NV4500 clutch pedal/arm/throw adjustment

[73azbronco]

Edit: fixed see last post

My clutch pedal is stock bronco, same for clutch bracket mounted on frame to redirect arm. Clutch arm to clutch fork and fork stock.

I have an NV 4500 with dual clutch I think it's the big orange one. Use the throwout bearing for the clutch.nv4500,

I'm trying to dial this in but issue is I do not get clutch movement/disengagement until about 2 inches off the floor, and to get that I had to adjust clutch fork rod, the one off the frame bracket a little more than I would with stock ford clutch, there is no endplay.

Basically, I have to push the clutch pedal further than anything I used on a ford. Not bad just different. Anyone else with an nv4500 notice this? Can;t find any comments like this in forum search.

 

[orygunbou71]

I have nv4500 using stock linkage at bellhousing. I do have adjustable linkage from pedal to frame mounted bracket. Using centerforce clutch as well. No issues here. Maybe need the adjustable rod like I have from pedal to frame.

 

[73azbronco]

I have that adjustable rod but set the pedal to be even with the brake pedal, I might try raising brake pedal an inch to get another inch on clutch pedal. Problem is setting the brake pedal to the height it recommended.

 

[trailpsycho]

It has nothing to do withe the 4500 and everything to do with how you set up the linkage. You will need to make adjustments to the rod or elsewhere.

Good luck.

 

[DirtDonk]

I think it was finally determined that the diaphragm style clutch covers require more movement than the old three-finger "Long" style that came on Broncos.
I think it was years of swaps before someone on one of these forums finally asked what's up with the pedal to the floor thing. That was the first I'd heard of it, even after encouraging many swaps for the light pedal pressure they provided, and because Centerforce and others were using exclusively the diaphragm style.

And it didn't help that newer Fords were using them. But the difference must be that they have more pedal travel available, or a higher ratio.
A stopgap measure is you can just raise the pedal height, then re-adjust the linkage to suit. But you're right that the pedals should be as equal in height as they can be made to be.

Speaking of ratios... You could try changing the ratio of the pedal, or of the cantilever Z-bar assembly. Will lead to a stiffer pedal feel, but seems like if you just change it a tiny bit it would not be too stiff.
I wonder if we can come up with a lever design that accelerates as it travels farther? Like the progressive linkages on throttle assemblies.

Paul

 

[73azbronco]

I was considering using a longer throw point on the rod coming off the frame

 

[73azbronco]

Wondering if anyone has used a ford style pressure plate with the kv4500, or is that even possible. Pretty sure I have a stock flywheel for a 5.0/

Carpet almost done done for 4th time, then get this thing moving.

Anyone use the hydraulic clutch actuator, which one, and did pedal have to go to floor.

So used to any clutch starting to slip within an inch of pushing pedal,

I am also wondering if I didnt get the wrong pressure plate, I'm reading up and there are high perf pressure plates with virtually same specs of movement to the old for three finger, and actually hi perf versions of the 3 finger but all say strip use no street.

Lastly wondering why i couldn't just get a hi perf ford 3 finger PP, and use a 29 spline clutch? I figure that would make clutch engagement standard.

 

[DirtDonk]

Not sure about physical incompatibilities, but the main reason most were going with diaphragm style clutches for the last 30 years or so was simply because you could get the same spring pressures on the clutch plate with less pressure at the clutch pedal.
That and the fact that everyone wanted to use a Centerforce clutch, and they were only available in diaphragm style. Hence all the early conversions.

But whether there is an actual problem with a "Long" style 3-finger and perhaps the thickness of the necessary clutch discs, I don't know.
Hopefully someone has done it and lived to tell the tale.

Paul

 

[73azbronco]

Hope so, just not seeing why stock linkage with any pressure plate means having to hit the floor to make it disengage. Only thought is the fulcrum points on the pressure plate are made for much longer throw than a ford needs.
I'm finding reports on web of mustang guys having pedal to floor issues if they used the wrong pressure plate, mainly multi plate vs one plate.

Either way just sent an email to advance adapters see what they know.

 

[mrdrnac]

As Paul mentioned I added a hole on the arm of the Z bar that connects to the pedal. This increased the pedal pressure slightly but also made the clutch disengage sooner.

 

[73azbronco]

i will look at that but I'm not getting any sign of disengage until 1-2 inches off the floor.

 

[DirtDonk]

That far? Even with free-play verified at just that little tiny bit that's specified? Are you sure you're not also dealing with some flex in the Z-bar setup?

Paul

 

[73azbronco]

thats a good question let me get my helper on this. I was sure I replaced all the little white bushings that hold that thing.

