problem refitting clutch slave cylinder

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Re: problem refitting clutch slave cylinder

Post by Bob46320 »

If no fluid comes out with the slave cylinder bleed screen slackened off (Assume the hole in the nipple is not blocked), then suspect the master cylinder piston is not returning to the "home" position. Remove the tube from the top of the cylinder, and place a 2mm diameter rod into the hole. You can determine if the piston is at the top of its stroke - if it is, gently push the rod in to push the piston to the bottom of its stroke as it may have got stuck. (It may be time to replace the master cylinder seals ??).
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Re: problem refitting clutch slave cylinder

Post by Crack Pot »

Exminiman wrote: Sat Nov 23, 2024 8:30 pm Sorry to sound pedantic, but can you describe how you are bleeding the system ie are you pumping the pedal etc…
No I just hold the pedal down, unscrew the bleed valve and nothing happens
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Re: problem refitting clutch slave cylinder

Post by Exminiman »

Crack Pot wrote: Sat Nov 23, 2024 11:25 pm
Exminiman wrote: Sat Nov 23, 2024 8:30 pm Sorry to sound pedantic, but can you describe how you are bleeding the system ie are you pumping the pedal etc…
No I just hold the pedal down, unscrew the bleed valve and nothing happens
You need to be pumping the pedal with the bleed screw open until fluid comes out. Unless you have some sort of non return valve type thing on the bleed nipple this is a job for two people as while one pumps the other has to close the bleed nipple.

This is why earlier I suggested you buy an eezibleed, this uses tyre pressure to push the fluid through.

However, first, if you open the valve and pump the pedal, you should be able to pump fluid through, if not then it’s the master cylinder seals that need replacing.
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Re: problem refitting clutch slave cylinder

Post by AndyPen »

Do you have anyone with a little more experience able to help you with this? Doing it on your own is OK if you have the correct tools, for example a bleed pipe like this helps to avoid drawing air back in.

https://www.ebay.co.uk/itm/391971960746 ... K7EALw_wcB

It is so much easier with two people though, and the person in the engine bay can keep the fluid topped up as you pump it out too.
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Re: problem refitting clutch slave cylinder

Post by Crack Pot »

Exminiman wrote: Sun Nov 24, 2024 8:05 am
Crack Pot wrote: Sat Nov 23, 2024 11:25 pm
Exminiman wrote: Sat Nov 23, 2024 8:30 pm Sorry to sound pedantic, but can you describe how you are bleeding the system ie are you pumping the pedal etc…
No I just hold the pedal down, unscrew the bleed valve and nothing happens
You need to be pumping the pedal with the bleed screw open until fluid comes out. Unless you have some sort of non return valve type thing on the bleed nipple this is a job for two people as while one pumps the other has to close the bleed nipple.

This is why earlier I suggested you buy an eezibleed, this uses tyre pressure to push the fluid through.

However, first, if you open the valve and pump the pedal, you should be able to pump fluid through, if not then it’s the master cylinder seals that need replacing.
So your saying that the pedal needs to be pumped rather then you just pressed down on it while the bleed nipple is open for this to work right?
Austin Metro MK1 1982 1.3L (same engine and box as the mini)
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Re: problem refitting clutch slave cylinder

Post by Crack Pot »

AndyPen wrote: Sun Nov 24, 2024 10:03 am Do you have anyone with a little more experience able to help you with this? Doing it on your own is OK if you have the correct tools, for example a bleed pipe like this helps to avoid drawing air back in.

https://www.ebay.co.uk/itm/391971960746 ... K7EALw_wcB

It is so much easier with two people though, and the person in the engine bay can keep the fluid topped up as you pump it out too.
I know Daz with the garage down the bottom of the street, but he has be ill of late so dont see much of him
I think you need a one way valve along with the pipe. At a guess at the moment I would say the bleed nipple tail end bard is about 3/8". Buying a bit of pipe to slide onto it should be an easy find. Infact I am sure a couple of meters of 8mm fuel pipe should do the job
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Re: problem refitting clutch slave cylinder

Post by Exminiman »

Crack Pot wrote: Sun Nov 24, 2024 8:20 pm
Exminiman wrote: Sun Nov 24, 2024 8:05 am
Crack Pot wrote: Sat Nov 23, 2024 11:25 pm
No I just hold the pedal down, unscrew the bleed valve and nothing happens
You need to be pumping the pedal with the bleed screw open until fluid comes out. Unless you have some sort of non return valve type thing on the bleed nipple this is a job for two people as while one pumps the other has to close the bleed nipple.

