Bleeding Clutch Slave Cylinder
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Bleeding Clutch Slave Cylinder
Hi All,
By the 3'rd day of my last DE I noticed that the clutch pedal was not coming all the way back up every single time. It would come up about 7/8'th of the way and then sit there for a few seconds before popping up the rest of the way. This didn't appear to affect clutch performance but it did make the clutch pedal feel a little wierd. This went away after the DE was over and I didn't think much about it until we started experiencing some really cold weather about a month ago. On a couple of really cold mornings ( around 20F ) I once again noticed that the clutch seemed a little sticky and would hang up from time to time.
Research on Rennlist seemed to indicate that a bleeding of the clutch slave cylinder or maybe even a replacement was in order. Note: Earlier in the year I had switched to ATE gold brake fluid -- completely flushing the brake system but not touching the clutch system.
I followed the DIY for the 993 clutch slave cylinder here on Rennlist. My first thought was -- Why would anybody put something with a bleed screw in that location??? ( those of you who have done this know what I'm talking about ). My second thought was -- Wow, it takes over a pint and a half of new brake fluid to completely flush the old brake fluid from the clutch system. The old brake fluid in my clutch system had not yet turned brown or black, but it was definitely opaque. I used my Motive power bleeder to make this a one person job.
The results have been amazing. It's been two weeks now of daily driving including several cold mornings in the teens. The clutch has been smoother than it has ever felt before and, of course, no "notchiness" or "hang-ups" in its operation. I was not aware that the clutch in this car could be so smooth.
This is a DIY that I'll be doing every couple of years. I believe that keeping up with this particular maintenance will extend the life of the slave cylinder -- not a DIY I would ever want to be forced to perform!
Thanks Rennlist,
George Jones
Williamsburg, VA
By the 3'rd day of my last DE I noticed that the clutch pedal was not coming all the way back up every single time. It would come up about 7/8'th of the way and then sit there for a few seconds before popping up the rest of the way. This didn't appear to affect clutch performance but it did make the clutch pedal feel a little wierd. This went away after the DE was over and I didn't think much about it until we started experiencing some really cold weather about a month ago. On a couple of really cold mornings ( around 20F ) I once again noticed that the clutch seemed a little sticky and would hang up from time to time.
Research on Rennlist seemed to indicate that a bleeding of the clutch slave cylinder or maybe even a replacement was in order. Note: Earlier in the year I had switched to ATE gold brake fluid -- completely flushing the brake system but not touching the clutch system.
I followed the DIY for the 993 clutch slave cylinder here on Rennlist. My first thought was -- Why would anybody put something with a bleed screw in that location??? ( those of you who have done this know what I'm talking about ). My second thought was -- Wow, it takes over a pint and a half of new brake fluid to completely flush the old brake fluid from the clutch system. The old brake fluid in my clutch system had not yet turned brown or black, but it was definitely opaque. I used my Motive power bleeder to make this a one person job.
The results have been amazing. It's been two weeks now of daily driving including several cold mornings in the teens. The clutch has been smoother than it has ever felt before and, of course, no "notchiness" or "hang-ups" in its operation. I was not aware that the clutch in this car could be so smooth.
This is a DIY that I'll be doing every couple of years. I believe that keeping up with this particular maintenance will extend the life of the slave cylinder -- not a DIY I would ever want to be forced to perform!
Thanks Rennlist,
George Jones
Williamsburg, VA
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+1 The clutch slave cylinder seems to be often ignored (myself included). I bled the clutch and brakes as part of my winter project and couldn't be happier. For me, since the way I use my car, I'll be bleeding every year along with the oil change. The Motiv unit is very helpful. Glad you have your clutch operation in tip top shape
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It appears that a previous owner or two had kept up with the clutch on my car. The fluid was halfway between clear gold / yellow and a light brown -- not too bad. Plus, the hex on the bleed screw appeared to be somewhat stripped when I put the 12 point 7mm box wrench on it. Just to be safe, I used a tiny pair of vice grips to do the final 1/4 turn locking down the bleed screw when I was finished.
Note: I forgot to mention that I had to remove the bleed screw completely when I first started this DIY -- the tiny hole in the screw had become plugged with goop. Cleaned it out with a very fine piece of wire and it worked fine.
The difference in clutch performance is amazing.
