General MG Clutch master/slave cylinder questions - Midget 1500

[thefunkaygibbon]

I have replaced both the master and slave cylinder for the clutch on my Midget 1500, but the clutch was still not disengaging. When I bled it I used the pressure bleeding system you connect to a tyre on the master and a one way valve on the slave. This bled very nicely.

Before I took the pressure bleeder off the master, I put the car in gear and it rolled, but the same does not happen when I take the bleeder off.

My assumption is that there is some internal leak in the master, but I wanted to check my working:

If there was an issue with the slave, or alignment of the push rod onto the clutch release, this would not work, right?

 

[JPSmit]

Hey there, bleeding a 1500 clutch can be really annoying. It is unlikely that there is an internal leak, that said.

1. Did you replace the clutch line as well? A few years ago I replaced mine and spent an entire summer trying to get a solid clutch only to discover that the line ends weren't seating properly. Increasingly new parts aren't reliable because they are jobbed out to the lowest builder. I ended up going back to my original ends and finding a new hose to use from a hydraulic shop.

2. It is remarkably easy to get an air bubble in the slave cylinder. As well the clutch line curve is higher than the master cylinder. What I have discovered over time is that the easiest way to bleed the clutch is from the master cylinder. Remove it from the car (annoying but it gets quicker - don't ask me how I know ) and hold it carefully higher than the hose. Pump the pushrod until it gets hard. I put a screwdriver through the holes and wear a heavy glove.

reinstall and you should be good.

good luck!

Oh and check the clevis pins for wear if you haven't already.

 

[maynard]

On my brother's midget I was able to successfully reverse bleed the system. Pumped the fluid from the slave into the master.

 

[thefunkaygibbon]

The bleeding seemed to go well, and as I say, with the pressure bleeding system attached and in gear, the car could roll, suggesting the clutch was disengaged. (as if the pedal was pressed)

Hey there, bleeding a 1500 clutch can be really annoying. It is unlikely that there is an internal leak, that said.

1. Did you replace the clutch line as well? A few years ago I replaced mine and spent an entire summer trying to get a solid clutch only to discover that the line ends weren't seating properly. Increasingly new parts aren't reliable because they are jobbed out to the lowest builder. I ended up going back to my original ends and finding a new hose to use from a hydraulic shop.

2. It is remarkably easy to get an air bubble in the slave cylinder. As well the clutch line curve is higher than the master cylinder. What I have discovered over time is that the easiest way to bleed the clutch is from the master cylinder. Remove it from the car (annoying but it gets quicker - don't ask me how I know ) and hold it carefully higher than the hose. Pump the pushrod until it gets hard. I put a screwdriver through the holes and wear a heavy glove.

reinstall and you should be good.

good luck!

Oh and check the clevis pins for wear if you haven't already.

I did not change the line, that is in good condition. Under pressure there are no leaks.

I cannot bleed with the master detached, on my Midget, a 1500 with the Triumph engine, there is a hole cutout for the master cylinder, not a slot. That means I will need to remove the clutch line as well, meaning another rebleed

 

[YakkoWarner]

I struggled for days to get a decent clutch pedal on my MGB. What ended up working for me (and I'm pretty sure the system is basically the same on the Midget) was to remove the slave cylinder from the transmission (2 easiily accessible bolts and a clevis pin - MUCH easier to do than removing the master!) and let it hang from the hose (its light enough to not damage the hose, unlike a brake caliper). In that position the bleeder tip was pointing straight up, and opening the bleeder allowed it to gravity bleed completely. When I did this I could hear the air bubbles coming out even after 2 days of forward and reverse bleeding using other techiques. Once it stopped bubbling I let about half the capacity of the master flow out thru the open bleeder at the bottom to be sure (monitor that closely, that master holds very little so topping up while gravity bleeding is important) I closed the bleeder, remounted the slave on the transmission and had perfect pedal. Gravity bleeding with the slave installed on the transmission did not work, it had to be hanging with the bleeder pointing straight up to get that last bit of air out.

 

[thefunkaygibbon]

I struggled for days to get a decent clutch pedal on my MGB. What ended up working for me (and I'm pretty sure the system is basically the same on the Midget) was to remove the slave cylinder from the transmission (2 easiily accessible bolts and a clevis pin - MUCH easier to do than removing the master!) and let it hang from the hose (its light enough to not damage the hose, unlike a brake caliper). In that position the bleeder tip was pointing straight up, and opening the bleeder allowed it to gravity bleed completely. When I did this I could hear the air bubbles coming out even after 2 days of forward and reverse bleeding using other techiques. Once it stopped bubbling I let about half the capacity of the master flow out thru the open bleeder at the bottom to be sure (monitor that closely, that master holds very little so topping up while gravity bleeding is important) I closed the bleeder, remounted the slave on the transmission and had perfect pedal. Gravity bleeding with the slave installed on the transmission did not work, it had to be hanging with the bleeder pointing straight up to get that last bit of air out.

So the 1275 midget has that slave setup, but the 1500 has a single retention bolt that is difficult to remove.

My question was mainly because I don't want to remove it again, the master cylinder is a cinch to remove.

Looks like I'm getting under the car this weekend

 

[JPSmit]

The bleeding seemed to go well, and as I say, with the pressure bleeding system attached and in gear, the car could roll, suggesting the clutch was disengaged. (as if the pedal was pressed)


I did not change the line, that is in good condition. Under pressure there are no leaks.

I cannot bleed with the master detached, on my Midget, a 1500 with the Triumph engine, there is a hole cutout for the master cylinder, not a slot. That means I will need to remove the clutch line as well, meaning another rebleed

I have the same - 1500 (Big Block ) and when I suggested bleeding with the MC detached - I meant from the car not the hose. So as per your next post - the MC is easy to remove - remove it - keeping the hose attached and bleed it from the top by pumping the pushrod gently. I don't think you need to go under it at all.

(Sorry I wasn't clearer)

 

[thefunkaygibbon]

Ah, gotcha! Let's see what happens on the weekend then