Ok Gents... I know what you're thinking. Another schmuck that does not know the proper procedure for bleeding a clutch system. I recently purchased an 08 G37 6MT to hoon around on the weekends. Upon purchasing the car I noticed the fluid in the clutch reservoir looking like Turkish coffee with a tad of dot3. The clutch engagement was not the smoothest and it would bite a little higher than I thought it should and not as gradual or articulate as I would have liked.
I figured a good flush/Bleed would do it justice and I wanted to see where it would end up on the decency scale. Naturally I called one of my mechanic buddies and we started the bleed process.
- Car was lifted
- I sat inside and pumped the clutch a few times then held it down the last time while he loosened the bleed valve under the car.
-We went at that for about 30 Min. and noticed my pedal actually hit the floor!!!
-keep in mind i had not experienced a loss in pedal pressure previously and knew that is was actually pretty stiff.
-We kept at it and the best we were able to come up with after repeating the process in various ways ( reservoir cap closed/open/more pumps/less pumps/ shortening time bleed valve is open etc;)
The best result we came out with was a spongy pedal that came up ok, but no where near like it was before.
We took it for a test drive and the clutch slipped at first under heavy throttle.
after a bit I noticed that the slipping had gone away and clutch engagement was noticeably smoother and was actually much easier to modulate.
I thought GREAT! We did it.....NOT SO FAST KIDDOS
As I hit the freeway, the pedal sunk about halfway down and would not come back up.
I pulled into the emergency lane as I had it in neutral. I was unable to get it into gear and was forced to sit there and let it cool off (hey.. idk figured maybe it would work??) . After about 15 minutes of not knowing exactly what i was waiting for...I tried forcing it into first gear (no go on that) and limping it down the exit ramp. As the car got moving a bit, I was able to put it into first and make the exit. I called my buddy and he said to try to jack the car up and get some air out of the system. I drained some fluid from the bleeder valve and poured some in at the reservoir without letting it go empty, I was able to at least drive it home this way.
The next day I ran across a video that was an instructional on why and how you should bleed BMW, porsche, and VW clutches using the "reverse method"
This involves using an oil can with a pistol trigger (local auto parts store.. about 10 American pesos)
with a clear flex hose (3/8"??? I think) hooked up to the tip of it and one end on the slave bleed valve on the left side of the tranny...
So the idea here is that air in your clutch system naturally wants to travel upwards towards the reservoir...(makes sense)
The conventional bleed method tries to force this air through your fluid and out the bottom which is harder than you think sometimes.
- I emptied the majority of the reservoir of fluid and hooked up my oil can at the bleed valve under the car
- I had My brother waiting at the reservoir with a syringe in order to suck out all the black fluid that would come out as i pumped the fresh fluid from the oil can into the bleed valve and up the the clutch lines to the reservoir.
-As I continued to pump fluid, I would close the valve and wait for him to empty the reservoir.
-we repeated this process about 3 times
-I told him to let me know of any bubbles that were coming up...there were some that came up obviously.
(Just not as near the amount as i was expecting)
-for kicks and giggles, I had him pump the clutch then hold it while I squirted fluid from the oil can up the lines. Lets just say the fluid did not go anywhere and I was hosed with brake fluid.
The clutch fluid that came up to the reservoir at this point was clear (I used dot4)
At this point I closed the valve and told him to get inside the car and hit the clutch.
He mentioned it felt stiff as it was when I purchased the car.
I got in and tried it for myself. HMMMMM...That felt "normal"....
We dropped the car off the jack and went on a 1.5 hour test drive. I was blown away. The pedal pressure was all there like before. The only difference was, I was able to modulate engagement with ease! It was more precise feeling and the actual engagement point in the clutch travel was towards the middle maybe under half a bit!
After an hour, I still not convinced and kept driving it for another 30 minutes. I kept taking note of the pedal feel as I flogged it around.
It was identical throughout the test drive.
-My test drive consisted of city/highway driving.
-0-60 launches, 80-120 pulls in Mexico
- 0-120 also in Mexico
I was blown away considering my buddy and I had spent a couple of hours attempting to bleed the "conventional" way with zero results.
I hope this helps anyone with bleeding problems, I would say this is def worth a try!!!!!!!!!
Not saying this is going to be the answer to your problems; but after combing the internet for answers, I found out that the good folks who make posts regarding there car issues don't always like to revert back to the forums and enlighten the rest of us poor peasants when they stumble upon a solution.
I will update this post should I experience any other pressure related problems!
You peeps have my word on this...
Sorry for the lengthy post guys...just wanting to put as much info on here as possible...
Fellas, have a fantastic Day!