Clutch pedal will not move, rock hard WTF?

[Ecomike]

Usually problems are spongy no resistance pedals, brake or clutch. But today my 85 XJ clutch pedal is rock hard, like the MC is seized and stuck? Has any one ever had this happen? I mean it is like somebody welded it in place, i has about 1/8" of flop (zero resistance, up and down, so it is not the pedal hardware under the dash, I don't think). Then it is 100% rock hard welded like ZERO movement. It was working perfectly last week.

Any feed back, history, causes, fixes???? This is a new one on me.

 

[Bobbie]

Sounds like the throu out bearing froze up.Tap the clutch arm with a hammer and see if it will move.

 

[Ecomike]

Sounds like the throu out bearing froze up.Tap the clutch arm with a hammer and see if it will move.

Bearing should have nothing to do with it. Also the engine was off, transmission in neutral. The arm moves by compressing the fingers in the clutch plate assy through the static non rotating bearing surface. The bearing has maybe 5 stop and go miles on it (In and out of the driveway last 5 months), plate and clutch are also new.

I am thinking of disconnecting the arm at the slave cylinder to see if it is the MC or SC, but that assumes it is one of them.

Thanks for the reply.

 

[Green Mesa XJ]

Old school mechanic buddy I was helping get a long neglected 80s 300zx running. It had the clutch pedal frozen like this, his old school trick was to break it free by just about standing on it. Can't remember if it was hydraulic clutch, think it probably was.

My 85 clutch felt froze up last year it had been months since I ran it and I just kept pressure on it until it moved, didn't take too long to brake free or that much force. I assumed it was the master acting up.



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[Alaskan89XJ]

Different vehicles of the '50s, and '60s vintages; Had a throw out bearing fork arm crack bending the whole business and jammed similar. Also another where a wedge shape rock got hung up into the linkage. Heard others have had fluid leak, or air in the line preventing actuation. Just 1 cent.

 

[Heavyopp]

I had this happen on the road on a ford ranger -- when I took it apart the clutch came out in pieces...

 

[Green Mesa XJ]

Just rear a thread about a 91 with the same issue, seems it was a broken spring in the master


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[trippled]

I would disconnect the slave if it's external. Just barely move the pedal. If it moves it's in the clutch or throw out (which I suspect it is). I've seen many exploded throw out bearings cause this.

 

[JeepNoob]

Bent clutch pedal Z-arm, maybe? I seem to remember when mine got tweaked, it didn't move much. It wasn't like rock-solid, welded in place, but I seem to remember it not having as much movement as it should have. I did have movement in it though, squealed like a pig whenever I pushed on it. And that's how I knew I had a toasted throw-out bearing...

 

[Bobbie]

If you already know what the problem is are not,why bother to ask us.

 

[Ecomike]

I would disconnect the slave if it's external. Just barely move the pedal. If it moves it's in the clutch or throw out (which I suspect it is). I've seen many exploded throw out bearings cause this.

Thanks, we just tried that, removed the slave from the bell housing, no change. Bleeding the slave to let some air in right now. I suspect it will turn out to be the MC gone bad. God news is, it is not anything in the transmission. Down to a bad MC or SS.

Edit: Slave does not seem to want to bleed or leak fluid.

Edit 2: Got it bleed some. No Change.

Also disconnected the clutch pedal from the MC, the pedal moves freely, so it is not there. That leaves just the MC and Slave. Going to replace the MC. This time I may be picky about the source. Too many bad parts from AZ the last few years.

 

[Ecomike]

Interesting that a spring in a MC could do that. Is there a check valve in the MC that could have plugged up with crude, or ball check that could have stuck? I think yes, but I never gutted a clutch MC.

Just read a thread about a 91 with the same issue, seems it was a broken spring in the master


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[90xj06]

Old school mechanic buddy I was helping get a long neglected 80s 300zx running. It had the clutch pedal frozen like this, his old school trick was to break it free by just about standing on it. Can't remember if it was hydraulic clutch, think it probably was.

My 85 clutch felt froze up last year it had been months since I ran it and I just kept pressure on it until it moved, didn't take too long to brake free or that much force. I assumed it was the master acting up.



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all 300zx's had hydraulic clutches. i have an 86 in the garage! :shocked:

 

[Ghost]

Careful standing on the clutch pedals in the xj. The part that attaches to the MC is known to bend which decreases it's throw which will make the clutch not disengage. Yep I've done that...... :banghead:

 

[Green Mesa XJ]

all 300zx's had hydraulic clutches. i have an 86 in the garage! :shocked:

It was a gold turbo parked for at least 8 years without moving (probably around 2003-4 when she got the mechanic to fix them this was before the Hurricane leveled most of the area) The owner of the property would seem to just buy another vehicle to drive when it broke in some fashion she'd park it. she had a convertible 70s vw Beetle next to the Zed and a early 90s corvette next to the Beetle. All sat for years until she hired a mechanic to get them moving and sold them on. I think she got a citation for they way the sat so close to the street or maybe one was in the street. I know the zed was in her yard next to the driveway for years where we got it running.

There was a neat trick on the Non turbo zeds, when the air flow meter would go it didn't send codes. Cars drive like crap with a bad AFM. Eventually the owners would sell to get out from under what they thought was a large repair. One of my buddy's flipped cars in the late 90s, anyway before Craig's list he'd hit the local thrifty nickel the morning they came out by the afternoon he'd have a a few stops. One was a super sweet 300zx, talked the original owner down by paying cash, drove a bit to to a convenience store I think it was, swapped the airflow he had with in the truck and the Zed was right as rain.



Back to topic, yeah those brackets on the XJ firewall I wouldn't test them so much.
When mine felt froze up I'm fairly certain it was the old master sticking a bit, didn't take a monumental effort to free it up.
Other thing is on the 85 it's a odd break line kind of deal with the metal fitting then a rubber section that goes around the back of the motor down to the slave where it becomes a metal line again. At least on the 2.8 w/AX5. I've got a spare new line if Mike needs one. I've been thinking of when I upgrade the transmission to upgrade the clutch to a mid 90s deal where they (master, slave + line) are sold as all one piece and pre-bleed. I'm not sure it the newer masters would mount correctly on the 85 firewall.



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[Ecomike]

Careful standing on the clutch pedals in the xj. The part that attaches to the MC is known to bend which decreases it's throw which will make the clutch not disengage. Yep I've done that...... :banghead:

Yep, I already weld repaired mine years ago on the pedal assy after it cracked and I had to reinforce the firewall as it had rusted and stress cracked where the MC attaches. Good threads here on both that I did about 6 years ago.

 

[Ecomike]

Looks like I forgot to update this thread. We replaced the Clutch MC, and that fixed the problem, so it was something in the guts of the clutch MC that seized up.:woohoo:

Then the brake MC went limp. :tear: And rust ate a few holes in the hood.:bawl:

JEEP = Just Empty Every Pocket LOL

At least I have 2 spare hoods, wrong color, but...