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the famous clutch master cylinder

Posted: 03 Dec 2017 16:33
by smoking joe
Long story short, changed slightly leaking master cylinder, must have been original, ran for few weekends, then returned to find clutch pedal went flat to floor.

Slave, leaked out rear, having read the items about not pulling the push rod forward , how risky/difficult is it to do without it coming forward when removing the cylinder, or should I get the mobile mechanic ?

I have attended to most of the work so far myself, been used to classic minis, we have 3, so, ok with spanners. Car 1980 DHC with 44k on clock, appears genuine.

many thanks.

SJ

Re: the famous clutch master cylinder

Posted: 03 Dec 2017 16:50
by darrellw
smoking joe wrote:Slave, leaked out rear, having read the items about not pulling the push rod forward , how risky/difficult is it to do without it coming forward when removing the cylinder, or should I get the mobile mechanic ?


The rod isn't attached to the slave, and there is a plastic clip that holds the rod to the fork. So as long as the clip isn't broken, it is unlikely that just pulling the slave cylinder out is going to be a problem. Just something to be aware of, and of course, once the slave is out, don't go tugging on the rod.

Re: the famous clutch master cylinder

Posted: 03 Dec 2017 18:05
by saabfast
Slave is not difficult at all really, once it is partly pulled out you can hold the exposed part of the rod to stop it pulling out if you want but should be fine if you so it smoothly and don't jerk it. Remember the bleed nipple goes to the upper side of the slave to vent it.
I have rebuilt both slave and master in the past. I seem to remember with the master, if working alone, I had to use some Mole grips to hold the nuts under the dash while I did up the bolts under the bonnet. The other thing to consider is the clutch pipe. The original plastic ones can go a bit soft, bulging when the pedal is pressed rather than putting all the effort into the clutch arm. I changed mine for an Aeroquip type pipe.

Re: the famous clutch master cylinder

Posted: 04 Dec 2017 15:22
by FI Spyder
Yes, if you are replacing clutch hose, replace it with braided steel hose. The replacement hoses were thicker but too soft to hold the pressure thereby useless. Don't know if that was fixed in current hoses but why take the chance.

Re: the famous clutch master cylinder

Posted: 06 Dec 2017 02:05
by UKPhilTR7
I remember when I had to turn my slave cylinder as the bleed nipple was on the lower side. I decided to take the cylinder and was concerned that the push rod may come out of the clip as I had heard that it is a pain to connect again without taking the gear box off. So when I took the cylinder off I was as slow and careful as I could be. I got to the point where I could get hold of the rod to secure it and then pull the rest of the cylinder off. This worked well and it all stayed connected. Slow and steady was the name of the game here.

Re: the famous clutch master cylinder

Posted: 13 Jan 2018 22:29
by trekcarbonboy
If you have any pressure left at all in the line, remove the slave bolts and push on the pedal. The rod will push the slave cylinder out. Then you can easily remove it without pulling the clutch fork off. If you have zero line pressure just remove the line and use air pressure.

Re: the famous clutch master cylinder

Posted: 14 Jan 2018 15:40
by FI Spyder
The slave cylinder is not connected to the push rod so when you remove the cylinder the only thing pulling on the rod is the friction of the dust cover on the rod. Carefully and smoothly removing the cylinder should prevent any sudden friction that would pull the rod free assuming the clip that holds the rod to the clutch fork isn't broken already. Putting it back in the cylinder piston is dome shaped so the rod will seek the centre spot as you push it back into place. When putting the cylinder back in make sure the bleed nipple is at the top as air rises in brake fluid (like it does in water) so it will be at the top where the bleeding takes place.

For those that have a broken clip (it's made out of nylon type material and could harden with age) you can install it (new one) without dropping the transmission but you are working blind. There are pictures on this site (if they are still there) of how to do it.

Re: the famous clutch master cylinder

Posted: 14 Jan 2018 17:48
by busheytrader
When converting to V8 back in the day, that retaining clip was very brittle.......

I found out the hard way.

Re: the famous clutch master cylinder

Posted: 14 Jan 2018 18:21
by smoking joe
OK thanks for everyone's help.

I have not be able to get to the garage for best part of 2 weeks due to this flu
that has been going around. Whilst tempted to get on with it, lying on the floor in cold garage
seemed unwise in the short term.

SJ

Re: the famous clutch master cylinder

Posted: 14 Jan 2018 20:48
by UKPhilTR7
I know where the retaining pin goes but I have also see a small square metal washer. Where does that go?

Re: the famous clutch master cylinder

Posted: 16 Jan 2018 08:24
by j.johnson23
Out of interest more than anything but is the port on the master cyl the same size as the slave?
There is such a mix and match of metric and imperial sizes I never know whats what. :?
One last thing,is there an alternative for the screw on lid,mine has corroded and a plastic one would be a bit more weather resistant.

Re: the famous clutch master cylinder

Posted: 18 Jan 2018 21:24
by busheytrader
Rimmers have a plastic lid listed as "original". https://rimmerbros.com/Item--i-500201A

IMHO, the lid's only original if it's the metal one that goes furry with age. I haven't seen a wedge with a plastic one.

Re: the famous clutch master cylinder

Posted: 24 Jan 2018 17:16
by smoking joe
Well, finally got around to sorting the clutch slave and, it went very well,
installing the new clutch hose took longer. She runs like a dream now, so thanks for
everyone's assurances.

SJ