80 series clutch pedal raising slowly and firmer to press down

Submitted: Saturday, Jul 12, 2014 at 18:57
ThreadID: 108712 Views:2909 Replies:3 FollowUps:6
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Hi
Randomly my clutch pedal started to not return as quick as it used to and felt firmer than normal
I reconditioned the master cylinder inspected the bore all ok I reconditioned the slave cylinder as we'll, bore was slightly surface corrosion but was cleaned out Easley, I checked the pedal linkage system re lubed and bled the clutch system multiple times but didn't change a thing I bought the car 6 months ago and I was told it had a new clutch 50 000 ago i tried to block of the damper made no change I haven't done any serious 4wd driving yet with it, has anyone had this problem ?? Cheers
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Reply By: Athol W1 - Saturday, Jul 12, 2014 at 19:35

Saturday, Jul 12, 2014 at 19:35
Jake
That sounds like some sort of blockage in the hydraulic line, possibly the flex hose collapsing internally.

Was a common problem on early model Holdens
Regards
Athol
AnswerID: 535977

Follow Up By: Jake B - Saturday, Jul 12, 2014 at 19:45

Saturday, Jul 12, 2014 at 19:45
Is there any way to visually check for that or check by feeling ?
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FollowupID: 819973

Follow Up By: Athol W1 - Saturday, Jul 12, 2014 at 19:55

Saturday, Jul 12, 2014 at 19:55
Jake
If you fully open the bleeder valve on the slave cylinder then depress the clutch pedal it should go to the floor rapidly and with little or no resistance, likewise if you depress the pedal and hold it down whilst rapidly opening the bleeder valve the slave cylinder should rapidly return. Should either or both of these happen then I would be looking very closely at the flex hose.

Unfortunately disassembly then becomes necessary.
Regards
Athol
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FollowupID: 819974

Follow Up By: Jake B - Saturday, Jul 12, 2014 at 20:25

Saturday, Jul 12, 2014 at 20:25
When i bled the system the slave moved back and when I reconditioned it it moved moved freely hopefully it's the hoses like your saying is there a way to check the hoses without taking to a pro ?
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FollowupID: 819978

Reply By: Ross M - Saturday, Jul 12, 2014 at 19:46

Saturday, Jul 12, 2014 at 19:46
If the clutch is sound, is there a twist in the slave cylinder hose which is preventing return fluid from freely reaching the master.
Does the pedal push rod have slight freeplay in the back of the master cylinder? It must be free when pedal is completely out.
AnswerID: 535978

Follow Up By: Jake B - Saturday, Jul 12, 2014 at 20:31

Saturday, Jul 12, 2014 at 20:31
The rod is firmly there but no free play and can't adjust any further.
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FollowupID: 819979

Follow Up By: Athol W1 - Saturday, Jul 12, 2014 at 21:08

Saturday, Jul 12, 2014 at 21:08
Jake
It is essential that there be some free play in the clutch pedal, between the pedal and the master cylinder piston. A lack of free play will cause the compensating port in the master cylinder to be closed, or partially closed. There should be an adjustable stop that is against the pedal high up under the dash, or it could be the clearance between the mushroom head of the pushrod and the piston and retaining washer within the master cylinder (Girling style cylinder)

Regards
Athol
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FollowupID: 819987

Follow Up By: Ross M - Saturday, Jul 12, 2014 at 21:44

Saturday, Jul 12, 2014 at 21:44
Primary port perhaps? Big one is compensating.
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FollowupID: 819989

Reply By: Chris (Qld) - Sunday, Jul 13, 2014 at 08:49

Sunday, Jul 13, 2014 at 08:49
I had exactly the same problem with my 80 after I fitting a new clutch, master and slave cylinder. The problem ended up being that I used the wrong brake fluid.
I had used Dot 4 instead of Dot 3. everything I read said they are all the same and can be interchanged but it seems this is not the case. After changing to Dot 3 I had no more problems.
Chris
AnswerID: 535996

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