ozh_hawaiian

I have searched, but found no definite answer... I am having issues with my clutch, and have previously changed my slave cylinder, now I want to change my clutch master... what i need to know is
A. Do I NEED to bench bleed the clutch master cylinder before I install, or can I install, and bleed the system the normal way?
B. If I need to bench bleed, how exactly do I do it? I have bled a brake master, and that came with fittitngs so you could bench bleed it easily, but the clutch master did not.
I am looking for an answer from someone who has ACTUALLY done this procedure, and not a guess, or assumption.
any info would be appreciated

TatDc5

Hey OP

I actually have not done this procedure before but was able to find a basic how-to online.

With that being said, I have swapped Master cylinders previously without bench bleeding and had no issues at all just takes more time.

cheggie

I found it easier to bleed the clutch master cylinder installed in the car. It makes a mess either way, but there's less risk of spilling brake fluid on the paint if it's already attached to the firewall. Have a can of brake cleaner handy if you're worried about spillage in the engine compartment. The fittings are not necessary - I just put my finger over the output hole and have a helper pump the clutch pedal a few times to get most of the air out. You'll always have a little air left in there when you take a few seconds to attach the line to the master cylinder. At that point, your helper can pump while you do the final bleed at the slave cylinder. A vacuum pump with a reservoir is helpful too, but I've found the job is so much easier with another person.

To sum up:
A:You really don't need to "bench" bleed - it sits the same way in the car as it does in a vise, and it's less messy when you don't hoist a wet master cylinder over your fender.

B: Use your finger as the "valve" to prevent sucking air into the clutch M/C. Just put your finger over the output and have your helper pump a few times, slowly. Fluid will escape past your finger, but it will prevent air being drawn back in. When there's fluid present at the output, then hook up the hard line.

I've done this lots - I never bleed on the bench anymore.

ozh_hawaiian

thanks, i will try this. I was also thinking of finding a hose barb small enough to screw in, and running the output to a container to prevent air sucking in... and I figured i would get a little bit of air in when putting the output line back in

cheggie

You will, it isn't going to be a perfect seal - you just need enough fluid in there for it to start pumping. Good luck!

ozh_hawaiian

turned out the hose barb that I saved from when I got a brake master cylinder fit in the output hole, and it made it easy to bleed