Interesting Issue with Clutch, Need Opinions

[Evan_]

Hello,

I'm not usually one to post on a forum asking for help or opinions because I never encounter anything I need help with, but this issue has left me pondering...

You know when you brake with the car in gear, the engine rpm will drop because you are stopping an engine rotating a clutch that is engaged and connected to the rear wheels. Well lately, my car (stock sr20det and trans) has been doing this thing where it will bog down like that with the clutch disengaged.

In other words, when rolling to a stop light in second gear, I'll push in the clutch but it will act like the clutch is still engaged. I have to physically "pop" it out of gear. It seems to only occur in gears 1-3 and hasn't been a huge issue but it gets annoying in traffic because I'll bump the clutch in 1st gear to move forward a few feet and it will start jerking forward while braking like the clutch is engaged, but it should be disengaged.

I've replaced the clutch master and slave cylinder with no change. It shifts through all gears smoothly... It only does it when pressing the foot brake and holding clutch in while leaving it in gear. Sometimes it will stall the engine and sometimes it will suddenly stop doing that and come back to normal operation.

Has anyone else had this issue or heard of people having this issue? It is a new one in my 5 plus years of working as a mechanic... Internal issue with trans? Pressure plate gong out? Throwout bearing failure?

Clutch and tob have only an est. 2000 miles top

Any insight would be appreciated,

Thanks

[derass]

I'm assuming you've bled the system including the damper? Perhaps there's a pinhole in the hard or flex line letting air in. How about the pedal adjustment? Mine needed to be done after replacing the clutch.

[Evan_]

Damper box has been deleted... I let it gravity bleed for a good 5 minutes, never letting fluid run down. That is certainly possible, but it hasn't lost any fluid over the past month or two it has been doing it...

[derass]

I've never done a gravity bleed so can't comment on whether it's a good technique or not. Maybe get a helper and try a 2-person bleed.

[Evan_]

Meh, I did a two person bleed a couple weeks ago... No change, bleeding method doesn't matter as long as its bled properly in professional opinion. Thanks though

[NiSilS14]

was the flywheel resurfaced when you had the clutch done? A flywheel that has too much material taken out of it will change how it engages in a hydraulic system and the clutch pedal height. Over time the symptoms get worse as the clutch gets worn in. Typically anything more than .020 off the flywheel will require a shim between the crank and flywheel to re-position the clutch assembly.

[Evan_]

Yes it was, at a local machine shop I take all my flywheels too. I never got the exact number of material taken off, but the flywheel wasn't in bad shape, so I assume not much. That's a good idea though, the clutch engages at the tippy top, but all my clutches have, on KA's and sr

[Kingtal0n]

Have someone press the clutch while you inspect the slave. Look for it to move, then have the person hold the clutch while you keep inspecting it. Watch for it, to see if it slowly moves back by itself (indicating a leak).

If it isn't leaking and slowly allowing the clutch to re-engage, you might need more throw, adjust the clutch pedal to give more throw at the slave. Make sure you leave some play at the top of the pedal also, you do not want the TOB riding the pressure plate.

The issue could be geometry related, or a leak, it sounds like the clutch is dragging. Not good because it will put additional wear and tear on the synchros.

[Evan_]

Cool. Thanks! I tried adjusting the pedal, but I'll verify there aren't leaks and go from there. Thank you