I recernley changed clutch and have the folowing problem

When the pedal gets hard to push it means the clutch disk is worn out (the worn disk changes the mechanical advantage), this means of course you need the clutch replaced.

You may have an internal transmission problem or clutch issue. If you can shift the car into gear while running without using the clutch pedal, suspect a defective clutch

if it has a hydraulic clutch ,the problem is a failing clutch slave cylinder not holding pressure
the leak is probably from the slave cylinder
the indications are that the clutch pressure plate is not properly clearing the clutch plate and the drag is causing the problems

Your Clutch slave cylinder may be bad.here's a link to it. SAVE 20 GET 10 GIFT CARD ON ONLINE SHIP TO HOME ORDERS OF 100 OR MORE Here's a link to a new one. http://www.autozone.com/drivetrain/clutch-slave-cylinder/duralast-clutch-slave-cylinder/nissan-datsun/maxima/2005/6-cylinders-b-3-5l-sfi-dohc/557935_0_0

Check clutch cylinder please

Go with the related help links,to replace the clutch assembly:----Click the link below:---

2004 Peugoet: Clutch not going in gears?
http://whoisbyme.blogspot.in/2012/05/peugeot-307-clutch-will-no-go-in-gears.html
----------
Manual Transmission Clutch System Failures?

http://repairhelpcenter.blogspot.com/2011/11/manual-transmission-clutch-system.html

------------
Car makes noise when clutch is pressed gently? http://schematicsdiagram.blogspot.com/2011/12/car-makes-noise-when-clutch-is-pressed.html

------
How does Clutch works in car?

http://vwrepairhelp.blogspot.com/2011/11/how-does-clutch-works-in-car.html

Clutch pedal hard? http://schematicsdiagram.blogspot.in/2012/02/clutch-pedal-hard.html

---------
2001 Toyota Celica: Grinding noise when Clutch pedal is Pushed? http://howtobyme.blogspot.in/2012/05/2001-toyota-celica-grinding-noise-when.html Toyota Celica Noisy Clutch? http://howtobyme.blogspot.in/2012/05/toyota-celica-noisy-clutch.html

---------
No Clutch Pedal No pressure http://whatisbyme.blogspot.in/2012/07/no-clutch-pedal-no-pressure.html 2006 Cadillac cts-v Clutch Getting stuck? http://schematicsdiagram.blogspot.in/2012/04/2006-caddiliac-cts-v-clutch-getting.html

---------

check the clutch master cylinder to be sure it has fluid in it... then check the clutch slave cylinder to be sure it is moving freely.

Well, it sounds like the clutch cylinder / clutch linkage is not properly adjusted or the clutch cylinder is not fully bled, or it is malfunctioning -- it's not fully depressing the pressure plate when the pedal is pushed down, therefore, the clutch is still engaged.

Charlie

Might be time to change the clutch.

Did you bleed air out of slave cylinder? Was the pressure plate and clutch release bearing in good shape? Did you make sure the disk was turned with the springed side facing the pressure plate and not the flywheel?