ausmini
https://www.ausmini.com/forums/

Clutch slave cylinder spring attachment
https://www.ausmini.com/forums/viewtopic.php?f=2&t=102548
Page 1 of 1

Author:  Chaz [ Mon Jun 02, 2025 4:41 pm ]
Post subject:  Clutch slave cylinder spring attachment

Hi all
First time replacing the (preverto) clutch slave cylinder on my 76 mini. Everything went ok except
for fitting the new spring (old one flew off into the wilderness of my garage) to the lever arm. It’s the right spring as I bought it from a popular mini parts supplier but I can’t stretch it far enough to clip it on.
Help!

Author:  Barkfast [ Mon Jun 02, 2025 4:57 pm ]
Post subject:  Re: Clutch slave cylinder spring attachment

Mine was a pain to put on too. I found a trampoline spring puller works a treat

Author:  1071 S [ Mon Jun 02, 2025 5:17 pm ]
Post subject:  Re: Clutch slave cylinder spring attachment

Springs are obviously far too strong.... All you need is something to stop the release bearing from bouncing against the pressure plate. You should be able to attach it with a light pull using your index finger...

I haven't actually used one for years... makes the clutch self adjusting.

Cheers, Ian

Author:  drmini in aust [ Mon Jun 02, 2025 5:41 pm ]
Post subject:  Re: Clutch slave cylinder spring attachment

Grab it with vice grips.
@Ian,
I ran with no spring for a while but it's back on so I can adjust the take up point. It was too high like a Corolla. :mrgreen:

Author:  Bill B [ Tue Jun 03, 2025 3:56 pm ]
Post subject:  Re: Clutch slave cylinder spring attachment

An experience we have all had....
I have extended the links holding the spring. Anything will do.

Attachment:
Clutch lever return spring.jpg


The brake booster was added just to increase degree of difficulty.

Author:  winabbey [ Tue Jun 03, 2025 5:28 pm ]
Post subject:  Re: Clutch slave cylinder spring attachment

The spring is part 1G5999.

A Google search shows lots of Mini parts places selling a spring under that part number. I wonder if the spring dimensions and specification are the same across all suppliers? Perhaps some are shorter/longer or stronger/weaker than the factory spring?

I see Minispares show it as being 90mm in total length.

Author:  eightfifty [ Tue Jun 03, 2025 7:36 pm ]
Post subject:  Re: Clutch slave cylinder spring attachment

1G5999 return spring is used on all model Mini and Moke with the traditional clutch and has a free end-to-end length of 3 3/8" which is 86 mm. The Minispares one seems to be about right in proportions. The spring has to be strong enough to push the slave cylinder piston back down its bore against the light spring inside. If you are having trouble, then the chances are that your pushrod is too long. In many cases, owners have put in longer pushrods, or lengthened their existing pushrod, in the belief that this will restore pedal. If it is too long, then the lever arm will be stuck way out to the left with the slave cylinder piston bottomed out against the back and so the spring has to be stretched too far to fit. Bill's car has other problems - probably worn ball end or bent lever. Regards, Tony

- edit., Actually now that I think about it some more, your lever arm may also have these problems and so when the adjustment bolt and locknut are set at the correct clearance, the lever is too far out to the left. Might pay both of you to remove the lever arm and check the ball end. I've seen some cracked away a little not to mention well worn at the contacting surface. As a further thought, you could also check that the throwout plunger has been installed the right way up (with the taper in the hole on the top side). And as a further point of interest, this spring dates from 1947.

Author:  Bill B [ Tue Jun 03, 2025 9:06 pm ]
Post subject:  Re: Clutch slave cylinder spring attachment

Thanks for your comments Tony.

The car in the photo has only done 100 miles since its rebuild. The lever is a used one but not bent and with the ball end built up by weld and reshaped.

In fact this clutch adjustment issue has been covered before here in Ausmini, with many stories of owners bending the lever, renewing the throw-out carrier, welding the ball end or lengthing the pushrod.

