Diagnosing a bad clutch master cylinder?

[onlyjuancannoli]

So I'm trying to figure out whats going on with this piece of shit so I can finally drive it tomorrow after 2 months of being down for renovations. On the last few days I drove it I noticed that the clutch pedal was getting more and more light, almost as if air was starting to get in the system. Now I'm trying to get the car back on the road after extensive work and I can't seem to build any pressure.

-New Sachs clutch slave
-Reservoir nipple feeding the clutch master is NOT clogged
-Slave cylinder bleeder screw has no fluid coming out
-Slave cylinder quick release fitting has no fluid coming out

I should add that I'm using a Motive power bleeder, and with 15psi in the system it still doesn't spit anything out, regardless of the orientation of the clutch pedal being against the firewall, or all the way up. I'm suspecting the clutch master has failed, or is clogged, anyone encounter this before or have an alternative theory before I drop another $160 to fix this thing?


Update: Master cylinder was clogged, replacement was required. For future reference the:

OEM VAG Part #: 8E1721401AJ
FTE Part number #:KG190125.01
Luk Part number #: LMC417 (Photos in the Amazon listing show a plastic master cylinder, however upon arrival I found a metal FTE master cylinder in the Luk box. Amazon currently sells this for $87.22 w/ prime shipping as of 9/25/2019)

[SJorge3442]

So I'm trying to figure out whats going on with this piece of shit so I can finally drive it tomorrow after 2 months of being down for renovations. On the last few days I drove it I noticed that the clutch pedal was getting more and more light, almost as if air was starting to get in the system. Now I'm trying to get the car back on the road after extensive work and I can't seem to build any pressure.

-New Sachs clutch slave
-Reservoir nipple feeding the clutch master is NOT clogged
-Slave cylinder bleeder screw has no fluid coming out
-Slave cylinder quick release fitting has no fluid coming out

I should add that I'm using a Motive power bleeder, and with 15psi in the system it still doesn't spit anything out, regardless of the orientation of the clutch pedal being against the firewall, or all the way up. I'm suspecting the clutch master has failed, or is clogged, anyone encounter this before or have an alternative theory before I drop another $160 to fix this thing?

So strange that the motive isn't pushing pressure through. I'm not well versed enough in the operational setup of the master, but it seems like a blockage to me. Would it be wise to maybe try to push fluid up through the slave? I have no idea. Sounds really frustrating. Maybe the guys at JHM might know? Im not sure who are the tranny experts for our platform, but this would also be driving me nuts.

[old guy]

According to the Bentley Manual you need to use 2.5 bar (36 psi) to bleed the slave. In reality you do not need that much pressure. But 15 psi is probably below the threshold. In the past I have had to pump my Motive up to just below 30 psi to gete the slave to bleed.

[onlyjuancannoli]

According to the Bentley Manual you need to use 2.5 bar (36 psi) to bleed the slave. In reality you do not need that much pressure. But 15 psi is probably below the threshold. In the past I have had to pump my Motive up to just below 30 psi to gete the slave to bleed.

Wow, 36 is crazy high. While I'm only doing that at a 3rd of the pressure called for, shouldn't the slave cylinder capable of some kind of gravity bleeding as well? I've read a lot of posts on here of people suggesting to do it that way so originally I did. I left the bleeder open with a hose leading to a large bottle under the car for a good half a day because I kept checking and nothing came out! I'll try more pressure tomorrow, though I'm afraid of causing damage. Someone else mentioned they cracked their reservoir from too much pressure.

- - - Updated - - -

So strange that the motive isn't pushing pressure through. I'm not well versed enough in the operational setup of the master, but it seems like a blockage to me. Would it be wise to maybe try to push fluid up through the slave? I have no idea. Sounds really frustrating. Maybe the guys at JHM might know? Im not sure who are the tranny experts for our platform, but this would also be driving me nuts.

That's what I'm leaning towards too. I'm going to try with a bit more pressure tomorrow before the new master shows up in hopes that it unclogs itself.

[Kevin C]

15 psi and assist the bleed by pressing the clutch pedal down as you open the bleeder. Close the bleeder as you get close to the bottom. Repeat until the air is out. Getting the back end of the car higher than the front will help. I was able to bleed mine this way using a Harbor Freight vacuum bleeder.

[onlyjuancannoli]

15 psi and assist the bleed by pressing the clutch pedal down as you open the bleeder. Close the bleeder as you get close to the bottom. Repeat until the air is out. Getting the back end of the car higher than the front will help. I was able to bleed mine this way using a Harbor Freight vacuum bleeder.

Yeah, the Master was clogged so a replacement fixed it. Comically enough it seems the FTE wholesaler raised the price or so thats what FCP Euro told me so unless its in stock then the retailer will have to raise the price. I happened to stumble across the Luk part number for the B6 master cylinder, ordered it on amazon one day prime shipping. I get it, open the box and its a metal FTE master cylinder haha!