Brake caliper O ring seals

[yamaha_george]

Hi,
young fellow has a problem with the two halves of his calipers weeping Hydraulics. Taking them apart shows that the P.O. did NOT put back the O rings between the two halves round the feed hole to each piston !!!!!!
I can find no stock here and I therefore need the size to go to an industrial supplier & post them to him (he is the boonies) )

Needless to say we could buy another set of calipers but so far this is the second set he has bought (the originals were VERY rusty & mangled) , the new owner thus is very reluctant to do anything that costs even more.

I thought i had the sizes written down here in the UK but it seems likely the old grey stuff is just old and forgetful ::-{
Help will be appreciated by all concerned

[DonTZ125]

Hi, George. If you mike the o-ring groove OD and depth, we can check different charts for a match. Depending on where your friend is, it might be easier to match inch AS-568 sizes or metric. Be very careful about the compound - EPDM is the only one I remember that was good for brake fluid, and it was severely degraded by hydrocarbons.

[yamaha_george]

Hi, George. If you mike the o-ring groove OD and depth, we can check different charts for a match. Depending on where your friend is, it might be easier to match inch AS-568 sizes or metric. Be very careful about the compound - EPDM is the only one I remember that was good for brake fluid, and it was severely degraded by hydrocarbons.

Don,
Unfortunately my young friend is not a tech head and has no "engineers" tools for measuring being in a very rural area there is no backup what so ever hence him asking me and me going fishing for specific sizes.
Once i have the size the company i buy O rings from will sort the material out as i will tell the the job the ring is doing
Thanks for come back

[Stig]

I'll strip a spare in the morning and get some measurements for you

[yamaha_george]

I'll strip a spare in the morning and get some measurements for you

Thanks mate , our young friend may just keep all his hair after all.
I know my supplier of O rings will sort me out if i give them something to work with.

The next hassle is to get him some piston seals for said calipers as a pound to a penny they are shot too.
Good UK supplier anyone ? at a push a US supplier ?

as ever thanks for the input

[Stig]

George,

I recently bought some seals to rebuild my rear caliper....and then a few weeks later noticed fluid on the paintwork of the rear wheel.

The new seals had failed so i did another rebuild but this time used genuine items...not the cheapest option but i'd sooner be safe than sorry when it comes to brakes

[yamaha_george]

George,

I recently bought some seals to rebuild my rear caliper....and then a few weeks later noticed fluid on the paintwork of the rear wheel.

The new seals had failed so i did another rebuild but this time used genuine items...not the cheapest option but i'd sooner be safe than sorry when it comes to brakes

Ok stealership it is Thanks STIG

[Stig]

OK so stripped the spare cailper. Seems it too suffered from the hands of a lunatic in the fact that only one of the joining seals had been installed!

Prob is, the grooves in the casting are too corroded to take an accurate measurement. I have the remaining seal in front of me and its slightly perished so can only supply a reasonable account to its original size, also being as its rubber its not EXACTLY circular

best bet is 14mm OD, 8.25mm ID, 2.15mm thick

hope this helps

[yamaha_george]

OK so stripped the spare cailper. Seems it too suffered from the hands of a lunatic in the fact that only one of the joining seals had been installed!

Prob is, the grooves in the casting are too corroded to take an accurate measurement. I have the remaining seal in front of me and its slightly perished so can only supply a reasonable account to its original size, also being as its rubber its not EXACTLY circular

best bet is 14mm OD, 8.25mm ID, 2.15mm thick

hope this helps

Stig,
wonderful people PO's aren't they <BG>

I will feed those figures to the supplier and see what they offer . will let you all know how we get on.

my guess would be that the original was probably (Carlesberg theory) 14mm OD by 9mm ID and material 2.5mm thick

[taggy]

Been Long time away but..Is it a 3en1? Ive got a set of calipers from one in the garage if memory serves. I can split em and messure if needed. Or if wanted they can be had for postage cost. Not got 3en1 anymore so redundant! I do seem to remember that they need pad pins though.