RngTrtl

All,

I have a pentosin leak that looks to be coming from the center of the car and I need to inspect the area and see what the deal is. Can I pull the front or rear up on ramps and put the opposite end on jack stands and be high enough to work on the clutch system?

dumb question, but if I have a jack under the jack point, how do I also get the jack stand under there if the jack is using the jack point? Many thanks!

jpflip

That was my set-up for the first job I did on my TT in 2008. Drove the front wheel on bricks and jack the rear end by the engine block and installed stands. You have to raise the front a little bit to prevent the front lip from touching the ground while you are raising the back....

Jacking from the engine block: Lots of talk about it ;-)
https://rennlist.com/forums/996-turb...ck-stands.html
https://rennlist.com/forums/996-turb...-on-996tt.html
https://rennlist.com/forums/996-turb...-your-car.html

danspach

I found it helpful to get the car high enough to get under it but not much higher as everything you're working with is mounted on top of the transmission.

Also for inspection (and later reference) the iPhone camera was invaluable since you can just stick it up there and start snapping away.

RngTrtl

Thanks for the tips. I think I will back the car on to the ramps and then jack up the front bit by bit and put 2x6s under the front tires until high enough to work. Thanks for the help!

danspach

This is what I saw when I put my car on stands to originally do an oil change:



This is looking from the passenger side toward the driver's....front of the car is to the right. The two black rubber hoses at the bottom of the pic are the water lines you'll need to move/tie out of the way and protect from Pentosin and the green line in the background is the line from the front of the car carrying said Pentosin.


It looks like engine oil in this pic because it's dripped down the side of the trans and collected some dirt along the way but once you clean and dry everything, you'll see it's a clear/tan-ish color.

The "good" news is that your trans will be free of Cosmoline when you're done.

<shoulder shrug>


I have lots of pictures. If any would help for reference, let me know.

RngTrtl

That would be great! I noticed a series of drips when I moved the car over the weekend and checked the PS reservoir and it was pretty low. clutch fluid looked normal. Clutch is kinda hard before start up and feels normal after start up. I am hoping for something leaking that I can tighten up, but I doubt I will be that lucky and will likely be replacing something down there

danspach

If the clutch is hard to depress before the car is running then your accumulator is bad. It's job is to hold hydraulic pressure when the car isn't running so if it's hard to depress before you start and the normal once it's running, that's one part of the puzzle. Once the car is running, hydraulic pressure is made by the hydraulic pump which does this for both power steering and the power-assisted clutch.

Check the reservoir in the frunk again to make sure it isn't high (even a little)....look for any kind of dampness. That would be a signal that a check valve inside the clutch slave has left the building and sending too much fluid to the front reservoir for the clutch ("fluid migration" if you're searching). You also don't want Pentosin leaking into that compartment....or anywhere, really.

If you're planning on replacing the accumulator, most would recommend doing the slave as well since it's a known weak point in the car, you're emptying the system anyway and taking the slave out requires removing just two more bolts.

Welcome to the club!

(I've just finished doing this on my car with a few slight alterations.)

RngTrtl

from what I read I kinda figured on the accumulator since the clutch is kinda hard to depress before starting. Ill recheck the clutch fluid when I get home to see what the actual level is. Thx!!!

mffarrell

Is there a block diagram of the clutch hydraulic system?

danspach

That would have made my life a lot easier.

I can't explain how the slave works it's dark arts (I'm looking at you, jpflip) but now (after trial and error) understand which ports on the slave and reservoir do what.

In the photo below of the slave:

1. Receives the line from the master cylinder at the front of the car
2. Is the return line (quick connect) which send fluid back to the reservoir in the engine bay
3. Where the accumulator screws in
4. The high pressure supply line from the hydraulic pump in the engine bay

(1. Is toward the front of the car and 4., the rear.)




In the photo below of the hydraulic reservoir:

1. Is the line OUT to the slave (connects to 4. In the picture above)
2. Is the line IN from the hydraulic pump below (yes, it goes into that casting and right back out but notice they’re two different sized lines
3. The return line for the power steering system
4. The return line from the slave (connects to 2. In the picture above)


(NOTE: Not pictured is the high pressure supply for the power steering system….it comes directly out of the pump below the reservoir.)

danspach

...and here are the relevant diagrams from the PET



For reference, Part # 6 is the line that connects to 1. in the photo above of the reservoir.





In this diagram, #16 only goes from the pump below up to the reservoir (2. in the photo of the reservoir)...from there it goes out of the reservoir (1. n the pic of the reservoir) to the slave.


In this photo of the underside of the reservoir lid, you can see the casting where the line goes into and then back out of the reservoir:

dprantl

One thing I don't understand about this system, why are there two reservoirs? Why can't line #1 on the first picture in post #10 route back to the PS reservoir in the engine bay? Or I guess not that line, but one of the lines from the master cylinder...

Dan

danspach

It's two separate circuits....though they are "connected".

The one in the frunk is specifically for the fluid needed by the master to drive the slave. It's the "signal", if you will that says, "please activate my clutch".

The reservoir in the engine bay supplies high pressure hydraulic fluid from the hydraulic pump for the power assist for both steering and the clutch.

They're supposed to be separated by the check valve in the slave which is why when the valve fails, you end up with too much fluid in the front.


(more experienced dudes: please correct me if I'm wrong on any of this....I don't do this for a living....but I did stay at a Holiday Inn Express last night.)

dprantl

Makes sense, I guess it's just strange... same fluid, same system, you could have a single reservoir feed and return both parts of the overall system. That would avoid a (flammable) pentosin leak in case there is a failure of the slave check-valve, and may even save on production costs by replacing the front reservoir with a clutch line... or maybe that line would not be feasible due to bubbles?

Dan

danspach

Porsche thought better of the whole setup with the GT2.

More streamlined (read: less complicated)