62 slave cylinder push or pull?

[tj62]

I've replaced the master cylinder, slave cylinder, bled the slave cylinder and when I push the clutch it forces the push rod backward, toward the back of the truck. The plate the end of the pushrod sits on is already pulled toward the back of the truck by the hold spring.

I still can't get it in gear, though I know its bled and installed correctly. Just to clarify, the slave cylinder PUSHES the rod back which pushes the plate toward the back of the truck right now. This doesn't make sense due to their being a spring already pulling the plate back.

Any ideas? Its not supposed to pull the plate forward right? Is something going on in the transmission to keep that plate toward the back? Just got this truck and they told me the slave cylinder needed replaced, but they hadn't worked on the transmission.

Help me!! thanks!

Edit: I just put it in gear adn tried to start it and the truck jumped so I know it'll go into gear. Whether I push the clutch in or not, it still jumps and the truck rolls. It stays in gear until I try starting it and it rolls and i can pop it out of gear. The bar that the pushrod is in is staying toward the back of the truck (the direction the slave cylinder is supposed to push it) and doesn't come forward. What does that mean and how is it best fixed? And does it mean there is something wrong in the trans if the forked plate is already all the way back and I can't get it to go into gear with the truck running? Sorry, just starting to get into the rebuild, not much prior knowledge of vehicle work. Thanks!

[markeb01]

Here’s what the stock setup on a 1960 looks like. It sounds like your spring may be installed backwards. And yes the slave cylinder pushes the clutch fork toward the rear of the truck. I believe the pull type arrangement was still several decades in the future when these trucks were made.





It sounds like you may also still have air in the lines. In my experience it is sometimes necessary to block the clutch fork from moving (like with a 2x4) to prevent any movement at all during bleeding. This increases line pressure enough to force any remaining air bubbles either out through the slave cylinder or up through the master cylinder. I don’t know why these can be so hard to bleed, but it seems to be a common problem in this application, and blocking the clutch fork usually cures the problem.

[raycow]

Have you worked on the clutch recently? If the fork is all the way to the rear and you still can't disengage the clutch, you MAY have a wrong combination of pressure plate and throwout bearing. Another possibility is that you have the disc in backwards.

Ray

[Heater63]

Good instruction ray cow, you can get different throwout bearings to get the proper alignment of the fork.
A really good write up on this is at Novak Adapters. They have an aftermarket slave kit, I put one on my 63. The principles are the same.
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[tj62]

I got the truck as is. Someone has likely been working on it. They told me the slave cyl needed replacing. Good idea on the spring, ill check. With the fork stuck back where it would be with the clutch pushed in you think ot could he something in the trans? Or the clutch plate could be frozen? It hasn't been driven in about 8 years or so. Thanks for the hrlp all.
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[Heater63]

Adjust the slave pushrod until it is very slack or even remove it. Then see how much play you have in the range of motion of the fork. Pulling the fork end FORWRD towards the front of the truck will place it against the front of the tranny. In that position, the fork should be at 90 degrees or the end a little towards the front. Now move the fork end REARWRDS towards the rear of truck, after very short motion, the throwout bearing should contact the arms or fingers of the pressure plate. If there is a lot of movement, your throwout bearing is too short. If there is only a little slack, reinstall the slave pushrod, adjust it till it compresses the piston in the slave (open the hydraulic circuit for this) to seat the piston all the way in, but with the spring attached there should be 1/8 " or so clearance between the throwout bearing and pressure plate fingers at rest.
Rebleed and try again. The slave should move the rod, thus the end of the fork lever, towards the rear of truck. Probably 1-2 inches, and this should release clutch disc IF flywheel, disc, pressure plate, and throw out bearing are all correct and good.
Go to NOVAK adapters site
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[raycow]

Ya know, if the truck has been sitting for 8 years, the disc could very well be stuck to the flywheel or pressure plate. If it is, you have some work ahead of you, but it won't cost you any money.

Take off the bellhousing bottom cover if it is still on there. Turn the flywheel so you can see the edge of the disc. Now watch what happens while a helper pushes the clutch pedal all the way down. If the disc is stuck on either side, you will be able to see it.

Ray

[62 C10shorty]

Got to adjust the slave cylinder rod clearance tomorrow....can it be done easily from under the truck, or do I have to go through the cab floor? Any one of you guys out there from 2 years ago?!

[markeb01]

I’m still around, but I never adjusted the stock clutch in my truck. Right after I bought it I swapped in a 350 with a 350 Turbo Hydro. Looking at the photos it seems it would be much easier to do it from above, but they might have done it that way for the sake of the photography.

[62 C10shorty]

Okay, guess I'll start underneath and see how it goes. My floormat is original, and brittle like a taco shell so I'd rather not go at it from above or I'll be ordering $300 worth of stuff from LMC to re-insulate and replace. I'm sure you know what I mean!

[62 Barnfind]

When I was looking at mine the PO told me the rear wheels are locked. I looked at the engine and it was free. Then I checked the shifter and it wouldn't move. So when I got home I disconnected the drive shaft just to get it off the trailer. I went and bought a new duel master cylinder which I needed because I had no brakes. The problem was the column. It was setting for so long it was locked up. I put some WD 40 on it and worked it until it freed up. Bleed the clutch and it works fine now. I am in the Also you can find most of the engine and trans parts for this truck at Advance Auto. They are cheaper than LMC and the other parts suppliers.

[62 C10shorty]

O.k, used up my stooopid question quota for the week. It's accessible from above, but you do not have to go through the cab....markeb01 was right they took that picture in the shop manual through the cab, but the slave clyinder is right there on the passenger side of the housing looking down from the engine well.

[Pizzaholic]

I know this thread is several years old, but I found it searching for info on the SM420 4 speed manual in my '62 C10, so in case others also find it in the future...I think that the original post said that the previous owner had the return spring pulling the clutch fork toward the back of the truck. I think the return spring needs to be mounted such that it pulls the clutch fork toward the front of the truck so that it "returns" the fork to the original position thereby re-engaging the clutch, hence the name "return spring." That may have been the issue all along.