Clutch bleeder valve nut size

[TO AWSUM]

It is VERY rare that you will need to bleed the one on the firewall at all.

I agree with this especially if you use a Motive Power Bleeder which never lets the clutch reservoir get empty thus eliminating the possibility of getting air into the system. If you use the technique of pumping the clutch pedal and then repeatedly refilling the very small clutch reservoir then there is a possibility of getting air into the system if you accidently let it get too low on fluid whether you bleed the firewall valve first or not. I also only bleed the farthest point which also changes the fluid in the firewall point. Works great for me so far.

 

[Wwabbit]

I agree with this especially if you use a Motive Power Bleeder which never lets the clutch reservoir get empty thus eliminating the possibility of getting air into the system. If you use the technique of pumping the clutch pedal and then repeatedly refilling the very small clutch reservoir then there is a possibility of getting air into the system if you accidently let it get too low on fluid whether you bleed the firewall valve first or not. I also only bleed the farthest point which also changes the fluid in the firewall point. Works great for me so far.

Exception is during severe use conditions, such as tracking, where the clutch fluid can become heated and boil out any water the fluid may have absorbed. If you get enough of it the resulting separated air will seek the high point - the firewall bleeder. You should bleed your brakes for the same reason even though yoiu may not have lost any fluid.

 

[RALPHIE]

Exception is during severe use conditions, such as tracking, where the clutch fluid can become heated and boil out any water the fluid may have absorbed. If you get enough of it the resulting separated air will seek the high point - the firewall bleeder. You should bleed your brakes for the same reason even though yoiu may not have lost any fluid.

I don't understand this. Where did the air come from? If you boil out water vapor, it's still water in a gaseous form, not gaseous air (nitrogen, oxygen, argon, etc.) When it cools down, it will reconvert to liquid water (an incompressible fluid) and would either stay as water, or be re-dissolved in the brake fluid. How did you get air in the closed system?

 

[Kingman]

There have been a couple references to the Motive Bleeder (which I have purchased to do the brakes), what attachment (Motive part#) is used for the clutch bleeding? Thanks!

 

[Wwabbit]

I don't understand this. Where did the air come from? If you boil out water vapor, it's still water in a gaseous form, not gaseous air (nitrogen, oxygen, argon, etc.) When it cools down, it will reconvert to liquid water (an incompressible fluid) and would either stay as water, or be re-dissolved in the brake fluid. How did you get air in the closed system?

When the stuff super heats from use, volatility of some of the constituent components of the fluid chemistry can result in a partial decomposition of the fluid. After many cycles the gases accumulate and may be generalized as 'air'. That's why it eventually turns a yucky color and we change the stuff. As important, is the accumulation of water that happens as a matter of moisture vapor entering the system slowly from all directions.

There have been a couple references to the Motive Bleeder (which I have purchased to do the brakes), what attachment (Motive part#) is used for the clutch bleeding? Thanks!

You don't need a real tool, use a length of aquarium hose and an empty botlle to slip onto the nipple and follow the instructions in the manual. You'll need an assistant and takes 10 min.

 

[TO AWSUM]

There have been a couple references to the Motive Bleeder (which I have purchased to do the brakes), what attachment (Motive part#) is used for the clutch bleeding? Thanks!

I ordered my Motive as a deluxe model that came with about 6 attachments. The small round cap with hose fit the clutch master.

 

[RALPHIE]

When the stuff super heats from use, volatility of some of the constituent components of the fluid chemistry can result in a partial decomposition of the fluid. After many cycles the gases accumulate and may be generalized as 'air'. That's why it eventually turns a yucky color and we change the stuff. As important, is the accumulation of water that happens as a matter of moisture vapor entering the system slowly from all directions....

I understand the need to replace the fluid due to the water accumulation in the brake fluid, as the fluid is somewhat hygrocopic and thus will accumulate water over time. Thus, when heated to high temperatures, the water will come out of solution as water vapor, and will give a "soft" pedal due to the compressability of the water vapor. The more water in the fluid, the softer the pedal will feel as the temperature rises. Yet, upon return to ambient temperature, I've never encountered bubbles which have stayed out of solution upon bleeding the lines, unless the line was opened inappropriately. And, while I would agree that other gases may also dissolve in the brake fluid, their vapor pressures would also be such that upon return to ambient temperatures, they would alxo redissolve in the fluid.

 

[Wwabbit]

There is really no driving force to put the gas back in once it's out. It's just free gas in a zero pressure system with the pedal up and will seek a high point. I usually see a small stream of micro bubbles when I bleed brakes, (about the size of bubbles from good champagne) not so much the clutch. Sometimes I can't seem to get to the end of the bubble stream even after a few cycles. So I just quit there, but they are in there - usually. You're right about water, it eventually just get reabsorbed - hopefully before it freezes.