27 replies to this topic

[nicklouse]

The early one, 13H21, is the shorter one of the two (that I know of) , I'm not sure when they changed to the later 13H396.

 

I found out by accident I guess, then looked in to it.

 

I'm pretty sure the longer one can be used in place of the shorter types, but as I found out (by accident) the shorter one can't always be used in place of the longer one.

 

Just wondering if you guys that have been putting nuts under them have the shorter one?

nah tends to be worn out pivots.

[liirge]

The early one, 13H21, is the shorter one of the two (that I know of) , I'm not sure when they changed to the later 13H396.
 
I found out by accident I guess, then looked in to it.
 
I'm pretty sure the longer one can be used in place of the shorter types, but as I found out (by accident) the shorter one can't always be used in place of the longer one.
 
Just wondering if you guys that have been putting nuts under them have the shorter one?

Is this one used on the very early 850s before they used the diaphragm spring? The very early minis had a very different clutch system to the verto and pre-verto diaphragm spring type. Maybe that's when they changed them over

[tiger99]

The lever and slave cylinder were the same. If the push rod was shorter that would suggest that the clutch assembly including thrust bearing was slightly thicker. I had one of these a long time ago, with umpteen coil springs, and although the vehicle was well worn I never experienced clutch problems of the several types that we see regularly on this forum. I am wondering if when the clutch and push rod were changed, the lever would then be operating at a different angle to the original, and maybe that is non-optimal?

[liirge]

The lever and slave cylinder were the same. If the push rod was shorter that would suggest that the clutch assembly including thrust bearing was slightly thicker. I had one of these a long time ago, with umpteen coil springs, and although the vehicle was well worn I never experienced clutch problems of the several types that we see regularly on this forum. I am wondering if when the clutch and push rod were changed, the lever would then be operating at a different angle to the original, and maybe that is non-optimal?

You could be onto something here, I've seen the spring type clutch, never used one though. I think I may have some of those little springs lying around somewhere.

I have to say the Verto setup they moved to in the early 80s is quite nice, it has a good feel to it.

[Gil-galad]

My '77 pre-verto was displaying many of the symptoms of worn components so I recently decided to swap out all of the linkage and hydraulics. Due to the seeming lack of available replacement OEM clutch arms I decided to try out the aftermarket Minisport arm.

 

When I laid this arm next to the original on the workbench I noticed that it was much straighter, and the angle between the pivot ball and arm considerably different. Being that it was advertised as a direct replacement, I went ahead with the installation. Imagine my surprise when I went to set the return stop gap, and I practically pulled the push rod completely out of the slave cylinder. As it turns out, the end of the clutch arm sits nearly a full inch further from the business end of the slave cylinder.  So I ended up procuring an adjustable push rod and extending it to nearly its full length, then re-set the return and throw-out stops to their proper tolerances.

 

The good news is that the clutch now operates perfectly and with a very pleasing bite point. I plan to customize a new spring clip for the end of the clutch arm to reduce the additional tension induced on the return spring.

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Edited by Gil-galad, 25 August 2016 - 01:37 PM.

[tiger99]

Neither of these arms is the shape of the one on my old van. It was almost but not quite straight, but leaned over more towards the slave. You are on to something when you mention the alignment of the ball and arm. They are just not making these parts correctly any more! Hence lots of misery, and forum threads.

 

I think the original arm was forged, but it should be possible to replace it with a welded fabrication. Like many things on a Mini, there is an opportunity for someone to undertake small scale production of well engineered replacements.

 

There is also an opportunity for someone to develop a direct acting slave kit, as fitted to modern cars. It would need a modified wok, but the piston and cylinder would not need to be annular as there is no shaft to pass through the middle. A typical brake calliper piston would be about the right diameter to get suitable stroke and force, and if running in a bore with the same type of seal as a calliper would also be self-adjusting.

[Spider]

 

The early one, 13H21, is the shorter one of the two (that I know of) , I'm not sure when they changed to the later 13H396.
 
I found out by accident I guess, then looked in to it.
 
I'm pretty sure the longer one can be used in place of the shorter types, but as I found out (by accident) the shorter one can't always be used in place of the longer one.
 
Just wondering if you guys that have been putting nuts under them have the shorter one?

