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Clutch Pedal OR Leg Press :/

7K views 44 replies 23 participants last post by  happystang 
#1 ·
Well, I am depressed because I can hardly depress my clutch pedal. Toploader 4 speed and this McLeod super street clutch https://www.summitracing.com/parts/mcl-75213.

Clutch pedal is insanely hard to push with the original z-bar system. I bought a new zbar kit from CJ ponies and the clutch from Summit. My garage was crushed during the hurricane and so I have no place to try and pull the engine and trans anymore. No motivation to pull the trans back out. Hoping there is some type of external hydraulic clutch kit that works without removing pilot bearing. I have successfully pulled off the 8" bolt transmission slide to replace a clutch fork once before so that is my last resort. If there is any type of extra assist spring or trick to reduce clutch force please let me know. I cannot drive the car how it is now, but I'm guessing I could manage if I installed a seat which gave me more back support for leverage. Looking for advice from the creative ones here, it's a long shot. Thanks!
 
#5 ·
I wish I was just missing the spring. I installed it myself so I know it is there :wink:
Perhaps the spring needs to be replaced tho. It seems very strong and firm, but it is original (just blasted and zinc'd)
 
#3 ·
What type of HP levels are we talking about ? You might not need the clutch currently in the car. I used a Centerforce I in a couple of GT350's that had a vintage Paxton installed. Easily a 80-100 HP boost. It was very easy to push in the clutch, even for my 16 year old daughters who learned how to drive in the car.

Before I'd think about adding on hydraulic assist as a bandaid, I'd think about the clutch selection .

Z
 
#4 ·
The hp was really the limiting factor when we were selecting clutch. The 333 stroker engine makes almost 440hp from the flywheel. The engine builder really might have gone overkill on the engine. We were looking for a street/autocross car, but the high horsepower has caused us several occasions in which upgrades became necessary.
 
#9 ·
The Summit link shows a diaphragm style pressure plate so if you are having trouble pushing the clutch pedal something is wrong. Have you done the roller bearing mod on the pedal pivot?
I have a Centerforce diaphragm style with the roller bearing mod and the clutch pedal effort is just about zero.
 
#10 ·
As AWHTX put it if you have that clutch you have a different issue. I put a Mcleod diaphragm behind my FE and I can push the pedal down with my hand. Check to make sure the linkage not binding or rubbing on anything, and also make sure that z bar is aligned and not at some weird angle relative to the engine, should be about 90 degrees relative to the centerline of the block. How does the pedal move without all the stuff hooked up? What about the z-bar does it move smoothly with the linkage disconnected? Did you get the right arm for the release bearing, and is it on the proper pivot point?
 
#11 ·
I have the stock 289 High Performance 10.5" semi-centrifugal clutch, and it's quite easy. Of course, the clutch and linkage are in perfect condition, and properly adjusted. I betcha your pedal bushings are trashed. Eventually, I'll install a roller kit on the pedal, then it'll get really easy. I'd suggest you do that now, and consider a less ridiculous clutch. The one I have was also used on the BOSS 302. You have more power than the BOSS?
 
#13 ·
Don't rule out friction from worn parts too. When I converted to a 4 speed Toploader from a C4 I unstalled roller bearing clutch pedal kit from Mustang Steve and made my own linkage with rods ends. it eliminates a lot of friction. I'm not saying it'll cure the problem but it will help.





 
#14 ·
I converted my 68 to T-5 with that same clutch. But at the same time did the rod ends and the roller bearing on the clutch pedal. It is stiff but I had not pushed a clutch pedal in 35 years. After driving a little I think it is going to be fine or maybe the leg is getting stronger.
 
#16 ·
Diaphram clutch needs to be in your future. The old 3-finger is "caveman stuff"!
Also....I will "bet dollars-to-doughnuts" the clutch pedal bushings need repair/replaceing with roller bearings.
(A major pain to remove but well worth the effort) Remove it and send it to Mustangsteve and he will refurbish it and ship back in a few DAYS. (He's retired now so he can do Mustang stuff full time!) GREAT guy BTW.
Replace all the pivot points with Heim joints help a lot too! Take a look at repairing the Z-bar too. All of these spots cause friction and should be addressed.
Good luck
6sally6
 
#17 ·
I vehemently disagree with your characterization of the clutch. The so-called "caveman" is a semi-centrifugal plate, which increases it's grip with increased rpm. The diaphragm clutch uses spring pressure, and was mainly adopted because it's cheaper.

