Myford Super 7 mk2 clutch

[ken frewinParticipant @kenfrewin10473]

Hi, Can anybody help with the dismantling procedure for the S7 mk2 clutch. mine works ok but sometimes it makes I can only describe as a low grumble, I want to replace all the bearings but cannot find any information on which way to proceed. any info would be appreciated.

[ken frewinParticipant @kenfrewin10473]

Low grumble sometimes.

[DMRParticipant @dmr]

Search for "Clutch" and you will find lots of previous Myford info. Not a job to be taken on lightly as the long internal spring needs a lot of compressing, but there are ways people have worked out.

[ken frewinParticipant @kenfrewin10473]

Hi DMR, Thanks for reply I have trawled the forum several times but no real information on taken it apart, just which end to start on would be helpful, I can't believe no one on the forum has tackled this job successfully. Regards Ken.

[Alan Wood 4Participant @alanwood4]

Would be interested in any result on this as my S7 constantly needs both oil pots topping up suggesting I need to do something with the bushes.

[Michael GilliganParticipant @michaelgilligan61133]

Ken,

Try using the dedicated search box on the home-page, entering the term

myford clutch

MichaelG.

.

It then does a site-specific Google search:

https://www.google.co.uk/search?q=myford+clutch+site:model-engineer.co.uk

Edited By Michael Gilligan on 13/02/2017 10:05:47

[Mike PooleParticipant @mikepoole82104]

There are two lots of bearings in an S7 clutch, the pulley containing the bronze clutch plate has two ball races and the main shaft has two plain bronze bearings. If the clutch rumbles while it is disengaged then the ball races need attention but if it rumbles while the clutch is engaged then maybe the plain bushes are loose but it would be odd for them to cause a rumble I would have thought. Are the belts in good condition? And are all the pulley grub screws tight and woodruff keys in good condition? There is a thrust race in the clutch end main shaft bearing housing, are the circlips that locate the main shaft in their grooves?

The clutch can be removed as an assembly by removing the grub screw from the multi v pulley, check there are not two in the hole, this should let the multi pulley slide along the main shaft, remove the circlip adjacent to the thrust bearing, it will slide along the shaft, you should be able to expose the woodruff key for the multi v pulley and remove it with pliers. The whole clutch and main shaft can now be withdrawn and a small spring and ball bearing will escape from the push rod end of the shaft, it may be found in the operating lever housing or fall out while the shaft is being withdrawn, look out for it. Shaft and bush wear can be assessed at this point and the condition of the thrust bearing.

To dismantle the clutch further you will need to compress the spring and be able to unscrew the driving key from the centre of the clutch which will just leave the pulley and bearings on the shaft which will need to be pressed out by whatever means you have.

It may not be necessary to totally dismantle the clutch depending on what you find, the pulley bearings can be given an inspection by disengaging the clutch and removing the belt, if it spins smoothly it may be ok but sometimes things only really show up when under belt tension and loaded.

Reassembly is straightforward as long as you put all the bits back on the shaft in the right order, don't forget the circlip, the ball and Spring will probably require the help,of some thick grease and bad language but it can be done. If the clutch lever is removed I would replace it before the main shaft as I would say it is impossible to fit the ball and Spring and then the lever. Before taking anything apart I would try and pin down the rumble, dropping off the belts might narrow it down. Run the motor on its own then add the first belt and try the clutch in and out then the second belt and clutch in and out, this might build a picture of where the trouble lays. The manual has a sectional view of the clutch and is worth studying in conjunction with your machine to see how it works.

Mike

Edited By Mike Poole on 13/02/2017 17:02:00

[Nigel BennettParticipant @nigelbennett69913]

Get a really good pair of bent circlip pliers for the job. It's a beast to remove the circlip if they aren't just so.

[ken frewinParticipant @kenfrewin10473]

Hi Mike, Great just the information I was looking for, Its given me a lot of confidence to tackle this job, I was beginning to think no one had tackled this before, and thanks to Nigel for the circle pliers tip. I shall be away for a while,I will post when I have completed the job or not !. Regards Ken.

[Mike PooleParticipant @mikepoole82104]

I note that I described the plain bushes for the main shaft as bronze, they are actually Oilite which is a sintered porous material that will absorb oil to provide continuous lubrication, they are pre sized and must not be scraped or reamed as this will compromise the porous nature of the bush and will not allow oil to pass through and lubricate the shaft.

Mike

[SandgrounderParticipant @sandgrounder]

Hi Mike,

That's great, I don't need to do mine, but I've copied and filed your instructions away in case I have to in the future.

John

[ken frewinParticipant @kenfrewin10473]

Hi, I tackled the job as per instructions, easy to do if you follow instructions , oilite bushes were fine no wear at all I just replaced the thrust bearing not that I could see any sort of wear, replaced all the parts and it runs great no more rumbles. thanks to all who replied to my call for help. Regards Ken.

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