Is this one used on the very early 850s before they used the diaphragm spring? The very early minis had a very different clutch system to the verto and pre-verto diaphragm spring type. Maybe that's when they changed them over

 

 

I am not sure if this was the change over point, but I don't think so.

 

All I tend to think in regards to this change was that it was a design over-sight in the first instance. The shorter one may have well worked when all parts are as per the blue prints, but what I found was it didn't take much at all before the Piston in the Slave was doing it's level best to either push the Circlip out or shear it flush.

 

Fitting a longer or shorter pushrod won't change the angle of the arm or the overall geometry of the system, that's set by the adjustable stop and all the other parts. The shorter rod merely limits the travel before the slave runs out of travel.

[Spider]

There is also an opportunity for someone to develop a direct acting slave kit, as fitted to modern cars.

 

Already well on to that.

[Carlos W]

My '77 pre-verto was displaying many of the symptoms of worn components so I recently decided to swap out all of the linkage and hydraulics. Due to the seeming lack of available replacement OEM clutch arms I decided to try out the aftermarket Minisport arm.

 

When I laid this arm next to the original on the workbench I noticed that it was much straighter, and the angle between the pivot ball and arm considerably different. Being that it was advertised as a direct replacement, I went ahead with the installation. Imagine my surprise when I went to set the return stop gap, and I practically pulled the push rod completely out of the slave cylinder. As it turns out, the end of the clutch arm sits nearly a full inch further from the business end of the slave cylinder.  So I ended up procuring an adjustable push rod and extending it to nearly its full length, then re-set the return and throw-out stops to their proper tolerances.

 

The good news is that the clutch now operates perfectly and with a very pleasing bite point. I plan to customize a new spring clip for the end of the clutch arm to reduce the additional tension induced on the return spring.

Where did you get the adjustable push rod?

[Gil-galad]

 

My '77 pre-verto was displaying many of the symptoms of worn components so I recently decided to swap out all of the linkage and hydraulics. Due to the seeming lack of available replacement OEM clutch arms I decided to try out the aftermarket Minisport arm.

 

When I laid this arm next to the original on the workbench I noticed that it was much straighter, and the angle between the pivot ball and arm considerably different. Being that it was advertised as a direct replacement, I went ahead with the installation. Imagine my surprise when I went to set the return stop gap, and I practically pulled the push rod completely out of the slave cylinder. As it turns out, the end of the clutch arm sits nearly a full inch further from the business end of the slave cylinder.  So I ended up procuring an adjustable push rod and extending it to nearly its full length, then re-set the return and throw-out stops to their proper tolerances.

 

The good news is that the clutch now operates perfectly and with a very pleasing bite point. I plan to customize a new spring clip for the end of the clutch arm to reduce the additional tension induced on the return spring.

Where did you get the adjustable push rod?

 

 

Here's my source:  http://www.minimania...l-Slave-Pushrod

 

-

[Carlos W]

 

My '77 pre-verto was displaying many of the symptoms of worn components so I recently decided to swap out all of the linkage and hydraulics. Due to the seeming lack of available replacement OEM clutch arms I decided to try out the aftermarket Minisport arm.
 
When I laid this arm next to the original on the workbench I noticed that it was much straighter, and the angle between the pivot ball and arm considerably different. Being that it was advertised as a direct replacement, I went ahead with the installation. Imagine my surprise when I went to set the return stop gap, and I practically pulled the push rod completely out of the slave cylinder. As it turns out, the end of the clutch arm sits nearly a full inch further from the business end of the slave cylinder.  So I ended up procuring an adjustable push rod and extending it to nearly its full length, then re-set the return and throw-out stops to their proper tolerances.
 
The good news is that the clutch now operates perfectly and with a very pleasing bite point. I plan to customize a new spring clip for the end of the clutch arm to reduce the additional tension induced on the return spring.

Where did you get the adjustable push rod?
 

 
Here's my source:  http://www.minimania...l-Slave-Pushrod
 
-

Thank you

[GraemeC]

Some repro slave cylinders don't help.
I replaced a leaking slave with one from my local motor factors - clutch originally worked fine other than slight weep but new slave hits circlip before full disengagement (and stops pedal hitting floor)

[tiger99]

That is a clear indication that the push rod is too short, and nothing to do with the quality of the slave cylinder.