Need to replace clutch master cylinder
02-07-2004, 12:01 AM
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Hi,
The slave cylinder sits on top of the G50 tranny. It's really hard to get to and to replace it you'll need to do at least a partial engine drop. I haven't done one my self, but I just helped a friend drop the engine and tranny (G50) on a '87. After getting the tranny down a bit you can disconnect the line and then take the slave off the tranny. Leave the clutch pedal in the 'up' position to avoid any additional drainage of the brake reservoir. When new slave is mounted you'll need to bleed it before putting the engine/tranny back in place.
At least this would be the way I would do it. You might get more suggestions from the 964 list.
Michael
The slave cylinder sits on top of the G50 tranny. It's really hard to get to and to replace it you'll need to do at least a partial engine drop. I haven't done one my self, but I just helped a friend drop the engine and tranny (G50) on a '87. After getting the tranny down a bit you can disconnect the line and then take the slave off the tranny. Leave the clutch pedal in the 'up' position to avoid any additional drainage of the brake reservoir. When new slave is mounted you'll need to bleed it before putting the engine/tranny back in place.
At least this would be the way I would do it. You might get more suggestions from the 964 list.
Michael
02-08-2004, 08:10 PM
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I'm talking about the Master Clutch under the floorboards near the Clutch pedal not the slave by the tranny.Lots of info for the 944 in the archives but nothing on the 911!!!! HELP
02-13-2004, 11:48 AM
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Hi Chris,
Sorry I misread you first Q. I have never needed to replace the Master Clutch cylinder before so can't offer direct experience. Anyhow, looking in the manual it looks fairly accessible. My guess would be to go through these steps.
- You possibly need to drain the fluid from the MC reservoir, or have a ton of papertowels available.
- Take out the driver side floor mats.
- Remove the pedal floor cover.
Now from looking at the picture I have attached I'd guess the following would be needed.
- The CMC (Clutch Master Cylinder) sits between the brake pedal and the accelerator pedal. There is a fluid line at the top and I bet there is one just below on the back side there as well. I would use a flared wrench and just crack them open, just to see how sized they may be. Better to do this while the cylinder is hold in place by its mounting HW.
- Just above the #1 on the picture there is 1 bolt that attaches the cylinder to a bracket. I would remove that bolt, and since there possibly is one more (we just can't see it on the picture) I'd remove that one too.
- Next I'd unscrew the fluid connections and then undo the final (probably a ball joint) at the end of the cylinder where it attaches to the axel that is controlled by the clutch pedal. Just to the right of #2.
- To reinstal I might add fluid to the new CMC before install so I know it's 'bench bled' first. Then install reverse of removal.
- Add fluid to the MC reservoir and then bleed both brakes and Clutch Slave Cylinder (on top of tranny). Since the system has been open it's important to get all the air out.
#1 on the picture is the boost spring adjuster. I wouldn't touch that one at all.
#2 is the switch for the brake pedal.
#3 is the push rod for the brake pedal, connected to the vacuum booster.
Before I would start this replacement I would double check the Slave Cylinder on top of the tranny first, by carefully pressure bleeding the system. I bet that there is air in the system if your clutch pedal feels funny or different, or the Slave Cylinder is the bad one. I haven't heard of many CMC failing.
Again cross post this to the 964 and 993 forum since the G50 tranny is used on those 911s and others may have had similar problems.
Michael
Sorry I misread you first Q. I have never needed to replace the Master Clutch cylinder before so can't offer direct experience. Anyhow, looking in the manual it looks fairly accessible. My guess would be to go through these steps.
- You possibly need to drain the fluid from the MC reservoir, or have a ton of papertowels available.
- Take out the driver side floor mats.
- Remove the pedal floor cover.
Now from looking at the picture I have attached I'd guess the following would be needed.
- The CMC (Clutch Master Cylinder) sits between the brake pedal and the accelerator pedal. There is a fluid line at the top and I bet there is one just below on the back side there as well. I would use a flared wrench and just crack them open, just to see how sized they may be. Better to do this while the cylinder is hold in place by its mounting HW.
- Just above the #1 on the picture there is 1 bolt that attaches the cylinder to a bracket. I would remove that bolt, and since there possibly is one more (we just can't see it on the picture) I'd remove that one too.
- Next I'd unscrew the fluid connections and then undo the final (probably a ball joint) at the end of the cylinder where it attaches to the axel that is controlled by the clutch pedal. Just to the right of #2.
- To reinstal I might add fluid to the new CMC before install so I know it's 'bench bled' first. Then install reverse of removal.
- Add fluid to the MC reservoir and then bleed both brakes and Clutch Slave Cylinder (on top of tranny). Since the system has been open it's important to get all the air out.
#1 on the picture is the boost spring adjuster. I wouldn't touch that one at all.
#2 is the switch for the brake pedal.
#3 is the push rod for the brake pedal, connected to the vacuum booster.
Before I would start this replacement I would double check the Slave Cylinder on top of the tranny first, by carefully pressure bleeding the system. I bet that there is air in the system if your clutch pedal feels funny or different, or the Slave Cylinder is the bad one. I haven't heard of many CMC failing.
Again cross post this to the 964 and 993 forum since the G50 tranny is used on those 911s and others may have had similar problems.
Michael
