Slave line leak at connection, Duralast & USP line

**killerkali** · 08-18-2018 03:27 PM

Hey all, I've been dealing with a clutch swap for months now. Finally got the motor in and gravity bled the slave, I've found the slave line is leaking where it connects to the slave cylinder. I'm using a new Duralast metal slave and the USP braided line. The line has a good amount of in/out play where it connects to the slave, I'm using the clip that came with the Duralast SC. I don't recall there being any o-rings or fittings on the USP slave line, just the tapered end.
What gives here? Do I need to try a different slave, or could this be a missing o-ring or fitting issue? I recall a thread where the OP removed the female fitting on the slave and put a larger o ring of some sort. I'm mainly concerned why the slave line is able to move so much

**TylerT** · 08-18-2018 03:38 PM

I have the same issue with the in & out play, but haven’t had any leaks.

I’m sure you’ve verified but make sure that clip is fastened properly & the line is in all of the way.

**killerkali** · 08-18-2018 03:55 PM

Interesting. I believe its fastening correctly, I removed it a few times and the clip is surely holding it in. But from where it stops at the clip, it can be pushed in that extra 1/8" or so.

**vavJETTAw36** · 08-18-2018 04:03 PM

Same setup as me. There’s def some in and out play. No issues in fact this setup solved my previous leaking issues.

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**killerkali** · 08-19-2018 06:32 PM

Originally Posted by vavJETTAw36

Same setup as me. There’s def some in and out play. No issues in fact this setup solved my previous leaking issues.

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No o ring on the line itself right, or adapter of any sort?

**vavJETTAw36** · 08-19-2018 06:33 PM

Originally Posted by killerkali

No o ring on the line itself right, or adapter of any sort?

Nope

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**killerkali** · 08-20-2018 12:04 PM

Any ideas on a solution? I spoke with USP and it may be possible that this combo isn't compatible. They offer a larger o-ring that may solve this, worth trying that or should I get a stock slave?

**vavJETTAw36** · 08-20-2018 12:27 PM

Originally Posted by killerkali

Any ideas on a solution? I spoke with USP and it may be possible that this combo isn't compatible. They offer a larger o-ring that may solve this, worth trying that or should I get a stock slave?

Do you have any pics of any of the parts you installed? I want to confirm that your slave is the same as my slave. I have the part handy so I will post a pic of it.

This is the fitting that mine has

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**killerkali** · 08-20-2018 07:50 PM

Originally Posted by vavJETTAw36

Do you have any pics of any of the parts you installed? I want to confirm that your slave is the same as my slave. I have the part handy so I will post a pic of it.

This is the fitting that mine has

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It's in the car ATM, but yes that is the exact Duralast slave, same fitting and all. Not sure if you encountered this but my Duralast SC had a small nub in the casting on the mounting point, I had to dremel it off to fit it in. A few users in a prior post told me that was normal, soooooo leaves me lost. My only guess is that maybe I got a dud SC that has the incorrect O-ring, because I know there is one in there.

**Nollywood** · 08-21-2018 04:41 AM

It’s pretty normal for the hardline to have in and out free play.

Make sure there’s no grit in the sealing area, and there are no nicks.

**vavJETTAw36** · 08-21-2018 06:46 AM

Originally Posted by killerkali

It's in the car ATM, but yes that is the exact Duralast slave, same fitting and all. Not sure if you encountered this but my Duralast SC had a small nub in the casting on the mounting point, I had to dremel it off to fit it in. A few users in a prior post told me that was normal, soooooo leaves me lost. My only guess is that maybe I got a dud SC that has the incorrect O-ring, because I know there is one in there.

yep had to grind down the nub in the back

**vavJETTAw36** · 08-21-2018 06:49 AM

You could try pulling it and having Autozone replace it. They have lifetime warranties. At least this might get you a good "fitting". I am sure it's something to do with the seal inside of that fitting. The fitting itself is two-piece.

**killerkali** · 08-21-2018 02:34 PM

Originally Posted by vavJETTAw36

You could try pulling it and having Autozone replace it. They have lifetime warranties. At least this might get you a good "fitting". I am sure it's something to do with the seal inside of that fitting. The fitting itself is two-piece.

Yeah agreed, nothing wrong with the line itself so it must be the slave. Going to swap it out and if that fails I'm just going to get the entire USP setup with the threaded line....

**JVD** · 08-21-2018 04:24 PM

Doesn't that whole slave adapter bit just unthread from the slave body?

If so, remove that and slap an AN fitting in there. Hack the push in fitting off the line and put on AN.

