Back bleeding the clutch

[psbnsx]

Has anyone ever back bled the clutch hydraulics? In this method hydraulic fluid is forced through the slave cylinder bleeder valve and it exits at the clutch fluid reservoir. It's a reverse flow obviously.

This technique was particularly effective at removing air from my clutch lines on my Porsche. I was wondering if anyone has done it on an NSX.

Thanks

Philippe

 

[TyraNSX]

Don't know and don't see the need. Given the amount of crud that came out of mine when I did it, you don't want to be pushing all that backwards through the system and your spiffy new slave and/or master cylinder. Stick with the conventional method.

 

[shawn110975]

its like pushing a huge rock uphill.

 

[ralph cerbone]

I've posted this before but I'll do it again . I use a Mighty -Vac made by Sliverline to bleed brakes and hydraulic clutches. When doing a clutch ,I remove the slave cyl. bleeder ,wrap the last 2/3 of thread (stay away from the taper seat portion of the bleeder screw)in teflon tape ,thread it back into the slave cyl ,(I'll explain later ). Fill the master cyl, have a helper available to add fliud as you bleed . Connect the bleeder hose to the slave cyl. bleeder ,(the kit comes complete with a bleeder bottle to capture the fluid . Crack open the bleeder and GENTLY pump the Might-vac . It will draw the fluid right out the M/C thru the slave cyl. and your done . The reason I wrap the bleeder fitting is because I have seen Techs pump the hell out of the mighty -vac and complain the air bubbles never stop . The reason is they pull too much of a vacuum ,open the bleeder too much and air is sucked thru the bleeder threads . :wink:

 

[pgilliam1]

The clutch hydraulics on the NSX are easily bled just by gravity alone.

 

[dirtbag]

When installing a new master cylinder, it helps greatly to bench bleed the unit first.

I skipped this step thinking to myself I've never had to bench bleed any units in my life, so why should this be any different?

Boy was I wrong and encountered an issue when too much air entered the lines along with a partially dry master cylinder. For the life of me I could not get fluid to move. I tried vacuum pump on the slave valve, gravity, raising the front of the car up and lowering the back.... It was only until I put the master cylinder reservoir under pressure I finally got fluid to move.

I've used the reverse bleed method on other cars and it's fantastic. Unfortunately I don't have the proper equipment anymore. But the NSX having such a tiny reservoir would be easy to overflow I don't think I'd attempt it by myself.

 

[ralph cerbone]

The clutch hydraulics on the NSX are easily bled just by gravity alone.

Not just the NSX ,any vehicle or piece of equiptment, with a reservoir higher than the actuating cyl will gravity bleed eventually , whats the old saying "you can lead a horse to water but you can't make them drink !

 

[pgilliam1]

Not just the NSX ,any vehicle or piece of equiptment, with a reservoir higher than the actuating cyl will gravity bleed eventually , whats the old saying "you can lead a horse to water but you can't make them drink !

This is true, and the clutch system is very easy because it gravity bleeds fluid at over twice the flow rate the braking system does on this car. Maybe 30 minutes, and you're done.