Bleeding Alfetta Clutch Slave Cylinder

[Craig C]

I need some suggestions and advice.  I have been bleeding away for days with no bubbles but still can't get any pedal resistance or movement at the clutch fork.  I have tried pushing the slave piston in to expel air, have rotated the slave so the nipple is at the highest point and have left the master cylinder full of fluid above the min line. In the absence of any suggestions for doing it manually I am now looking at pressure bleeding but there appears to be two very different tools.  One operates by vacuum at the nipple and one by pressure at the reservoir.  I am guessing that the pressure one would be better for the clutch slave but not quite sure why.  Vacuum ones seem to be more readily available I have only seen the pressure ones on the internet.

Any suggestions for me?

Thanks

[Domenic]

Did you compare the old slave cylinder to the new one you put on the car??


Depending on the brand that you have there are differences between them and don't allow the pin to move enough to push the clutch fork.

Seen a few cheap aftermarket ones over the years that the thickness where the bolts go through to mount it is thinner and doesn't allow the cylinder to work properly. Check that first and compare it with the one you took off the car.

[Cool Jesus]

There's a DIY for making a pressure unit which is my preference. I'm about to build one myself. The vaccuum style needs proper sealing at the nipple and you'll run the risk of sucking air there and not really performing a proper line bleed. 
No pressure? Are you sure the seals on the master or slave are functioning? Sounds like the fluid is flowing passed a knackered seal, giving you no fluid pressure, but only enough to push fluid through for bleeding? Clutch Master cylinder would be my first guess, as you'd have leaking at the slave cylinder if it was stuffed.

[Cool Jesus]

Here the YouTube vid on a DIY pressure bleeder which I'm going to build. Should only cost about the price of the vaccuum units on the market.

http://m.youtube.com/watch?v=Mdcn1USVQ-w&desktop_uri=%2Fwatch%3Fv%3DMdcn1USVQ-w

[LukeC]

Another thing notoriously hard to bleed in Alfettas.

I bet you didn't take measures to ensure the master didn't empty itself when you were changing the slave... ? The outlet port points down: not the best orientation for bleeding. Having been through this process recently, I found that a number of different methods were required to get it perfect.

Pressure bleeding to start with to get fluid into it. Then two person bleeding with the person in the car pumping furiously, then holding the pedal down while the bleeder is cracked. Bleeding from the slave only by pushing in the piston. You name it: try it all. And then you may just have to drive it around a while until it comes right itself. Worst case is to take the master off, bench bleed, put back on while the outlet port is sealed, connect up and then go bleed the slave.

My GTV has the 75 TS casting for on the firewall and so the master points downwards, so it took about 5 goes to get it perfect...

[Mick A]

Gday,

Pump the pedal up (you need to pretty much kick it into the firewall not a slow pump) and then crack the 12mm at the clutch master cylinder.

Make sure you have a rag handy to catch fluid, do this a couple times and if you've already bled at the slave with no pedal you should find the pedal will come.

Hopefully. haha.

Cheers - Mick

[Al Campbell]

+1 for bleeding anything on these cars is a Mongrel. I think the best thing to do is accept that, set aside plenty of time and relax  . If ALFAs were easy, every one would have one.

Did you actually replace either cylinder? or seals?

I had a non genuine Master, which made adjusting the master yoke necessary (another mongrel). The slave cylinder rod had also been lengthened. Only changed the seals and had to adjust yoke after. Go figure .

I had to rotate the slave so the bleed nipple was uppermost, put the back wheels on stands so that bubbles could have a free flow "up hill" to the bleed nipple.

Cheap pressure bleeder (only way for rear brakes) I made was an old tyre foot pump tube attached to the spare tyre with the other end on a nipple on a spare master cylinder reservoir cap. Let the tyre down to 15 to 10 psi as there have been stories of too much pressure stuffing the brand new seals  (Brakes on 105s I think). A tee piece and pressure gauge for your home made bleeder would be real nice.

We feel for you,

AL.

[Craig C]

Thanks for all the suggestions, there are a few things for me to try there.

To answer some of the questions, I swapped the transaxle so all of the fluid circuit elements are unchanged from before, so same master, slave, reservoir, seals.

Also the brake master cylinder reservoir also supplies the clutch master through a hose take off part way up. I assume this is different to earlier models.

When I dismantled everything many weeks ago I blocked off the line but fluid could have leaked out over such a long period.

First thing I will try is the rapid pumping method, previous advice was to pump slowly but that appears to be outnumbered by the alternate view.

I will also try raising the rear of the car.

Fingers crossed I might get some action this morning.

[Craig C]

Success!

The trick was, as advised, vigorous pumping and then cracking the 12 mm connection at the base of the master cylinder.  When I did that i heard the phfssst and after doing it a few times it took in about 30ml of fluid.

Something else I did to assist was to pull out the hose from the reservoir clamp it up in view with a large syringe in the end.  This initially showed some bubbles from the vigorous pumping and then showed the fluid drop each time i cracked the 12 mm connection.

I think a contribution to my problem was the circuitous link through the flexible hose between the brake reservoir and the clutch master.  Clamping it up let gravity help and now that it is back in place siphoning will take over.

Thanks everyone for the help, cant wait to get it all assembled and back on the road.

[Mick A]

Glad to hear it worked mate.
-Mick