VF-4SS Tool release piston retracting slow

I've been having tool change issues for longer than I care to admit, banging, slow retract. This morning I fixed the banging with new quick exhaust valves, I'm still having slow retract issues, I'm starting to wonder if I have a broken return spring - it has a partial wind that you can't see in this video but it can be seen in the back if I look around the other side - maybe it's what's causing the problem? I notice that when I insert a tool in by hand, I can give it a little jiggle before that last little bit is taken up.
The spring looks very similar to this one: TRP BASE, 2 PROX SWITCHES INLINE | TRP Base | Tool Release Piston | Spindle Head | Find Replacement Parts | Haas Parts | Genuine OEM Haas Automation(R) Parts Factory-Direct

Video of the release piston actuation:
VF-4SS TRP retracting slow - YouTube

Video of 100% rapid tool change, watch how the tool pulls up 1/8" at the end of the tool change.
VF-4SS Slow TRP retract - YouTube

My VF2 doesn't have any slowness to release, straight up, no hangups.

Check your pre-charge pressure, and make sure the solenoid valve is shifting properly.

pmack said:

Check your pre-charge pressure, and make sure the solenoid valve is shifting properly.

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I haven't checked the pressure yet, it does make the release work properly, it's retraction.

pmack said:

Tool Release Piston (TRP) - Troubleshooting Guide | Customer Resource Center

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I have followed that, I have removed the mufflers, lubricated the o-ring, and the return spring seems to be there as it should.

The pressure must be dumped off the top side of the tool release piston once you let go of the tool release button. I was thinking that may be the sticking solenoid, leaving pressure on the piston. Have you checked the draw bar pressure lately? Maybe some broken belleville washers in the drawbar?

pmack said:

The pressure must be dumped off the top side of the tool release piston once you let go of the tool release button. I was thinking that may be the sticking solenoid, leaving pressure on the piston. Have you checked the draw bar pressure lately? Maybe some broken belleville washers in the drawbar?

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Thanks for the input, I started with the cheapest components first, might be time to buy some new valves.

I haven't tested draw bar pressure, I think it's about time to check that.

Turns out it was the mufflers all along, The quick exhaust valves seemed to fix the banging now that it's getting a precharge, I tried removing one muffler before but it didn't seem to help, but it definitely did this time! 2 new mufflers and we're ready to go.

my vf-3 needs that little in-line flapper valve doohickey periodically.

mkd said:

my vf-3 needs that little in-line flapper valve doohickey periodically.

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lol thanks?