91 F250 351 4x4 5 speed "camper special"

I HATE hydraulic clutches......I literally replace it every couple of years.

Problem has been constant.....once heated up it really chatters if you try to ride the clutch to go "soft" on something....I mean really chatters.

I have replaced clutch, throw-out bearing, pressure plate, flywheel....still the same problem.

This has been going on for years and it's time to redo the dang throw-out bearing so if there is ANY chance of fixing this problem while I have it torn down.....I'm open to any suggestions.

I had the tranny rebuilt 50k ago, might have some slack in the transfer case....but that should be a separate issue.

 

Some possible causes:
Oil or grease on clutch faces.
Glazed linings.
Warped clutch disc.
Warped pressure plate.
Sitcking release levers.
Unequal adjustment of release levers.
Uneaven pressure plate spring tension.
Loose engine mounts.
Loose splines on clutch hub.
Loose universal joints.
Misaligned bellhousing or loose bellhousing bolts.

 

Several NEW clutches, pressure plates, flywheels and hydraulic clutch parts......all of them can't have been defective.

Motor mounts....not a problem....they are perfect.

U joints.....perfect (brand new this year)

Bell housing really shouldn't affect clutch performance, it's only a protective cover isn't it?

Everything has been replaces several times....it's really weird.

 

What brand of clutch are you using? What size? Do you do a lot of towing? Are you over your tow rating?

If you do a lot of towing then I'd recommend going up to an 11" disc. Your flywheel is already drilled for the larger size.

 

All parts are "NAPA GOLD"....best I can find.
Tried factory replacements too....same deal.

Running the heaviest and biggest and best parts available (that I know of).

That truck doesn't really do much towing, carries a lot of payload now and then back and forth hunting but not much in the towing capacity.

Overloading the clutch isn't the problem....it's something else and it's chronic.

I was hoping someone else had the same issue and worked through it before?

 

What about the slave? Is that original?

At first I was thinking your fork might be bent or isn't moving freely, but then I saw you have a 91 F-250 with a 351w, so you should have a ZF with a concentric slave cylinder.

Here's what I would do, if I was as sick of the problem as you are.

- Go to the Ford dealer and buy a new slave cylinder. Yes, they're expensive but the aftermarket hasn't figured out how to make a slave cylinder that lasts more than 6 months.

- Go to carolinaclutch.com and order an 11" Luk Pro Gold clutch kit. I don't know who makes Napa clutch parts and I'm sure they're rebranded. They may be Luk parts as they make the majority of clutches used today but I don't know.

- Resurface the flywheel at a competent machine shop. I guess the quality of the steel in the flywheel might be an issue. If you really wanted to go nuts, go to the junkyard and get a used one with a Ford part number on it. Have it resurface and the ring gear flipped if it needs it.

If you still run into problem then sell the truck because I have no idea what else would cause these kinds of persistent problems.

 

When you get it replaced does it chatter immediately, or does it work good for a while?

 

White 97 - it is immediate (after it warms up). Usually worse in low/low when backing up. Not as bad forward but backing up is a real issue.

Andym - selling the truck isn't an option....nobody would give me what I have in it ;-)

Good advice though.

The slave has been replaced at least three times that I remember (had the truck since it was new) and I'm not sure if they used a OEM part of a NAPA part....probably both at some point.

I will check when it's torn apart and see but I think I will follow your advice and see if that fixes the problem.

I've had clutches most of my driving life and I have never had these issues that just won't go away. We've all had them at one time or two but when you replace everything the problem usually goes away.

I can't seem to make this one go away.....yet

 

Yes, the bellhousing is a protective cover but also much more. Proper alignment of the bellhousing to the engine ensures that the transmission input shaft (carrying the clutch disc) is in line with the pilot bearing and is at 90 degrees to the flywheel. Missing/damaged/distorted alignment pins (dowell pins) can cause all sorts of clutch problems.

 

I have also had the same problem with my new clutch, also has had 2 different slave cylinders in it to. It really only does it when its hot but its really bad when its hot. You almost have to pop the clutch when its hot or itl rattle the crap out of the truck. Dont have any idea what the issue is though, ive just tried to deal with it.

 

There it is! (IME) :)

My '75 was that way from the factory. Chevy and Dodge were sloppy at
making bellhousings but Ford (during that era) has the worst reputation.

It's not the fact that it's a hydraulic clutch that's causing your trouble, it's
something out of alignment. I've had exactly the opposite experience
you've had. The one hydraulic clutch I've had and now got is the best
clutch I've ever used in my life.

"some thing's crooked"

If your setup has a separate bellhousing it'll be a cinch to check and fix.
All you need is a dial indicator with a magnetic base (they're cheap) and
time and patience.

If it's a ZF with an integral bellhousing, I wouldn't know where to even
start with that. My guess it's the engine not the ZF unless the ZF's been
overloaded and the bellhousing tweaked?

Seen pictures of ZF bellhousings broken to pieces. :)

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Another problem that sounds like isn't the OP's ...is the clutches with the
coil springs and levers need to be adjusted. Yeah, that's right, the levers
need to be adjusted so they pry the plate up even all around. I've never
seen a Diaphragm pressure plate that lifted the plate crooked/angled.

Alvin in AZ