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Discussion Starter #1
Ive got a 78 f150 that had a 351m/c6 stock. Swapped in a 460/t-18 from an 85 f250. The bellhousing was for hydro clutch. I got all the stock 70s clutch linkage and its installed correctly. I cut the slave cyle mount off the bellhousing and just put the clutch rod to it like it would be on a stock 78. Now when i push in on the clutch it is stiff enough to make the firewall pop. Anyone got any ideas what the hell the problem is? Clutch kit is new. It was all installed the correct way and the engine slid right into place. Didnt have to force anything together and it lined right up on the input shaft. Would the pressure plate for a hydro clutch be stiffer that a manual clutch maybe?
 

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The 460/T18 combo you swapped in was together and working before you put it in? If not and you found your parts piecemeal you might have a modified motor bell, not a 385 series bell. Was the bellhousing aluminum? Not going to solve anything now, but why would you remove the hydraulic setup for mechanical linkage? Seems like a step backwards...

Later,
Jason
 

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Discussion Starter #3
460 and bell setup came from the same truck.Trans i already had.Its the aluminum bellhousing with the cast in slave mount. Im on a time crunch and had the clutch linkage already in the truck. It was either cut the mount out of the way or buy all the hydro stuff and fab a mount and reinforce the firewall. I assumed that with the stock clutch linkage and the bellhousing having the clutch fork sticking out it wouldnt be a problem.
 

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I can't honestly say that I have a ton of experience with Ford manual transmisions, I haven't messed with any besides the ZF, but I have parted quite a few out. Anyhow, point is I'm just pretty much thinking outloud but take it all with a grain of salt. C6 is my flavor of trans...

Anyhow, I would really doubt that the pressure plate is made much if any differently, especially since as you say it uses a clutch fork and external slave. My thoughts are: is it possible your clutch fork is bound or missaligned on the throwout bearing? Throwout bearing bound on the input shaft? I wonder if this is just a matter of leverage-- if the clutch fork is shorter for use with the hydraulic system I could see it being much more difficult to disengage, but from your description it sounds like the fork does not move at all... Can you get the clutch to disengage at all? Can you get a decent view at the throwout bearing via the clutch fork opening? My buddy had this happen with a SM465, and in the end it turned out to be a jacked up clutch fork.

Hopefully some of the guys who run manuals will chime in. I know there are quite a few of them in here. I doubt I have been of much help, but maybe it will spark some ideas.

Good Luck,
Jason
 

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There's a mechanical advantage in the hydraulics, 1" bore slave and IIRC 3/4 or 7/8" master. I believe the lever ratio of the hydraulic clutch forks is different than the linkage ones.


In short, change the lever ratios so you get more force, less travel on the clutch fork from less force, more travel on the clutch pedal.
 

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Discussion Starter #6
Ill have to check the clutch fork verses a 70s manual one. Everything has free range of movement. If i take the linkage off the clutch fork i can move the fork back and forth all the way without any problems at all. The bottom of the inspection cover is missing so i can watch the throwout bearing and it moves fine and free by hand when using the fork. I think youre correct about the length and leverage but ill have to check it out.
 

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Discussion Starter #7
Well not only is the clutch fork on a manual clutch longer the pivot point is different. That looks like what my problem is. I guess ive gotta pull the fuckin t18 and 205 back out. Fuck that shit is heavy.
 
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