Post by swissdave on Sept 21, 2022 17:43:35 GMT
Changing a diaphragm or seal in our weirdly wonderful Variomatic transmissions can seem like a daunting task but with a couple of tricks it's not a difficult job.
I had to change a diaphragm in the primary of my 66 a while ago and thought I would put the details on a separate post here although it's on this forum already.
I sourced a used part from Danny in Holland, I think Graham may have some now as well and maybe the club but I haven't asked.
Although the workshop manual advises removing the vario to work on it I worked on mine in place on the car.
I used the "pin through the air hole" as described here by our Nick;
essexdafs.proboards.com/thread/335/46-diaphragm-change
BEFORE any part of the vario is removed it MUST be marked for position with the other components, I used white paint. If you do not pay serious attention to this point you will end up with an out of balance unit that will be horrible to drive with.
The first job is to remove the outer cover, there is a large spring clip on the outer edge of the middle bell shaped part, remove this carefully with a screwdriver and remove the bell shaped cover, you may need to tap it with a soft mallet to help it off.
.HEIC)
.HEIC)
Once the cover is off you can see the diaphragm held in place by the large rubber cup seal with a large nut inside it.
.HEIC)
There are two issues with removing this nut, first it's incredibly tight, I can't remember the torque setting but it's significant.
The second is the powerful spring behind the diaphragm which if not restrained will open up as you undo the nut and you won't be able to compress it back enough to put the nut back on afterwards, the manual suggests a special tool but of course with the vario off the car.
First issue is solved using a rope around the primary dum several times then twisted round a large hammer handle or similar to stop it turning as you undo the nut.
.WEBP)
Second problem solved by the " pin in the hole" method, if you get you fingers behind the rubber part of the diaphragm and feel about you will be able to pop a pin, or in my case, a drill bit through the air hole in the centre parts as shown. This will stop the spring moving the weight carrier out too far to get the nut back on.
.HEIC)
Once you have replaced the worn parts, reassemble, remembering to put the required amount of oil behind the diaphragm and torque up the big nut properly, the spring clip that holds the bell shaped cover in place can be a fiddle to get back on, the manual suggests using vacuum to pull the cover tightly into place but I managed with a couple of pairs of mole grips to ease the clip into place
I hope this helps someone, any questions please ask.
I had to change a diaphragm in the primary of my 66 a while ago and thought I would put the details on a separate post here although it's on this forum already.
I sourced a used part from Danny in Holland, I think Graham may have some now as well and maybe the club but I haven't asked.
Although the workshop manual advises removing the vario to work on it I worked on mine in place on the car.
I used the "pin through the air hole" as described here by our Nick;
essexdafs.proboards.com/thread/335/46-diaphragm-change
BEFORE any part of the vario is removed it MUST be marked for position with the other components, I used white paint. If you do not pay serious attention to this point you will end up with an out of balance unit that will be horrible to drive with.
The first job is to remove the outer cover, there is a large spring clip on the outer edge of the middle bell shaped part, remove this carefully with a screwdriver and remove the bell shaped cover, you may need to tap it with a soft mallet to help it off.
Once the cover is off you can see the diaphragm held in place by the large rubber cup seal with a large nut inside it.
There are two issues with removing this nut, first it's incredibly tight, I can't remember the torque setting but it's significant.
The second is the powerful spring behind the diaphragm which if not restrained will open up as you undo the nut and you won't be able to compress it back enough to put the nut back on afterwards, the manual suggests a special tool but of course with the vario off the car.
First issue is solved using a rope around the primary dum several times then twisted round a large hammer handle or similar to stop it turning as you undo the nut.
Second problem solved by the " pin in the hole" method, if you get you fingers behind the rubber part of the diaphragm and feel about you will be able to pop a pin, or in my case, a drill bit through the air hole in the centre parts as shown. This will stop the spring moving the weight carrier out too far to get the nut back on.
Once you have replaced the worn parts, reassemble, remembering to put the required amount of oil behind the diaphragm and torque up the big nut properly, the spring clip that holds the bell shaped cover in place can be a fiddle to get back on, the manual suggests using vacuum to pull the cover tightly into place but I managed with a couple of pairs of mole grips to ease the clip into place
I hope this helps someone, any questions please ask.