Hydraulic clutch bleeding with pressure

[Higgins56]

In the you tube there are some examples of clutch pressure bleeding.

I tried to bleed my hydraulic clutch from below=through the slave cylinder ( McLeod) bleed nipple.

I used a big injection spray tool but when doing it manually I hardly could get any fluid into the system to see it coming to the reservoir in the engine bay.

The clutch pedal was not pressed during this operation.

From some messages in the internet I have learned that manual power ( pressing the injection piston by hand) should be enough to get the fluid into the system.

Someone else has been using an oil dip can to make the pressure( how much pressure can it create compared to pressing with an injection spray tool ?)

Is anybody familiar with this method. Theoretically it should be OK to make the air in the system to go to the highest point - to the reservoir.

 

[Don C]

It shouldn't require much pressure. Slave cylinders are at one of the lowest points in the hydraulic clutch (and brake) system. As such they accumulate rust and other gunk. It's possible you're attempting to force some of this back through the line.

It's also possible that the flex line internal lining is bad, clogging the line.

Another possibility is that the master cylinder/clutch pedal is not releasing completely, and obstructing the internal ports.

 

[Cwithers]

Theoretically it makes sense to do it that way. However issues of air coming in around threaded nipple and as don mentioned, dirt and junk in the slave being pushed up become an issue. I've always bled them with the traditional two man method. Sometimes, when bleeding, manually pushing the slave cylinder piston all the way back at the end of the bleed with the valve open can sometimes get rid of stubborn air.

 

[Higgins56]

It shouldn't require much pressure. Slave cylinders are at one of the lowest points in the hydraulic clutch (and brake) system. As such they accumulate rust and other gunk. It's possible you're attempting to force some of this back through the line.

It's also possible that the flex line internal lining is bad, clogging the line.

Another possibility is that the master cylinder/clutch pedal is not releasing completely, and obstructing the internal ports.

All components are new so there is no dirt in the system ( at least should not...)

I can figure out the only obstacle on the way is the master cylinder.

Otherwise it is only a hose line with five connections ( in my case).

When pushing the fluid through the slave cylinder bleed nipple I opened one of the hose connections after the slave and the fluid came out nicely with hand pressure but when I closed this connection it was like pushing against the wall...

Perhaps I have to dismantle the system ( which is an awkward job as the master is under/ in the dashboard where the clutch pedal pivot point is: you can reach it but not see it....

One question: is the fluid line from the reservoir to the master cylinder critical regarding the air tightness ? This connection is a rubber hose to a nylon connector - a tight fit to get the hose on the nipple as it bends with force and I do not want to crack it. The hose is in only ab. half an inch secured with a clamp but it is very difficult to tighten the clamp under the dash board.