Unable to disengage Clutch

[Wilcey]

Hi all,

Yesterday after a little belt around Newcastle, my slave clutch cylinder (PBR P4510) physically broke from its mounting bracket, resulting in an immovable car. (I figure this was due to old age and an unnecessarily heavy clutch). Got a new Bosch replacement today, fitted it and bled the system.

Hoping all would be sweet went to start the car, and once running even with the clutch pedal fully pressed I was unable to shift into any gears, and starting the car in gear with the clutch pedal pushed did very little, the car still wanting to jump forward.

The clutch does have pressure when you push it, however it feels drastically different to what it did before all this, perhaps more spongy?? The clutch pedal also doesnt seem to fully depress to the position it should when you take your foot off.

If anyone has any ideas please let me know, its got Dad and I stumped...

Wilcey

[mcl1959]

It could be a few things but the one I am leaning towards is a cracked throw out fork. If it looks bled correctly and moving all the way forward, then this is probably the problem.
It is a fairly common breakage on FE FC and gives a strange sort of feeling as you describe.
The FX FJ fork was cast steel and bullet proof. It was lightened on FE and FC and gave problems.
Ken

[hsv-001]

You are probably correct Ken . The slave cylinder breaking like that can twist and dislodge the wire spring clip off the pivot ball inside the bell housing and either direction will change the fork position on the throw out bearing and therefore the feel and travel .
 

[ardiesse]

Clutch slave cylinders don't normally break like you've described.  When you replaced the cylinder, did the alignment of the cylinder, the pushrod and the hole in the clutch fork look right?  The pushrod should be on-axis with the slave cylinder and not at an angle.  Did the "ears" on the slave cylinder sit down square on the machined pads of the bellhousing?

Dumb question, this, but I have to ask - is your gearbox out of an FX or FJ?  The early gearbox cases have extra ribs on the bellhousings, running from the side bellhousing bolt holes to the front of the gearbox "sump".  These ribs get in the way of the later (FE-EK) slave cylinders.

The only other thing I'd suggest is adjustment.  I normally have to "unadjust" the slave cylinder pushrod a lot to get the slave cylinder out.  If you don't mind, get under the car, grab the end of the clutch fork with your fingers and push on the end of the slave cylinder pushrod with your thumb.  There should be about 3 mm free movement at the end of the clutch fork.  If your clutch is really badly out of adjustment (a lot more than 3 mm free travel), it won't release, the pedal will feel soft for most of its travel, and it may not even come back to the top of its travel if you take your foot off the pedal.  (Air in the hydraulic system will produce the same symptoms too.)

The normal stroke of a properly bled and adjusted clutch is about an inch at the end of the clutch fork.

Rob

[ardiesse]

I should add - if you do the "thumb and forefinger" check of clutch adjustment, a broken clutch fork will have way too much free travel too . . .

Rob

[Errol62]

I had the same symptoms on my FB Ute recently. Re-bled the slave and all good now.


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[fcute]

I had the same thing a few years ago, it was hairline cracking on the clutch fork.