HJ60 Clutch problem

[Changa88]

Hey guys,

I’ve got an occasional issue with my clutch. It randomly becomes a lot easier and plusher to use for about 4 or 5 pumps.

A little back ground. I have a 1985 HJ60 with a clutch booster. I got a new master cylinder installed as I had a leak. After the master cylinder was changed the clutch feeling was slightly heavier. After a fair bit of use it suddenly became extremely light or plush but only lasted a couple pushes before reverting back. Now this happens now and then, never consistently. It could happen when the engines cold or hot. With little use or after heavy use.
When it becomes plush, it’s still engaging properly and the gear changes actually feel smoother.

So I’m unsure weather it’s actually working correctly when it becomes plush and then not working correctly the other 95% of the time.

Any ideas what could be causing this dilemma?

 

[relaxedcruiser]

The initial heavier clutch feeling could be down to a properly bled clutch hydraulic system after the master cylinder was replaced. Air in the system makes the feeling more plush. It can still operate ok, it depends on how much air is in it.
It is important that the mechanic who put your new master cylinder in has checked the adjustable gap between the pin of the booster and the master cylinders piston. If that adjustment is not correct it could also lead to a inconsistent clutch feeling.
But as you have a clutch booster in the system, it makes me wonder whether that one is working correctly all the time.
That clutch booster itself could also be foulty. To encircle the problem I would take the vacuum hose of the clutch booster -(block the hose with a bolt or any proper airtight fitting bung to prevent vacuum loss) and drive it like this - the clutch will be a lot heavier now - but if it is consistently the same - therefore always heavier it would lead to a bad booster which can indeed work a bit randomly on its way out.
But also ask the mechanic if he has checked that crucial measurement. The gap should be just zero or about zero but the pin should not push the piston at all.

 

[duncanrm]

I always change the Slave and Master as a pair, I'd do that, then rebleed.