Clutch Master not pumping

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The Neck
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Clutch Master not pumping

Post by The Neck » Mon Aug 12, 2019 11:01 pm

Hi everyone,

I'm taking a little break from the engine tonight since it's a bit too late to be making a bunch of noise and decided to flush and bleed the clutch. I have a new slave, rubber line, and hard line, and removed and cleaned up the master cylinder.

As I started to bench bleed and then install on the actual line, I noticed I was having fluid push back into the reservoir when I pressed the clutch pedal. I am able to flush the line, however there doesn't seem to be any actual pressure building up in the line itself. Every time I push the clutch pedal/arm, fluid immediately goes back into the res.

I pulled the cylinder apart, cleaned it out a little, and it's still doing this. Would this mean the actual seals on the piston are shot? I can only assume so since the fluid isn't going where it should.

Mike
1968 CJ-5
2007 Audi S4
2003 Audi Allroad Stg 2
1967.5 1600

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Nissanman
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Re: Clutch Master not pumping

Post by Nissanman » Mon Aug 12, 2019 11:16 pm

I would advise putting a recon kit through the master, especially if you have fitted a new slave.
Also check for any scratches or corrosion in the M/C bore.
Anything that your finger nail catches on requires replacement/repair.
Nissanman, just trying to help.
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bossbob
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Re: Clutch Master not pumping

Post by bossbob » Mon Aug 12, 2019 11:27 pm

Your fluid pressure is bypassing the seals. New seal kit as above if your cylinder is good, or new replacement. I did both the mc and slave at the same time.
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The Neck
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Re: Clutch Master not pumping

Post by The Neck » Mon Aug 12, 2019 11:35 pm

That's what I was thinking, thanks for verifying!
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zippy67roadster
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Re: Clutch Master not pumping

Post by zippy67roadster » Tue Aug 13, 2019 1:14 am

I sell a rebuild kit for the clutch master but you need to make sure the cylinder walls are not pitted as the seals will just fail again. The kit is located here: http://sincitydatsuns.com/store/p121/Af ... inder.html
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mraitch
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Re: Clutch Master not pumping

Post by mraitch » Tue Aug 13, 2019 11:28 am

a) Just to reiterate, unlike the brakes, clutch is merely 'gravity' filled.

b) I had similar problem - Skip said just tap the cylinder - all went away.

c) follow instructions below about rebuilding.

Good luck.
Peter Harrison
1970 1600 (Stroker) - TOAD SAN (Eliza)
1970 1600 (Stock) - As Yet Unnamed
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The Neck
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Re: Clutch Master not pumping

Post by The Neck » Tue Aug 13, 2019 1:27 pm

mraitch wrote:
Tue Aug 13, 2019 11:28 am
a) Just to reiterate, unlike the brakes, clutch is merely 'gravity' filled.

b) I had similar problem - Skip said just tap the cylinder - all went away.

c) follow instructions below about rebuilding.

Good luck.
a) Please elaborate on gravity filled versus the brakes. Do you mean the bleeding procedure is different?

b) What do you mean by tap the cylinder?

c) rebuild kit is ordered and should be all back together soon.
1968 CJ-5
2007 Audi S4
2003 Audi Allroad Stg 2
1967.5 1600

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mraitch
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Re: Clutch Master not pumping

Post by mraitch » Tue Aug 13, 2019 4:17 pm

a) just fill the reservoir, let some fluid drain out to remove water, then tighten and fill up to line - there is not the same pressure needed as with the brakes

b) apparently there is something inside that gets stuck - some sort of valave - happened to Dave Emsley as well. Tapping the cylinder freed it up.

c) have fyn
Peter Harrison
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gnoplos
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Re: Clutch Master not pumping

Post by gnoplos » Wed Aug 14, 2019 2:10 am

I had the exact same problem just a bit ago. There was a spare M/C in the trunk as well as a "new" one installed. Both did exactly what you're talking about. I was skeptical since both appeared to be doing the exact same thing but a new master fixed it right up!
1969 1600 jalopy with U20 transplant