JeffHs
|
| posted on 8/6/15 at 04:05 PM |
|
|
Hydraulic seals help
Does anyone know the correct name for the lipped seals usually found in master and slave cylinders? I'm trying to source some for an odd
application and can't find them online - it doesn't help that I don't know what they're called!
|
|
|
|
|
Dingz
|
| posted on 8/6/15 at 06:22 PM |
|
|
Usually just called lip seals, for piston or rod use, or equi-lipped which will do both. Usually the dynamic lip is shorter than the static. Assuming
you are using std brake fluid you will need them to be in EPDM material.
Although having once bought an expensive Wilwood cylinder I was suprised to discover that they just use cheap and cheerful O rings which will always
weep in that application!
Phoned the local ramblers club today, but the bloke who answered just
went on and on.
|
|
|
JeffHs
|
| posted on 8/6/15 at 07:02 PM |
|
|
Thanks for reply. It's for an aircraft application using OM15 a superfine mineral oil so the seals will be nitrile. It begs another question
though. Why did the automotive industry use brake fluid instead of mineral oil? The old bits (60s) I'm using have no corrosion or wear unlike
anything you would find on a similar aged car.
|
|
|
Dingz
|
| posted on 8/6/15 at 07:27 PM |
|
|
Citroen of course until recently always used mineral oils for brakes and suspension systems. I don't really know why automotive went for the
Glycol based Dot fluids, they absorb water, attack paint need different materials for seals and hoses, needs to be changed regularly. It has a higher
temperature range though than the older mineral oils and probably the Americans said it must be used.
Commercial Aircraft use Skydrols which are even nastier but don't burn. I believe military planes use mineral oils though.
Phoned the local ramblers club today, but the bloke who answered just
went on and on.
|
|
|
britishtrident
|
| posted on 8/6/15 at 07:32 PM |
|
|
quote:
Originally posted by JeffHs
Thanks for reply. It's for an aircraft application using OM15 a superfine mineral oil so the seals will be nitrile. It begs another question
though. Why did the automotive industry use brake fluid instead of mineral oil? The old bits (60s) I'm using have no corrosion or wear unlike
anything you would find on a similar aged car.
This link is interesting but doesn't say why
http://www.carhistory4u.com/the-last-100-years/parts-of-the-car/brakes
[I] “ What use our work, Bennet, if we cannot care for those we love? .”
― From BBC TV/Amazon's Ripper Street.
[/I]
|
|
|
v8kid
|
| posted on 8/6/15 at 09:24 PM |
|
|
quote:
Originally posted by britishtrident
quote:
Originally posted by JeffHs
Thanks for reply. It's for an aircraft application using OM15 a superfine mineral oil so the seals will be nitrile. It begs another question
though. Why did the automotive industry use brake fluid instead of mineral oil? The old bits (60s) I'm using have no corrosion or wear unlike
anything you would find on a similar aged car.
This link is interesting but doesn't say why
http://www.carhistory4u.com/the-last-100-years/parts-of-the-car/brakes
I vaguely remember it has to do with water absorption. You can't stop condensation and glycol absorbs water up to a point and won't let it
freeze into a solid lump blocking the brake pipes. Also although glycol does lower its boiling point with water it is still higher than a water
globule in a pipe.
Up to a point is the critical bit.
Would like to know the proper story though.
Cheers
You'd be surprised how quickly the sales people at B&Q try and assist you after ignoring you for the past 15 minutes when you try and start a
chainsaw
|
|
|
