Hydraulic Clutch Travel- is One Inch enough?

[chevybill]

After doing several husband and daddy duties over the past month I finally got a chance to work on the truck today. In the picture below you can see my linkage setup inside the cab. The plunger is moving about 1 inch when the clutch pedal is pressed all the way to the floor. Is 1 inch of travel enough for the clutch to work correctly?
Welding a metal bracket around this plastic clutch cylinder assembly was stressfull and tedious to say the least.Thanks for the help, this is a NV 3500 late model tranny and clutch assembly from a 98 model with a home made bracket bolted to the firewall.
It's the best I can do with my limited tools and working alone.

[chevybill]

any one ?

[Yukon Jack]

My setup is from a 1989 Chevy 1 ton 2wd with the SM465. Looking at my old pictures I believe my pushrod moves maybe 1 1/4" - I will get an accurate measurement for you though.

Let me tell you I had one heck of a time bleeding my system. While I was having trouble I was getting no movement of the slave rod. I had so much trouble I don't remember at this point how I finally got it bleed out. I will do some searching of my old posts to see if I can help you.

Are you getting any movement at the slave when you work your clutch pedal?

[cdowns]

my hydraulic clutch on the 60ford is close to 2"

[shifty]

It would really be dependent on what the slave cylinder requires for volume. Best thing to do is to find out the bore/stroke that the stock master cylinder on the car you took the slave cylinder from was using, then figure out the bore/stroke of the master you're currently using, and adjust accordingly.

I know for my T-56 6spd, the stock master cylinder (98-02 F-body) requires a .750 bore + 15/16" stroke. I bought an MC with slightly smaller bore (.700) and figured up the stroke required to be a little over 1".

If the clutch is engaging/disengaging, I would leave "good enough" alone. And, for the record, you can get more stroke by moving the welded tab on the pedal up and down - you get more stroke at a lower mounting position on the pedal. I forget what this is called, but ...

[chevybill]

Thanks for the replies.

If I understand correctly no bleeding of this is required, I bought a clutch m'c assembly complete and full of fluid and plugged in to the throw out bearing on the tranny.

Yukon Jack, this later model does not have the external slave cylinder like 1989 that you used, and
thanks for your fast reply to my pm.

How can I tell is clutch is engnaging and disengaging? Truck is not running yet.

[shifty]

Ah, I thought it was running. I don't know how you would tell, the only thing you could do would be looking up in the bellhousing while someone is pushing the pedal and make sure the TO bearing is actually sliding up and down the shaft.

I honestly would not worry about this one until you can fire the truck up, but if you really want to calculate it all out ... here are some things I jotted down which may be of help. If this crap is over your head, just ignore it.

You can caculate the volume of fluid moved by your master cylinder by using this formula: ((BORE/2)² x 3.14) x STROKE = volume

Note: When using inches as the values for the bore and stroke, the resulting volume will be in cubic inches

Here are some figures (specs) for stroke/bore/displacement using SUMMIT part numbers on various master cylinders:

Stock master cyl for 98-02 F-Body = 0.75" bore/1.0" stroke = 0.4417ci = 0.00723816617 liters
WIL-260-1304 = 0.750" bore/1.4" stroke = 0.6185ci = 0.0101353991 liters
WIL-260-2636 = 0.625" bore/1.4" stroke = 0.4295ci = 0.00703824399 liters
WIL-260-6579 = 0.700" bore/1.4" stroke = 0.5388ci = 0.00882935008 liters

Here is what I suggest:

Find out what year your engine/tranny came out of, then go look up what the stock master cylinder for that vehicle has for bore and stroke.

Find out what the master cylinder you currently have has for bore and stroke.

Use the formula above to calculate the volume of fluid moved by each MC, and see how they compare.

Otherwise, just try to find out what the stroke/bore is of the MC you're using, then figure out what the slave cylinder requires to engage. If your MC has too large of a displacement, you can blow out your slave cylinder (supposedly...logically, it makes sense).

If they're close to being the same,

[chevybill]

The tranny is from a 99 s-10 and the hydro clutch assembly is from a 98 chevy full size.
So I think the 2 parts are compatible since this same tranny is used in full size trucks.

Based on fluid laws, I would think if the plunger move a little over one inch, then the throwout or release bearing would move that same amount is this correct thinking?

Thanks for all the information, Shifty.

[shifty]

I am uncertain on that. I can very quickly tell you that the S10 hydraulic MC has the same stroke/bore as the F-body and uses the same quick connect. I had several guys at LS1tech tell me that either MC would work for me.

So - in theory, anything from 15/16" to 1-1/16 stroke should be absolutely adequate, if not perfect, for your setup. I would leave it as is and be happy.

I am uncertain what the translation is between pedal mov't/stroke and actual mov't of the TO bearing is, so I cannot answer your question. I'm still pretty new to this stuff, but I have been trying like hell to understand it all.

Apparently, an MC is an MC is an MC. Whether brakes or hydr. clutch, they all work on the same basic principle, and ... once you figure out one of em, you can figure out any of them. Before dorking with the clutch, I was soooo freaking confused about what brake MC I could use .... now, it all makes sense .

[Yukon Jack]

I measured mine tonight and I have roughly 1" of travel, a little hard to get a precise measurement but very close to 1".

[Huck]

My 72 with a 96 truck hyd clutch setup---had no slave cylinder. Just the clutch master and the throwout bearing which was hydralic and self adjusting. An inch of movement at the Ms Cyl piston should be plenty to release the disc assuming there is no air in the line. What I found is that the pedal was actually harder then a stock system which was not expected. The other isssue is the "self adjusting" properties of the throwout bearing. Not sure just how to make certain that is doing it's job. I swapped the entire system from a 96 1/2 ton to my 72 1/2 ton. Believe it was a NV4300. I loved the 5th gear and the tall 1st gear. From what I have learned, the best application is from a late 80's to early 90's 5speed which can be retro fitted with a gear driven speedo in the tailshaft and you run a slave cylinder to a mechanical clutch arm and traditional throwout bearing. Less headaches.
I did loose hydraulics once when I pushed the Mast Cylinder thru the firewall---that is best avoided with reinforcing as you pictured. Hope this helps-Huck

[chevybill]

Thanks for all the replies, it sound like I am in good shape and that is what I was hoping for.

Can I expect to still need to bleed the system when time comes to start the truck and drive around?

[shifty]

It never hurts to bleed, and bleeding these systems is supposed to be pretty easy. If yours is anything like mine, there should be a bleeder post on the side of the tranny - they make one-man bleeder units (my friend just bought one for his S10), they're around $30-40 at your local auto parts store and worth every penny - talking 5 minutes tops to bleed, no help required.

[chevybill]

Shifty, there is a bleeder post right beside the connection for the clutch.
Are you talking about the one man bleeder that could be used on brakes as well? or something specific to this application?

[chevybill]

back to top one last time

[shifty]

Sorry, I am talking about the generic one you can use for brakes or tranny - the one you get at the local auto parts store. My T-56 also has the bleeder right by the quick connect on the bellhousing.