Clutch Bleedings Tips
As an experienced mechanic, I will never be more humbled than I was by this simple solution to a problem that caused me many a wasted evening.
OK. New clutch master and slave cylinders. Install. (This is the crux, but read on.) Add fluid. Crack slave bleeder, attach tube, put in bottle. Pump clutch pedal ten times. Look in bottle. Nothing. Repeat ad nauseum. Zippo.
Tried gravity bleeding. Kinda, but not really. Zippo.
Get out Mity-vac. Set it up. see a little fluid. Repeat, ad nauseum. Zippo. Open beer and give up.
Finally, online, I found this:
"I think the biggest reason it is so hard to bleed the clutch system is because the bleeder valve is lower than the incoming fluid line. Gravity bleeding will work to clear the clutch line of air, but there will be a bubble left in the slave cylinder. What I found that works is to simply unbolt the slave cylinder and hold it such in a way that the bleeder valve is at the highest point, relative to the incoming line. Holding it this way, the air bubble in the cylinder will naturally float up and out by gravity, e.g. the slave will fill up from the bottom and push the air out the top. Since gravity is doing all the work, this is a one man job. When the air bubbles stop, close the bleeder and attach the slave to the bell housing."
Slapped myself in the forehead and caught a lesson in humility.
Tip by Mike Maddux
the bleeder valve SHOULD ALWAYS be above the inlet hose. But, you shouldn't have
to unbolt to achieve this.
This is a very common happening. I can't post a pic right now, because I'm using my
iPhone, but, if your bleeder screw is below your inlet hose, you need to remove them
both and swap places.
For some crazy reason, these are packaged incorrectly, it has been like this for 30
years. Take a look at your manuals, you'll see the picture of what it should look like,
or do an archive search of my name "BManBrian" and "slave cylinder" and you'll see a
Why they package them wrong, I'll never know, about 50% of MGB enthusiasts miss
this. It'll only happen once though! Hahahahahaha
I have gone thru this system 6 times anyways ans yet this is the only thing holding me back.
The car ran and drove for about 2 miles and then I had an instant dead pedal. I also tried the first suggestion of removing the slave, tapiny it up so the piston does not pop out and bleeding it....did'nt work. If any one near Concord, NH can fix this, I will pay for it gladly!!!!! Call Jon Eriksson 603-226-0106
The Slave Cylinder comes packaged incorrectly. The bleeder screw needs to be removed
from the lower INLET, and screwed into the UPPER hole.
I am posting two pictures on the MGB forum right now, as, I can't seem to figure out how
to post pics here.
email me if you can't get it, and I can help:
Any gravity bleeding or pressure bleeding is no good for expelling all the air. Once you have most of it out, open the screw fairly wide and get a helper to push down heavily on the clutch pedal the quickly close the screw. Repeat one or two times if necessary. The force of the clutch pedal being firmly depressed is enough to drive all the air out.
set-up, ALWAYS! I bet if you look at the two holes they are identically threaded, just switch
the hose & bleeder screws. Originally, if memory serves me here, the clutch slave cylinder
on those cars had both bleeder and hose holes on the top, but, subsequent part
substitutions have one on the top and one on the bottom. The bleeder screw MUST BE ON
THE TOP, ALWAYS. Good Luck
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