Is that vac. line supposed to collapse when i start the car, what causes it to collapse ?

This is a car forum, not a vac forum. Perhaps you got a bad filter. Get another and try it. Otherwise contact the manufacturer for support.

Replace it

Yes the check valve holds vac in the booster.
Not sure about the line you replaced.

a vac. problem several possible causes a vac. line off at the vac. canister under the hood. a broken vac line with time some lines crack and are no longer functioning a bad activator under your dash. a bad control head on your dash if it just started acting up I would look to source vac.

Hi. There are many causes for this occurrence. I will list the most common culprits below:

1. Vac line disruptions(separated, collapsed,soot filled)
2. MAF sensor malfunction
3. Malfunctioning injectors
4. Malfunctioning EVAP assembly
5. Malfunctioning spark plugs
6. Inadequate or excessive fuel pressure
7. Improperly functioning EGR valve
8. Bad O2 sensor

I would recommend to access and check all the above for faults. replace failed component, if needed. A ECM/PCM scan would be in order at this time to isolate the actual culprit.

The purge valve is supposed to keep sucking vapor from the gas tank, through the charcoal canister, and it never works right.
A loose gas cap can not only cause it to flash a problem, but will also cause too lean of a mixture and harm the engine.
The purge valve system is prone to way too many leaks, and the consequence of not letting enough vent air into the gas tank, can be a collapsed tank or a blown fuel pump.
It is not worth the risk.
The easiest thing to do is vent the tank to the open air after the charcoal canister, as all boats, lawn mowers, etc., are, and all cars used to be. But then also plug the line going to the air intake, because otherwise it will be a leak and cause too lean of a mixture.
The purge valve is another bad idea that eventually is bound to have catastrophic results. Too many car engineers forget cars spend a decades in freezing cold, blistering heat, torrential rain, vibrations, etc.

Vacuum for the controls originates at the intake manifold. Check to see if there is a vac. diagram under the hood and or "dog house" (inside engine cover) if there is you can trace the source. It is not uncommon for vac. lines to collapse from age or contact with various chemicals (oil, cleaners) over time.

Check the vacuum hose for inside collapsing. Sometimes the vac lines inner lining will seperate & cause all kinds of similar problems when the brake peddle is depressed. Also check your egr valve operation. It could be blocked up with carbon or leaking vacuum. Good luck!

Starting with the vac reservoir behind the battery box, working towards the IWEs, check for cracks in the vac lines and that the check valves are working.

You can place a vac gauge on the IWE vac input, and check to see if it holds vac as a first step. This is the rough outline of the IWE vac components. The IWE without vac will not lock in. Usually the vac lines are the cause of the IWEs not locking into place. Without this, the 4x4 indicator lamps on the cluster will not illuminate ( that is actually a confirm everything is OK, and the status is locked into place ).

They are vac. controled. The leak could be behind the controls, but first check under the hood usually near the fire wall and check for any cracked or broken vac. lines and repair as necc. this should solve your problem. The vac. lines under the hood go bad first due to engine heat. If you have a length of line to replace make sure you use vac. line so it wont collapse. Soft softs in vac. lines is another sign of a bad line replace these also.