...about hydraulic fluid?
Yesterday, whilst not particularly doing anything, I had a sudden
thought about the clutch on the beemer. A quick google revealed I'd used
the wrong fluid. (I used brake fluid, shoulda used mineral oil). The internet is divided about whether I've borked the seals or not. There
are no seal kits available for either the master or slave cylinder.
Anyway, it will be sometime before I can get back to the bike to change
to the proper fluid, so we shall see.
Today, I had another easy (so I thought) job, to change the pressure
gauge on a new to me hydraulic press. The old gauge permananently read >
0 and didn't move.
Got myself the right size spanner and started to remove the old gauge,
it was tight but then began to turn. It was still a bit tight so
contuinued to use the spanner and then suddenly WHOOOSH, I, and half of
the garage, was covered in hydraulic oil.
I dunno if I managed to close my eyes in time or not, but, I can still
see ok.
Pretty scary tbh, I think I've got away with it but I'm well aware of
the dangers of exposure to high pressure fluids.
Can't work out why it was under pressure. The piston wasn't pressing
down onto anything.
The new gauge reads 0 unless I'm pressing something, and it returns to 0 when I'm not.
I don't really understand the DOT3/DOT4 thing, but I think a mix-up with those is not instantly catastrophic. The mineral oil gotcha seems
considered rapidly terminal to seals by the usual AI suspects, but time
will tell. Surprised pattern seals are not available on Ali Express.
On 06/06/2026 07:26, Peter Fisher wrote:
I don't really understand the DOT3/DOT4 thing, but I think a mix-up with those is not instantly catastrophic. The mineral oil gotcha seems considered rapidly terminal to seals by the usual AI suspects, but time will tell. Surprised pattern seals are not available on Ali Express.
Maybe not instantly, but it's going to be nearly a month before I can
flush it out. I've found a couple of references saying that the OEM
seals are nitrile. Nitrile apparently is attacked by the glycol in brake fluid.
Those kits of a zillion o-rings, of which I have one, are apparently
nitrile. So I may have a go at replacing them. Not as critical as
braking systems, obviously, but still a PITA if the clutch stops working.
--
/Simon
In reply to "Simon Wilson" who wrote the following:
On 06/06/2026 07:26, Peter Fisher wrote:
Maybe not instantly, but it's going to be nearly a month before I can
I don't really understand the DOT3/DOT4 thing, but I think a mix-up with >>> those is not instantly catastrophic. The mineral oil gotcha seems
considered rapidly terminal to seals by the usual AI suspects, but time
will tell. Surprised pattern seals are not available on Ali Express.
flush it out. I've found a couple of references saying that the OEM
seals are nitrile. Nitrile apparently is attacked by the glycol in brake
fluid.
Those kits of a zillion o-rings, of which I have one, are apparently
nitrile. So I may have a go at replacing them. Not as critical as
braking systems, obviously, but still a PITA if the clutch stops working.
--
/Simon
From memory, and that is not a sreliable as it used to be! I pretty sure that
DOT 3 & 4 can be mixed, as they are mineral.
DOT5 on the other hand is Silicone and is in a world of it's lonesome.
If it were me, (thankfully it ain't) I would just pump a few hundred ml through
the system and leave well alaone.
I think Clutch slaves are normally a right PITA to get to and sort out. :-/
Just did a quick Google and it seems to agree, with a caveat(obv).
Greybeard
T-Bird - 1600
Bonnie T140V - 750
On 06/06/2026 14:23, Greybeard wrote:
In reply to "Simon Wilson" who wrote the following:
On 06/06/2026 07:26, Peter Fisher wrote:
I don't really understand the DOT3/DOT4 thing, but I think a mix-up with
those is not instantly catastrophic. The mineral oil gotcha seems considered rapidly terminal to seals by the usual AI suspects, but time will tell. Surprised pattern seals are not available on Ali Express.
Maybe not instantly, but it's going to be nearly a month before I can flush it out. I've found a couple of references saying that the OEM
seals are nitrile. Nitrile apparently is attacked by the glycol in brake fluid.
Those kits of a zillion o-rings, of which I have one, are apparently nitrile. So I may have a go at replacing them. Not as critical as
braking systems, obviously, but still a PITA if the clutch stops working.
--
/Simon
From memory, and that is not a sreliable as it used to be! I pretty sure that
DOT 3 & 4 can be mixed, as they are mineral.
DOT5 on the other hand is Silicone and is in a world of it's lonesome.
If it were me, (thankfully it ain't) I would just pump a few hundred ml through
the system and leave well alaone.
I think Clutch slaves are normally a right PITA to get to and sort out. :-/
Just did a quick Google and it seems to agree, with a caveat(obv). Greybeard
T-Bird - 1600
Bonnie T140V - 750
It's not a dot3 versus dot4 thing. It's dot3 (wot I used, bad for
nitrile seals) versus mineral oil (wot I should have used, and ok with nitrile seals). The slave is relatively easy to remove.
