, 11" diameter.
I found one post where someone noted that there could be issues with GM disks fitting on Toyota splines. Does anyone have more info about this.
Any suggestions for the disk to use?
Other suggestions?

 

[4x4veteran]

Been running GM disk on stock Land Cruiser three speed for years.
On my second disk now.
First was when I did the conversion in 84 and then replaced with second disk in late 90's when I rebuilt the engine.
Never had a problem with spline fitment but the stock master slave had been an issue when it come to moving the pressure plate diaphragm far enough to fully disengage the clutch.
Either I lucked out and just got the right disk both times or there is no fit problem for the GM disks.
If the splines on the input shaft and clutch disk are clean and lubed there should be no problem.
Quarter inch is not much but if fits even that far I would check for burrs or some dirt that is making the close fit even tighter.
Ps. My Toy is a 70 and I see you have a 65 so there might be a difference in splines on the transmissions.

 

[lcwizard]

It's supposed to work but I guess that doesn't mean it has to in every case. You might try a different disc. It might be an individual issue.
I use an input shaft from a GM SM420 as the alignment tool for Land Cruiser clutches. In almost 40 years no one has asked me to do a V-8 conversion with a 3 speed but I've done dozens with 4 speeds. No issues with a GM clutch to 4 speed so far. The splines are the same on the 3 and 4 speed. The part number for the clutch disc is the same for both

 

[Downey]

GM disc will fit Landcruiser input shaft from 1963-87 for sure, probably more years. I've sold many hundreds of Chevota conversion kits for 63-87 during Downey's tenure, always supplied the same GM disc. In regard to 4X4veteran's comment above about slave cylinder not having enough travel to disengage a Chevy clutch, that's true. A Chevy pressure plate takes .500" of travel (at the T.O. bearing) to disengage, your Landcruiser hydraulics only produces .450" of travel (at the T.O. bearing). Many on Mud use the LUK clutches that only take .420" of travel to disengage, but they are very border line, my Downey Chevota clutches only take .375" of travel to disengage.

 

[lcwizard]

Since my first conversion in 1979, to the factory 4speed, I've switched to 12" clutches for a couple reasons.
In 79, information was harder to find, there was no MUD. Being young and inexperienced I read the hotrod magazines
and bought a racing clutch. 10.5", 4500 lb Hayes with the cool pucks on the disc. Sucked in water, slipped off road and
the 4500lb parts destroyed the thrust bearing on the crank so in about 15000 miles I had to rebuild the lower end.
I replaced it with a 12" pressure plate ( from a Dodge application with 1600lb pressure) and a stock 12 chevy disk .
Since then I've used Chevy 12" pressure plates without issue. The 1600lb 12" never slipped and worked much better in water
crossing. A 12" disc has 44 extra square inches of friction surface over the 10.5 and about 36 sq/in over the 11"
Always test for interference between the disc hub and your crankshaft. Nothing worse than spending the day installing
a clutch then finding out it won't engage because the hub, riding on the crank, elevated the friction surface off the flywheel
or the hub springs are grinding on your flywheel bolts

 

[Shyrock]

It's supposed to work but I guess that doesn't mean it has to in every case. You might try a different disc. It might be an individual issue.
I use an input shaft from a GM SM420 as the alignment tool for Land Cruiser clutches. In almost 40 years no one has asked me to do a V-8 conversion with a 3 speed but I've done dozens with 4 speeds. No issues with a GM clutch to 4 speed so far. The splines are the same on the 3 and 4 speed. The part number for the clutch disc is the same for both

Do you have a part # for the clutch disk?
After much more searching & reading, I found several posts indicating that Toyota splines are tapered a bit, and GM splines are more of a squared configuration. I believe that is the issue I'm dealing with, and I'd just like to find a disk that will fit the "tapered" spline.

