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Clutch problems on 66 Mercury

5K views 21 replies 12 participants last post by  broncoII88 
#1 ·
I need some input on some problems I am having with my clutch. Last year my clutch went out on my 66 Mercury Comet and I had a shop replace it. The new clutch then expired after 30 miles of use and the shop owner refused to do anything about it. My car then sat until just 2 days ago when I finally had enough time and money to fix it. The problem I am having is when I push in the clutch it hardly moves the fork and then the pedal sticks to the floor. This is the same problem I had with the Centerforce Clutch I just replaced. The shop who replaced it last year had to lengthen the clutch adjustment rod to just get the clutch to work. I bought a Ram Clutch to replace the Centerforce Clutch, this was the same clutch I used before the Centerforce Clutch. I did not have any problems with the Ram Clutch until it expired last year. Does anybody have any ideas, could there be something wrong with the mechanical clutch linkage or is something else wrong?

BTW, the clutch isn't slipping it just isnt engaging and the pedal isn't releasing.
 
#3 ·
The throwout bearing came with the Centerforce Clutch, it wasn't a bad or installed wrong. I am going to pull the fork boot this afternoon and check to make sure the thowout bearing on my new clutch didn't slip off the fork when I stabbed the tranny last night. The tranny went in pretty easy last night so I doubt this will be the case, but I am going to check it out anyway.
 
#4 ·
Since that shop dicked around with the clutch linkage :nono: , they prolly messed something up bad which is haunting you now. The cheap clutch that shop used I'M thinking was prolly the WRONG ONE. If they used the wrong one, then something might have screwed up the linkage/fork mechanism. :pain: :confused:
 
#5 ·
Start from the ground up.

Take it all down. Remove the flywheel, have it surfaced. replace the shaft bushing in the middle. If it is a bearing replace with bushing.

Next buy a 180 lb 8 spring HD clutch plate, and roller release bearing with grease fitting. (dont forget to grease it 2x a year)

Check to make sure the release bearing was not install backwards and the petal return spring move the petal freely when no hooked to the clutch fork.

Also check to see is the pivot rod between the petal assy and the release bearing fork isnt adjusted all the way out. If the wrong plate or bearing was installed, a way to compansate would be to crank it out, restructing the fork travel.

Also anyways post engine size, 3 or 4 speed and floor or 3 on the tree linkage
 
#6 ·
Try this. Have some one push the clutch petal in real slow while you are under the car and watch it. I have seen the flat pieces of metal peal away from the pivot shaft when the clutch is pushed. I have seen forks that are cracked flex when the petal is pushed. Its amazing how you wont even see the crack in the metal unless the clutch is pushed in. Just watch it and see if there is anything wrong.
 
#7 ·
I'm going to echo what 454 said-I had a Mustang 4 speed that did that as soon as I put in a performance clutch. I pulled down the linkage,welded and gusseted the pivot arm,beefed up the rods . The problem disappeared.
Check the nylon bushings on both ends of pivot arm-they add a lot of play when they're gone also.

Good Luck,George :cool:
 
#8 ·
The clutch works fine, it is not slipping a bit at all, the pedal is just stuck on the floor and it wont adjust out. I had my girlfriend press on the clutch pedal as I was under the car and everything looked good. I pulled the dust boot off the fork and checked for movement of the throw out bearing and to see if anything was not right, everything was good there. I checked the pivot points and nylon bushings on the equalizer bar and everything is good. The last thing I checked was the rod coming off of the pedal assembly and the pedal return spring. The rod looks like it is coming out at a angle and the clutch return spring on the pedal assembly wont tension when the pedal is pushed. I went over to Ford Forum.com and somebody over there said that since my car was originally set up for a long style clutch that a diaphragm clutch wont work unless I get a weaker clutch pedal return spring. Is this true or is it a bunch of BS, I cannot find anything else wrong besides the pedal return spring and clutch rod. This is the second clutch that has been put in my car with the exact same problem. This is driving me nuts and I am about ready to say forget it and let it sit another year.

BTW, the engine is a 66 289 with a cast iron 28 spline 4 speed Borg Warner T10 out of a 65 Ford Fairlane Fairlane. The flywheel was resurfaced and the clutch is a 10" Ram for SB Ford.
 
#11 ·
Clutch

It seem to me that if you are seeing little to no movement of the fork and the pedal is stuck to the floor then you have a linkage problem. The clutch would return without a return spring. The return spring only holds the throw out off of the fingers so its not spinning all the time. I am assuming that this is a purely mechanical clutch linkage. It almost sounds like a hydrolic that needs to be bled. If teh disk was installed backwards then it would not engage at all period. If someone turned down the flywheel to much it will move it away from teh throh out bearing but that is a long shot. My guess is they monkeyed with the linkage more than they are admiting. When you said the clutch only lasted 30 miles. What was wrong with it. Was it slipping or was it that it would not disengauge. If it was slipping it was probable adjusted wrong and it will burn up real quick. If it wouldnt release my guess is the linkage broke or bent somewhere.
 
