Clutch keeps pumping air

Engine, Transmission and related drivetrain.
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Nerius
Posts: 39
Joined: 12 Jul 2020 08:29
Location: the Netherlands

Clutch keeps pumping air

Post by Nerius »

Hi all,

I'm having a problem. I've changed the slave clutch and hardline but after bleeding it seems it's pumping air into the system. I've bleed the master as well. In the video you can great the sound it's making. It's making that sound with the cap on as well.
https://youtu.be/Gu4zmlpyOqo

Does anyone have a clue what my next step could be?

Thanks,
Werner
Even the pain is fun.
https://www.instagram.com/dutchydatsun510/
datzenmike
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Re: Clutch keeps pumping air

Post by datzenmike »

What exactly happened that you had to replace the slave?

Was it leaking???
"Nissan 'shit the bed' when they made these, plain and simple." McShagger510 on flattop SUs
Nerius
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Joined: 12 Jul 2020 08:29
Location: the Netherlands

Re: Clutch keeps pumping air

Post by Nerius »

The slave sometimes got stuck. It became very unpredictable.
Even the pain is fun.
https://www.instagram.com/dutchydatsun510/
datzenmike
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Re: Clutch keeps pumping air

Post by datzenmike »

So everything was working, then slave replaced and problem began. This would indicate to me the new slave brought the problem with it.

I recently needed a new slave I didn't have time to sort through my pile of original parts and bought on of those $23 Chinese POS. Naturally I took it apart to confirm all the parts were there and to lube with brake fluid so it didn't start up dry. The 'rubber' seal was like it was made from very soft flimsy RTV and very unlike the original that are very firm rubber. I'm not impressed with the quality one bit and this is another thing on my list to replace.

I've rebuilt slaves before and the Nissan kit was only $12 and had everything in it but the metal piston. No longer available.
"Nissan 'shit the bed' when they made these, plain and simple." McShagger510 on flattop SUs
Nerius
Posts: 39
Joined: 12 Jul 2020 08:29
Location: the Netherlands

Re: Clutch keeps pumping air

Post by Nerius »

Hi Mike, thanks for this, I'll check if I can do a rebuild on the original one.
Even the pain is fun.
https://www.instagram.com/dutchydatsun510/
datzenmike
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Re: Clutch keeps pumping air

Post by datzenmike »

Sure would be nice if a seal could be found for this. Back in the '70s our fork lift had leaking wheel cylinders. The estimate was $550 to haul it away to a shop to fix. I measured the seal and went down to the local Canadian Tire store and rummaged through their parts department. A '63 Studebaker rear seal kit fit perfectly. I think it was $3.50 a side. Can't do this to-day, no one keeps parts available, you have to order them. I bet there's a seal out there somewhere.
"Nissan 'shit the bed' when they made these, plain and simple." McShagger510 on flattop SUs
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tycot1
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Re: Clutch keeps pumping air

Post by tycot1 »

Check that the clutch master isnt leaking inside at the rod, behind the boot also. It sounds like Mike is on the right track though.
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Nerius
Posts: 39
Joined: 12 Jul 2020 08:29
Location: the Netherlands

Re: Clutch keeps pumping air

Post by Nerius »

datzenmike wrote: 25 Jan 2021 07:30 Sure would be nice if a seal could be found for this. Back in the '70s our fork lift had leaking wheel cylinders. The estimate was $550 to haul it away to a shop to fix. I measured the seal and went down to the local Canadian Tire store and rummaged through their parts department. A '63 Studebaker rear seal kit fit perfectly. I think it was $3.50 a side. Can't do this to-day, no one keeps parts available, you have to order them. I bet there's a seal out there somewhere.
That's a crazy story!
Even the pain is fun.
https://www.instagram.com/dutchydatsun510/
Nerius
Posts: 39
Joined: 12 Jul 2020 08:29
Location: the Netherlands

Re: Clutch keeps pumping air

Post by Nerius »

tycot1 wrote: 25 Jan 2021 07:52 Check that the clutch master isnt leaking inside at the rod, behind the boot also. It sounds like Mike is on the right track though.
Good idea, it sounds as it's sucking up air at the master
Even the pain is fun.
https://www.instagram.com/dutchydatsun510/
Nerius
Posts: 39
Joined: 12 Jul 2020 08:29
Location: the Netherlands

Re: Clutch keeps pumping air

Post by Nerius »

there was a vacuum leak at the master. I've replaced and all works fine now!
Even the pain is fun.
https://www.instagram.com/dutchydatsun510/
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