--
/Simon
not sure you have grasped it yet.
Simon should not have put any DOT fluid in the clutch system
BMW & KTM insist on using this stuff https://www.sportsbikeshop.co.uk/motorcycle_parts/content_prod/ 238293?glCountry=GB
Cyclists will be familiar with it as it is used in their brakes
Often Magura Blood mineral fluid.
...about hydraulic fluid?
Yesterday, whilst not particularly doing anything, I had a sudden
thought about the clutch on the beemer. A quick google revealed I'd used
the wrong fluid. (I used brake fluid, shoulda used mineral oil). The internet is divided about whether I've borked the seals or not. There
are no seal kits available for either the master or slave cylinder.
Anyway, it will be sometime before I can get back to the bike to change
to the proper fluid, so we shall see.
Today, I had another easy (so I thought) job, to change the pressure
gauge on a new to me hydraulic press. The old gauge permananently read >
0 and didn't move.
Got myself the right size spanner and started to remove the old gauge,
it was tight but then began to turn. It was still a bit tight so
contuinued to use the spanner and then suddenly WHOOOSH, I, and half of
the garage, was covered in hydraulic oil.
I dunno if I managed to close my eyes in time or not, but, I can still
see ok.
Pretty scary tbh, I think I've got away with it but I'm well aware of
the dangers of exposure to high pressure fluids.
Can't work out why it was under pressure. The piston wasn't pressing
down onto anything.
The new gauge reads 0 unless I'm pressing something, and it returns to 0 when I'm not.
On Wed, 17 Jun 2026 19:51:12 +0100, Simon Wilson <simowilso+newsdemon@nodamnspamn.gmail.com> wrote:
A long time ago we learned that its often (especially when time has a
Long story short I've bought another whole tractor. Which is almost a
runner.
value applied) cheaper to buy another (working) tractor than fix the
old one.
I'd got rid of all of them (and the spare parts) but recently I was
weak. So now I own a 1940's tractor with a blown head gasket that I
haven't got time to fix......
On 17/06/2026 20:14, Mark Roberts wrote:
On Wed, 17 Jun 2026 19:51:12 +0100, Simon Wilson
<simowilso+newsdemon@nodamnspamn.gmail.com> wrote:
A long time ago we learned that its often (especially when time has a
Long story short I've bought another whole tractor. Which is almost a
runner.
value applied) cheaper to buy another (working) tractor than fix the
old one.
I'd got rid of all of them (and the spare parts) but recently I was
weak. So now I own a 1940's tractor with a blown head gasket that I
haven't got time to fix......
Ooh what did you buy?
Bad things come in threes....
Long story short I've bought another whole tractor. Which is almost a >runner.
On Wed, 17 Jun 2026 19:51:12 +0100, Simon Wilson <simowilso+newsdemon@nodamnspamn.gmail.com> wrote:
Bad things come in threes....
Long story short I've bought another whole tractor. Which is almost a >>runner.
Oh Simon...never change :-)
I think after a lot of pratting about I can fix up the 3 point lift and ignore the small crack,
On 17/06/2026 19:51, Simon Wilson wrote:
I think after a lot of pratting about I can fix up the 3 point lift and
ignore the small crack,
You could have a go at braising the crack to seal it?
And we look forward to hearing how efficient the rural French fire
brigade are as you burn the barn down afterwards.
On 17/06/2026 19:51, Simon Wilson wrote:
I think after a lot of pratting about I can fix up the 3 point lift
and ignore the small crack,
You could have a go at braising the crack to seal it?
And we look forward to hearing how efficient the rural French fire
brigade are as you burn the barn down afterwards.
In reply to "Simon Wilson" who wrote the following:
It's not a dot3 versus dot4 thing. It's dot3 (wot I used, bad forGlad the slave is easy :-)
nitrile seals) versus mineral oil (wot I should have used, and ok
with nitrile seals). The slave is relatively easy to remove.
If 3 and 4 can be mixed with no problems, surely the seals shouldn't
be affected in the short term, so a good flush through with the right
stuff should (hopefully) be all that's needed. Nitrile seals have been
around a long time, as has dot 3?
This is one of those conundrums that could cause serious sleepless
nights!
Long story short I've bought another whole tractor. Which is almost a >runner.
| Sysop: | Amessyroom |
|---|---|
| Location: | Fayetteville, NC |
| Users: | 70 |
| Nodes: | 6 (0 / 6) |
| Uptime: | 39:35:07 |
| Calls: | 948 |
| Calls today: | 2 |
| Files: | 1,325 |
| Messages: | 280,644 |