Safe Fork Seal Replacement
Posted: Thu May 14, 2009 12:26 am
This is a safe and easy way of finishing off a fork seal change. Please read it in conjunction with Diesels fork rebuild in the workshop on the main site and masterofinsanity’s picture post on viewtopic.php?f=55&t=6035&p=47091&hilit ... vel#p47091
As the man said this aint no 5 minute job but here is a home made tool that makes the task a whole lot easier. The problem is that when you get to the bit where Diesel says “put the allen bolt back in the bottom to hold the internals together and stop oil leaking out of the bottom.†You need to compress the fork spring which may require 50% of the force you would need to bottom the forks out braking from 130mph with the back wheel hovering in the air. That is a very heavy friend.
So in Blue Peter style this is what you will need:
6mm Hex key
2 tie down straps ratchet variety.
2 M8 eye bolts – made by dismantling a pair of M8 anchor bolts
1 piece of hardwood approx 15mm thick x 200mm long x 80mm wide.
Cut a 28mm hole in the centre
File 25m wide guides for the straps either side of the hole. About 100mm gap between them.
The task – The hex bolt with its copper gasket washer has to be screwed into the bottom of the fork internals.
Put it together.
Screw down the fork cap. Carefull not to pinch the O ring.
Now we will use the parts we collected to compress the fork almost the full distance of the exposed chrome. Insert one eye bolt into each side of the bottom of the fork. Put the hex bolt and gasket into the bottom of the fork first as the eye bolt stops you doing this later on one of the forks.
Pass the tie down straps through the eyes.
And round the wooden block placed over the fork cap.
Here is a second view of the straps and wooden block.
The exiting bit is how easy it is to compress the fork with the ratchet tie downs.
With the fork fully compressed, screw in the hex bolt using some non permanent loc tite.
And dismantle the contraption.
Then remove the end cap and fill with 424cc oil.
Thats it, celebrate.
Take care the cup washer on the bottom of the spring inside does not drop off as it can stop the compression and you will need to start again. To prevent this try to keep the whole thing up-right untill the compression is done and you have got the screw in.
As the man said this aint no 5 minute job but here is a home made tool that makes the task a whole lot easier. The problem is that when you get to the bit where Diesel says “put the allen bolt back in the bottom to hold the internals together and stop oil leaking out of the bottom.†You need to compress the fork spring which may require 50% of the force you would need to bottom the forks out braking from 130mph with the back wheel hovering in the air. That is a very heavy friend.
So in Blue Peter style this is what you will need:
6mm Hex key
2 tie down straps ratchet variety.
2 M8 eye bolts – made by dismantling a pair of M8 anchor bolts
1 piece of hardwood approx 15mm thick x 200mm long x 80mm wide.
Cut a 28mm hole in the centre
File 25m wide guides for the straps either side of the hole. About 100mm gap between them.
The task – The hex bolt with its copper gasket washer has to be screwed into the bottom of the fork internals.
Put it together.
Screw down the fork cap. Carefull not to pinch the O ring.
Now we will use the parts we collected to compress the fork almost the full distance of the exposed chrome. Insert one eye bolt into each side of the bottom of the fork. Put the hex bolt and gasket into the bottom of the fork first as the eye bolt stops you doing this later on one of the forks.
Pass the tie down straps through the eyes.
And round the wooden block placed over the fork cap.
Here is a second view of the straps and wooden block.
The exiting bit is how easy it is to compress the fork with the ratchet tie downs.
With the fork fully compressed, screw in the hex bolt using some non permanent loc tite.
And dismantle the contraption.
Then remove the end cap and fill with 424cc oil.
Thats it, celebrate.
Take care the cup washer on the bottom of the spring inside does not drop off as it can stop the compression and you will need to start again. To prevent this try to keep the whole thing up-right untill the compression is done and you have got the screw in.