Clutch bleed apprehension
 

Hello, I have a 2019 370z Nismo with about 20k miles on it.

I would like to bleed the clutch but I am worried because it seems like people always have major issues doing this. I am not sure why it is such a problem on these cars.

Can I just connect a tube to the bleeder valve and crack it a little to let it gravity bleed? Will that get air in the line or something?

I read story after story of people bleeding the normal way, i.e. hold the pedal, open valve, close valve, repeat, and they can never get it working. I do not want this to happen to me...

I bleed my clutch the "normal" way also, and didn't have any issues. Replaced my MSC and CSC.

Only issues I had was adjusting my RJM pedal.

maybe I was one of the lucky ones.

Clutch bleed apprehension
 

Same here. Bled the normal way and it was fine. The pedal was mushy at first but repeated the process a few more times and it was fine. Make sure you press and release the clutch slowly. Whole process took me less than a half hour.

I used the “pole against the seat pressing on the clutch pedal” method which wasn’t ideal so getting a 2nd person is recommended.


Sent from my iPhone using Tapatalk

The only way I got mine to bleed properly was via a pressurized brake bleeder, which I think is typically discouraged because of the added pressure on the slave cylinder.

No issues on my system since bleeding 8k miles later.

Just gravity bleed it. Make sure you don't let the master cylinder run dry. That is how I do it all the time.

It's because almost everyone sees themselves bleeding new components.

You and spooler are correct, a gravity bleed will do.

You are not removing any air from the system and as long as the reservoir doesnt dry you will be good.

Do yourself a favor, empty the reservoir first, fill with new fluid and have new fluid run down the line.

Agreed! I do this once a year without any issues. Fluid remains clean and pedal stays firm.

Good timing for topic.

When I had my OEM components, I did the old fashion two person method. As this was the normal practice. Did it twice on my 2017. never had issues.

Until recently, when I had the mysterious high engagement did I have issues.

I went ahead and replaced entire clutch system.

Now I am having a hard time bleeding the Tilton MC and CMAK slave.

One thing I noticed is the new SC will not RETRACT back far enough. I had to keep bleeder open and manually push the piston back (towards bleeder) and low and behold, tons of air bubbles in my hose.

Obvioulsy, this will introduce some air back UP into clutch hose towards MC.

So, I had to repeat this a couple more times and I have no bubbles showing.

However, pressing down on the RJM pedal, still feels spongy at top 1/2-3/4".

I'm going to go ahead and adjust pedal to where it should to start and see if some of that play will be taken up or still feels spongy.

Yes, I did bleed with pedal at 0 AFM, clevis fork set to longest stroke. (almost at end of MC rod near pedal attach point.

I left the switches out for maximum stroke.

Hope that helps.

I always bleed it down until it get's to the bottom and then wipe the junk out. Fill back up and gravity bleed some more.

Did you bench bleed the MC before you put it on? If not, that was your problem.

I've bled the clutch three times, and I've never had a problem. (Each time I was simply replacing dirty clutch fluid.)
Did the standard, simple 2-person method.
As others said, the key is not to let the fluid reservoir run dry. Otherwise easy-peasy!

Ok... I am still nervous, I had a G37 and now this car and heard countless problems from people where they tried to bleed it and had a failure and had to replace the CSC. What!!?? So it was fine until they tried to bleed it and then it failed?

Even the Infiniti dealership refused to bleed my clutch. How the heck can bleeding the clutch break it?

Back on topic - let's say I want to gravity bleed. I have never done this. Do I just take the top off, suck the fluid out, put fresh fluid in, then crack the bleeder with a tube on it and let it slowly drip out?

Will air get sucked into the cylinder when I open the bleeder? Any sort of prep I need to do beforehand?

Thanks very much.

Yup, that is what you do. You don't need the tube on it. Just have it drip into a pan. Do not press the clutch pedal or let the MC run dry. If you do so, it may be a pain.

It's because of this issue why most of the bleeds fail.
Almost nobody cleans the reservoir first, even if it's micro debris you're still trying to pump it through a seals in a cylinder and through a slave cylinder that also uses seals that are fragile when debris is present.

Emptying the reservoir first could buy you a year or two.

