Cold Weather Hydraulic Clutch Problems

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I left it with the mechanic Friday the 22nd and left on vacation. Just got back. He bled the system again and drove it home and back to make sure it is okay. Left it at my house last Wednesday. I just took it for a spin tonight and it works, but the clutch pedal has a very light feel (not necessarily undesireable) and the engagemet is about half inch off the floor. It just doesn't seem right and I am tempted to have my regular mechanic check it. But for now will drive it and see how it goes.

Also, the mechanic who did the clutch says the brake fluid level is correct, but I see it about halfway down the reservoir and book says fill to the step, which is higher, maybe only 1/3 or 1/4 the way down.
 
You can fill it, but remember that if you push the caliper pistons back in their bores for a brake job, it will spill out of the reservoir.
I like a rather full reservoir - less chance of moisture from any air. Don't jam it in there all the way up to the top, however.

How is the clutch pedal freeplay? If it is too much, there is a quick freeplay adjustment on the rod to the clutch master cyl. that you can tighten up.
 
Separate reservoir from the brakes. Free play, well it engages about 1/2 inch above the floor--if that. But it is working. I asked him if there is an adjustment for the pedal, he said no. Maybe there is for the reservoir? I'll have to look under the dash and see what I can see. It's working so I haven' gotten around to it yet. Mechanic said that as the clutch wears the engagement point will get higher. Seems reverse of what I would expect. Time will tell.
 
OK. The pedal height adjustment on a hydraulic clutch system is usually the upper stop. Sometimes there is a little switch there [of course, there is also a little switch on the bottom for the starter lockout].
Do this first, THEN the pushrod adjustment.
You can set the pushrod's freeplay for a hair more than zero.
This gives the fastest disengagement, and a slightly higher release point.
 
Originally Posted By: TallPaul
Separate reservoir from the brakes. Free play, well it engages about 1/2 inch above the floor--if that. But it is working. I asked him if there is an adjustment for the pedal, he said no. Maybe there is for the reservoir? I'll have to look under the dash and see what I can see. It's working so I haven' gotten around to it yet. Mechanic said that as the clutch wears the engagement point will get higher. Seems reverse of what I would expect. Time will tell.


A hydraulic clutch pedal height should in theory remain the same during the life of the clutch, unless someone changes or adjusts something. As the clutch wears the fluid level in the reservoir will increase, and the pedal will become harder to push down. The problem is with a good driver you will hardly notice the change because it is slight and hopefully takes a very long time to occur. That is why with a brand new clutch assuming the spring pressure is close to the same as the old one, the replacement will feel very easy to push down. The pedal should grab higher than 1/2" up from the floor, so something isn't right.

Did this guy cut the flywheel? There have been problems with the M5OD and clutch engagement when the flywheel is cut too much, it is not as forgiving as an older style clutch with a fork. What I learned from a buddy that worked for Ford is the flywheel can be cut once or twice, only to clean it up if a very small amount is taken off. If a lot has been taken off they should be shimmed or replaced. Too much taken off the flywheel with that design can cause problems with grinding going into Reverse as the clutch starts to wear. It can also cause the clucth go engage to close to the floor.
 
He did not cut the flywheel. It was in very good shape, just minor touch up, can't remember how, fine sandpaper maybe for minor scratches or something.

Possible that with 179,000 miles and flywheel maybe was cut before, that it is too far.
 
It could be very well be. We found out the hard way with a work truck my brother had. He bought the truck from someone who had replaced the clutch. About 1 year later the slave cyl let go and we had to do the clutch again. We had the flywheel cut, it was blue from heat. It grabbed low and started giving us a hard time going into Reverse. We lived with it for a while.

I started gathering info and was told about that designs short comings from a Ford tech I knew. We did the clutch job ourselves changed the flywheel and put a Centerforce CFT II clutch in, going from 10" to 11" on the clutch. The difference was amazing.

Another thing to check, if you can get under the truck, and have someone press the clutch pedal down, engine off. Watch the fire wall where the clutch piston comes through the floor. The name for that piston slips my mind, sorry! Anyway watch the floor for flexing. Ford offered a plate as an add on to beef up the floor, because as these trucks aged the floor started to flex. This flexing screwed up the workings of the clutch including how high it grabbed from the floor along with grinding going into first and reverse. If the floor is sagging or moving at all when the clutch is pressed down it will cause all kinds of problems and drive someone who doesn't know about this problem NUTS!!!!!!!!!!!!!!!!!!!!!!!! The PITA part is the floor has to be worked back as close to the original position as possible. We welded our own plate to beef up the floor. Finding its original position wasn't terrible.

Please check what I said out, it could be your whole problem!!!!!HTH
 
I'll check the firewall flex, had that on my '84. Last night I replaced the cheezy plastic bushing on the master cylinder plunger where it connects to the pedaql lever. Bushing was so bad the plunger was about to come off. With the new bushing, pedal improved some.
 