I repaired a 69 428 CobraJet one time. Clutch so stiff I had to use both feet to shift it to get it into the bay. Pedal support was trashed. I put the Drake roller pedal kit in, put it all back together, adjusted it to factory spec, and had an 11-year-old girl try it out. I never even touched the clutch itself. No problem for her, it was that easy. So, anybody who thinks the OEM performance clutches are difficult either has a damaged linkage, or is truly a girly-man.
 
#18 ·
I just did the Mustang Steve bearing mod, it's much smoother than even a pedal with new stock bushings. If your pedal shaft is worn you need the sealed bearing in the Mustang Steve kit vs the Drake kit.
 
#19 ·
22GT and other have nailed the issue with a stiff clutch.

although the aftermarket clutches do require more effort to disengage, most of the problems with a stiff clutch can be traced to the linkage and worn pedal bushings. There are great upgrades available today like the pedal support repair kits that Mustang Steves and others offer, and the roller set-up on the Z bar, either from Opentracker or homemade.

But just repairing the problem areas back to a like new condition will have a dramatic effect on the ease of operation. A very little attention goes a long way.

Z
 
#20 ·
I struggled with a stiff clutch for a whole season after putting in a new clutch kit. It turned out my linkage was at a slight angle so when I pushed on the pedal it went in at an angle making it very hard. Once I adjusted the linkage to be straight (adjusting the chassis mount) my clutch goes in smooth as silk no effort at all
 
#23 ·
I had that problem with a Dodge Charger I converted to a 4sp. The clutch is a diaphragm type dual disc. Everything was new and well greased and my geometry was correct. It was suppose to be an EZ to push clutch. I relocated one of the pins on the Z-bar about 3/4" and it made it much more drivable. It took a little grinding, drilling, welding and pressing to relocate the pin, but it only took an afternoon to do.
 
#25 ·
The roller clutch linkage will make a world of difference, even in a car with properly working stock linkage. Changing the pivot points to bearings is a huge improvement over the stock system. We have the Scott Drake roller pedal kit too.

Roller Clutch Linkage 65-70 Mustang - Opentracker Racing Products

1967-70

1965-66


 
#28 ·
This is definitely not a me problem it is a clutch problem ;). I will try a roller bearing kit to begin. If that does not work I will try the roller linkages and if that does not work... Come to think of it the Zbar might not be mounted completely straight due to the IFS kit, so I will check the angle first. Thanks for all the helpful responses.
 
#29 · (Edited)
Here's my lesson learned about linkages: I had the stock Z bar, stock plastic buttons stock. I decided Hydraulics were going to change my life and since I diy everything (read cheap bast#$%d), I measured the clutch arm throw per pedal push and matched the leverage on my hydraulics. Imagine my surprise at not predicting that I would not feel any pedal pressure difference. Turns out my stock clutch system actually worked as well as hydraulics. Soooo, cable, hydraulics, electro-mechanical, same leverage - same umph. That said, look elsewhere for your solution first, then if you still have the issue, see if you have enough throw to change the leverage in the system e.g. drill a new hole. In other words, see if you can drive the car fine with 3/4 clutch push - I could, so I went down a size on my master cylinder and changed the leverage, made a huge difference. I will say hydraulics gives the definite illusion of being smoother (imagined or not I'm gonna believe it!) and my header life got a lot easier and when I dropped my motor an inch, NP!
 
#30 ·
Lower Clutch linkage is at a pretty decent angle pointing towards driver headlight almost... :( Do you guys think this solution will work or have sugestion of own? Need zbar further towards trans or just need to move linkage head closer to engine. Heres my crazy diagram!
 

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#32 ·
Are you sure that the clutch itself isn't just bad right out of the box?

I ask because I got a brand new RAM diaphragm clutch that was completely bad right out of the box last year. This clutch was supposed to be a nice light pedal and was made for fairly mild motors, so nothing nuts. But when I installed it it was impossible to push down, and was only "all-on" or "all-off" - no in-between to feather it or anything. Have no idea what was wrong with it as it was all installed per instructions. Returned it and just bought a different 3-finger clutch and all was fine.
 
#33 ·
The upper and lower rods should be as straight as possible. I don't think changing that angle is going to fix you problem on it's own. It's possible you have several issues with the linkage, all adding up to a stiff pedal. You can fix that lower rod angle with a rod end, a grade 8 bolt and spacers. I have a stiff 3 finger clutch with roller linkage in my Falcon. I like the feel they have over a diaphragm clutch.
 
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