 

[Shyrock]

GM disc will fit Landcruiser input shaft from 1963-87 for sure, probably more years. I've sold many hundreds of Chevota conversion kits for 63-87 during Downey's tenure, always supplied the same GM disc. In regard to 4X4veteran's comment above about slave cylinder not having enough travel to disengage a Chevy clutch, that's true. A Chevy pressure plate takes .500" of travel (at the T.O. bearing) to disengage, your Landcruiser hydraulics only produces .450" of travel (at the T.O. bearing). Many on Mud use the LUK clutches that only take .420" of travel to disengage, but they are very border line, my Downey Chevota clutches only take .375" of travel to disengage.

Do you know specifically which GM disc was supplied?

 

[Shyrock]

Since my first conversion in 1979, to the factory 4speed, I've switched to 12" clutches for a couple reasons.
In 79, information was harder to find, there was no MUD. Being young and inexperienced I read the hotrod magazines
and bought a racing clutch. 10.5", 4500 lb Hayes with the cool pucks on the disc. Sucked in water, slipped off road and
the 4500lb parts destroyed the thrust bearing on the crank so in about 15000 miles I had to rebuild the lower end.
I replaced it with a 12" pressure plate ( from a Dodge application with 1600lb pressure) and a stock 12 chevy disk .
Since then I've used Chevy 12" pressure plates without issue. The 1600lb 12" never slipped and worked much better in water
crossing. A 12" disc has 44 extra square inches of friction surface over the 10.5 and about 36 sq/in over the 11"
Always test for interference between the disc hub and your crankshaft. Nothing worse than spending the day installing
a clutch then finding out it won't engage because the hub, riding on the crank, elevated the friction surface off the flywheel
or the hub springs are grinding on your flywheel bolts

Any specific info/part #'s/etc. you could provide for 12" pressure plate and disk would be appreciated.

 

[Shyrock]

Been running GM disk on stock Land Cruiser three speed for years.
On my second disk now.
First was when I did the conversion in 84 and then replaced with second disk in late 90's when I rebuilt the engine.
Never had a problem with spline fitment but the stock master slave had been an issue when it come to moving the pressure plate diaphragm far enough to fully disengage the clutch.
Either I lucked out and just got the right disk both times or there is no fit problem for the GM disks.
If the splines on the input shaft and clutch disk are clean and lubed there should be no problem.
Quarter inch is not much but if fits even that far I would check for burrs or some dirt that is making the close fit even tighter.
Ps. My Toy is a 70 and I see you have a 65 so there might be a difference in splines on the transmissions.

Splines are clean and lubed - no burrs or dirt. The old disk slides on with ease. The new one just stops about 1/4" in. This is all test fitting on the shaft prior to install. Do you know specifically which disk you installed?

 

[FJBen]

I just had a similar issue with my BJ74. The old clutch disc would slide on, but the new one wouldn't go on. I swore I had the wrong disc. It's possible you have the wrong clutch disc, but if the alignment tool fits both without sticking my guess is that you still have a burr on something on the shaft or the disc. I had to use some emery cloth and smooth it up. After that the new one slide right on and no issues.

Do you have calipers you can measure to make sure it's the same size?

 

[lcwizard]

Any specific info/part #'s/etc. you could provide for 12" pressure plate and disk would be appreciated.

I've never asked for a specific make or number. The discs should all be the same spline. I go to the local Oreilly
and ask for a mid 70's clutch for a chevy 3/4 ton truck. The only thing I watch for is the hub. If the hub is too deep
on the flywheel side I ask to see other brands or years. I'm not completely sure anything aftermarket is correct in
every way for any brand or model anymore. I've gotten parts that don't fit for everything I've worked . OEM parts are usually
the best bet but in this case there's no such thing as an OEM Toyota disc for a Chevy clutch...however I don't see why a Toyota disc
would not work with a Chevy pressure plate. Line up a Toyota disc on the GM clutch and if there's no interference, try that

 

[Shyrock]

Just thought I’d post some photos. Hit the spline w emery cloth just in case there was a burr causing problems. Still only goes on the shaft about 1/4”.