Perhaps some of the issues come down to the difference in height between the running surface of the backing plate (where the driven plate seats) and the height of the 3 horns that attach to the diaphragm - as when you get a scored backing plate milled and the horns have to be machined to match.
Still thinking about it.

Author:  eightfifty [ Wed Jun 04, 2025 7:37 am ]
Post subject:  Re: Clutch slave cylinder spring attachment

Bill, I see what you mean. If the pillars/posts/horns were not machined in sympathy with the face, would not the problem be in the other direction? If that pushrod in your photo were such that the green paint was at the edge of the rubber boot it would look much better. Perhaps the clutch friction plate is too thick? Maybe flywheel not sitting in the right place for some reason (thrust washers? taper?) Release bearing too thin? thrust plate in the middle of the spring unit installed the wrong way around or the wrong one (the one with the self aligning bearing is different to the fixed bearing)? With the lever all that way to the left, you probably don't have much clearance at the tapered end of the hole in the plunger.

Author:  drmini in aust [ Wed Jun 04, 2025 7:40 am ]
Post subject:  Re: Clutch slave cylinder spring attachment

Also if you fit the flat release bearing (designed for the old coil spring clutch) with a diaphragm clutch, this bearing is thinner than the later one.
I put a flat washer behind it.

Edit
Re the throw out plunger, clutch feel on release is much better if the ball hasn't worn a groove into its bore.
New plungers are not nearly as hard as originals, I have put a hardened steel bush into them. :mrgreen:

Author:  eightfifty [ Wed Jun 04, 2025 8:16 am ]
Post subject:  Re: Clutch slave cylinder spring attachment

A good suggestion from Kevin. I have calculated (from the dimensions of the parts) that replacing the original flat face bearing with the narrow face bearing makes a difference of just on 9 mm at the top end of the clutch lever arm. Not enough to give relief to Bill, but a significant amount never-the-less. Perhaps a combination of issues are happening here.

Author:  TK [ Wed Jun 04, 2025 3:40 pm ]
Post subject:  Re: Clutch slave cylinder spring attachment

Easy to fit with a big flat screw driver with a nick in the middle of the blade. I also use it for the seat diaphragms.

Author:  Bill B [ Wed Jun 04, 2025 9:56 pm ]
Post subject:  Re: Clutch slave cylinder spring attachment

For the rebuild on this motor, I had the clutch pressure plate machined to have the diaphragm spring sitting close to being flat to give the best spring tension. This involved having an extra small amount taken off the 3 horns.
When the clutch was assembled, this meant the diaphragm housing and pressure plate now sat towards the centre of the car, away from the clutch throw-out bearing end and requiring the clutch lever to be adjusted further away before the throw-out bearing contacts the diaphragm to disengage the clutch.

If the above is the case, Drmini's solution to fit a spacer behind the throw-out bearing will remove the need to fit a longer pushrod to work the clutch.

(Apologies to Chaz for hijacking his post. But the workings of clutches can be a mystery.)

Author:  kirby [ Thu Jun 05, 2025 8:03 pm ]
Post subject:  Re: Clutch slave cylinder spring attachment

This might explain why an odd lever in my parts bin has a dogs leg kink at the spring end.
It could only have been done on purpose... with any oxy. Or some horrible mode of failure.

Author:  drmini in aust [ Thu Jun 05, 2025 9:59 pm ]
Post subject:  Re: Clutch slave cylinder spring attachment

kirby wrote:
This might explain why an odd lever in my parts bin has a dogs leg kink at the spring end.
It could only have been done on purpose... with any oxy. Or some horrible mode of failure.


That's what's in mine now. A less common mod. I have oxy but didn't do it. :mrgreen:
This box was in a wrecked Clubman GT before I transplanted it into the wasaMatic.

Page 1 of 1 All times are UTC + 10 hours
Powered by phpBB® Forum Software © phpBB Group
http://www.phpbb.com/