George Jones
Williamsburg, VA
Note: I forgot to mention that I had to remove the bleed screw completely when I first started this DIY -- the tiny hole in the screw had become plugged with goop. Cleaned it out with a very fine piece of wire and it worked fine.
The difference in clutch performance is amazing.
George Jones
Williamsburg, VA
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Especially important for those who leave their cars out in freezing weather, please remember that any moisture which may be present in the system will settle at the bottom, namely the slave cylinder....and it will freeze solid. Yet another reason for keeping the system bled.
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George Jones wrote:
George: Is this for the brake system as well as the clutch, or just the clutch alone?
it takes over a pint and a half of new brake fluid to completely flush the old brake fluid from the clutch system.
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Hi BobbyT,
That was about 1.5 pints for the clutch system by itself. To be more accurate, it was almost exactly 3/4 of a 1 liter can of ATE Super Gold brake fluid.
George
That was about 1.5 pints for the clutch system by itself. To be more accurate, it was almost exactly 3/4 of a 1 liter can of ATE Super Gold brake fluid.
George
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Hi George,
Thanks for the response. So, is this to flush the clutch system, including the fluid in the reservoir? I'm asking because I just did mine, brakes and clutch, and used one liter total for everything. I switched from ATE blue to gold so I could see when all the old fluid was gone.
Thanks for the response. So, is this to flush the clutch system, including the fluid in the reservoir? I'm asking because I just did mine, brakes and clutch, and used one liter total for everything. I switched from ATE blue to gold so I could see when all the old fluid was gone.
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Hi BobbyT,
It's tough to say. I did the brakes in the fall and the clutch a couple of weeks ago. I never checked to see if the fluid in the reservoir had been discolored by the old fluid in the clutch system -- which would have caused me to flush the fluid in the reservoir a total of two times.
I know when I did the brakes I over flushed it a bit to make sure that all the old fluid had been pushed out. ( I didn't want to stain the reservoir blue so I used ATE Gold even though it took a little bit more fluid to make sure the system was completely flushed ) Flushing the clutch was easier to get exact because the fluid in there was an opaque yellow / gold. Even so, I probably over flushed it a bit just to make sure it was perfectly clean. ( brake fluid is cheap ) I also bled each brake caliper after I was done with the clutch just to make sure there wasn't any air anywhere in the system -- although that process didn't take much fluid. In the end, I started with two 1 liter cans, completely flushed both systems, and now have a slightly less than half of one can.
Could the job be done with only one liter of brake fluid -- probably. If it was done all at once and the colors were switched like you did. I would think that as long as everything is now bleeding blue and there are no bubbles you are good to go.
George
It's tough to say. I did the brakes in the fall and the clutch a couple of weeks ago. I never checked to see if the fluid in the reservoir had been discolored by the old fluid in the clutch system -- which would have caused me to flush the fluid in the reservoir a total of two times.
I know when I did the brakes I over flushed it a bit to make sure that all the old fluid had been pushed out. ( I didn't want to stain the reservoir blue so I used ATE Gold even though it took a little bit more fluid to make sure the system was completely flushed ) Flushing the clutch was easier to get exact because the fluid in there was an opaque yellow / gold. Even so, I probably over flushed it a bit just to make sure it was perfectly clean. ( brake fluid is cheap ) I also bled each brake caliper after I was done with the clutch just to make sure there wasn't any air anywhere in the system -- although that process didn't take much fluid. In the end, I started with two 1 liter cans, completely flushed both systems, and now have a slightly less than half of one can.
Could the job be done with only one liter of brake fluid -- probably. If it was done all at once and the colors were switched like you did. I would think that as long as everything is now bleeding blue and there are no bubbles you are good to go.
George
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I cant wait to do mine in the spring. I am having all the same symptoms and hope I have the same good fortune as you. BTW...where do other bleeders dispose of their brake fluid?
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Good question, I've been wondering the same thing myself. I think I've got over a gal. of old brake fluid sitting in the corner of my garage. I used to pour it in with the used oil which I took to the parts house recycling dump but have been told not to contaminate the old oil with such products. So I'm at a loss now.
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Our city fire department will take materials such as this on Saturdays. You may want to check locally to see if your city has a similar setup.
#14
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We have a city run EcoStation that takes household products such as automotive oils, anti-freezes, paints, refuse, metal ,plastic, etc. It's great being able to get rid of this stuff responsibly and at no cost for the recyclable items and automotive wastes.