New here lon the forum and excited to learn more about working on my favorite vehicle I've ever owned

1986 F250 with less than 50k miles. Used to drive perfect on the rare occasion it gets driven, but then all of a sudden, the clutch does not disengage completely when warmed up, making it difficult to shift. But I don't know what to service first--the clutch itself, or the master/slave cylinder?

The transmission is 4sp, clutch is hydraulic. I don't know what the previous owner serviced (prob nothing since I bought it with 29k) but I've never serviced either. The master reservoir is full and no noticeable leaks near the master or the slave. Pedal "feels" normal both in compression & release, not too soft or hard. Engages right near the floor (I don't know if that's normal, but I haven't noticed any gradual changes in the distance of clutch pedal travel before it engages). The clutch doesn't shimmy and the throw out bearing is quiet. The clutch never slips (Although I haven't tested with heavy load)

It requires force to shift in and out of gear. I have to use both hands to jam it into 2nd and 3rd, although high revs make it shift a bit easier. The clutch seems to remain partially engaged, even with the pedal to the floor. Pumping the pedal before shifting does not seem to help.

there isn't any rust/damage of the firewall where the master is mounted and I don't notice any visible movement of the master at the firewall when I press the pedal

If the truck was high miles and clapped out, I'd be inclined to think that maybe it's time for a new clutch, but because the mileage is so low, and I'm really easy on it, I just can't believe that the clutch plate would be worn already

The one "mechanic" I've spoken with went straight to "needs a new clutch", (although he never drove it), and maybe it does. Whatever it needs, I'll do the work myself (or try to) but I just need a little direction on what to start servicing first

Any pointers or directions would be greatly appreciated!

 

A few more questions. Which 4 sp do you have?

Have you checked the lube level in the trans?

This trans shifts normal when cold?

Have you ever topped off the clutch master reservoir? If so when?

I doubt you need a new clutch. When in gear is the transmission of power to the rear end positive, no slipping?

Have you checked measured the throw of the lever on the trans? It's rare for me but I think it's possible to bypass a seal without leaking. Could be the master or the slave.

These hydraulic clutches do engage low. But if air is in the hydraulics they engage even lower....like sometimes do not disengage.

One more thing to check is if the slave is secure in the clip to the trans. I had a slave come loose from the clip recently.

 

thx for the reply Blue!

I'm not sure which 4spd I have. I'll call the dealer tomorrow and have them look up the VIN. Should be able to figure it out

haven't checked lube level in trans (not sure how, to be honest). but it lives on a clean concrete drive for the past 10 yrs and I've never noticed a leak. It's always shifted smooth until just the past couple of weeks. I'll check fluids tomorrow just to rule that out as a possible problem.

shifts really smooth when not running. shifting gets a little harder when starting the engine and I take off down the road. As it heats up (a few miles), shifting gets progressively more difficult. Won't hardly find reverse without a bit of grinding.

checked master yesterday. pulled the "ducky" out and fluid was right below the mark. Didn't take much but I topped it off a bit anyhow. Didn't seem to improve performance.

no slipping at the rear end (not that I can feel anyway). I haven't towed with it or put a load on it since it's started acting up. The pedal and transfer of power to the rear end feel like they always have other than it's now all of a sudden just having a hard time shifting.

Haven't measured the throw distance of the lever at the trans but I'll do that tomorrow when I can round up a 2nd set of hands

My 1st guess (based on very limited experience with manual trans) was that maybe the clutch was engaging too close to the floor. I've scooted the seat up and really mashing it to the floor when I shift. I don't drive it enough to be positive, but I think it's kind of always been like that. I thought there might be an adjustment somewhere like on manual clutches but don't see anything that I can adjust on this hydraulic clutch.

I have a slave cylinder I bought (just because I was already at the parts store). but it's not prefilled and I'm reluctant to just dive in and swap it out if unnecessary since I've read that swapping the line, getting the ball into the lever, and bleeding are all sort of a pain.

Guess maybe I could crack the bleeder at the slave and try to flush it without introducing air into the system just to make sure I don't have water in the fluid. I have a vac tool if I need to bleed it.

thx again for the help. I really appreciate it.

 

Check for firewall flex failure. Have someone depress the clutch pedal fully while you observe the master. If the master moves out into the engine compartment more than about an eighth inch the firewall is flexing. When they fail it can be several inches of movement.

 

Blue--I think you're right. I initially looked at the firewall and didn't see "much" flex or movement at all. But on your recommendation, I looked again, and although it barely moves (less than an 1/8), I think even just that little bit of movement is enough to keep the clutch lever from being pushed all the way. I guess I feel relieved that at least it's not something more serious like the clutch itself or the cylinders.

Now I just have to source a stiffener bracket. ebay doesn't have one.

Does anyone know of a place that carries old OEM stock that I might check? Part #E8TZ-7K509-A Firewall stiffener bracket

 

Here's the bracket brand new. https://shop.broncograveyard.com/83-...gaAsRNEALw_wcB

 

You might be able to get one from a ford dealer parts dept. They might be able to source one for you. The Bronco Graveyard reinforcement plate should work too. A wrecking yard might have one too.

