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Free MT6 wonder mod: OEM bleeder delay removal

LeGti

Ready to race!
Location
France
Thanks to all the previous posters on this forum and others that explained the benefits of removing the flow-limiting diaphragm from the OEM bleeder block. And explained how to do it. Big, big thanks!!

Following is a quick explanation of why and how I modified my OEM bleeder, and the difference felt in driving afterwards:

Driving the Gti at first left me wondering: I often fumbled shifts, regardless of whether I was on it or not. Shifting casually, I couldn't avoid an occasional jerking of the drivetrain, as though I had misstimed clutch release... Though I am no pro, I have 30 years' experience with manual gearboxes. My other cars include a synchro-less 1967 SIIA Land-Rover which requires double-clutching & rev-matching, a 1971 Citroën SM with a peculiar gearbox/clutch... I know how to use a gearbox. Yet this Gti threw me curve-balls I couldn't manage!

Very fast shifts brought out another strange behaviour: when very quickly shifting and releasing the clutch, the pedal would stay down for a split second then pop up. Not good.

Thanks to other posters, I learned that VAG designed & implemented a flow-restricting diaphragm in the hydraulic line between the master cylinder (clutch pedal) and the slave cylinder (transmission). Its purpose is to delay the action of the clutch with respect to the position of the clutch pedal.

Removing it means that the clutch engages & disengages in direct relation to the pedal position. Without the diaphragm, poor pedal use is no longer hidden by the delay in hydraulic fluid flow. And without it, the above strange behaviors completely disappear: no more strange clutch actuation. No more clutch popping in very fast shifts. Wonderful, and I wish I had done it sooner.


Two ways to do it: buy and install the ECS bleeder valve or remove the diaphragm from the OEM piece. The ECS valve is reported to flow more than the modded OEM piece and also incorporates a one-way bleeder valve. I'll pick one up next time I order stuff from the US!

I simply modded my OEM piece, and here's how:

- remove airbox and you'll see the bleeder block: it's the black plastic piece that has a rubber hydraulic line going into it, and it's attached to the transmission just ahead of the gear selector shaft,




- using a thin screwdriver, lift up the two clips (they don't need to come all the way off,





- the block can be removed from the transmission, and the line can be pulled from the block (brake fluid will escape from both ends so prepare with lots of rags/paper towels),




- looking inside, you will see the yellow diaphragm:




- it's blocked on one side by a ridge and on the other by the base of the bleeder valve which protrudes into the block. A 9mm wrench will let you unscrew the valve, and a narrow screwdriver will let you simply push the diaphragm out:





Installation is straightforward, but air that got into the line now has to be bled out. To do so, a helper makes things easier. If you are alone here's how I did mine: cut down an old broom stick the correct length to keep the pedal all the way down. Push & pump pedal by hand a few times, wedge stick between pedal and seat base hardpoint. Open brake fluid réservoir cap. Go to bleeder block with lots of rags, remove nipple from bleeder valve, open valve slowly, hear & see bubbles coming out, close valve. Release pedal. Top up brake fluid réservoir *don't let it go below minimum level*. Repeat a few times. Five rounds did it for me.

And voilà!! The clutch now just follows your left foot. Swapping gears is now devoid of strange, obtrusive behavior, and fast gearchanges are hangup-free!!

An absolute must imho!!!

Hope this helps,
Ben.
 
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xl1200r

Ready to race!
Location
Albany, NY
I plan on doing this to mine when it gets in. I, like you, have tons of manual transmission experience on high performance cars (and bikes) and found the clutch action on my GTI test drives to be kind of annoying.

Does removing the diaphragm add any 'feel' into the pedal?
 

LeGti

Ready to race!
Location
France
"Feel"? You bet!!

The engagement & disengagement points are more faithfully transmitted to the left foot. Better yet, the driver's brain relishes in the newfound clarity in the relationship between clutch out and motion.

