Paging Lozzo

When you rebuilt those calipers, did you replace the O-rings between the
caliper halves?

I'm guessing you probably did, but if not I'll put new ones in to see if
it cures the air leak.

 

Eddie says...

I did. They had a complete new set of seals all round - cost me a small
fucking fortune they did.

Might be worth a go.

--
Lozzo
Triumph Daytona 955i SE (Black with added black bits)
Suzuki GSX-R750L trackbike (Shite with added shite bits)
Yamaha SR250 Delusion (It's "Special")
I ride way too fast to worry about cholestorol.

 

I thought you had, but I wanted to make sure.

I'll bet.

I'll try new O-rings, nipples and copper washers. I can't think of any
other possibilities.

 

The master cylinder?

 

Hah!

Been there, done that, no difference whatsoever.

 

Thing about this concept of air being drawn in is that's it's difficult to
imagine fluid under pressure not coming out. Some kind of diffusion perhaps,
I dunno, had the same problem though. New seals, new lines, new fluid, it
still kept getting spongy. I sold the fucker.

Gas diffusion through micro cracks in the caliper material or somesuch
perhaps. I've worked with the situation where hot sodium ions could progress
through micro cracks in weld areas but nothing moved through from the steam
side.

 

My favourite major industrial disaster waiting to happen....

 

I'm guessing that when there's pressure against the seals (e.g. braking,
or with the lever tied back to the bar overnight), they deform
sufficiently to prevent fluid escaping.

When there's no significant pressure, the gaps are small enough the
surface tension (maybe) keeps the fluid in place, but allows the fluid
to absorb air from the atmosphere... perhaps.

When I try bleeding the right-hand caliper, I get a line of very small
bubbles, however much fluid I pass through the system; I assume it's
getting drawn in wherever the leak is, but I can't think of a way of
determining where that point is.

I'm fairly confident that it's something in the calipers, as the rest of
the system was fine with my original calipers.

It's much more likely to be a dodgy O-ring or nipple, I'd have thought.

 

Umm in France only, not in the UK

 

Great. I live in France.

 

Whereabouts?

Oh, and it'd be really useful if you could change your posting name
ever-so-slightly.
--
_______
..'_/_|_\_'. Ace (brucedotrogers a.t rochedotcom)
\`\ | /`/ GSX-R1000K3 (slightly broken, currently missing)
`\\ | //' BOTAFOT#3, SbS#2, UKRMMA#13, DFV#8, SKA#2, IBB#10
`\|/`
`

 

Above Onnion, which is above St Jeoire, which is on the way to Samoens.

You must have been out of the room when we discussed this before. There is
no possible risk of me being confused with any Jeremy who knows anything
about bikes. Or computers. Or wildlife[1].

Oh alright, I've done it once today already ... just this one post, mind.

[1] This reminds me - Jeremy, I don't think you told us what became of the
deer.

 

Well well. I drive past your door a few times each ski season - just
the once this year, as it happens, due to injury. At busy periods I
always prefer to use the Vallée Verte rather than the motorway.

Sure, but it's nice to be able to see from the posting name whether
it's likely to be something worth reading...

--
_______
..'_/_|_\_'. Ace (brucedotrogers a.t rochedotcom)
\`\ | /`/ GSX-R1000K3 (slightly broken, currently missing)
`\\ | //' BOTAFOT#3, SbS#2, UKRMMA#13, DFV#8, SKA#2, IBB#10
`\|/`
`

 

I thought you'd know the area. Maybe we should meet up next season.

My commute. Well, that or the surrounding lanes.

 

message

"Red rubbery stuff"? That narrows it down. Some kind of brake caliper
grease, I guess, rather than instant gasket...

My brake caliper grease isn't red and certainly isn't rubbery; it's more
like normal grease, but kind of translucent white in colour. I'm not
sure that it would help, but I suppose I could give it a try.

The calipers are no longer wearing the nipples that Lozzo supplied;
there is no trace of anything red or rubbery.

 

Nidge says...

I do remember giving the one sachet I had away. It came with a set of
genuine Yamaha seals I got. I've no idea if it's sold seperately.

--
Lozzo
Triumph Daytona 955i SE (Black with added black bits)
Suzuki GSX-R750L trackbike (Shite with added shite bits)
Yamaha SR250 Delusion (It's "Special")
I ride way too fast to worry about cholestorol.

 

In any case, if it's the nipple threads that're suspect, a drop or
three of Threadlock will sort it out, as well as making sure the
nipples a)don't come loose and b) are easy to slacken off next time.
--
_______
..'_/_|_\_'. Ace (brucedotrogers a.t rochedotcom)
\`\ | /`/ GSX-R1000K3 (slightly broken, currently missing)
`\\ | //' BOTAFOT#3, SbS#2, UKRMMA#13, DFV#8, SKA#2, IBB#10
`\|/`
`

 

That's what the pipe tape's for, surely?