I also found zero benefit to metal slave over plastic. Maybe they last longer? Never run one long enough to find out.

**killerkali** · 08-21-2018 04:46 PM

Originally Posted by JVD

Doesn't that whole slave adapter bit just unthread from the slave body?

If so, remove that and slap an AN fitting in there. Hack the push in fitting off the line and put on AN.

I also found zero benefit to metal slave over plastic. Maybe they last longer? Never run one long enough to find out.

It does, I actually left the slave in and removed that portion to try a new one. And how would I fit an AN fitting to the existing line, IF i did go and hack it up? Some type of collar clamp to convert it I'd guess?

Also, I only installed a metal slave as my entire motor/clutch pull was caused by a failed plastic slave, when I tried to remove the slave it exploded and shot the rod into my bell housing...... Never again.

**killerkali** · 08-21-2018 08:26 PM

Well it looks like the duralast slave I bought was missing a small nylon ring that the tapered end of the line seals against. Every Autozone seems to have superseded that SC with a different one that is all cast, so the adapter is not removable. The new style also is more like the OEM plastic, with a very long connection. This coupled with the straight end of the USP line makes this combo not work as it runs into the downpipe.

I need to source another SC that has the short connection like the original duralast. Any quality options?

**JustManson** · 08-21-2018 10:52 PM

Why not just get the USP Metal Slave. Tried and true.

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**JustManson** · 08-21-2018 10:53 PM

https://www.uspmotorsports.com/USP-A...xoCm1cQAvD_BwE

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**JVD** · 08-22-2018 06:15 AM

Originally Posted by killerkali

It does, I actually left the slave in and removed that portion to try a new one. And how would I fit an AN fitting to the existing line, IF i did go and hack it up? Some type of collar clamp to convert it I'd guess?

Also, I only installed a metal slave as my entire motor/clutch pull was caused by a failed plastic slave, when I tried to remove the slave it exploded and shot the rod into my bell housing...... Never again.

It's most likely a standard AN line. So you just need to put a new end on. Then find an adapter that threads into the slave. A bit of work... but then you're not getting a new slave and new line.

**vavJETTAw36** · 08-22-2018 07:08 AM

That stinks, you could have just had a line made for the threads on the old DUralast. Yea easiest solution is USP slave and line, then sell the line you have to recoup some money.

**B501S4** · 08-22-2018 02:00 PM

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**killerkali** · 08-22-2018 03:03 PM

Well I sourced another of the Duralast slaves with the threaded on fitting. It appears visually the same as my current one, with no nylon seal where the hardline sits. This is compared to the "new" style Duralast which is 1 piece cast, and it has the nylon fitting. I'm almost positive that it will leak again, going to give it a shot and if no luck I'm going the USP threaded option..... What a pain in the ass this has been, really surprised I haven't found any other cases of this

**Nollywood** · 08-26-2018 03:21 AM

Originally Posted by JustManson

Why not just get the USP Metal Slave. Tried and true.

Are they made by USP? I only ask, because I believe they are genuine Audi parts, I’m just not sure how the USP reference came about.

**JustManson** · 08-26-2018 05:48 AM

I don’t recall seeing any markings on the Slave when I received it... it’s been awhile. Their site (USP) doesn’t mention anyone other than their brand for the Slave and Clutch line.

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**Zingrox** · 08-26-2018 05:52 AM

I have a second, new unopened in box USP stainless steel clutch line if anyone's interested

**durfA4** · 08-26-2018 03:21 PM

I went through a similar episode with Duralast slave- there are two versions, a new one that was completely cast made in china and an older style that was made in Italy with the screw on fitting and O-ring (rebranded Febi IIRC).

The new style cast slave would not seat the factory clutch line at all, the bore was not deep enough.

IMG_8997.jpg
IMG_8996.JPG

I wound up returning the defective new slave and happened to get an opened older style. the O ring was ripped. I disassembled at Autozone and had them throw in a box of O-rings put it in and and replaced the Master cylinder with a made in Italy metal duralast unit. Clutch feels great, no leaks.

**Nollywood** · 08-26-2018 05:10 PM

Originally Posted by JustManson

I don’t recall seeing any markings on the Slave when I received it... it’s been awhile. Their site (USP) doesn’t mention anyone other than their brand for the Slave and Clutch line.

I only asked, as Audi do sell a metal one. B4 and early B5 slaves are aluminium, just like the “USP” item. Made mostly by BOGE.

I bet they are still cheaper than from USP. Last one I purchased was £53.