the B40 has been sat on a mx rising stand since it had the forks put in, must be all of 3 months now. front and back wheels dangling so I can check wheel and head bearings movement, I need to shim internals.
BUT, WHY has the drain screw now decided to leak, It hasnt since rebuild, the other side is ok, its been dry for months now all of a sudden there is a puddle on the floor, not a spot but I suspect 25ml.. WHY?? >:(
Sods Law . It shouldnt happen but low and behold it did .
I've had that happen too!
Always surprised how much can leak out of a drain screw that still appears tight!
I wonder if it's the fibre washer that gave up?
Ive started to try using aluminium or copper washers in certain places fibre washers would traditionally have been used.
Pete
Over the years what I have found that happens is that the fibre washer breaks down but the screw is usually sealed by paint from when the legs are painted. One day when you are fiddling with the legs the paint cracks and the leak starts. It happened on my Velocette and on my Shooting Star. I usually put the screws back with a small O ring under the fibre washer.
it does seem to amuse me why, Japanese bikes use aluminium washers and seal but British dont seal with fibre which is more forgivng on rougher surfaces. Its not dripping now but there must be a weep as tissue I put around is wet but not enough to drip into tray I put under.
They were new washers so shouldnt have broken down, but as said Ive not touched the front end and happened overnight in a locked unit.
I've found the trouble with O rings is that they can tear when tightening a screw.
I tend to use a new thick good fitting fibre washer with some blue hylomar on it. Then relighting a few days later when it has bedded in.
:) :) :)
For some reason only just seen this.
A couple of years ago I had the same problem and both my A50 rebuilt fork legs suddenly started leaking. Days were hot and getting hotter.
I reckon that just standing in the heat the temp inside the legs increased considerably and this caused a pressure increase. The oil would have thinned as well. The pressure had nowhere to go Couldn't go up because of the oil seal and it had to go somewhere. I would imagine the first time it happened the seals and the plugs(screws) retained the increased pressure. On the basis that eventually something had to give the bottom washer was the weakest link and the thinned oil wept past. With a washer leaking its only a short step from a weep to a leak
Whether that is what happened----don't know but I would imagine its probable. Certainly all that made any sense to me
Mike 8) 8) 8) 8)
even in the middle of summer, my unit is still around 18 degrees, this time of year I need a hoody and fleece so, definately not overheating problem which is really useful as tools dont suffer from sweating and rusting also fuel, cleaners etc dont get affected, unlike my garage hot, cold and damp. ideal for rusting
The screws are often a bit wobbly in the threads so I usually wrap some PTFE tape around to help.
BSA used a Dowty seal (68 5197) on these 2 ba screws from early 1967, having gone from fibre (part 2 292) to aluminium (Part 68 5198) first.
:) :) :) :)
What I used in the end was a leather washers cut from an old shoe and covered in Vaseline and then I put in 2BA hex Hd screws which I believe allowed me to tighten a little more than the originals.
Successful!!!
Mike 8) 8) 8) 8)