That sounded trite, lemme try again: there's no more BS. Move foot, clutch reacts!


I guess I can understand VAG implementing the delay: it masks improper clutch use. But it drives enthusiasts batty!! Should be a free option, imho, and certainly has no place on a "Gti".
 

wave

Ready to race!
Location
SW Florida
Ever since I bought my GTI, the only thing I've been unhappy with was the clutch feel. 30 minutes and a bit of elbow grease, and it now feels excellent. Thanks for this!
 

RedReplicant

Ready to race!
Location
Arizona
If someone wants to check the thread for the bleeder it'd be easy to order a Speedbleeder for $7. Basically the same thing as the ECS one at that point - if the purported size difference isn't noticeable, that is.
 

glina126

Ready to race!
Location
staten island
Awesome!! Thanks for posting this :D i knew something was really off with the clutch.. My mkv felt much better. Time to do this :D
 

gn4rwhals

Go Kart Champion
Location
Detroit, MI
Awesome, was going to order the ECS block but now I'll just get a speed bleeder and some brake fluid and do this.
 

wave

Ready to race!
Location
SW Florida
If someone wants to check the thread for the bleeder it'd be easy to order a Speedbleeder for $7. Basically the same thing as the ECS one at that point - if the purported size difference isn't noticeable, that is.

I doubt the size difference would be noticeable, as the inside diameter of the stock block is already larger than the rubber line that feeds it, therefore, the line would be the bottleneck long before the block that it attaches too.
 

BravoMike

Go Kart Champion
Location
Indianapolis
LeGti, THANK YOU for the wonderful DIY write up that is FREE!

Since I have the ECS bleeder valve on order, I will do this mod tomorrow morning first thing and next week I'll install the ECS bleeder valve block. I'll report back with my impressions on this free DIY in comparison to the ECS bleeder valve block.
 

LeGti

Ready to race!
Location
France
just got back from my favorite "rallye" road: thrashing gears 1-4 over & over & over: the delay delete is a wonderful, wonderful mod. Haven't yet seen a single drawback!!

Make sure you bleed the system well, and be careful never to let the brake fluid drop to the min. level!!!!!

I'll be putting the braided steel hose next week: we'll see if it helps in any way :)
 

RedReplicant

Ready to race!
Location
Arizona
I doubt the size difference would be noticeable, as the inside diameter of the stock block is already larger than the rubber line that feeds it, therefore, the line would be the bottleneck long before the block that it attaches too.

That's what I was thinking too, I just didn't want to get jumped on for suggesting that the stock piece with a $7 part would be better. :)
 

wave

Ready to race!
Location
SW Florida
That's what I was thinking too, I just didn't want to get jumped on for suggesting that the stock piece with a $7 part would be better. :)

Haha I hear ya, but I inspected it pretty thoroughly while I had it apart, and seeing as I work with industrial hydraulics every day, I can't see this being made any better by something like the ECS block due to the line size restriction. Of course, anything billet aluminum is pretty sweet... so I can't argue that it isn't still a badass part if anyone is so willing to spend the cash. :cool:
 

BravoMike

Go Kart Champion
Location
Indianapolis
This is a must do mod!

I don't quite have 30 years experience driving manuals, but I have been driving many different manual cars for about 18 years now and all of my cars have been manual. When I bought this GTI, I couldn't figure out why I had trouble timing my shifts correctly, specifically my heel toe downshifts. Thanks to this forum, I now know the problem was with this little orifice! Once removed, the clutch is much more "direct" feeling and very predictable. I can now shift fast, smoother and my heel toeing once again keeps the car in balance through a turn!

This was a very easy mod and I didn't spill as much brake fluid as I thought I would. I used LeGti's broom stick method to bleed out the brake line. It only took about 15 minutes for me to complete this.

My wife even noticed the difference and said she thinks it makes the car easier to drive. I agree with her because it makes this car's clutch feel like others we have driven.
 
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