Clutch master cylinder replacement question - ZR-1 Net Registry Forums

8cam · 05-30-2016

Yesterday I replaced the clutch master cylinder because of a badly leaking original. Not too difficult a job really once I figured out all the little things, and I'm sure I could cut the time in half now. Hardest part was that damn clip on the pushrod. My wrist still hurts from the twisting.

One thing I noticed about my replacement, the flange is considerably thicker than the original. That means when I add the spacer, it sits further from the firewall and the pushrod throw is a bit less. I can feel this in the pedal, definitely a shorter throw and the difference is noticeable. Everything seems to work fine - I was careful to prime the cylinder before installing, so I don't believe I have any air in the system. And the car drives just fine, but the clutch definitely feels different, shorter, than it did, and a little less positive effort. It's almost like it would feel with air in the line. Is there any issue with this? Or should I look for a different master with the thinner flange?

I am going to recheck it today and try to get any air out.

ghlkal · 06-01-2016

I'm sorry I can't give you a good answer, but what brand master did you use?

I used a Dorman and I didn't think to compare it to what was on there before (which I don't know if it was original or not), but it must have been similar in size since I didn't notice a difference in the pedal afterwards.

8cam · 06-01-2016

I ordered it from Eckler's, reasonably priced and supposedly the correct part. It is a bit different from the original, but it works. The reservoir cap is a much better design and the cylinder itself seems a bit larger diameter. The biggest difference is that flange thickness.

But after I popped the cap and pumped it a couple dozen times, then put about 20 miles on the car, the clutch feels MUCH better, better in fact than it ever has. The pedal requires a bit more effort now and the feel is way improved from the leaky original - I had no idea how bad it was. So yes, the design is a bit different, but it is installed and working well. I'm really happy with the improvement, and even happier I don't have to keep adding fluid to it any more.

ghlkal · 06-02-2016

Quote:

Originally Posted by 8cam

I'm really happy with the improvement, and even happier I don't have to keep adding fluid to it any more.

Great.

Yeah, I had been carrying a bottle of fluid with me ... maybe I can leave that home now

05-30-2016	#1
8cam Join Date: Jul 2013 Location: Atlanta Posts: 451	Clutch master cylinder replacement question Yesterday I replaced the clutch master cylinder because of a badly leaking original. Not too difficult a job really once I figured out all the little things, and I'm sure I could cut the time in half now. Hardest part was that damn clip on the pushrod. My wrist still hurts from the twisting. One thing I noticed about my replacement, the flange is considerably thicker than the original. That means when I add the spacer, it sits further from the firewall and the pushrod throw is a bit less. I can feel this in the pedal, definitely a shorter throw and the difference is noticeable. Everything seems to work fine - I was careful to prime the cylinder before installing, so I don't believe I have any air in the system. And the car drives just fine, but the clutch definitely feels different, shorter, than it did, and a little less positive effort. It's almost like it would feel with air in the line. Is there any issue with this? Or should I look for a different master with the thinner flange? I am going to recheck it today and try to get any air out. __________________ Mark '90 ZR-1 #1322 Daily Driver, 64k and counting Black/Gray [IMG]http://i208.photobucket.com/albums/bb49/mlitherland/IMG_0326_zps3d50d8cb.jpg[/IMG]

06-01-2016	#2
ghlkal Join Date: Jan 2012 Location: Wisconsin Posts: 886	Re: Clutch master cylinder replacement question I'm sorry I can't give you a good answer, but what brand master did you use? I used a Dorman and I didn't think to compare it to what was on there before (which I don't know if it was original or not), but it must have been similar in size since I didn't notice a difference in the pedal afterwards. __________________ 1990 ZR-1 #2180 Red/Black Many of the usual mods for 460HP, tuned by Marc Haibeck ZR-1 Net Registry Member #1548

06-01-2016	#3
8cam Join Date: Jul 2013 Location: Atlanta Posts: 451	Re: Clutch master cylinder replacement question I ordered it from Eckler's, reasonably priced and supposedly the correct part. It is a bit different from the original, but it works. The reservoir cap is a much better design and the cylinder itself seems a bit larger diameter. The biggest difference is that flange thickness. But after I popped the cap and pumped it a couple dozen times, then put about 20 miles on the car, the clutch feels MUCH better, better in fact than it ever has. The pedal requires a bit more effort now and the feel is way improved from the leaky original - I had no idea how bad it was. So yes, the design is a bit different, but it is installed and working well. I'm really happy with the improvement, and even happier I don't have to keep adding fluid to it any more. __________________ Mark '90 ZR-1 #1322 Daily Driver, 64k and counting Black/Gray [IMG]http://i208.photobucket.com/albums/bb49/mlitherland/IMG_0326_zps3d50d8cb.jpg[/IMG]