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Another Slave/Accumulator Failure

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Old 04-29-2019, 07:00 PM
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SteveS83
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Default Another Slave/Accumulator Failure

At least it's my assumption my slave or accumulator failed. Reservoir in the frunk is dry & pedal to the floor. This happened 1 week after having my driveline fluids changed, but I think it's coincidental. The pedal was very heavy when starting the car for a few months leading up to the fluid swap and I also had a slow leak on the garage floor that I assumed was the RMS. The leak has since stopped.... I do plan to have the indy shop that did the maintenance have a look to identify exactly what's going on before I spend, however in an effort to preempt my decision I'm looking for any advice on which route to go.

Stick with OEM slave/accum replacement
- I personally don't like the pedal feel - engagement point is not ideal
- I don't want another failure. Car has 50k miles and it's the first failure but it's not a DD like the original owner used it. Is that a potential reason the slave failed - lack of driving?
- Keeps the system stock (have EP1 + UMW tune so...not a big concern)

BBI
- Looks to be the easiest conversion to install. Also appears to be high quality.
- Pretty spendy....
- I've read issues where the master cylinder, BBI slave and various lines have failed after the install due to some mixing of pentosin & DOT 4. Is this a risk with BBI?
- Heavier more direct feel of the pedal, along with the GT2/3 clutch assist spring

EVOMS GT2 Conversion
- Using OEM components seems like a better route to go - and no tapping of the housing which is good
- Again has a heavier more direct feel of the pedal, along with the GT2/3 clutch assist spring
- Kit comes with braided lines, new master, clutch assist spring, etc. IMO this almost eliminates the chance of mixing fluids IF the EVOMS kit requires DOT 4.
- More labor intensive to install?

So in reality for me it's between BBI or EVOMS. It's not a daily driver and I'm a larger guy so I have no issues with a heavier pedal - but will opt for the GT clutch assist spring regardless.

Any thoughts from those who have owned or driven each? I have the stock clutch BTW. Any other suggestions or things to look out for?
Old 04-29-2019, 07:12 PM
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o7silverturbo
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Originally Posted by SteveS83
At least it's my assumption my slave or accumulator failed. Reservoir in the frunk is dry & pedal to the floor. This happened 1 week after having my driveline fluids changed, but I think it's coincidental. The pedal was very heavy when starting the car for a few months leading up to the fluid swap and I also had a slow leak on the garage floor that I assumed was the RMS. The leak has since stopped.... I do plan to have the indy shop that did the maintenance have a look to identify exactly what's going on before I spend, however in an effort to preempt my decision I'm looking for any advice on which route to go.

Stick with OEM slave/accum replacement
- I personally don't like the pedal feel - engagement point is not ideal
- I don't want another failure. Car has 50k miles and it's the first failure but it's not a DD like the original owner used it. Is that a potential reason the slave failed - lack of driving?
- Keeps the system stock (have EP1 + UMW tune so...not a big concern)

BBI
- Looks to be the easiest conversion to install. Also appears to be high quality.
- Pretty spendy....
- I've read issues where the master cylinder, BBI slave and various lines have failed after the install due to some mixing of pentosin & DOT 4. Is this a risk with BBI?
- Heavier more direct feel of the pedal, along with the GT2/3 clutch assist spring

EVOMS GT2 Conversion
- Using OEM components seems like a better route to go - and no tapping of the housing which is good
- Again has a heavier more direct feel of the pedal, along with the GT2/3 clutch assist spring
- Kit comes with braided lines, new master, clutch assist spring, etc. IMO this almost eliminates the chance of mixing fluids IF the EVOMS kit requires DOT 4.
- More labor intensive to install?

So in reality for me it's between BBI or EVOMS. It's not a daily driver and I'm a larger guy so I have no issues with a heavier pedal - but will opt for the GT clutch assist spring regardless.

Any thoughts from those who have owned or driven each? I have the stock clutch BTW. Any other suggestions or things to look out for?
I have the GT2 set up. I just put the kit together and tapped the transmission.

Either way both kits can be done with the transmission in the car and if you are going to go with the BBI slave I would suggest changing the master just so there is no issue with fluid.

