Hi, I;m a new member & I love this site. I've learned quite a bit. Here's my problem: My 85 F250 had a new clutch installed just before I bought it. (Or so I'm told) The hydraulic clutch engages just before the pedal hits the floor. After the truck warms up, it is nearly impossible to shift and it seems as though the clutch is not fully engaging. There's plenty of fluid in the master cylinder, and I don't think there are any adjustments (or are there?) Any suggestions?

 

I had a similar problem with my 84. First of all have you checked the master cylinder, hydraulic line, and slave cylinder for leaks? Next try bleeding the system. Also try going under the dash, follow the clutch pedal linkage up to where it goes into the firewall. At the top of the pedal arm there is a threaded adjustable pushrod, its retained by a cotter pin. Remove the cotter pin and the looped end of the pushrod from the arm. Back off the pushrod 3 or 4 turns, reinstall the pushrod and cotter pin. Pump the pedal a few times and take the truck out for a ride. While you're working under the hood have someone pump the pedal a few times, watch the master cylinder to see how much it moves, it should have little to no movement. In my 84 the area on the firewall where the master cylinder bolts into the body, the sheetmetal had rusted and become weak eventually that section ripped lose and my pedal went to the floor. The cure for this: I cut a piece of 1/8 inch steel plate about 2inches by 4inches. Remove the master cylinder from the firewall, held the plate over the hole where it mounts and had someone trace the opening for the inside with a marker. Drill the holes where needed. Finally have someone hold the master cylinder in position install the plate on the inside of the firewall install the 2 nuts and tighten them a little more than snug. Doing this will strengthen the mounting area of the master cylinder. Here are some things that you can try before you go spending tons of money that you may not have to spend. If none of the above fixes your problem you may have a bad slave or master cylinder. A slave cylinder runs about 80 to 100 dollars and the master cylinder runs about 60 to 80 dollars. I hope this will help you get the problem fixed.

 

i would 2nd the above suggestion to check the firewall for flex, i was plagued by clutch disengagement problems in my previous truck, an '84 f250, turns out the firewall had cracked where the master cyclinder mounts and was a common problem. if you aren't the custom fix type of person there is a Ford repair kit available which reinforces the firewall.

 

i too had the problem of the firewall cracking out in my 85 3/4 ton and my buddies and i did a custom fix to it that has worked well so far. But where might i find this kit that you speak of and how much does this kit normally run for.

 

In all honesty I had no idea how common this problem is. I also did not know that Ford offers a kit to fix the problem nor do I know how much it goes for. But if you have some extra time on your hands you may find a truck in a junkyard that had one of these kits installed on it, and I'd bet you could grab it for little to nothing. Good luck!

 

While looking for flex in the firewall also check and make sure that the adjustment rod that goes into the master cylinder is properly adjusted. When the clutch pedal is in the up position the master cylinder adjustment rod should be able to slide on and off the lever arm post without the rod being longer or shorter then necessary to connect to the post. If it is too long or short it will affect how much fluid the master cylinder sends to the slave. Also, check and make sure the plastic bushing is still in place. If not this will create slop and a small amount here make a big difference in clutch activation. Plus, while in there, grease up the busing real well.

Next, check for leaks in both the master and slave cylinders by carefully pulling back the dust boots and looking for fluid. Some seepage is okay. but there should not be any real accumulation of fluid under the boot. If there is then replacement is necessary. On my `85 w a 460 engine the master and slave come as a pre-assembled package with fluid and there is not a way to bleed them (that I know of anyway).

Good luck,

Mark

 

i got the kit from my local Ford dealer, it was a long time ago so i don't recall how much it was or have the number, sorry, they should be able to look it up though, it was a real deal ford kit.

 

gravityhouse

I have a few suggestions according to your posted statements. If your slave cylinder has an air bleeding valve these procedures will work for you.

For:
"it seems as though the clutch is not fully engaging"
-this could be due to the slave cylinder not retracting back enough to allow the clutch fork to fully release the throw-out bearing. I have had this problem when bleeding my hydraulic clutch system.

What you might try for this is: start up the truck and let it warm up to normal temperature. Then shut off the ignition and pump the clutch 10-15 times. Next crawl under the vehicle and open up the bleeder valve for the slave cylinder. If there is a lot of tension on the clutch fork you will see the slave cylinder retract as you open the valve. Close the valve once the clutch fork is somewhat perpendicular to the transmission. Next start up the vehicle and pump the clutch several times and drive the vehicle to see if it is any different. This procedure worked for me when I had this problem.

