Does my Clutch Master Cylinder need replacing?
Thread Starter
Rennlist Member
Joined: Apr 2010
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From: NYC
Does my Clutch Master Cylinder need replacing?
I've been reading the threads on the clutch master cylinder and I'm not sure if I have a real issue or am suffering from seasonal upgrade-itis!
I replaced my slave cylinder and hydraulic hose last year (thanks board for the help on that) because I tried to bleed it and the bleed nipple was seized. I noticed an improvement on the actuation of the clutch and the smoothness with which the car would move from a standing stop.
Well after a few thousand more miles I still have a tough time getting the car rolling smoothly from a standing stop unless I am supremely delicate and slow with lifting the clutch pedal. Making a quick getaway from a stop is nearly impossible without a serious amount of jerking.
Now I've never driven another 964 so I do not know if this is the nature of the beast or if I can improve my clutch pickup by replacing the master cylinder.
Thanks!
Mike B
I replaced my slave cylinder and hydraulic hose last year (thanks board for the help on that) because I tried to bleed it and the bleed nipple was seized. I noticed an improvement on the actuation of the clutch and the smoothness with which the car would move from a standing stop.
Well after a few thousand more miles I still have a tough time getting the car rolling smoothly from a standing stop unless I am supremely delicate and slow with lifting the clutch pedal. Making a quick getaway from a stop is nearly impossible without a serious amount of jerking.
Now I've never driven another 964 so I do not know if this is the nature of the beast or if I can improve my clutch pickup by replacing the master cylinder.
Thanks!
Mike B
Three Wheelin'
Joined: Nov 2005
Posts: 1,250
Likes: 44
From: Bahrain = somewhere in the Middle East
Mine feels like that under normal conditions... I find the 964 a difficult car to drive smoothly off the line.
The RPMs seem to drop quite fast when the clutch starts to bite. Smooth only works for me if letting go at higher RPMs or, very, very gently. So either try to get away fast or just very slow.
My cylinders have been replaced (both) as well as the line and the clutch and it's been bled properly. My mech also confirmed my car operates as it should.
The RPMs seem to drop quite fast when the clutch starts to bite. Smooth only works for me if letting go at higher RPMs or, very, very gently. So either try to get away fast or just very slow.
My cylinders have been replaced (both) as well as the line and the clutch and it's been bled properly. My mech also confirmed my car operates as it should.
Drifting
Joined: Mar 2010
Posts: 2,655
Likes: 8
From: London UK
I've just been though this...
The next thing to do if you've bled the system and changed the slave is check to condition of the master... is the rubber boot intact? Is the master leaking at all?
Change the master, if that doesn't work, change the roll pin, if that doesn't work change the bushes in the pedal assembly... or do what I did and install a 993 pedal box!
Anyway as said, just been through this, my thread should help! https://rennlist.com/forums/964-foru...and-video.html
The next thing to do if you've bled the system and changed the slave is check to condition of the master... is the rubber boot intact? Is the master leaking at all?
Change the master, if that doesn't work, change the roll pin, if that doesn't work change the bushes in the pedal assembly... or do what I did and install a 993 pedal box!
Anyway as said, just been through this, my thread should help! https://rennlist.com/forums/964-foru...and-video.html
Rennlist Member
Joined: May 2007
Posts: 2,296
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From: Portland, Oregon
+1 on the above... AND this will sound funny to some, but I have a LWF in the car, and I go through periods where the clutch is more finicky. Cold/damp weather will change how it reacts. I can go for months with perfect harmony, and then I'll blow one stop light event (stall) and then for a few days its complete PMS with the clutch.
My "theory" is that the clutch material acts differently, and one blown stall will create crap on the surface. One day I lost my temper with it and slipped it a lot (you know the smell, like burning money). After that it was dreamland for months. I think it helps to get a little slip now and then to burn off any material that is unevenly distributed.
My "theory" is that the clutch material acts differently, and one blown stall will create crap on the surface. One day I lost my temper with it and slipped it a lot (you know the smell, like burning money). After that it was dreamland for months. I think it helps to get a little slip now and then to burn off any material that is unevenly distributed.
Thread Starter
Rennlist Member
Joined: Apr 2010
Posts: 713
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From: NYC
I just bought a new Master Cylinder online for $84 shipped...cheap enough that I figure it is a worthwhile experiment and a much easier project than replacing my plug wires!
I will report my findings after it goes in. It can't get any worse right?
I will report my findings after it goes in. It can't get any worse right?
Nordschleife Master
Joined: Dec 2006
Posts: 5,405
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From: S.E. VA
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Thread Starter
Rennlist Member
Joined: Apr 2010
Posts: 713
Likes: 6
From: NYC
I just finished replacing my clutch Master Cylinder. It was not the most fun I had this weekend but I am glad its done. The old cylinder had a ripped rubber boot but otherwise looked fine on the outside.
The lower nut holding the cylinder is really hard to get at and removing the hard line from the top of the cylinder was a real pain. In order to get it out of the old cylinder I had to place vice grips on the nut holding the hard line and give it a couple of love taps with a hammer. I then did the reverse to re-seat the line and threads into the new cylinder. Upon inspection I notice that I scraped the hard line a little bit. Not enough for me to freak out (yet) but it was a bummer.
After bleeding the slave cylinder I was off for a test drive with lots of stops and starts. At first the clutch moved freely for the first 3/4 of travel but quickly firmed up (I went for a 20 minute drive). When I finished there was still about 1" of free travel at the very top. Apparently this is normal from what someone posted earlier about this.
I can say that the new master is a big improvement over the old one. Getting moving from a standstill is much easier and smoother. The whole pickup of the clutch feels more controlled and less grabby. All in all this was a very worthwhile project. I can't wait to go for a longer drive.
Do you think I should I should bleed the slave again in a few weeks or am I OK? I really hate being around brake fluid and I always seem to make a mess of things.
The lower nut holding the cylinder is really hard to get at and removing the hard line from the top of the cylinder was a real pain. In order to get it out of the old cylinder I had to place vice grips on the nut holding the hard line and give it a couple of love taps with a hammer. I then did the reverse to re-seat the line and threads into the new cylinder. Upon inspection I notice that I scraped the hard line a little bit. Not enough for me to freak out (yet) but it was a bummer.
After bleeding the slave cylinder I was off for a test drive with lots of stops and starts. At first the clutch moved freely for the first 3/4 of travel but quickly firmed up (I went for a 20 minute drive). When I finished there was still about 1" of free travel at the very top. Apparently this is normal from what someone posted earlier about this.
I can say that the new master is a big improvement over the old one. Getting moving from a standstill is much easier and smoother. The whole pickup of the clutch feels more controlled and less grabby. All in all this was a very worthwhile project. I can't wait to go for a longer drive.
Do you think I should I should bleed the slave again in a few weeks or am I OK? I really hate being around brake fluid and I always seem to make a mess of things.
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