*DIY*-Stainless Slave Line - a must have for all 6MT owners

[rtl5009]

The factory line from Audi has a pressure valve in to ease engagement. This valve wears out our clutches faster as engagement is over a longer period of time regardless of driver finesse and also KILLS pedal feel. USP sells a great stainless line replacement. Link Clutch feel is awesome with the line.

Below is a DIY to minimize master fluid loss, you can do it in the reverse order and start on the bottom.

Huge shout out to my good friend Christian @ AZ Euros in Tempe, AZ for giving me some lift time last night and aiding in the install. http://azeuros.com/

Pressure valve and installed line


First pop the hood, remove the rubber seal on the firewall and the cowl. The slave line hooks into the master right to the right of the booster underneath then ecu's main harness. This area is tight. Remove the washer bottle pour induct from the drivers side fender, next remove the ecu cover. Remove the metal guard around the master reservoir.



Remove the ecu and fuse tray (unbolt the hot 30 redwire- everything is plastic in the tray so it'll be just fine) and take out the 4 bolts to allowing you to move the lower part of the tray around. You wont be able to remove it completely with the wiper trans still in the way, but itll give you alot more room. You may have a boost line routed here if you have a boost gauge.



Now you have just about as much room as you are going to get- get the replacement line ready. Put a vacuum cap on the thicker fitting end to limit fluid loss. The thinner end will hook into the master.



Place alot of paper towels underneath the slave hook up to capture the fluid you lose. Pop the clip off the existing line, be gentle and it'll slide to the top and remain on the hook up. Slide out the existing line and slide in the thinner end of the new stainless line. Once the line is flush push the clip back down.



The hard piped line is extremely difficult to fish out, I cut it in half where it comes through the body and then pulled out the remainder from behind the firewall with vice grips. We fooled around for 15 mins trying to get it out without cutting. We also deleted the loop around on the side of the transmission.



We routed the new line through the drivers side cowl drain, removing the rubber grommet. This is wayyyy easier then routing it through the OEM hole and lines up with the slave an shielding perfectly.



This exits underneath the heat shied by the steering column, pop the fastener off and pull back the heat shielding and pull the line through.



Hook it into the slave and bleed the clutch. I used a power bleeder, if you dont have one gravity bleed it on a level surface and then pump it up and bleed until no air comes out.

All buttoned up! Reinstall all the remove components in reverse order. minus the clutch lines.



Make sure to spray degrease to clean and wash in the cowl were the brake fluid leaked.

[AudiS4TW]

Awesome tip! Thanks for sharing this.


Sent from my iPhone

[PitchS4]

T/F - You could leave the old line in if you wanted? Seems the major PITA is getting to and removing the old line. You could just cut it underneath and leave it the cowl/ECU box since you are running the new line down through the drain hole.

Thanks for the write up. I am going to do all my fluids soon so this would be a logical thing to do. What was your start to finish time?

Also what was the point of the stock valve? To reduce drivetrain shock on a hard launch?

[Ze_Nardo6]

Great write-up, thanks much.

[Vogz]

Thanks for the write up!!! Can't wait to install mine. Doesn't seem too bad at all.

[littleredwagen]

Nice write up, but I would be concerned about the line chafing going through the drain hole, maybe put a grommet insert in there to protect the body and line?

[rtl5009]

Nice write up, but I would be concerned about the line chafing going through the drain hole, maybe put a grommet insert in there to protect the body and line?

The line is is coated. You could leave the grommet in if you are truly concern. It'll be just fine as is.

[rtl5009]

T/F - You could leave the old line in if you wanted? Seems the major PITA is getting to and removing the old line. You could just cut it underneath and leave it the cowl/ECU box since you are running the new line down through the drain hole.

Thanks for the write up. I am going to do all my fluids soon so this would be a logical thing to do. What was your start to finish time?

Also what was the point of the stock valve? To reduce drivetrain shock on a hard launch?

False -Weight savings ;). The valve is there just to ease clutch engagement. Took about an hour and a half.

