Changing the gearbox
piston seals
I recently changed the piston
seals on my RM gearbox because there was a hissing and bubbling from the
gearbox in 1st gear.
You need the replacement
seals and three gaskets for the cylinder heads of gears 1,2&3, 4 and
reverse. Try http://www.queensbridgeltd.co.uk/
for these.
On this picture of the
underside of the gearbox you can see the cylinder head for 1st 2nd
& 3rd gears. They are different sizes, 1st, on the
right of this picture, is the largest and is on the right. First drain the
gearbox, you can see the drain plug in the bottom right of this picture. Then
disconnect the air pipes. You can see the eight nuts you need to remove to
remove the cylinder head. The pistons come out very easily, they are sprung and
pushing them in will loosen them.
Clean up the cylinder head,
pistons and springs. Remove all traces of the old gasket.
You can see the metal
circlips that hold the piston seals in place. They are easily removed by
opening them up with a screwdriver blade.
Here are the new piston seals
in place. Check the cylinders for any damage before replacing them.
Replace the cylinder head and
reconnect the air pipes. Don’t forget the replace the drain plug before
refilling the gearbox.
Please email me with any corrections and
additions to this article.