Sounds to me like you're on the right track. Let me know how the floor flex checks out. It had us going for a while.
 
The flex on the 84 was because the firewall was rotted out. Anyhow, I like the way this clutch feels, nice light pressure, which will help extend the plastic bushing life. I hosed the peg with silicon lube before snapping the rod w bushing over it.

That silicon spray lube is superlube. I used it on the motorhome dump tank valves which were sticking and very hard to slide. After draining the tanks I hosed the stuff liberally up the dump hole then slid both slides like crazy. Both slides work like brand new now (6 months after hosing them with the silicon). That on a 10 year old motorhome. Nice!
 
Sounds good! This work truck I mentioned had no rot at all, but boy did that floor flex when you stepped on the clutch. Seems there must be a lot of force exerted on it. Once we nailed the problem the repair wasn't bad. I'm glad my brother has all sorts of welding equipment, a local welder wanted about $300 to do the job IIRC. We banged it out in about an hour.
 
I think my firewall/floor is fine, will check when I get around to it, but she is working great now. Clutch feels real good, fairly light pressure too. Driving it today it felt quite normal. Seems to engage higher now, hard to imagine the bushing made that much difference, but seem to get at least an inch off floor before first hint of engagement and full engagement probably halfway off floor. I am quite pleased with it now.

Alas, the Michigan rust is going to kill this truck like a cancer long before it's should die.
 
Good to hear. Those clutches were very touchy and everything had to be just right to get the proper pedal height. We thought the floor in our work truck was fine, since the body was great and there was no rust at all. When I got under it and my brother pressed the clutch pedal down I almost [censored]. I couldn't believe how much it moved. Glad things are working out well for you now!
 
The kit he is referring to was a joke. We got one, then ended up making our own and welding it in place. The firewall could have taken a shot from a 20mm cannon when my brother got done with it.

Seems our problem was a bit different than yours. The few F Series Trucks, and one of my E-150's with a stick had the floor flex problem at some point in their lives.

Thanks for the link!
 
That plastic bushing on the master cylinder plunger is a joke too. Sure saves cost and time on the assembly line though--that is the bottom line. I bought 2 of those bushings and still have one left, should get me through till the rust eats the rest of the truck. Now if the spring and the firewall hold. You may have had a HD clutch, mine is pretty light, I would not expect firewall/foor problem unless it rusts.

Haha, I do have an 'oil canning" effect in my floor from the thinner metal they use. For those born in the age of plastic oil bottles, "oil canning" is the noise of the metal end cap flexing in the old cardboard oil cans.

Yeah, we put a heavy metal brace on the firewall in that '84 when the clutch started to break through the firewall.
 
I've seen the floor flex problem more than once, in fact with the stock clutch the trucks came with. I could never understand why in the light duty trucks they used a 10" clutch, yet the flywheel is machiened for an 11" clutch. We'd used the 11" Centerforce Clutch, a really nice unit. My brother had said the floor was flexing for a long time before we put the clutch in. Truth is that Mazda M5OD was a POS and not good for that application, although it had nothing to do with the floor. I wish we had a ZF gear box with the granny gear.
 
My M5OD is doing fine, partly I attribute that to use of synthetic fluid, graduating from M1 to Redline MTL, which is the best I have had in it.

Is 99,000 miles decent for a 10" clutch? A coworker has a later 90s F150 4.2L with about 165,000 and still on the original clutch.

My 77 F100 had 11" clutch per spec sheet. 10" works for me now as I rarely do any hauling.
 
Well hey, I fixed it. The clutch pedal was too week on the return, there is a spring under the dash which first compresses then expands as the clutch pedal is depressed. The expansion part was okay, so in cold weather the pedal would come half way up, but the compression part was not working. For some reason on the compression part the spring was tilting backward, so I beat an angle iron into shape and wedged it behind the back of the spring, bolting it down. Clutch pedal feels like new now and has great return. As for the engagement being close to the floor, it all has to do with clearances. The guy should have put a very thing shim, perhaps 1/32" behind the flywheel to account for wear. But it is working, just maybe will be a problem after the flywheel wears some more.
 
Still have cold weather clutch engagement problem. 30F this am and had to put it in gear, then start engine and go. Once I drive a mile I can shift into gear from a stop.

Can't be flywheel wear as the pressure plate assembly bolts to the flywheel face, it has to be either the disk is too thick (in which case I can dump the clutch at 4000 rpm a few times and maybe get it working right), air in lines (pumping pedal does not help), or the hose is so old (1995) that it is bulging when I depress the clutch pedal. Or could it be that they installed the throwout that came with the slave (Borg Warner) instead of the throwout that came with the clutch (DyanPac)?
 
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