Hydraulic disc

[rosscla]

Cheers, warts. It is definitely M7 x 1.00 though. The one I have has 16mm below the hex part and will not seal. I managed to find one on fleabay for a couple of quid that claims to be 19mm so have ordered one and will see if that sorts it.

Last resort will be to dremel down the area where the nipple goes I guess.

[rosscla]

19mm long bleed nipple seals it.

Next problem is I changed the seals and now can't get the piston back in. Drops in nicely with no seals fitted but will not go in with the seals in place...

Nothing worthwhile is easy

[warts]

Is there not a slight chamfer on the edge of the piston? If not, I would very carefully break the leading edge.
If you use a bit of clean, fresh brake fluid as lube, will it ease in?

Glad your nipples sorted, BTW.

[rosscla]

Is there not a slight chamfer on the edge of the piston? If not, I would very carefully break the leading edge.
If you use a bit of clean, fresh brake fluid as lube, will it ease in?

Nope tried that.

There is a rounding on the edge of the piston but doesn't seem to make any difference.



Always seems to get a little off straight and then there's no shifting it in either direction by hand. Have had to knock it out with a hammer and a punch.

[warts]

Did you try with the piston the bench like in your photo, then push the cylinder down onto it? Maybe with something to help alignment, chunk of wood? Or gentle application of a g cramp? (with suitable protection for the bits of course).
Double checking the seal seating for anything untoward? Could there be something adding an extra nuance of snugness?


The clearances are obviously tight, but the only thing changed is the seal, sure it's the right one? Fu cups with orders have been known!

[vintage65scoot]

Hi i had the same problem with an MB one new seals and couldnt get the piston back in got it over the first seal but wouldnt budge over the second one.Was using just brake fluid as a lubricant then resorted to red rubber grease and although tight did go in.Just make sure it is RED RUBBER grease as this does not affect seals etc good luck !!!

[rosscla]

Is exactly that , can get it past the first double lipped seal but not the second plain one.

I've ordered some red rubber grease, will give that a go.

Cheers for the responses.

[rosscla]

Ok red rubber grease didn't make any difference to attempting to fit it by hand. The problem was that whatever I did it went in coggled.

However tonight I had a bit of a brainwave -



This pushed it in straight and surprisingly little force.

Now all sorted by the look of it.



Thanks to all who offered suggestions and I hope this helps somebody else fixing one of these up.

[gaz_powell]

nice to see it all sorted

gaz

[warts]

Good job!
Nice when a plan works.