G'day hi and hello,
This might be my first post on forum, leaving it here bcs it can be a nice addition to this particular solution, after I read everything you (and internet) had about Hyundai dumbass clutch :-). I'm sure friendly mods will move it wherever appropriate if it's of any worth.
I got 2008 1.6 CRDI relatively recently, about 145000km, so here I am :-), with the low clutch bite, worse when it's warmed up. Cold was just low and annoying, hard to shift, plus when warm, crunchy in reverse and notably different feeling on the clutch. I concur I'm bit late with this, maybe everyone else has already moved on, but just in case...
Some blokes here (and YT) were replacing and/or deleting dampers (thanks for all these helpful threads), that's where I started too (easiest, right). Actually, first thing was to flush the fluid, reasoning behind it being if it has absorbed moisture, it could be loosing some properties when warmed up. (I've got a measuring thingy from ebay and it was over 4%, so...). I could have done the damper at the same time, but didn't, because I'm weird and only doing it one thing at the time would enable me to deduct what was wrong. All of that would produce so much pain in bleeding the system, but I've got this sucker thingy, so I could get the air out by myself without much drama.
That didn't help, and replacing the damper next didn't make any difference. All about the damper was already explained around the forum (thanks for that), so I won't get into details. I got a Mitsu one, because Kia dealer near me got merged with Mitsu so I could get it easier with info I got on this forum. I've got Kia Cerato, so I'm familiar with those guys. I've never found a useful Hyundai dealer for parts around me.
Note that I did much more research that I can picture here, took rod movement measurements and it was clear to me that all I need is a mill or two to be happy, if any of the rods were adjustable, that would be a 2 mins job. But, before I got myself to start with cylinder and rod work, while reading around some workshop manuals, I realized that I never checked if there's a CDV (Clutch Delay Valve). It was never mentioned in all these talks, so I got an impression that damper is diesel thing, while petrols have CDV. My Kia had no damper, had CDV, which was taken out long time ago because clutch would not release quickly. Some CDVs are also designed (as they say) to resolve different clutch feeling on different temperatures (expanding and restricting the flow when hot) in addition to the one way flow restricting.
So. I did find it in slave cylinder.
I took it out and no more clutch worse when hot, still low, but the same low regardless how long you drive or how hot is outside. At this point, could have left it like that, and I did (this saga started somewhere at the end of last year lol).
But, that would have been too easy, plus I already got used master cylinder from wreckers and made a plan for adjustable rod. I'll let few pics tell the story here:
Plastic rod ends couldn't be taken off without damaging it (that's why I got a spare cylinder, and so I can still drive the car until I make it). First idea was to take of top end, make thread and make it adjustable. I also designed and 3d printed rod end, but I didn't trust it would be strong enough to drive the clutch (but I made it anyway, just for fun).
To get the rod out, there's a circlip in cylinder, even if I managed to take it out on the spot, I don't see how could I put it back, plus I would get the fluid inside the car, so cylinder out first, and to take out the cylinder had to take the clutch pedal out, major pain in the bum. All clutch masters I remember from old days, were easy to take out from the engine bay side, this one was... I couldn't even apprehend why would anyone design such mess. Luckily I learned how to do it at the wreckers, easier to disassemble things if you don't have to assemble it again.
I didn't have tap /die set, so I gave it to a friend, he was nice enough to cut the rod in half and make threads. It's 6mm, so got a 6mm coupler and two nuts (ugly but works). You can see it in a photo, it did go a bit sideways, but still good to go. I also took a chance with this spare cylinder to measure and make sure piston has more place to go in.
We get to the point where zatos99 was at his first post, with few additions.
Pedal has a limit above it, at the limit switch. It's not a "hard" limit, because it hits the switch over the rubber, before it gets to the screw/nut. What is obvious when you disconnect rod from pedal is if pedal is resting on it's limit, or it stops when rod gets to his stop at the beginning of cylinder when it hits the circlip. If you need to push the rod a bit in to attach it to the pedal, not good, clutch might slip, you could be riding the clutch all the time. In that case, adjust the nut above pedal. In my case, I had to pull down the pedal to attach the rod. Oh, I forgot to mention. I obviously swapped the cylinders too. Even though used, the spare one looked better. I measured rod and adjusted to the same length, so I can see if it's gonna be different with replaced master cylinder. Started the car at that point, nope, it was the same low.
Magic happened next, when I took the rod off the pedal, released the top nut, turned top rod end a few turns, tightened nut, attached rod back to the pedal, and voila, no low clutch anymore.
I was surprised how little adjusting it took to make vast difference, I even took it a turn back later. (I guess driving koreans got us all quite used to the low clutch bite by now).
Unfortunately, no good photos of end result, I guess my hands were shaky after all the exercise, but here's a blurry one how it looks like at the spot .
Again, big thanks to zatos for sharing this idea and following up on mistakes so I can learn from it!