1" Bore Clutch Slave Cylinder

[VooDoo]

Because I have a clutch slave cylinder clearance issue with my project seen here. I will be trimming off the spot welded sheet metal lip.



I need to locate a 1" bore clutch slave cylinder that is shaped like this 1990-2005 Mazda Miata NA01-41-920BA one. I believe the Mazda one is only a 3/4" bore (faintly visible on the side of the cylinder).



It would be best to have a bore the same as the OEM IH Medium Duty Loadstar original if I can find one. If not, do you think a 3/4" bore is okay to do the job? I'm running a 12" 15-Spring pressure plate.

Finders fee paid in kudos and smily faces!

[jeff campbell]

here's 1 on rockauto..'68 int. 1300 C 392 clutch slave cyl. 1"..$39.79 pt.# SC 54698,jeff

[VooDoo]

Originally Posted by jeff campbell

here's 1 on rockauto..'68 int. 1300 C 392 clutch slave cyl. 1"..$39.79 pt.# SC 54698,jeff

That's a match for the OEM one that has the hydraulic line coming off to the side. I need one just like that, but has both the bleeder AND hydraulic line coming off the top to give me another 1/4"-1/2" clearance.

Maybe an aftermarket racing Mazda Miata Heavy Duty 1" bore clutch slave cylinder exist? Gonna try some more searching on the net. Got to see the Mazda one in person today at Autozoners. I confirmed it has a 0.751" bore. Aside from the smaller bore, it looks to be exactly what I need!

[Bill Bennett]

That 15 spring clutch will build muscles in your leg! Going with the smaller 3/4" slave powered by the 1" master will mean the 'leverage' will be working against you. It will take even more muscle power to operate it. After a couple hours of offroad use, your leg will get pretty tired. Is there some way to modify the slave mount to get the full size unit in?

[VooDoo]

Originally Posted by Bill Bennett

That 15 spring clutch will build muscles in your leg! Going with the smaller 3/4" slave powered by the 1" master will mean the 'leverage' will be working against you. It will take even more muscle power to operate it. After a couple hours of offroad use, your leg will get pretty tired. Is there some way to modify the slave mount to get the full size unit in?

Bill, isn't the leverage working FOR you with a 1" bore master and a 3/4" bore slave? Less push on the pedal will give MORE push on the rod, because it takes less volume to move the smaller piston in the slave. I think I have that right. I see people on the net asking about switching to a smaller diameter clutch slave bores to gain travel. Can someone in the know confirm this??? And if there are any other consequences???

Not really able to modify the bracket, because it's in alignment with the throw out bearing rod lever now. If I have to use the OEM one, then I will modify the body more in that area...

I found OEM replacements at NAPA with two part numbers:

1) NCF 73471 $38.99 - Looks just like the Wagner Jeff posted (requires spacers to mount).

2) NCF 73463 $16.99 - Looks just like my original and the casting doesn't require any spacers (built into the casting).

QUESTION: What is the difference between these two clutch slave cylinders that justitfies a more than doubling in price of one over the other? They don't list bore size. The cheaper one visually matches my old one...

[Mt Hood Carl]

Bill is correct, a smaller slave bore means more effort for your leg. Also you need to watch out for running out of travel at the slave before the pedal travel stop. You could try to change both master and slave to smaller bore.

[VooDoo]

So more "effort" to push the pedal, but you push the pedal "less" distance for it to disengage the clutch. Is that right?

[Mt Hood Carl]

Yes. And that's where you can get into trouble with travel. You want the pedal stop to prevent the possibility of the slave bottoming out.

[VooDoo]

Thanks for all the helps guys! I'm just going to play it safe and go with the OEM 1" bore with the same casting as my IH stamped 68 one (NAPA: NCF 73463 $17, $0 no core).

Reserved one for my local NAPA store pickup tomorrow to inspect and confirm a 1" bore size.

PS: In the financial world, less movement in the underlying asset price (the pedal), yields more price movement in the leveraged product itself (clutch slave travel). Lol... The "effort" to move the underlying product isn't in the equation...

[cAlvis165]

Sorry to resurrect such a old post but I've been trying to search rather than start new threads. Voodoo, was the NAPA: NCF 73463 a 1" bore?

Thanks,

Chad