[switchedstance]

What's stopping us from just removing the valve from the line, it seems to have 2 fittings at either end?

[rtl5009]

Nothing but space, time and money.

[infinkc]

What's stopping us from just removing the valve from the line, it seems to have 2 fittings at either end?

Thats what i was thinking as i read your post, get a coupler and bypass it.

Great writeup, i got one also, but havent had time to install it. I was wondering if you can also just leave the old line in the car and just run the new one to save time.

What impressions do you have now how the clutch pedal feels? does it grab right away now?

[rtl5009]

Feel is night and day difference. Engagement point hasn't changed at all, just pedal feel. It feels much more mechanical and connected now.

[PitchS4]

What's stopping us from just removing the valve from the line, it seems to have 2 fittings at either end?

IMO if you are going to go through the trouble of accessing the line and bleeding the system, spend the 70 bucks on the stainless line.

[switchedstance]

IMO if you are going to go through the trouble of accessing the line and bleeding the system, spend the 70 bucks on the stainless line.

Has nothing to do with cost, I don't want to cut the OEM line to remove it and wan't to maintain an OEM appearance of the system. God forbid I have a clutch problem that may be warrantied, I wan't to be able to swap back. It looks like putting the oem line back in place does not seem possible.

[OMGHI]

Nice write up, but I would be concerned about the line chafing going through the drain hole, maybe put a grommet insert in there to protect the body and line?

Rob is right. Its coated and the "stainless steel braided" line under the coating. It would take yeeeaarrss of driving on the worst roads in America before it chafed through.

I <3 rtl5009

[littleredwagen]

Rob is right. Its coated and the "stainless steel braided" line under the coating. It would take yeeeaarrss of driving on the worst roads in America before it chafed through.

I <3 rtl5009

I would more concerned about the body allowing a spot start developing rust, that is all

[spitefulcheerio]

Has nothing to do with cost, I don't want to cut the OEM line to remove it and wan't to maintain an OEM appearance of the system. God forbid I have a clutch problem that may be warrantied, I wan't to be able to swap back. It looks like putting the oem line back in place does not seem possible.

Yeah I'm gonna just delete the little valve. A union and a little bending will make that work

[Canvasoso]

The OEM line is hard metal, the braided portion is the same as this expensive replacement line. So, there is really not much advantage to this new line. The key here for better pedal feel is removing the valve, not replacing the line.

[rtl5009]

The advantage to the line is that it deletes the valve for you and also adds metal to all of the connection fittings (both the slave and master sides of the stock line are plastic) and deletes an unnecessary connection (in the middle). Removing the valve and bridging the gap will be more costly in the long run after time and hassle is incorporated.

[rtl5009]

I would more concerned about the body allowing a spot start developing rust, that is all

Negative, the grommet actually holds dirt and debris in that area. Removing it will keep the area more dry.

[littleredwagen]

Negative, the grommet actually holds dirt and debris in that area. Removing it will keep the area more dry.

Your right grommet is the wrong word, I meant a problem piece of rubber around the edge of the hole to protect the metal and line. That's all

[infinkc]

which line went into the clutch master? the small hard line on the right? could you just connect the stainless line to that instead of removing the ecu box? just do it all for under?


Edit,
looks like the valve is at the top connection where the master is, so you would have to delete it all.

[Canvasoso]

The advantage to the line is that it deletes the valve for you and also adds metal to all of the connection fittings (both the slave and master sides of the stock line are plastic) and deletes an unnecessary connection (in the middle). Removing the valve and bridging the gap will be more costly in the long run after time and hassle is incorporated.

Good point. Yes, it would be cleaner with less connections and less chances of future possible leaks since there are less connection points. However, pedal feel wouldn't be improved just because of the line being replaced. The delay valve is the real issue here, how you eliminate it from the equation is another issue.

[rtl5009]

Good point. Yes, it would be cleaner with less connections and less chances of future possible leaks since there are less connection points. However, pedal feel wouldn't be improved just because of the line being replaced. The delay valve is the real issue here, how you eliminate it from the equation is another issue.

