Just finished F22B motor swap in my 94 Accord EX (F22B1 -> F22B (JDM)) and the motor started right up. However, when I went to depress the clutch pedal, it went to the floor.
"No problem", or so I thought... I hadn't bled the clutch hydraulic line. (I'd disconnected the line between the master and slave cylinders when I pulled the motor & trans), so I figured that would quickly restore the proper pedal action. Unfortunately, it did not.

After bleeding the line with 3 bottles of DOT 3 brake fluid, I'm still seeing air in the line, and absolutely no pedal firmness. There was no problem with the clutch before swapping the motor out. (I did replace the clutch, pressure plate, etc.)

I've been searching and reading forum posts recommending replacement of both slave and master cylinders, but neither of mine are leaking (and they were working fine prior to the swap). I haven't adjusted anything - just re-connected everything the way it was before.

What else could cause the pedal to go to the floor without resistance?

 

if the pedal sticking ?

 

The pedal is not sticking. But it is spring-loaded, apparently, so after it goes about half-way down (the only resistance coming from the spring) it pulls itself to the floor. It can be easily pulled back and it stays up.

 

Try using a vacuum to bleed the line. If there is any air in there, you will have this symptom. It can be an irritating process.

 

If the clutch master cylinder sees a portion of travel it does not normally see, mainly in an aged master cylinder, the seals can become damaged. Check the clutch master cylinder for leakage under the dash by pulling the dust boot off. It is possible to have a master cylinder that is drawing in outside air. Also check all your fittings and connections.

 

Great suggestion - I'll try the vacuum bleed and that should let me know if the pumping action is introducing air into the system. Looks like a much simpler approach, too. Thanks!

 

The connections all look good, but I'll pull the dust boots back on the master and slave cylinders to check for leakage. Thanks!

 

I checked the master and slave cylinders for leakage (pulled back the boots). The master was a little wet so I went ahead and replaced both (per recommendations from others in related threads). I then used the vacuum method to pull fresh fluid from the reservoir down through the slave cylinder, and then continued to bleed the system. This appears to have resolved the issue of air being re-introduced into the system, so THANK YOU VERY MUCH.