pictures/diagrams of clutch master cylinder

[markh1]

As a result of this thread;

http://www.pistonheads.com/gassing/topic.asp?h=0&a...

I need to see a diagram or picture or even better still! instructions on how to change the master cylinder.

Does anyone have any idea where I can find such info??

Thanks in advance.

[350Matt]

I'll give it a go

Remove the engine / lower windscreen cover undo the 2 bolts, pull apart wiper tube connection and lift off cover, there are 2 barbs which hold the cover to the base of the screen

Using a stanley knife or similar clear away the black silicone sealing the black hemispherical cover over the drivers feet, there should be two screws to remove as well, once this is cut away you should be able to prise the cover off

You should now see the master cylinder, with the aid of your glamorous assistant bleed the clutch circuit dry (remote bleed hose is the small braided hose ty-wrapped to something at the back of the engine bay), this will need the small nipple screw in the end of the hose loosening and the end placing in a container to catch the old fluid.

Once the master cylinder is dry, undo the solid pipe connection and wiggle the pipe out of the way.

Now with head in the foot-well looking up at the dash under side (you'll need a torch). You should see a rod poking through the bulkhead, one end of the rod will be attached to the other end of the clutch pedal.
There is a small pin held in place with its own spring clip this can be popped off by hand and the pin withdrawn.

The pedal should be now be free to move back and forth, on the top and bottom of the rod hole there will be a nut, this will need undoing and once again you need your assistant to try and hold the head of the bolt. These are on the top and bottom of the cylinder and are difficult to access. Bent spanners , screwdrivers wedged in place etc are the order of the day.

With both bolts removed you should be able to withdraw the cylinder.

I would recommend tapping a thread into the new cylinder mount holes so you have a captive nut and use a spot of loctite this makes re-fitting far easier.

Otherwise re-fitting is the reverse of removal as they say

You then need to bleed the clutch, As the master has been completely removed I would suggest using a pressure bleeder such as Easibleed to prime the system and fill it with fluid.
Then to get the last bubbles out;
With bleed nipple closed pump the clutch a few times and hold it down, your assistant then quickly opens and closes the bleed. Ensure you have a pipe on the end of the nipple running to a glass container
Its important to close the nipple before its stops flowing fluid otherwise it'll draw air back down the pipe.
You should see in the container any bubbles coming out, continues until pedal feel is acceptable or you can no longer see any bubbles.
this method also works well for brakes

Matt

[FarmyardPants]

Nice write-up

Do you know if there's any adjustment for biting point on the rod? I know the pedal itself adjusts but that doesn't change how much the clutch moves, only how long your legs are (or those of said assistant).

Reason is, my new clutch bites higher up (and is very light fwiw) and I'm worried about overthrowing the fingers <- technical term

? Cheers.

[markh1]

Matt,

I cant thank you enough for that explanation its very clear and now seems a relative straight forward job.

Thanks again,

Mark

[350Matt]

FarmyardPants said:

Nice write-up

Do you know if there's any adjustment for biting point on the rod? I know the pedal itself adjusts but that doesn't change how much the clutch moves, only how long your legs are (or those of said assistant).

Reason is, my new clutch bites higher up (and is very light fwiw) and I'm worried about overthrowing the fingers <- technical term

? Cheers.

yes you can adjust the pedal in 2 places
The first one is the easy one where you unscrew the pedal
The 2nd is the end of the rod screws into a clevis ( fork with holes in the side) so you can adjust the length of the rod and so move the pedal back and forth.

I should point out that the main reason the AP clutch fails is due to the fingers being overstroked due to poor pedal adjustment.

Use the 2 adjustments to set the clutch pedal so that it just clears ( into gears with no crunching) with it jammed into the carpet.
You can also feel it reduce in effort slightly as the fingers go overcentre and release the plates, this is the point where the pedal should thump into carpet

Matt
I glued a piece of Carbon behind the carpet on mine to provide a positive stop for the pedal

[FarmyardPants]

Thanks, I suspect it's been adjusted at the rod in the past and now needs putting back. The pedal gets stiffer to push then easier again as you say.

[markh1]

Finally got round to changing it yesturday morning. It was a suprisingly easy job! and most importantly it has cured the problem completely.
I am off to a young drivers advanced driving day run by the High Performance Club this weekend so had to get it fixed for that.

Thanks again to those that posted hints and tips on how to do it.

Mark