And For:
"The hydraulic clutch engages just before the pedal hits the floor."
-this sounds like there is air in the system or not enough fluid being forced into the slave cylinder. As PKUPMAN82 suggested check for leaks on the hydraulic clutch system. If there is none move on to the Firewall protocol. If the Firewall is intact then move on to the clutch pedal assembly and check mechanical parts leading up to the master clutch cylinder. If you don't find anything wrong in the above protocols then you most likely have air in the hydraulic system.

What you might try for this is: This procedure will require two persons, one to open and close the slave cylinder bleeder valve and the other to engage the clutch pedal.
Warm up the vehicle and pump the clutch pedal several times. Next open up the master clutch cylinder resevior (which is under the hood). Check to make sure the resevior is filled with the correct type of fluid, in most cases it requires DOT approved brake fluid. STEP 1, While the other person is seated in the vehicle, crawl under the vehicle and open up the slave cylinder air bleeding valve. This valve should be located next to the hydraulic clutch line coming from the master clutch cylinder. The valve on my truck opens up using an Allen wrench. I have seen other valves opened with 10mm open-box wrenches. Now once the air bleeding valve is open have your partner completely push in the clutch pedal. While this is happening you will notice fluid and/or air coming out from the slave cylinder air bleeding valve. With the clutch pedal still fully engaged (to the firewall), close the air bleeding valve. Next check the master clutch cylinder resevoir and you will noticed the fluid level went down a little. Add more fluid to the resevoir and repeat STEP 1. Keep repeating STEP 1 until you notice no airbubbles coming from the bleeder valve. A good way to detect airbubble is to attach a clear hose to the bleeder valve while you are bleeding the system. Also make sure the master clutch cylinder resevoir does not run out of fluid while your are bleeding the system.

Well that's what I did when I had the problems you described and it got me back on the road.

85FordTruck guy
"Shop time is always Good Time"

 

Actually, my truck just had the same thing happen, I was pushing in the clutch to shift gears and the pedal hit the floor and stays there. With the truck running I can shift into every gear and nothing happens. I reach down and pull the pedal back up to the normal position with no effect. Is this my master/slave or the firewall issue?

 

Mine turned out to be a combination of a bad slave cylinder and the firewall flexing. churchsoundguy, yours sounds more like a cylinder. The flexing only prevents the clutch from fully engaging. Yours sounds like it isn't disengaging.

 

Sounds more like the linkage is misadjusted and allowing you to push the pedal beyond what the geometry would normally allow.

 

As others have said, bleed it and check firewall for flex. If the firewall flexes the kit you need is... E3TZ-7K509-A which is about $20. There is a larger kit if you firewall is really screwed that is E3TZ-7K509-B and costs significantly more.

Also they do make adjustable pushrods if your not getting full stroke from the master.

 

I've read this entire thread and here's my situation: pedal sags about half way, worked fine for a while throwing clutch, now barely any pressure when pushed to the floor and barely retracts. Checked for firewall rot, none; topped fluid and pumped, no change; moist but no real leak at slave;can't even see or feel high enough on the pedal shaft to check connection with master piston('84 diesel if that matters), oddest thing is theres no obvious bleed nipple on the slave cylinder but I'm looking for the like of a brake bleed nipple. Although I haven't yet, and I think I'll try this next: it seems the slave is loose enough, and as it's not bolted on, I can just slip it off the mounting bracket and take a look, but I'm really only wanting to find the bleed valve. Thoughts?

Thanks!

 

No nipple, just a Allen set screw in the top (forward of where the hose in pinned in place)
You will see a tiny hole on the front side of the slave. This is the bleed port.

Your firewall doesn't need to be rusty, just the pinch weld torn where it meets the cowl or transmission tunnel.
Have someone step on the clutch while you observe the master cylinder motion from the engine bay.

Sounds like your master cylinder is shot.
I would add the small reinforcement kit while you have it out.

 

Turns out my problem, not master or slave or cracking, but wear in the pin labeled "lever", see image below. Any ideas on the size of that pin and size of the pushrod hole? Appears a simple sleeve to eliminate play at that point is my solution, now I need specs.



Thanks Again All!