70 fastback 351C clutch return springs

[Rcodenewf 44]

Just installed a new clutch/pressure plate on the 70. The springs were not correct for the car and were gobbled up with some tie wraps. I ordered the correct springs. A small one for the clutch fork. I installed it form the little hole in the clutch fork forward to the hole in the Z bar. Keeps the rod from flopping around.

 

The other one, part number C9ZZ-7523-A I believe goes in a hole in the top portion of the z bar back to the firewall. Anyone have good pics of these springs correctly installed.

 

Also my understanding is that there should be about .080 clearance between the clutch rod and where it fits in the clutch fork for freeplay?

 

Thanks...john

[Print Dad 58]

Hello John,

I am pretty certain that on our 70 Mustangs there are only 2 springs

 

The first is installed as you have done between the fork and the Z bar.

I am sure there is a spring under the dash at the pedal

 

The spring you refer to - -the small one going from the Z-bar to the firewall

is NOT used on our year car.

I know there is not one on our Mach and no place to attach it at the firewall

I think this was used on earlier years.

 

You will be fine just the way you are set up

 

Yes a little free play is needed so that the throwout bearing

is not rubbing on the pressure plate. Not sure what the exact measurement is.

 

Hope this helps a little

 

Print Dad - Sam

[1969_Mach1 333]

The spring from the upper lever on the Z-bar to the firewall is the only spring that is intended to be the "clutch return spring".  The small eyelet it attaches to on the firewwall is on the reinforcement ring that strengthens the opening where the steering column passes through the firewall.  It seems lower than you would expect, but that's where it is.  It's actually easier to attach to the firewall eyelet from underneath the car.  The compression spring under the dash is an assist spring to help push the pedal down when applying the clutch.  It also helps a little to hold the pedal up but it's not intended to be a return spring.  Then, as you already noticed, the lower spring is to prevent the clutch rod from falling off of the clutch fork.  I think your free play adjustment is about right.  From my manuals, there should be about an inch of free play at the pedal.

[Rcodenewf 44]

Thanks guys. That helps a lot. I have the car on a hoist so i'll see if I can locate that eyelet on the steering column reinforcement ring. I've already overhauled all the bushings etc in the z bar and pivots.

Will keep ya posted.

 

Much appreciated!

 

John

[Rcodenewf 44]

69_Mach1:  You were right. I attached the spring that I ordered in onto that little eyelet on the reinforcement ring of the steering column opening and forward to the Z bar. Took a bit of 'fandangling' but as you say it was easier to attach the spring to that eyelet from under the car. Then in over the fender to attach it forward to the z bar.

 

I can see clearly now how it holds the z bar back and therefore pushed the clutch pedal up to the bump stop.

 

After adjusting the clutch on the hoist and letting the car down I note that the clutch pedal has to be let up quite a bit for the clutch to engage so i'm going to recheck my measurement at the fork for the correct 1/8" gap. In essence if i'm correct the rod will need to be slightly shortened.

 

Print Dad: I checked my R code mach1 and it too is missing the upper z bar spring but the eyelet is there for it as is the notch in the z bar for the spring.

I'll be replacing that one too.

 

Thanks again, John

[1969_Mach1 333]

Glad you found where it goes.  It's not the easiest spring to install.  Yeah, shortening the rod to the clutch fork a little will move the engagement down lower on the pedal travel.  I have to readjust mine again for the same reason.  I think it's normal but I prefer it to engage and disengage about in the middle of the pedal travel.  I've seen in NPD's catalog a concours correct spring for 428 Mustangs.

[Rcodenewf 44]

Yes it's a bear to install for sure. I'll have a look at that concours spring. thanks to all.

 

...john

[Print Dad 58]

Hello John,

I was wondering if there was any chance you could post a picture

of the spring in question. I think I understand where to look for the upper mounting

but not sure where it attaches to the Z-bar. I was only under the car a short while and

didn't look around when I installed my spring between the fork and the z-bar.

I know I ordered a spring - but thought they had sent me the wrong one

 

A picture would sure help me and likely others

 

Thanks - Sam (Print dad)

[1969_Mach1 333]

Print Dad, there should be a small hole or notch in the Z-bar at the first bend below where the upper rod attaches to it that goes to the brake pedal.

[barnett468 418]

if you installed a diaphragm pressure plate I would remove the spring under the dash.

[1969_Mach1 333]

Good point about the clutch assist spring with a diaphragm clutch.  I don't know how true it is, but I was warned against a diaphragm clutch with the stock clutch linkage.  The reason being with the stock clutch linkage geometry, you end up with a very small pedal travel from full disengagement to full engagement.  Therefore, making the clutch more difficult to operate smoothly.  I never tried it, so like I said, I don't know how true that is. 

[Rcodenewf 44]

Print Dad..i'll try tomorrow to grab a pic for you. We just installed a Mcleod diaphragm clutch in the 70 and it works great. Overcenter spring is still intact under the dash. Works very smooth.

 

John

[barnett468 418]

I've installed countless clutches . A diaphragm works noticeably more progressive WITHOUT the under dash spring, in fact, the spring can cause the pedal to return so quickly once it reaches the half way point n some cases that it tries to throw your knee into the steering wheel . A diaphragm pressure plate is NOT designed to work in this system . The best replacement is a stock type 3 finger pressure plate.

[stangs-R-me 120]

I found a pic of the firewall to z-bar spring on my car (1969 351W) that I took while I had my car apart doing a complete brake, trans, AC/Heater box, steering column, etc. overhaul back in 2011.

 

BTW ... I also updated to a Centerforce Dual Friction Clutch & Diaphram type PP kit while doing this overhaul.   All linkage is still stock (with the exception of removing the pedal assist spring and adding a Mustang Steve Bearing kit on the shaft) and could not be happier with the pedal action.

 

Anyway, I'm guessing this spring installation would be the same / similar on a 1970 351C ...