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Old 05-12-2018, 11:55 AM   #1
Old Truck Man
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converting hyd clutch to mechanical.

Ive got a 80.s 3/4 ton with a hyd clutch release. Now I don't like that setup. its troublesome and sometimes doesn't release very good. I was thinking of change to mehanical clutch linkage? Has Anyone done this conversion ?
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Old 05-12-2018, 12:45 PM   #2
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Re: converting hyd clutch to mechanical.

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Originally Posted by Old Truck Man View Post
Ive got a 80.s 3/4 ton with a hyd clutch release. Now I don't like that setup. its troublesome and sometimes doesn't release very good. I was thinking of change to mehanical clutch linkage? Has Anyone done this conversion ?
No, but I will buy your hydraulic clutch setup off of you when you remove it. PM me if you are interested.
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Old 05-12-2018, 01:03 PM   #3
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Re: converting hyd clutch to mechanical.

sounds like a air bubble hidding in the line is all .

everyone for the most part wants to go hydro clutch . . .

best way to blead them out i found is off the truck . hook it all up and blead it with the master upside down holding the resivor above it . and the slave above all that .

some aftermarket masters can have a bad molded nipple adaptor from the resivor hose to master body and can hold a air bubble up in them . mine did this to me years ago and thats how i found out blead it like i said . it can all be put in the truck still together . once i did this it was perfect till the day i parted out the truck .
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Old 05-12-2018, 02:38 PM   #4
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Re: converting hyd clutch to mechanical.

I prefer a mechanical linkage. When I got the truck it had been setting. got it running and the clutch would not release. fill the resivor full and pumped my leg off still no release. Thinking the clutch disk was stuck to the flywheel I pulled the trans. Nope the clutch and flywheel appears brand new. finally got on U tube and learned you have to remove the slanting master cyl fron the firewall and bleed it by hand, there is a bleed screw on the master and none on the slave cyl. yep I will sell the parts when I convert to mechanical linkage. Back in1960 GM trucks went from a below the floorboards pedals to firewall under the dash pedals. and went with a hyd clutch release. that changed to mechanical in 63. Those trucks had a dual master cyl and the brakes and clutch shared the same resivor. and if you got a leak you lost both the clutch and the brakes. I never liked any hyd clutch release and always converted every 60 thru 62 I drove to mechanical clutch linkage from a 63 thru 66 truck.
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Old 05-12-2018, 04:24 PM   #5
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Re: converting hyd clutch to mechanical.

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...there is a bleed screw on the master and none on the slave cyl...
My '87 has a bleed screw on the slave. Takes about 5 minutes to bleed it with two people. If it were me, I'd try a new master and slave(make sure it has a bleeder) before scrapping everything.

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...Those trucks had a dual master cyl and the brakes and clutch shared the same reservoir..
Interesting trivia. Most of the large-frame Ford tractors(80hp to 160hp) from the 1960's to the 1990's used that same master cylinder for the brakes. One side for the left, the other for the right. Their rubbers were different, since they ran mineral oil instead of glycol-based brake fluid.
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Old 05-12-2018, 05:38 PM   #6
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Re: converting hyd clutch to mechanical.

Here's the trick: Get a pump type oil can fill w/fluid,attach to slave bleed screw with clear tubing,crack the bleed screw, pump fluid up from the bottom until there are no bubbles coming through in the reservoir. Then close the valve on the slave without letting any air in. No need to touch the peddle. You may have to remove some fluid from the reservoir. The reason the system won't bleed out the air/bubbles is that there is so small amount of fluid being moved per pump that the bubbles just keep going up and down. The reason this method works so well is you are adding fluid from the bottom and the bubbles float up. I had the same problem and it drove me nuts. The hyd system works great and is in millions of cars and trucks. If you have a bad master or slave they are relatively cheap to replace. Please try this first ,works every time for me!! Good luck!! (Old Man with a truck too, 1982 K20) Look again there has to be a bleed screw on the slave cyl,

Last edited by akart; 05-12-2018 at 05:49 PM. Reason: add
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Old 05-12-2018, 05:55 PM   #7
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Re: converting hyd clutch to mechanical.

Im old and like simple stuff. I don't care if it works perfect to me its not as good as mechanical linkage. Just like my 1935 ford truck that has mechanical brakes no pesky leaking hyd fluid. or my 76 C65 chevy that has air brakes ive never had to bleed brakes or pour fluid in it. ive got part of what I need to convert to mechanical linkage.
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Old 05-12-2018, 06:03 PM   #8
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Re: converting hyd clutch to mechanical.

The thing is brake fluid absorbs moisture and that moisture eventually corrodes the internal parts of master cyls and slave or wheel cyls. And you also have to bleed them. and the GM clutch master is so tiny it only has enough volume to barely release the clutch if everything is perfect. A mechanical linkage even when rusty will move that throwout bearing more than enough and when released still have sufficient clearance between the throwout bearing and pressure plate. I just went to check on my cows. Drove my 66 GMC and realized what irritates me about a hyd clutch release. on the GMC when I press the pedal I can easily feel when the free play is gone and the throwout bearing contacts the pressure plate. I cant do that with the hyd setup.

Last edited by Old Truck Man; 05-12-2018 at 08:49 PM. Reason: add info
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Old 05-13-2018, 06:58 PM   #9
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Re: converting hyd clutch to mechanical.

It's the opposite of converting to hydraulic. Pedal assembly needs swapped, holes in the floor for the rod. Bracket for the pivot and pivot ball on the block. Change the bell housing and fork assy to mechanical.

I'd buy your hydraulic parts too btw.
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