Less than an eighth shouldn't interfere too much. Did you try multiple times with the clutch depressions? Sometimes the firewall cracks but gets hung up on the crack and doesn't flex everytime. The total throw of the slave and master are the same. I think it slightly more than 1/2"? You can confirm the travel at the master and that it's the same at the slave. Supposed to be 1:1.

 

Ford quit making them years ago. So then a guy on another board let another guy on the board borrow one. He copied it and had a waterjet machine and started making them. After a couple of years he got out of it. I do not know who is making them now for Bronco Graveyard.

 

I'm wondering what kind of driving you do? Lots of in town or city driving or lots of highway? You have 50,000 miles and members have reported firewall failure at 40,000 miles. But they only drove local city miles, ie lots more clutch depressions per mile than others who's firewalls failed at 200,000 miles but mostly highway miles.

 

Ford dealer didn't have one and neither did any of the local yards that I called around to. I just ordered the bracket from BG. Great recommendation. Bit more than I wanted to pay, but I really need to get the truck running ASAP. Also just read the thread where another member on here modified it so he didn't have to remove the steering column. https://www.ford-trucks.com/forums/1...made-easy.html. Very helpful and I think I'll do that once I get it.

In the meantime, just so I can use the truck for a job tomorrow, do you guys have any temporary quick fix ideas I might try just to get by for a few days? I can still sort of force it into gear driving it as it is, but I'm a bit worried about getting stranded and not able to shift at all if it gets progressively worse until I can fix it proper.

I also saw where Blue recommended lubing the clutch lever and fulcrum. That might at least take some of the strain off the failing firewall until I get the bracket, so I'm going to go try at least doing that right now and see if it helps any

I mostly drive it around town these days but in the past it's just been a rig I tow my trailer with. I'd say over the course of the time I've owned the truck, it's probably 50/50 city/highway

Blue, I saw a comment of yours on another post about the edges of the crack maybe getting hung up against each other. I tried multiple depressions of the pedal to see if maybe something was getting stuck but didn't seem to make a difference. And yes--total throw distance is about 1/2". Maybe lubing the lever will help. Going to try now...

 

Lubing the lever? I know I have commented to lube mechanical clutch pivot points. Lubing the clutch pedal can't hurt but it's probably not going to help shifting or disengagement much.

 

There is an adjustable rod to the master. It's supposed to be adjusted such that it just fits over the pin on the pedal stock. Check that adjustment. I think it's possible to add some stroke at that adjustment but I don't recommend that. If it's me I think I would gamble on a new master and slave and install them with the new reinforcement plate. After that it's looking deeper into the trans and clutch. As Karl would say load the parts catapult. Worst thing is that you might have spare hydraulic parts.

 

You're right--it was another member...

Just tried this and also lubed the bushings and all pivot points on the pedal.

I don't notice a discernible difference though

I might just have to go drive it "as is" and hope for the best until the bracket I ordered gets here.

It's soooo close though! I just need another 1/32" of travel and I think I could get it to at least shift well enough to limp around over the next couple of days

I'll try adjusting the rod at the master. I didn't realize it was adjustable until you pointed it out. I don't need much--just a tiny bit

And yes--I also like your idea of swapping out the cylinders when I do the bracket. I'd already bought a new slave, so at minimum I'll probably put that on and flush the fluid since it's never been changed (or not that I know of)

 

You'll be most of the way to removing the master to install the reinforcement plate. So may as well replace it. I've always replaced as needed piecemeal. I still have the original hydraulic line but both master and slave have been changed. On my third slave having changed it out last weekend. I only got 8000 miles and 4 years out of the replacement of the original with over 400k miles on it!! I'd keep any original hydraulic parts just in case they are still good.

 

I also like your idea of keeping the master and flushing the fluid and installing a new slave to see if that fixes it. You said you topped off the master. That could mean you have a leak. Air can get in when fluid leaks out. Maybe you haven't driven enough to work out air? When I changed my slave I filled the slave with fluid holding the slave on a slight angle. Moved it to change the angle and got it to burp and added till topped. Then slid under and attached it to the line then clip it in. Just keep the slave tipped up. For flushing open up the reservoir and it will drain for a bit but stops before dripping dry. Catch the flow in a bucket. Put a good light on the stream and then keep pouring in new fluid until you see clean fluid coming out. Then pop the cap back on. That should keep you from taking a fluid shower. You will have some air in the system and you will need to work the clutch to help it purge the air. I pumped mine till I had the pedal returning. Warmed the engine while pumping even more. Then turn off the engine, put it in gear and start it with the clutch fully depressed. The truck starts to roll and start together. Then drive the truck for a few miles pumping the clutch. A hilly course is good to help work out air. Try to go up hill first and then downhill. Pump the clutch intermittently up hill and constantly downhill.

If you think air is in your system try that now. You might be able to purge air faster than your leak. I say leak as when the system is tight you will not lose a drop and top off is not needed. You did top off.