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Yesterday I bled all calipers with a power bleeder and then moved onto the dreaded clutch bleed and now I'm stuck with only air coming out and the clutch being sucked to the ground.
I suspect I actually ran out of fluid so I'm going to get more and give it another go, but I've found conflicting statements on how to properly do the clutch bleed. (quoted below)
Use power bleeder or not?
Clutch down when the bleeder nut is open?
Can anyone confirm the proper procedure and if I did suck air in by letting the reservoir get too low do I need to re-bleed the caliper lines?
Originally Posted by cvtbenhogan
Okay now on to the clutch bleed. It’s a general waking nightmare, given the awful location of the bleed screw. It is nearly on top of the tranny/clutch housing and there is barely any room to maneuver. Additionally, I searched for nearly 15 minutes just to locate the nipple. Forum pics really didn’t help locating the nipple. HINT: Locate your head at the right (driver side) half shaft and look for a circular coil. This coil feeds the clutch slave and the bleed nipple is not far from the coil.
Anyway, the tough part is getting the 11m wrench on the nipple to drain the clutch fluid. I used a mini ratchet to break loose the screw and used my hand from there. Not good. Fluid drips using just a ratchet and it is tough to loosen or snug tight the screw with your fingers. Plus maybe I let air into the line. HINT: (Saw in half a mini 11m closed end box wrench). On the first bleed, no use of the pressure bleeder, just gravity with the clutch depressed. This method yielded only 1 1/4 inches of old fluid in the catch bottle tube. Repeat and a little more, but no new fluid showing. Finally, reattached bleeder at 20 psi and lots of fluid through with clutch depressed. Here is where the problem started. Pressure bleeder with clutch depressed pushed lots of air into the clutch line and I lost clutch pressure. Clutch would not come off the floor. After bouts of panic and thoughts of a flatbed truck in my driveway, I got some advice from my local mechanic. He instructed me to get pressure back into the system by slowly pumping the clutch up and down numerous times by hand. After numerous pumps, the bleed screw was to be opened with the clutch pushed to the floor. Air would be released and the process is repeated. After a number of times doing this, I finally got pressure back in the clutch line and the pedal emerged from the floor. A massive relief.
8. Should the pressure bleeder be used (in extracting clutch fluid)? My mechanic says no and advises to have an assistant push the clutch pedal down as you open the bleed screw.
9 If a pressure bleeder is used, do you open the bleed screw only when the clutch is pressed down? I suspect yes.
10. In jacking the car, I lifted the right side first and placec on jackstands. I started to lift the left side front and the whole front of the car lifted upward. Not good. Any thoughts?
Originally Posted by stronbl
Important notes on bleeding
The clutch hydraulics must always be filled or bled using a bleeding device. Furthermore, the bleeder valve
must be opened sufficiently and the gauge pressure at the bleeding device must be approx. 1.3 bar.
Once the filling or bleeding process has started, the clutch pedal must be moved (extremely slowly) into the
"Pedal fully depressed" position .
As there is no system pressure, servo kinematic effects will cause the clutch pedal to move forward abruptly.
In order to avoid damage, the pedal must be guided manually.
In general, a minimum filling time of 90 seconds must be observed. Once this filling period has elapsed,
check that no more bubbles appear at the bleeder valve (use a collecting bottle with transparent hose). Only
then close the bleeder valve. Filling/bleeding
Note
In general, a minimum filling time of 90 seconds must be observed.
Use only new Super DOT 4 class brake fluid. This brake fluid is available under the following part numbers:
•Container quantity 1 litre = 000.043.203.66
•Container quantity 30 litres = 000.043.203.67
1. Remove the cover over the brake fluid reservoir. Fill reservoir to its top edge with new brake fluid.
Connect the bleeding device to the brake fluid reservoir.
2. Switch on the bleeding device and set an overpressure of approx. 1.3 bar.
3. Open the bleeder valve -arrow- on the clutch slave cylinder.
4. Move pedal extremely slowly to the "Pedal fully depressed" position. When doing so, guide the
pedal by hand so that it does not move forward abruptly.
5. Allow the brake fluid to rinse through for 30 seconds.
6. Afterwards, activate complete pedal travel manually very slowly for a further 60 seconds. After
about 10 to 15 pedal strokes, leave the pedal in its normal position. Once this filling period has
elapsed, check that no more bubbles appear at the bleeder valve (use a collecting bottle with
transparent hose). Then close the bleeder valve (tightening torque = 7 + 6 Nm (5 + 4.5 ftlb.).
7. Switch off and disconnect the bleeding device. Check the brake fluid level. It should not be above
the MAX. mark.
8. Activate the clutch pedal slowly, five times.
9. Fit the cover over the brake fluid reservoir.
The most likely reason your clutch sucked in air was because you ran the clutch partion inside the brake fluid reservoir dry. Your instructions on the second quote looks correct.
To prevent this from happening you need two things:
- fill the brake reservoir to the top before bleeding
- have plenty of fluid (~1/2L to be safe) in the pressure bleeder
Update:
topped off reservoir more fluid
ran the bleeder at 10psi(master cylinder cap kept popping off at higher psi)
opened the bleeder until I got solid stream of new fluid
went through pumping procedure and didn't get pressure back in the pedal
no air comes out of the bleeder
clutch still gets sucked to the floor, what now?
Following the above no pressure in the pedal. I tried what the first qouted poster did and pumped without the pressure bleeder to build pressure then opened the bleeder. After several cycles I started to get pressure in the pedal, but it never fully reset and then all of a sudden it lost all pressure again.
I cycled nearly the full liter repeating the instructions, I am getting a solid stream out the bleeder, but still not building any pedal pressure. Thoughts? Does anyone have the hydraulic diagram to understand what might be occurring?
Did you close the system? (Take bleeder off put res cap and tighten your bleed screw)
You might try pumping the heck out that pedal, rapid and continuous. Pulling it up pedal now and again to see if it stays up. Possibly turn the motor on too. I did this and it worked. I did worry about the slave cyclinder but no issues. You might look at the slave to make sure it's not leaking or broke.
Using a power bleeder 997.1 non-S:
This I never understood: "Allow the brake fluid to rinse through for 30 seconds." In 30 seconds you can go through multiple litres of brake fluid. I think it is an error in the procedure. In the several times I have bled the clutch I have let it rinse through for maybe 5-10 seconds then called it a day, tighten bleeder, and the slave cylinder & clutch have never been a problem. Keep an eye on the amount of fluid you have left in the Motive/reservoir - brake fuid is cheap, always plan for more!
BTW, When you first crack open the bleeder have someone hold the pedal and gently lower it to the floor, don't let it slam down.
After finally closing the bleeder slowly while it is still rinsing thru proceed to pump up the pedal (check supply of fluid left!) about 5-8 times then it should be firm. Works for me.
the solution was to pump the hell out of it tens of times rapidly with the bleeder closed as per hogan's comment. The pedal slowly regained feel.
I think what happened is I might have let the master go dry due to the reservoir going low and I successfully filled he slave, but needed to pump a ton to regain the full in the master. The master cylinder saw a lot of venting and air being sloshed around under pumping that slowly reduced as pedal feel increased.
The clutch feels noticeably lighter and a bit smoother, more driving needed to properly evaluate. The brake bleed also seems successful.
I know it's an old tread but I will had something to the info here.
It's easy to look inside the reservoir and think that there is plenty of fluid but to actually getting it lower than the clutch line, especially if you've jacked only the rear like here:
10-16-2016, 02:54 PM
997.1s Clutch Bleed Issue