 

[73azbronco]

dont think thats it will check when i get seat back in

 

[73azbronco]

Talked with advance, they say everything they would have sold me 10 or so years ago was stock to ford except adapter and tranny, so guess I am going to open it up and see what damage I did somehow...... wish I took more photos of that pressure plate, like one.

thank god for huge backup drives, found the picture, it says centerforce that looks to be the one it should have. I gots other issues evidently. Anyone able to give me measurements of length of the throw of the clutch pedal arm, and each arm on the z bracket? Could I have a mustang clutch pedal assembly or something odd like that? I did mod a stock C4 non manual tranny into a manual by simply adding a clutch pedal to the brake pedal bracket, easy peasy, to easy?

I'm tending to think I have the wrong bearing length.

 

[lars]

Sample of one, so it doesn't make for good statistics. But...

I've had an NV4500 in my Bronco behind the OEM bellhousing with AA adapter since 2005, using the orange Centerforce clutch. The engagement band (travel required from full engagement to disengagement or vice versa) is long, much longer than with the early 3 finger pressure plate. At least in my experience.

The pedal to transfer bar link is what sets the height. I dumped the OEM part not long after swapping in the transmission in favor of one I made myself, incorporating spherical rod ends instead of the standard eyes, plastic bushings, etc. Smoother operation. Mine is set so the brake and clutch are the same height.

The transfer bar to clutch arm rod length sets the height above the floor at which the clutch releases completely. The OEM setup should have plenty of adjustment. There should also be a long coil spring between the clutch arm and frame, pulling the arm forward so said rod can't fall out of the socket in the clutch arm. When the last plastic bushing on mine finally died a few months ago I tossed that, bought another spherical rod end and some threaded rod and got rid of that cheesy joint. More clutch smoothness..

All that said, if you lengthen the last-described link above you should be able to set the disengagement point as high as you want unless something is wonky with the throwout bearing or clutch arm pivot inside the bell housing.

 

[73azbronco]

Thanks Lars, exact same issues, finding that higher HP pressure plate does need longer throw to disengage, considering dropping down to the 400hp zone, mine is a 475hp version going to call centerforce see what they say. I bet they say no change though. leads me back to wrong bearing thickness.

I am wondering if it is more the clutch plate itself, as it compresses or releases, it takes longer because it is built for more power so it compresses more resulting in some friction all the way to the floor. as it blends in.


Anyone have a clutch arm measurement from say front of bellhousing plane to detent point on arm in full forward position with clutch linkage installed and adjusted? That would be only way I can see to determine if bearing is to thin without dropping tranny. ouch.

My long ago regret is haunting me, only thing i did not measure and remeasure is the clutch plate throwout bearing setup, I just used the provided parts.

 

[73azbronco]

Talked with centerforce, they say the kit they sold to advnce adapt back in the day would have had a special machined clutch plate and throwout bearing. I do not think I had that, I recall having to drive across town to a heavy truck parts supplier to buy a clutch plate that fit. I'm going to have to drop a tranny. Not impressed having it adjusted with throwout bearing already pushing pressure plate arms.

I have a custom one piece welded exhaust going under the d20, dang, going to have to cut and mod that thing now. It never ends.

I did get a number, he said the diaphragm pressure plate needs 3/8ths movement to disengage, thats at the bearing not the fork arm, the three finger would move within a couple thou of that. Essentially, all things equal, I should not have to be going to floor to get clutch disengaged. A hydraulic actuator would just mask the issue.

 

[lars]

I made a couple of measurements. A little background first. My Bronco was a manual transmission model from the get-go. Stock bell housing, equalizer bar (bell crank or what ever you want to call it), clutch fork, throwout bearing. Stock pedals, linkage geometry, pedal height, etc. Now running (for the last 15 years) an NV4500 with Centerforce pressure plate and disc.

Pedal height/travel measured as best as I can from floor to pedal is about 7". I have a floor mat with padding underneath, so actual travel to metal floor would probably be more like 7-1/2". I made the clutch pushrod myself from a piece of round bar that I threaded with a spherical rod end at both ends, but it's otherwise stock length and geometry. FWIW the brake and clutch pedals are at the exact same height off the floor, though it may not look that way in the photo below.

I also made the clutch fork pushrod utilizing the OEM business end but again with a spherical rod end to replace the stock eye and a length of all thread. That piece is 6" long from center of rod end to tip of pushrod, as best as I can measure. Same length as the stock piece it replaced.

My clutch is released completely about 1-1/2" above the floor, again about as best as I can measure solo.

Hope this helps.

 

[73azbronco]

Thanks lars!!!!!! Thats service! Will look at robbing your idea for rod ends.