Biggest problem with the BBI is that if the seals inside fail you have to send the slave back to BBI and have them replace the seals they will not sell them to you.

Going the gt2 route if it fails order another 100 slave and have it done in a couple hours, I also like that the gt2 just blocks of the ports for power steering less areas that could leak.
Old 04-29-2019, 07:40 PM
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SteveS83
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Originally Posted by o7silverturbo
I have the GT2 set up. I just put the kit together and tapped the transmission.

Either way both kits can be done with the transmission in the car and if you are going to go with the BBI slave I would suggest changing the master just so there is no issue with fluid.

Biggest problem with the BBI is that if the seals inside fail you have to send the slave back to BBI and have them replace the seals they will not sell them to you.

Going the gt2 route if it fails order another 100 slave and have it done in a couple hours, I also like that the gt2 just blocks of the ports for power steering less areas that could leak.
I was thinking the same thing regarding the OEM advantage of having the GT2 kit over the BBI.

You said you tapped the housing - I assume you didn't use the EVOMS kit, you actually just converted the GT2 setup from the get-go? I believe with the EVOMS kit there's no tapping needed - or am I incorrect?
Old 04-29-2019, 08:14 PM
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bondjockey
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Another option given that you have an exhaust and a tune is to get the Sachs pressure plate and GT2 clutch disc from Kevin at UMW. It will give you a little more predictable pedal feel / engagement point without the very heavy feel of the other two options. But the kit and labor is not cheap. Good thing to do if you already plan to drop the engine.
Old 04-29-2019, 09:24 PM
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atcbi5
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I believe that a flush of the system every two years might prevent these failures. It’s not anything recommend by Porsche. When I removed my engine, I replaced the slave, accumulator and master. They were not defective I just decided to change them. I opened my slave the other day and it was full of fine aluminum deposits. I cleaned it all out and assembled it back. Wondering if these powder type aluminum debris is affecting the check valves within the unit?. I am flushing the reservoir, front and slave Wednesday. It’s been three years since I replaced those units.
Old 04-29-2019, 10:57 PM
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SteveS83
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Originally Posted by bondjockey
Another option given that you have an exhaust and a tune is to get the Sachs pressure plate and GT2 clutch disc from Kevin at UMW. It will give you a little more predictable pedal feel / engagement point without the very heavy feel of the other two options. But the kit and labor is not cheap. Good thing to do if you already plan to drop the engine.
So far no plans to drop the engine. At some point I'll do the coolant fittings that's when I'll asses and do something...and Kevin will be the first person I call. For now since my equip is shot I figured it's time to find an alternative.
Old 04-29-2019, 11:37 PM
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drob23
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I was faced with the same decision after some bad symptoms (engagement point moving around, couldn't get car in gear with clutch pedal to the floor), first bought a BBi slave and then chickened out with the DIY. For many of the reasons you listed - mainly the rebuild issue if pentosin wasn't removed.

Had a shop do the EVOMS install and it went less smooth than hoped, had a clearance issue with the bracket not fitting snug against the transmission, but got great support from EVOMS. After slightly dropping the trans, the issue was resolved with very minor grinding of the bell housing, Anyhow, love the GT2 pedal feel compared with the stock setup.

Way I see it each setup has some kind of compromise except tapping the bell housing in the correct gt2 oem location, but that is an involved process from what I've read.
Old 04-29-2019, 11:37 PM
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pfbz
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Originally Posted by SteveS83

1. Stick with OEM slave/accum replacement

2. BBI Kit

3. EVOMS GT2 Kit
4. Do an oem style GT2 clutch conversion.
  • Drop Transmission
  • Drill and tap is easy for a shop that has done it before,
  • New GT2 slave,
  • New GT2 reverse clutch fork.
  • New GT2 line,
  • New GT2 clutch pedal spring,
  • Flush/re-use existing master cyl.
  • Un-couple clutch circuit in power steering pump.
I recently had this done, along with a GT2 clutch, it is an incredible improvement. And honestly, saving all the extra $$ that BBI and EvoMS charge for their "kits" goes a long way to paying for the Tranny R&R labor. The OEM GT2 clutch slave/line/spring parts themselves are pretty reasonable.
Old 04-30-2019, 09:32 AM
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o7silverturbo
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Originally Posted by SteveS83
I was thinking the same thing regarding the OEM advantage of having the GT2 kit over the BBI.