A fluid exchange is just that, however by forcing old fluid down the line you're essentially doing the same as a transmission flush for automatics which is now standard knowledge to stay away from and in the clutch systems for these cars is definitely something you want to keep in top shape, after all the system is not complicated at all just sensitive for debris like most hydraulic systems.

A gravity bleed will be the least intrusive way to get this done. If you are extremely worried about the "old fluid" still trapped in the chamber you can change the fluid, pump the pedal a few times and then change the fluid again for additional assurance.

PS: most of this debris comes from the clutch reservoir hose that's been documented as the main fault of debris due to how it the brake fluid over time starts to melt the hose inside out.
Some members change the hose with an OEM replacement, others use Motorcycle hoses which work wonderfully.

Either way properly cleaning and keeping this system clean WILL extend it's life

Good luck!

I followed the RJM instructions. Which essentially bench bleeds it but installed.

Actually, re-reading the instructions, I'm ok with that 1/2-3/4" softness.

"At this point if everything went well you should have a nice firm clutch pedal with no softness at the top
for OEM pedal units and no more than ½”to ¾” of soft travel at the top for RJM Pedal Units. Please note
if you’ve just installed a new RJM Pedal along with the new master cylinder then the pedal feel at the
top will be softer then you were used to. With the design of the RJM HD Master Cylinder any small
amount of air left in the upper lines after this procedure will quickly and automatically get purged from
the system as you start driving it or continue to slowly pump it.

"

At the end of the day this is a standard MC and CSC or Slave.
An even more simplistic approach, this is just a hydraulic system.

The reason why folks have a hard time with these:

• The shape of the line tends to trap air
• The clutch softner main culprit (circular piece that attaches to the hard line) all that it is is a chamber that restricts volume by using a restrictor like turbos.
• This chamber does not like debris at all and once debris enters it's really difficult to clean just by fluid exchange.
• Incorrect shaft or pedal lenght
• Lack of bench bleeds
• Deteriorating CSC will make bleeding difficult as well

I recently did a VHR swap on a 350z using 370z pump, CSC and line.

16k mile donor and a brand new CM, had bleeding issues. Little to no fluid coming out of the bleeder. Better flow coming out the CM but not enough.
I deleted the clutch softner and was able to get better flow to the CSC but it barely moved.

In the process of trying to bleed the new CM with the bad line/sofner I killed it. Exchanged the CM for a new one. Bench bled it and installed the cover nipple on the CMC to prevent fluid or air to go into it.

Once installed I set rod length to max and loosened all of my fittings and started pumping. I would get small bubbles as I would pump and once they would disappear I would tighten. Clutch bleeding was a success

Now the next issue was my engagement was about 1/8th of the way from the top and felt like it would work however I would get some stickiness when I would pump all the way.

The issue ended up being that now the rod length needed to be scaled back a few turns and she is golden now.

I took the opportunity of this to make that hardline as straight as possible.

I realized that in all of my MT cars almost all of my clutch hydraulic problems would disappear when I would install a direct braided hose and ditch the softner.

I did this today after I changed my brake fluid. I did the gravity bleed, it was very easy and I had no problems.

I was surprised to see sludge in the bottom of the reservoir after I sucked the fluid out. So I added more fluid in and stirred it up and sucked it out a few times, then I wiped the inside of the reservoir out with a rag. I was also surprised when I started the bleed that the clutch fluid that was in there looked almost the color and opacity of peanut butter. It was not clear fluid, it was like peanut butter, maybe a little lighter.

I put a whole bottle of Motul 600 through it. Everything was fine with brakes and clutch on the test drive.

Thanks for all the help everyone, I am going to replace the clutch fluid more often. The car has 24,000 miles on it and I am guessing this is the first time the clutch or brake fluid has been changed. The brake fluid wasn't too bad, but there were some bits of rust and sediment in the fronts. Glad it is all fresh now.

does the fluid start dripping once you loosen the drain bolt or you have do something to get it going?

how long does it take to drip through the fluid in the reservoir assuming it's at the max level? Thanks.

Yep it started dripping right away I didn't have to do anything. Just have the reservoir cap off and make sure it's full, I cracked it so it was coming out really slowly. I jacked up the driver side of the car and took the front wheel off to get under there easier.

I did not touch the clutch pedal or anything else, just kept adding fluid in as it drained down slowly. It probably took 30 minutes to get through the bottle, by the end it was nice and clear.

thanks.... ;)