#13 ·
The last thing I checked was the rod coming off of the pedal assembly and the pedal return spring. The rod looks like it is coming out at a angle and the clutch return spring on the pedal assembly wont tension when the pedal is pushed.
Are you absolutely sure you have the correct pedal asm./pedal to bellcrank actuating rod and/or bellcrank? It sounds as if there is incorrect actuation of the bellcrank (due to incorrect/bent/out of alignment linkage) not allowing full release of the pressure plate.

Did the clutch asm. come with installation instructions? It used to be on GM applications that used these as stock (diaphram), whereas FORD used LONG or BORG-BECK style (finger actuated plate) that once installed, proper adjustment could only be made with an air gap measurement made between the disc and plate while fully depressed. If the linkage is not allowing full release, the pedal will hang on the floor or near to it.

Also heed the previous advice about a turned down flywheel. There are shims available to bring it back into the correct relationship with the clutch asm. The other poster that recommended reinforcing and gusseting linkage parts also has a good idea, especially on a race car. Have you checked the availability of a clutch cable conversion? It will rid you of all slop.
 
#14 ·
i'm going with the clutch return spring theory, as i've had this happen to me on a car i changed the clutch from the long style to a diaphragm style. the "return" spring is more like a helper spring that has a break-over point to "help" the pedal go down after a certain point (which long-style clutch pressure plates needed!). since you went to a diaphragm-style, pedal effort is significantly reduced. in a car i went diaphragm-style to, the pedal would stay on the floor. removing the original return/helper spring and installing a VERY light spring to just get the pedal from resting on the pressure plate worked for me! in fact, this method has worked for me in 5 different cars! have had NO problems whatsoever in the last 12 years....
 
#15 ·
sel2real said:
i'm going with the clutch return spring theory, as i've had this happen to me on a car i changed the clutch from the long style to a diaphragm style. the "return" spring is more like a helper spring that has a break-over point to "help" the pedal go down after a certain point (which long-style clutch pressure plates needed!). since you went to a diaphragm-style, pedal effort is significantly reduced.
:thumbup:

Very good point. The diaphram clutch does require a lot less of left leg pressure. I suppose that is why they have become so popular. I never liked the things because back in the sixties on a performance CHEV the diaphram plate would collapse on high RPM speed shifts. I guess they have overcome that problem. But you are correct in the spring strength helping to depress a finger style plate.
 
#16 ·
I haven't had a chance to look at it again with college starting, but everything from the equalizer bar down is correct. The only thing it can be is within the spring or maybe a worn out pedal support bushing. This weekend I am going to pull the pedal assembly and look everything over and make sure nothing is broke or worn out.

BTW where do I find a weaker pedal return spring???
 
#17 ·
Clutch

After re-reading the thread. If the clutch is on the floor and still fully engaged, it has to be something in the linkage. Something is either worn or broken or assembled wrong. If you pull the clutch all the way up is there a space between where the clutch rod hits the fork and the fork itself. If so the linkage is way to short. If not the problem is with the fork. If the helper spring was to heavy and it hung the pedal on the floor then the clutch would be disengaged. I would check the pivot point. There is a lot of stress there and you have a lot of leverage with the pedal. Perhaps when the linkage was modified it put to much stress on the pivot and broke something. This should be easy to see. If you go under the car and have someone move the pedal up and down the problem should become obvious.

Good Luck
 
#18 ·
I would have to go with the posts of those talking about the equalizer bar flexing/cracking. It is a common problem and used to be reinforced as a matter of practice when they were drag raced because of it. Another possibilty could be a slight misalignment between the frame support and the one on the engine, if the mounts have sagged. If the mount has failed on driver's side it could also allow the engine to lift under torque and bind it up.
 
#19 ·
There was a time when I had to pull the clutch pedal in my '66 Mustang back up with my toe. If the clutch linkage in your Merc is like the linkage in my Mustang, and I suspect it is very similar, several problems can make the linkage hang up. The nylon pivots at the ends of the equalizer tube have been mentioned; they contribute a lot of slop if they're worn. Make sure the bolts on the chassis-mounted pivot post are tight, too. The biggest culprits in the Mustang were the pot-metal bushings in the pedal support up under the dash. They were way beyond merely worn, and caused the pedal shaft to bind. I replaced the bushings with bearings and left out the large assist spring when I put everything back together. (I'll try to find the info about the bearing retrofit kit; just installing new stock-type bushings would be a big help, though.) I also replaced the pullback spring on the throwout arm with a new one. The linkage has worked smoothly ever since, and I'm using a diaphragm clutch. I'm going to put rod ends on the linkage rods one of these days to really make it smooth.
 
#20 ·
454me said:
Try this. Have some one push the clutch petal in real slow while you are under the car and watch it. I have seen the flat pieces of metal peal away from the pivot shaft when the clutch is pushed. I have seen forks that are cracked flex when the petal is pushed. Its amazing how you wont even see the crack in the metal unless the clutch is pushed in. Just watch it and see if there is anything wrong.

AMEN, glad you said it,,,,,,, I agree
 
#21 ·
I don't have any of these problems, but if I do it will be a PITA to find it because the fork is internally mounted inside the trans housing. (it;s a hydraulic unit) :( I want a regular style clutch, no hydro or anything to simplify it, but it would be impossible on my trans unless I swapped it. :( :(
 
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