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I drove my truck (1983 mechanical linkage np435) again yesterday after about a week of not driving, since I was installing shocks and bleeding brakes. Yesterday, I noticed part of the way into driving that the clutch makes a loud and tactile "click" when you push the pedal to the point the disc fully disengages.
The click sounds like it's coming from right under the dash. When it does it, the pedal gains extra resistance and then it clicks and falls the rest of the way to the floor easily. Sometimes it will click twice.
It does this only when the engine is running and the transmission is in gear. With it in neutral, it almost never makes the click. I have yet to experience it with the engine off either. But when you downshift or upshift and use the clutch, it does it most every time.
I inspected the linkage and found that there is a tiny but detectable amount of wiggle room in several of the metal rods, from side to side. But when you put pressure on the pedal, they stiffen up and cannot be wiggled.
It doesn't sound like something catastrophic -- but since I haven't been able to track down the source, I would like to get closure on whether it's something superficial or something I need to take care of!
Well you did the first part "inspected the linkage" and did not find anything out of whack.
Under dash I can only think of a few things.
Pedal has a pivot shaft that uses plastic bushings that could be bad. You would need to pull the pedal assy. from the truck to check.
That pedal assy. bolts to fire wall at master cly. and to the dash frame. I would say check where it bolts to to make sure that are tight.
There is an over center spring that pivots about half pedal when it flips that could be the noise.
Dave ----
Well you did the first part "inspected the linkage" and did not find anything out of whack.
Under dash I can only think of a few things.
Pedal has a pivot shaft that uses plastic bushings that could be bad. You would need to pull the pedal assy. from the truck to check.
That pedal assy. bolts to fire wall at master cly. and to the dash frame. I would say check where it bolts to to make sure that are tight.
There is an over center spring that pivots about half pedal when it flips that could be the noise.
Dave ----
I went and looked around the footwell just now.
I put a socket on the bracket-to-firewall bolts and the bolts on either end of the bracket itself and they all were tight. I found a bad looking plastic bushing on the left side of the shaft and I saw the spring you mentioned.
In normal operation that spring makes a few very quiet clicks that sound a little like the big one I've been hearing while driving. So that spring seems it could be the culprit. Putting spray lube on it didn't seem to help. I might try to get video of the spring while the click happens.
I looked at a linkage diagram to find a spring was missing between the clutch fork and a hole in the frame. I had a shorter spring and some twine so I fabbed a clutch return spring. Problem solved; see attached picture for documentation.
That's correct, only the hydraulic clutches break the firewalls around the clutch master cylinder location and above it where the hood seal is located.
It is a mechanical linkage, so I don't think there is much stress on the firewall. The clutch rod goes straight down almost parallel to the firewall. However, the mechanical linkage has the added excitement of flexing the motor mounts and the steering column when you push the pedal. Maybe I need to work on that eventually...
Also, please note at this time my issue has been solved as documented in the above post.
Three pics (upper/center/lower): Caption should read 1980/82 F100/350 & Bronco & 1983 F100/350 & Bronco except F250/350 6.9L diesel & 460 (these have a hydraulic clutch).
Upper pic: 2471 are the 4 nylon bushings the brake & clutch pedals ride on. 7526 is the upper nylon bushing on the clutch release rod.
Center pic: 7526 is the lower nylon bushing where the clutch release rod attaches to the equalizer bar. 7517 & 7543 are the nylon bushings that the equalizer bar's pivots ride on.
Over time, these bushings crack apart/disintegrate. Especially troublesome are the upper/lower 7526 bushings. When they "pass away" the clutch release rod 90 degree ends begin to crack, eventually snap off.
When this occurs, the clutch pedal drops to the floor, lays there like a drunken sailor. Not pleasant!
I looked at a linkage diagram to find a spring was missing between the clutch fork and a hole in the frame. I had a shorter spring and some twine so I fabbed a clutch return spring. Problem solved; see attached picture for documentation.
Good to hear you got it fixed.
Now Igot to get undermine to see if I have that spring as I cant remember now.
Dave ----
Good to hear you got it fixed.
Now Igot to get undermine to see if I have that spring as I cant remember now.
Dave ----
It's a good idea to check. The spring keeps tension on the parts in the linkage so that they can't wiggle around too much.
If you look at the first diagram in NumberDummy's post, it's part number 7523. Should be just a few pounds of force pulling opposite the clutch travel, if you want to make it with your own spring/twine since the replacement part is about $30 online.
I am somewhat convinced to check out those bushings now. My pedal still makes a normal, quiet click/groan when I use it, still not sure what that is. For now I'm keeping a good coat of oil on the pivots to keep it going till I pull the pedals and redo the bushings.
Those bushings on the cross bar between the frame and the engine are usually shaped like a ball or have a taper to them. That gives it plenty of give as the engine rocks back and forth on the rubber motor mounts. If those are the bushings you are talking about.