You must be a six sigma black belt with that root cause analysis.

[Brother Owl]

Good point. Yes, it would be cleaner with less connections and less chances of future possible leaks since there are less connection points. However, pedal feel wouldn't be improved just because of the line being replaced. The delay valve is the real issue here, how you eliminate it from the equation is another issue.

You must be a six sigma black belt with that root cause analysis.

Lololol

[melomandn]

You must be a six sigma black belt with that root cause analysis.

[rnkjr]

How do we know the "valve" delays clutch engagement. The only description I can find is this (identified as a frequency modulator):

"The vibrations are generated as a result of axial torque deviations in the crankshaft, which are transferred to the pedal via the clutch hydraulics. The frequency modulator suppresses
pulsations in the system's hydraulic fluid, thereby preventing vibrations on the clutch pedal."

http://www.uspmotorsports.com/Drivet...e-Audi-B8.html

[Senseless]

2nd on rnkjr's question about it actually being a clutch delay valve and if it's a problem or not. I had a BMW with a clutch delay valve that was clearly awful. It caused me to clash 2nd gear on quick shifts, so removing it was a huge improvement. But I don't notice any shifting or clutch problems in my 2012 S4.

[rtl5009]

How do we know the "valve" delays clutch engagement. The only description I can find is this (identified as a frequency modulator):

"The vibrations are generated as a result of axial torque deviations in the crankshaft, which are transferred to the pedal via the clutch hydraulics. The frequency modulator suppresses
pulsations in the system's hydraulic fluid, thereby preventing vibrations on the clutch pedal."

http://www.uspmotorsports.com/Drivet...e-Audi-B8.html

If modulates fluid in any way it will slow engagement..

And by a gut check, the clutch felt like shit before, and now it feel great. My first to second shifts would engage slowly. Now they are great. Others have reported similar findings o their shifts.

[S4tranquility]

If modulates fluid in any way it will slow engagement..

And by a gut check, the clutch felt like shit before, and now it feel great. My first to second shifts would engage slowly. Now they are great. Others have reported similar findings o their shifts.

I want to do this. Should've bought the SS line when it was on sale recently...

[rtl5009]

Yeah I'm gonna just delete the little valve. A union and a little bending will make that work

Part of the line will still be rubber. Rubber = poor feel.

[Canvasoso]

You must be a six sigma black belt with that root cause analysis.

I guess I'm a white belt because I have no clue on what you just said. Lol

[Sceanzo]

Unbolt the alleged valve from the lines. Blow air through it? Take it apart? I dunno, just thinking out loud

[rtl5009]

Unbolt the alleged valve from the lines. Blow air through it? Take it apart? I dunno, just thinking out loud

I threw it in the garbage. Best place for it.

[CELison]

Banjo

[skinnytirez]

which line went into the clutch master? the small hard line on the right? could you just connect the stainless line to that instead of removing the ecu box? just do it all for under?


Edit,
looks like the valve is at the top connection where the master is, so you would have to delete it all.

infinkc- where did you pull this graphic from? Anyway you could share your source

[Zaider]

Wish I'd seen this before my clutch failed. Now, with a new clutch and flywheel as of a week ago, I think this is on the list to do to save the new one.

[jimrobbington]

Thank you for putting together this diy. This is a modification that I know I'm going to have to do, I want to do and I will do but I know i'm going to order it and it's going to sit around for months. While the install doesn't look hard it doesn't appear particularly fun either - a pain in the a** it is operating on cars in tight places but the $ saved and lessons learned are worth it so I suppose I might as well get to it before the winter months.

Samesies. Though helpful, this diy doesn't give me the confidence to do this on my own. My shop quoted 3 hrs for complete install/bleed on this... So quite expensive compared to the $70 part.

[OMGHI]

I threw it in the garbage. Best place for it.

actually its sitting on top of my tool box...

[rtl5009]

actually its sitting on top of my tool box...

kill it with fire, or pry it open and post a picture?