Clutch pedal no longer provides resistance, clutch won't disengage, what likely failed?

Question

A little background information:

Car: 1993 Ford Mustang LX [2.3L I4], 5-speed T5 transmission.

I bought the car a few months ago, according to the previous owner the clutch was replaced fairly recently. I have no paperwork on this, and I can't speak towards the quality of the job.

That being said: the car drove just fine. The pedal has been very stiff since I got the car, and the clutch disengages at the floor, pretty much, but I wrote that off as "old car."

While pulling into a parking spot, I go to fully disengage the clutch so I can stop the engine. -- There was a loud "snap" and the car jerked into gear.

I slammed on the brakes, killed the engine, and had a flat bed tow it to my friend's house.

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What we know:

• The clutch quadrant doesn't seem to have failed; but the self-adjusting mechanism seems to be at the end of it's ratchet. (You can't pull the pedal "back" like you're supposed to, and it doesn't ratchet when you push down.)

• The cable itself seems OK. The clutch fork is exposed, you can see the cable move [as well as the fork] when the pedal is pushed.

• The pedal provides almost no resistance; however it does return when you let your foot off.

• The pedal provides some resistance at the end of it's travel, but I think this is the spring of the clutch adjusting mechanism providing some resistance.

• With the pedal at the floor, the clutch isn't disengaged. (At least, not enough to roll the car.)

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• The car is in gear, and can be held in place by the transmission [on a short incline, no less]... so I assume the clutch plate is still in contact with the flywheel.

The likely culprits were a failed cable, or a failed quadrant.

Both seem OK at first glance, though.

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At this point, it really looks like I have to bite the bullet and tow it to a garage so I can put it up on a lift. Is there anything else I can check before I do that?

Answer 1

Sounds like something went wrong with the pressure plate... Diaphragm spring snapped or something? Never heard of it before but anything is possible.

Might as well replace it and make sure the slave cylinder/throwout bearing are properly adjusted.

Answer 2

Here's what we figured out after a few days of resourceful tinkering:

• The clutch cable was not broken, but it was very worn. The cable was likely binding up, and I'd venture to say it was stretched. -- Replacing the clutch cable made the pedal much lighter; it also disengages farther from the floor.
• A worn clutch cable is putting a lot of strain on the stock quadrant [the plastic piece that adjusts cable tension; attached to the pedal assembly]. -- This was causing our quadrant's ratchet to slip. -- The loud "pop" was the sound of the teeth rapidly disengaging.
• The ratchet slipping effectively wore out all the teeth. We now have a worthless quadrant.

After gluing the quadrant into place, we are able to fully disengage the clutch, and drive the car!

All we did was wet the two halves of the quadrant (where the teeth are) w/ a damp cloth, apply gorilla glue, set the quadrant where we wanted it, and the pedal itself provided enough clamping force for the glue to cure properly.

We put a space heater by the pedal assembly because it's far too cold outside for this glue to cure properly.

After about an hour we were able to drive the car again.

I'd recommend getting a stronger-than-stock quadrant. You can get aluminum ones and a firewall adjuster. This way you can still manage cable-slack w/o relying on an old plastic piece that's difficult to replace.

So if your Mustang's clutch pedal loses tension suddenly: replace the cable and quadrant in one go. (The cable is only $20, and it's probably why your quadrant failed in the first place. -- The quadrant itself is about $40-60+ depending on which one you get.)