We are doing the seat assy at the moment and though this infomation might help some fellow restorers .
This included the Messinger seat cushions.
The original seat fitted to our 1925 Invincible Jap was a Messinger No 1 Air Cushion. While this is serviceable it was decided to uspsize this for well, comfort and support for yours.
The air cushions are one area that is often neglected and it was no surprise when we had pulled ours apart that we could find no support amongst the Harley or Indian restorers.
Infact many had not actually taken one apart, or if they had rebuilt them they had fitted modern o'rings and new pistons.
I thought it would be a simple task to buy new seals and fit.
These turned out to be not available, and after several questions to notable leather workers it was found that the seals are made from a unique tanning process to the more common vegetable tanning.
Hence it was not feasible to make them out of the wrong material.
Our search ended up at the leather warehouse and boy this was like a lolly shop to me.
So many goodies, decorative gadgets and leather tools and devices.
They advised that they specially ordered this material in for one customer who still made them for there old lights.
They were happy to pass on the detials.
Well, a trip down to the local lamp shop was an experience and step back in time.
They speciallised in oil lights going back to 1800's and were really an aladins den and for $25.00 Dollars we came out with the last of their stock of four (4) leather washers and a wealth of knowledge.
They explained that there are two different washers used in these plungers, one being the primary seal and the other being the secondary seal.
Depending on which way you place these leathers the cushion works in either the up stroke, or the down stroke.
The suggested that they would only work one way, and boy were they right.
We dissembled the cushions and cleaned everything up to spec.
New leather was fitted and the seals were placed in a small tub of oil fro 48 Hrs prior to refitting.
The cushion is yet to be re-assembled, but will have a small amount of grease fitted inside the canister prior to assembly.
After some discussion we decided to install ours to work on the down stroke, as this is what we are trying to cushion.
It if doenst work out we will pull these out and turn them 180 Degree's as it not a big task.
A good friend Ben B helped out on this, as he was interested in how they work for his own excelsior projects.
We both we surprised at the effect that these actually have, and how well they actually work.
I would recommend anyone else doing this to source the leather washers prior to pulling the assembly apart.
Hope this helps someone.