You said you tapped the housing - I assume you didn't use the EVOMS kit, you actually just converted the GT2 setup from the get-go? I believe with the EVOMS kit there's no tapping needed - or am I incorrect?
Yeah I tapped my housing because I had my engine and trans out already so it was easy to tap but yes if you go with the EVOMS kit you do not need to tap the trans it just bolts up to the factory location.
Old 04-30-2019, 01:10 PM
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lflouie
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Default Clutch slave

I recently purchased a 2007tt and found it had a stiff clutch pedal and the PS fluid was low....but the clutch reservoir wasn't over filled.....no leaking. Also had the inconsistant clutch take up point...drove me nuts. I was told that a failed pedal could be either a slave cyl and/or accumulator.

I thought I probably needed a slave cyl replacement so thought I'd get the BBI slave to also improve the clutch feel. There are a couple of tests that you can do to narrow down whether it is the accummulator and/or slave cyl. I don't recall the exact tests but if you start the car after letting it set a few days, and thn pump the pedal counting when the pedal becomes stiff. If it gets very stiff before 15 pumps, you likely have a bad accumulator. If the slave is bad you'll either have a leak in the right rear or at the clutch reservoir.....possibly right at the slave and PS reservoir will be low on fluid.

I thought I needed a slave cyl bc of the terrible and inconsistent clutch action as well as occasional stiff pedal.....but I didn't have any leaks.

Along the way I noticed that I needed to replace the motor and transmission mounts bc they had deteriorated, so i did this before tackling tge slave cyl. After installing the mounts, the clutch action was much much better, and for whatever reason, the clutch pedal vagueness and stiffness was drastically improved....no other changes.

I suspect that the clutch pickup point was affected by the sloppiness in the motor and transmission mounts to the point that the driveline was actually displacing under load (letting out the clutch) and causing the inconsistant pickup point.

Currently my clutch pedal will stiffen as I approach ~ 20 pumps, so at some point I may need to replace the accumulator and possibly a slave cylinder too. But for now, it is a much better driving experience.

The motor mounts are an easy install and parts are less than $300. The transmount is a little more involved but there are some great dyi on the site. I chose to replace the entire trans mount and added some upgraded easily dropped in aftmkt bushing stiffening inserts from Function First...approx $500 for oem mount and inserts. ALSO used the Function First semi-semi solid motor mounts to keep nvh to a minimum.
Old 04-30-2019, 07:20 PM
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SteveS83
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lflouie - that's a good point. I need to check the mounts because I have had pretty consistent rough shifts when jumping on the gas.... 1 - 2 and especially 2 - 3. The mounts might be shot (car is 12 years old) causing a slight misalignment. I will look into that as well.

Right now just trying to line it all up to see if it makes sense. I need to drive a car with the swap in order to really see if it makes sense for me. Otherwise keep the stock assisted setup (obviously repair it). If I do a swap, as pfbz suggested, I'll do the full GT2 swap - no kits. So drop the trans tap it, and so on. This then begs the question - what else do I do once the trans is off the car....?
Old 04-30-2019, 08:42 PM
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Originally Posted by SteveS83
l This then begs the question - what else do I do once the trans is off the car....?
Ahh the slippery slope.... Quality clutch components aren't cheap, but if the tranny is down and the clutch isn't fairly fresh, clutch disk and pressure plate refresh.. Skip the LWFW unless you have a specific reason for wanting it.
Old 04-30-2019, 09:57 PM
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Originally Posted by pfbz
Skip the LWFW unless you have a specific reason for wanting it.
LWFW? I'm drawing a blank...
Old 05-01-2019, 02:04 AM
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Lightweight Flywheel...
Old 05-01-2019, 07:50 AM
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Ahhh, got it. I think I have an idea on what to do but plan to discuss with the Indy shop soon.


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