clutch slowly seems to fail

Sergey

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Hello,
Yesterday, after a long period of truck sitting unused, I went to pick up a load of firewood.
Entire trip is under five(5) miles.

On way there I found shifting gears becomes progressively difficult. Upon loading firewood, found that I can no longer shift into reverse. None. Just grinding and that's it.
Managed to return home and found that, in addition, now cannot shift even into 1st gear either. 2-3-4 gears able to shift.
Another strange thing now is that when I leave truck in 1st gear and shut off the engine then park leaving it in 1st gear, then when starting the engine cannot shift out of 1st gear.

Background:
1985 F250 with T18. Second clutch, original rest of parts related to clutch, maybe 400 kMi total, of which maybe ? 100kMi on that 2nd clutch, figures are approximate since odometer was broken for years.

Checked fluid level in master clutch cylinder reservoir, and it is normal. Checked for leaks around clutch hydraulic line, seem none to find. Slave clutch cylinder is wet (always) with splashed oil from leaking rear main seal, I assume it is motor oil, not hydraulic fluid.
Slave cylinder appears undamaged, but feels a bit loose in its mount. Since it is all oily and dark, I cannot tell more at this time, needs to be washed and dried first for detailed inspection.

Clutch pedal operates normally, I cannot feel any difference before and now.

I have red a number of articles in this forum related to clutch, but still ask for an advise.
What do I need to check before assuming bad things occurred gradually ?

Thank you,
Sergey
 

IDIBRONCO

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Check around the clutch master cylinder to see if the firewall is cracked. Maybe the bushings in the pedal pivot (the piece that the clutch and brake pedals attach to) are worn. Maybe the arm on the end of the pedal pivot is worn. Maybe it's a combination of the above.
 

Sergey

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Thank you for the hint. I will inspect that are and report back.
Cheers
Sergey
 

Slicknik

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Sounds like your clutch is going bad, have you tried doing double/multiple pumps of the clutch pedal to see if it will shift in/out of reverse or when it gets stuck in first? Re-bleed the system and see if your situation gets better or worse, if you have a leak at the master or the slave cylinder then start there
 

BrianX128

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T18's first isn't synchronized, which would explain a lot of things since your symptoms indicate a clutch that is engaged even when you have the pedal pushed down. I'd say your pedal isn't fully depressing either from a bent rod or bent firewall or tired bushings in that area.
 

Old Goat

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Check around the clutch master cylinder to see if the firewall is cracked. Maybe the bushings in the pedal pivot (the piece that the clutch and brake pedals attach to) are worn. Maybe the arm on the end of the pedal pivot is worn. Maybe it's a combination of the above.
Check all this as IDIBRONCO mentioned.
If the Fire wall is flexing when you push in the Clutch, you will need one of these FW Reinforcement plates.
Have some one push in the clutch and check the FW as they do it. You might se some flexing or cracks. Ford made the sheet metal weak in this area, Ford did have plates available back in the day as they knew of the problem.
I have one installed on the 86.



Goat
 

Sergey

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Re-bleed the system and see if your situation gets better or worse,
As far as I read in repair manual this year truck was equipped with an integral, one-piece clutch hydraulic system which cannot be bled. So, assuming I have air in system then the whole hydraulic clutch setup may need to be replaced...
 

Sergey

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Check all this as IDIBRONCO mentioned.
If the Fire wall is flexing when you push in the Clutch, you will need one of these FW Reinforcement plates.
made an effort to get to that area, and found that it is too small to get my head into it to visually inspect it. All I could do was to insert phone camera there with one hand and hold flash light with another and take a picture.
I cannot tell if I see reliably if an area of firewall is flexing or not. Is there a way to inspect the area easily, or one must disassemble pedals area to gain access ?
 

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Sergey

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Sounds like your clutch is going bad, have you tried doing double/multiple pumps of the clutch pedal to see if it will shift in/out of reverse or when it gets stuck in first?
This suggestion is interesting! I do know about pumping brakes, but never heard of pumping clutch. Will certainly give it a try
 

BrianX128

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made an effort to get to that area, and found that it is too small to get my head into it to visually inspect it. All I could do was to insert phone camera there with one hand and hold flash light with another and take a picture.
I cannot tell if I see reliably if an area of firewall is flexing or not. Is there a way to inspect the area easily, or one must disassemble pedals area to gain access ?
Rod to the master cylinder doesn't look centered. I'd say that is egg shaped and it's wallowed out the metal on the pedal. I had this happen in my 90 F350 and had to put a new pedal assembly in.
 

Sergey

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Rod to the master cylinder doesn't look centered. I'd say that is egg shaped and it's wallowed out the metal on the pedal.
While all the pieces visually are in place and seem not much corroded, I tend to agree with this suggestion, since the eye end of the rod is loose. Maybe there has to be some endplay there (I cannot locate such info in Chilton's book).
Replacing entire pedal assembly likely is too big of deal for me at present. Is there any partial option?
 

Sergey

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In the first picture I circled the parts which supposedly will need to be replaced, instead of replacing pedal assembly.
Second photo shows an area where I can sense endlplay.
 

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BrianX128

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The problem is it's awful working on any of that where it is in the trucks. Even if you get the large nut off the top part of the pedal arm, it's pressed into the pedal with little burrs that dig in as it goes in so it can't pivot. I tried rigging mine when it started to depress the clutch only if I almost pressed it to into the floor but I ended up just taking it out and replacing it. A few bolts hold it to the firewall, then you disconnect assorted things attached to the brake and clutch, and you have to drop the steering column as well as some electrical connectors attached to the column. It's annoying, but you can probably get it out in less time than you'll spend trying to get anything out under the dash. I'd still check for flexing in the firewall also, you can prop your phone recording video towards your master cylinder in the engine bay and if it's flexing you'll see it.
 

IDIBRONCO

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Second photo shows an area where I can sense endlplay.
In this picture, I can definitely see that there is wear in the rod that goes to the master cylinder. There's probably most of your problem. Also, you look at the outside of the firewall to check for flexing. That's why you need a helper to push on the clutch pedal while you look at the firewall around where the master cylinder mounts.
 

Sergey

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In this picture, I can definitely see that there is wear in the rod that goes to the master cylinder. There's probably most of your problem.
Thank you for your thought.
Given that clutch failure was increasing gradually, and then progressed considerably over single trip, do I have correct assumption that there should have been a nylon or bronze sleeve between pin on that rusted lever and a hole in eyed end of push rod ?

If yes and I understand your point right then my clutch releasing was slowly degrading while nylon sleeve was wearing out, but once it became destroyed then wear mechanism switched to metal over metal and steel rod ate a cavity in aluminum eye quickly enough to cause clutch failure to release over single trip.

I am thinking in a direction that if there is any option to repair my truck clutch mechanism issue without removing pedal assembly then I will explore that option first.
 
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