NV4500/ NV3500 clutch master pushrod travel distance?

[Winchested]

Anyone have an NV4500 or nv3500 in their rig that could measure the clutch master push rod distance travelled when clutching all the way in?


(For my Scout II)

I'm trying to set up my clutch pushrod by modifying the stock arm. So far a center to center of 2.6" gets me 1.5" of pushrod travel, a center to center of 3" gets me 1.75" of travel.

Thanks for any help

 

[Lowrollin70gmc]

If someone hasn’t responded by this weekend, I’ll measure the stroke of my 84’s NV4500 master when I get to my hobby shop Friday evening/Saturday morning.

 

[Winchested]

If someone hasn’t responded by this weekend, I’ll measure the stroke of my 84’s NV4500 master when I get to my hobby shop Friday evening/Saturday morning.

Thanks man. Appreciate it.

I'm basically just hoping 1.5 to 1.75" is enough travel to disengage clutch. My Scout pedal has 5.75" travel but the bell crank being so high up on the pivot I only get a short amount of travel with the bell crank. Unless I make the center to center difference longer but that changes the pedal to travel ratio.

Unfortunately due to where the master is and where the fuse block is I can't go right off the clutch pedal arm I have to use the stock scout style bell crank at the top of the pedal box and put the master on the opposite side of the booster thru the firewall.

 

[toomany]

I'm not familiar with how the stock Scout style linkage. Does it use a crosstube through the pedal box, then down to the bellcrank? That's how mine was. Switched to this to get the master over some and inline with the clutch pedal.

Could you use something like this?

This is on a 70 K5, also with an NV4500.

 

[Winchested]

I'm not familiar with how the stock Scout style linkage. Does it use a crosstube through the pedal box, then down to the bellcrank? That's how mine was. Switched to this to get the master over some and inline with the clutch pedal.

Could you use something like this?

This is on a 70 K5, also with an NV4500.

The Scout pedal runs a mechanical rod through the floor with a 2.6" offset off the main pedal box pivot point. So mechanical bell crank clutch.

Unfortunately with vac boost brake I don't have room to run a master off the pedal itself. I've got to run it off the original rod offset but at a different angle to get a horizontal movement rather than vertical.

 

[Winchested]

This is the master/ slave I've got. Was for 92-95 external slave

 

[arse_sidewards]

Could you use something like this?

That seems like a real slick solution that would work in a lot of vehicles so long as you have room for the brake pedal to start off higher.

 

[Lowrollin70gmc]

Sorry for the delay, got caught up with some harvesting last night.

Stock 1986 C3500 master with 1986 GM hydraulic clutch pedal and pivots. (Installed in my 84 C1500 with an internal slave ~2000 GM NV4500)

Master has a installed 1.5" stroke with the bore listed at 11/16".

This pickup served as my daily driver last year and shifted well.

 

[Lowrollin70gmc]

I also just measured a 1993 K3500 NV4500 setup as it's parked in the shop as well.

I have the pedals, master/slave, and trans in my 53 Willys. All stock external slave NV4500
Measures a 1.5" stroke, bore lists as 11/16 as well.

Haven't driven this one, but all components are stock or stock replacement from the 93 donor truck.

 

[Winchested]

I also just measured a 1993 K3500 NV4500 setup as it's parked in the shop as well.

I have the pedals, master/slave, and trans in my 53 Willys. All stock external slave NV4500
Measures a 1.5" stroke, bore lists as 11/16 as well.

Haven't driven this one, but all components are stock or stock replacement from the 93 donor truck.

You're the man thanks very much!

 

[Lowrollin70gmc]

No problem.

More info for those that find this in the future:

Now that I've thought about it, I'm also 95% certain the NV3500 & T56 use the same internal throw out/slave as the NV4500.

I run a late model GTO slave on the 84's ~2000 NV4500, which is identical except for the input fitting to the slave that came off it. (I wrote a prior irate4x4 post with part numbers). I also have two 2WD NV3500s sitting here (1 S10 & 1 C1500) and their slave looks identical as well.

And I know I have too many old 5 speeds laying around. There's a spare early 2wd NV4500 in my garage at home as well.

 

[Winchested]

Yes I believe the early gm Nv3500s used the same external slave and master as the NV4500.

 

[Winchested]

I also just measured a 1993 K3500 NV4500 setup as it's parked in the shop as well.

I have the pedals, master/slave, and trans in my 53 Willys. All stock external slave NV4500
Measures a 1.5" stroke, bore lists as 11/16 as well.

Haven't driven this one, but all components are stock or stock replacement from the 93 donor truck.

I'm curious now how far your slave moves when pedal is full pressed.

I'm getting about 1/2" to 5/8" movement on the slave (bolted into the bell housing)

And you can def tell the pedal travel is full on the master because my pedal has about 1/4 more travel it could go.

Good news is my under dash pedal setup worked mint.

Double checked which clutch I put in to make sure I had the right TOB LUK 04902 which is listed for the 92-95 nv4500 with external slave.


Was sposed to be a pre-bled master/slave. I think I'm going to try and reverse bleed it this morn and see what happens.

 

[Winchested]

Figured it out. Clutch wasn't bled, so don't trust those pre-bled masters and slaves.

Bled it by just taking cap off, unbolting slave and pressing the slave all the way in/out a bunch of times. Then plugged the slave with a bolt (buried the piston) with a clamp. Pressed on the master and only had 1/8th inch of play. Which is perfect.

Vid shows no output movement when clutch pedal is in.