(
987.1
2.7, 5MT) Bled my brake fluids (using the Motive Power Bleeder) but didn't get to the clutch fluid because I was lazy and somehwat "scared" as I heard / saw some issues (the pedal hitting the floor or not returning after the bleeding, etc.).
Since this was my first time on a
Porsche
(although not significantly different) I used a plenty of new fluid (2L of Pentosin Super Dot 4, and less than 500ml left) and can assume the whole system is with new fluid (except for the clutch line).
Some questions:
1. Will the new fluid eventually "mix" with the old fluid in the clutch line?
2. Is there a factory recommended clutch fluid change interval? I do understand that the fluid is from the share reservoir?
3. After the brake fluid bleeding, the brake pedal definitely became more firm (I did see some bubbles and a tiny crud when bleeding from one side). Will the clutch become firmer? I like the current feel which is a bit on the softer side
Any insights / advice will be greatly appreciated!!! Thanks!
I'll give you my semi-educated take below (which is worth what you're paying for it, lol).
Anyway, if you've got the power bleeder I'd always just bleed the clutch at the same time. The service manual has you operating the pedal as you power bleed, but I can't see why that would be at all necessary for a regular flush (probably matters if you're replacing the clutch MC). I just pressurize the system, hook a hose up to the slave bleeder, open it for a bit to flush out the old fluid, and then close off the bleeder.
It's reasonably easy with two caveats. One is that the clutch slave bleeder is kinda buried and hard to get to, especially with the collection hose in place. I think what I did was use a crowsfoot wrench on a 1/4" socket extension to make accessing it easier. The other thing is that the bleed screw is plastic (if I'm remembering correctly) and easy to snap or round off. It seals with an o-ring, I think, so don't go nuts tightening it or you could damage something. I don't recall if there's a torque spec in the service manual or not.
In theory any moisture in the fluid should distribute itself through the whole system. How long this takes, I dunno
They share a reservoir so it should be the same interval as the brakes. The fluid itself doesn't "wear out", per se, but it absorbs moisture, and moisture in the system can lead to boiling brake fluid under extended braking or rust in the system.
Recommended interval for brake fluid is typically two years. Depending where you live that can be conservative: here in California it's pretty dry, and measuring the fluid I've never had significant moisture after two years but I always did the job anyway. I'm now using the newer Bosch ESI6 fluid on all my cars: it has a 3-year replacement interval and that's when I change it.
Unless you've got air in the clutch hydraulics now (which you
really
should not) then it will not change the clutch feel, no.
Thanks again for your advice. I just went ahead and flushed the clutch fluid and noticed:
1. the bleeder valve seems to be plastic so need to be "careful"
2. the access was easier than expected and was able to turn the valve with a 9mm wrench
3. need to open the valve a bit more than a brake bleeder valve for the fluid to drain sufficiently
4. I set the pressure close to 1.5 bar / 20 PSI but the old fluid doesn't flow / drain, hence the service manual instruction (of slowly, manually pressing the pedal) - I drained about 200ml
5. And as you advised, the pedal didn't become firm and actually became a bit more smooth (especially when returning) - seems like the "old bite point" has smoothed out
Thanks again!
Happy to help. I don't remember having to work the pedal, but I was using ~30 PSI (that's the
987.2
spec for brakes and clutch bleed) so maybe that was enough on its own?
Ah...i think
987.1
service manual says 20 psi...maybe
Porsche
changed the pressure for
987.2
...
Ah, you're right, the clutch is 1.3 bar for both cars. I just use the 2 bar spec for everything since I'm doing them at once.
