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Maintenance & Repair 350Z up keep and diagnosing/fixing problems

Master AND slave replaced in clutch... still problems

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Old 02-04-2017, 09:45 AM
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DreamZcometrue
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Default Master AND slave replaced in clutch... still problems

2006 350z

Pretty typical stuff for the Z, clutch coming half way up, having to pull it up with my toe. Replaced the slave, it helped it, but didn't solve it, so now we got a new master. Problem is worse than before. It has good pressure halfway, then stops.

Any ideas?
Old 02-04-2017, 11:02 AM
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HRMoneyPit
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Gravity bleeding for a couple hours
Old 02-04-2017, 11:13 AM
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timeltel
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Here's a thought: Check the adjustment at the back of the pedal. After both MC & SC have been replaced, guessing you're probably familiar with the linkage. A good photo can be found in the first post, here:

https://my350z.com/forum/engine-and-...ent-point.html

There's a fluid control valve in the master cylinder. It's purpose is to replenish fluid in the cylinder and line should fluid bypass the seals. This becomes more a concern as the system wears. With your new unworn assemblies, there's the potential the adjustment rod is now extended too far.

Adjusting pedal engagement at the threaded yoke will eventually push the piston in the M. C. forward, there is a small range of adjustment available before that port remains covered by the cylinder. At that point, fluid from the reservoir will no longer flow to refresh the line. Due to the reduced column of fluid in the line, hydraulic pressure provided by the SC return spring falls to the point that the pedal will eventually fail to fully return.

From the condition where the pin securing the yolk is just snug to the pedal, there are only a few turns when tightening the adjustment rod before it reaches the "point of no return".

Hope this helps?
Old 02-04-2017, 04:00 PM
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CUL8ER
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Sounds like you have air trapped in your system. You need to bench bleed you master and maybe your external slave as well. just bench bleed the master first and see if that fixes it.
Old 02-04-2017, 04:41 PM
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DreamZcometrue
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Originally Posted by CUL8ER
Sounds like you have air trapped in your system. You need to bench bleed you master and maybe your external slave as well. just bench bleed the master first and see if that fixes it.
So with the bleeder closed, you have to pump it like 30 times before you get any pressure. The first 5 or so pumps have very little to no pressure, then after that it has good pressure but won't push the peddle all the way up, what am I doing wrong?
Old 02-04-2017, 05:14 PM
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CUL8ER
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So the rod in your master cylinder with the pedal still hooked up. your only pushing the rod I just mentioned about half of the dissidence it needs to go hence the air. You need to remove the master and get that rod pushed all the way by hand to get all the air that's trapped in the body of the master.

Look up bench bleeding a master cylinder. and you will get the idea. It seems like a lot of work trust me I said the same thing it's not.. After bench bleed the master it took all of like 3 pumps on the clutch pedal once hooked up.

Pull the master the reservoir and the line going to the slave. Fill the res, put slave cylinder side of line into the res and push the rod all the way. with the help of a buddy to hold it or a vice. You should hear/see air escape with bubbles in the reservoir and see the res drop in volume. add more continue till the fluid stops dropping in the res. and put it back in slowly just to keep the mess down. So now that's done you have fluid in the piston of the matser cylinder it will stay in there till the rod gets pushed in so if a little leakes out while installing that's ok just dont push rod in or attach to clutch pedal until all lines are hooked up.
Old 02-05-2017, 09:32 AM
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i8acobra
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The trick to bleeding a Z clutch is to pump slowly. If you're furiously kicking the clutch like you're trying to kick-start a motorcycle, you'll be kicking for days. It should take a full 2 seconds to depress the clutch and a full two seconds to let it up. When you pump fast, instead of pushing the air out, you're just popping the big bubbles, forming tiny bubbles that turn the fluid to foam.
Old 02-05-2017, 10:41 AM
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CUL8ER
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The posts above(not mine) give you examples of when you already have fluid in your master. Since yours is brand new. it doesn't have fluid in it. And if you keep pumping the clutch pedal you will create friction inside the master cylinder where there is a piston with 2 rubber seals 1 on each side.

And with no fluid in the master body you will rip the rubber seals. Caused by no fluid/friction and have to buy a rebuild kit.. Just pull it how I described, bench bleed and be done with it. I spent 2 months dealing with the same thing and I did have to buy a rebuild kit from me over pushing in pedal. Just trying to save you the headache.




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