Rr. MC Res. O-ring?

[Schming]

I usually don't ask for any help 'cause up til now research has steered me in the right direction everytime. BUT, to polish my rear master cylinder, I removed the plastic resivoir and would like to use a new o-ring to reassemble it. I have searched threads for hours to see if anyone has done this with no luck. I'd imagine the o-ring is made to withstand brake fluid. Does anyone have experience with this? TIA

[fredintoon]

- - - to polish my rear master cylinder, I removed the plastic reservoir and would like to use a new o-ring to reassemble it. I have searched threads for hours to see if anyone has done this with no luck. I'd imagine the o-ring is made to withstand brake fluid. Does anyone have experience with this? - - -

Hi John,
nah, my old one survived. But 90% of o-rings are made to be used in hydraulic applications so they gotta stand up to brake fluid. Unless you specifically ask for a "food grade" or other specialized compound o-ring at the bearing and seal store the one they sell you will work fine.

[Schming]

"... 90% of o-rings are made to be used in hydraulic applications..." Hi Fred, Yes that makes perfect senseI tend to overthink things all too often. What doesn't make sense to me is that neither the front or rear MC rebuild kits (frt.-Tour Max from PNM and rr.-K&L from G-Fix)don't include this o-ring. By the way both front and rear are the same size 2.5mm thick and 48mm OD. I will try today to locate these. Thanks for your help

[Yahman]

I can get some but I have to order 50 of them. If I ordered them, they would wind up costing $1.00 each with postage shipped anywhere in the USA. Two of them would be $1.50 shipped. I am getting ready to make an order soon. If there is enough demand for them, I will add them to the order. If I do order them, I should have them around the 15th.

Larry

[CatatonicBug]

What doesn't make sense to me is that neither the front or rear MC rebuild kits (frt.-Tour Max from PNM and rr.-K&L from G-Fix)don't include this o-ring

Yeah, the rebuild kits only include the piston parts. To get that o-ring, you have to buy the new reservoir itself. If you look at the parts listing, the part number for the reservoir includes the o-ring. It is not sold separately by Yamaha, IIRC.

[Schming]

Found 'em...

Hi Larry, After two auto parts stores and one lumber yard/ hardware I was able to get 2 fer $2 at the second parts store which is family owned and usually comes through for me with the oddball items. I will Thank You for Your offer Hi C-Bug, I would like to first Thank You for showing me the correct way to spell reservoir (I knew somethin' didn't look right) secondly my reservoirs, front & rear, are in very good shape as this bike has spent all of its time in a clean dry garage so I'll keep them both and rebuild completely now that I have the o-rings. Thank You again for the info. Another ? Does anyone know of a coating that would hold up against DOT3 that I could use on the steel washers(?) that live between the top plastic reservoir cap and the fluted rubber seal? I don't want to switch to DOT5 and would like to keep them from rusting again. Thanks for Everyones Help

[fredintoon]

Does anyone know of a coating that would hold up against DOT3 that I could use on the steel washers(?) that live between the top plastic reservoir cap and the fluted rubber seal? I don't want to switch to DOT5 and would like to keep them from rusting again. Thanks for Everyones Help

Hi John,
switch the washers out for stainless steel ones.

[Schming]

Hi Fred, Do you know of a source that has both the front & rear diaphragm washer plates? If not I can make them. Lets see stainless or aluminum? What do you think?

[HobbyMan]

put in stainless washers. Aslo, technically flushing the brake fluid every once in a while should remove any water that has been absorbed into the system.
Also, I replace those o-rings every time I rebuild the MC. It sucks to see your MC leaking brake fluid all over your stock paint on your fuel tank

[Schming]

put in stainless washers. Aslo, technically flushing the brake fluid every once in a while should remove any water that has been absorbed into the system.
Also, I replace those o-rings every time I rebuild the MC. It sucks to see your MC leaking brake fluid all over your stock paint on your fuel tank

Hi HobbyMan, I'm just about ready to look through my scrap stainless and make patterns for both front & rear diaphragm washer plates. I won't put them back together with the old steel ones just to have them rust again. The exact reason I took my '80G off the road in 2001 was that the front MC started to leak and I lost the braking ability. When I tore into it I found that the caliper pistons were pitted around where the dust seal rides. My desire to replace them was halted by the dealerships "can't get them anymore" so the bike sat in my garage untouched for almost 4yrs. while i built my woodsbuggy. When I finally learned to turn a computer on in '05 Found this website and dusted the "G" off and been slowly bringing her back to well deserved glory. Thanks to the Fellowship here making this possible. Ok enough rambling when I get these made I'll have to teach myself to post a few pics. Thanks

[fredintoon]

Hi Fred, Do you know of a source that has both the front & rear diaphragm washer plates? If not I can make them. Lets see stainless or aluminum? What do you think?

Hi John,
I did wonder "what washer?" So, not a washer as in little round thing but the thin steel plate that supports the master cylinder reservoir seal rubber, right?
OK then, I wire-brushed the loose rust off mine, used a rust conversion spray on it so the fixed rust went black and put it back in.
If you can re-make it from sheet stock I'd say stainless.
The original is real thin; aluminum that thin would be a touch flimsy.

[Schming]

Hi John,
I did wonder "what washer?" So, not a washer as in little round thing but the thin steel plate that supports the master cylinder reservoir seal rubber, right?
OK then, I wire-brushed the loose rust off mine, used a rust conversion spray on it so the fixed rust went black and put it back in.
If you can re-make it from sheet stock I'd say stainless.
The original is real thin; aluminum that thin would be a touch flimsy.

Yes Fred, That 's the one or two I'm referring to. I am also pondering going the same route as you on a few particular parts on all my projects with this product:
http://1323464.estore.networksolutio...StoreFront.bok JAT Would that stuff, plastidip(?), that you dip tool handles in hold up to DOT3? I could make them out of a little thicker stainless sheet but i don't think the support for the diaphragm gasket in the thin areas would be sufficient because of the way the original is punched with the supporting lip that keeps the gasket from being sucked into the MC reservoir under application of the brakes. So, I'll most likely save what I have following Your advice and if I need to fabricate either one day I have some 3/16 aircraft aluminum I can mill replicas out of. Next a visit to Helperformance.com for the capillaries. Thanks