This is why earlier I suggested you buy an eezibleed, this uses tyre pressure to push the fluid through.

However, first, if you open the valve and pump the pedal, you should be able to pump fluid through, if not then it’s the master cylinder seals that need replacing.
So your saying that the pedal needs to be pumped rather then you just pressed down on it while the bleed nipple is open for this to work right?
Yes, so really a two person job unless you have an Eezibleed
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Re: problem refitting clutch slave cylinder

Post by Crack Pot »

Exminiman wrote: Sun Nov 24, 2024 8:41 pm
Yes, so really a two person job unless you have an Eezibleed
I undone the bleed nipple put a rag over to (to monitor fluid). Got into the car and pump the clutch several times and the pressure came back. Tightened the bleed nipple. then stated the car up (Started first time this time). It now goes into gear; but not well! I man is slightly stiff in 1st and 2nd and reverse kind of crunches. So I guess its part fixed now but will need something ells doing to it, what ever that be? I short drive out in it tomorrow might be a good idea to see if the problem get better or worse

Thanks

From a closer inspection, it looks like the MCC and the SCC are not engine driven. So it can only be the work of the clutch pedal creating the hydraulic pressure I guess. It would appear that the fluid is gravity feed from the MCC to the SCC for it to work (with no return pipe) However there is a siphon effect as the pipe leaves the MCC it come out of the top and goes up a few inches before going down. Not a good design or idea I must add!!!
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Re: problem refitting clutch slave cylinder

Post by AndyPen »

To get the best results if you don't have the kind of bleed tube I suggested, at each pump start the bleed nipple should be opened, and closed with the pedal held to the floor, then repeat. This is why you can't do it yourself without the correct tube - you need someone to pump from inside and someone to instruct as to when to pump / hold the pedal down when you loosen / retighten the bleed nipple.

It sounds as if you left the bleed nipple open and went around to it after pumping? In this case, air will get back in. So you have some improvement, but unless you do as above you'll not get a good pedal yet.
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Re: problem refitting clutch slave cylinder

Post by mab01uk »

As others have said you need a second person to hold the clutch pedal down while you tighten up/close the clutch slave bleed valve...otherwise as soon as the pedal is released with the bleed valve open some air will get sucked back in the system. Also make sure the master cylinder fluid level does not drop too low as that will also allow air to get in from that end.
It sounds like so far you have got some of the air out but not enough to give a good clutch pedal action to fully disengage the clutch, which will make getting gears stiff with crunching sounds.
An Eezibleed is the only way to make bleeding a one person job without getting air in the hydraulic system as it has a one way valve built in.

(Note: As you have found out the clutch hydraulics are only worked by your foot on the clutch pedal and are not affected by the engine running, as unlike hydraulic power steering there is no engine driven pump).
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Re: problem refitting clutch slave cylinder

Post by Crack Pot »

As the CSC is gravity feed from the CMC and with no return pipe, then it would make sence that air could easy be trapped in side of it

I did however put my woodan stick between the pedal and the seat so as to keep the pedal pushed down, then I bleed it and tightened the bleed nipple up again, then took the woodern stick away realising the clutch. But its still stiff and cranks in reverse
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Re: problem refitting clutch slave cylinder

Post by Tim »

Its not gravity fed, but yes air bubbles can get trapped inside it. You have to pump them through by repeatedly pumping the pedal, but you must tighten the bleed nipple between each stroke of the pedal, otherwise it will suck air back in when you let the pedal out. Also, make sure that there is a enough fluid in the reservoir of the master cylinder or you will pump it all out, air will get pushed through, and you will have to start at the beginning again.

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