Author Topic: Renewing brake hydraulic oil  (Read 1367 times)

Offline mattsz

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Re: Renewing brake hydraulic oil
« Reply #15 on: December 27, 2019, 03:40:55 PM »
I’m wondering whether I need to do it now, it was more the stuff in the bottom and the internet saying needs doing every 2 years that made me think I needed to do it?

Or, perhaps, the maintenance schedule in the owners manual?  (;)). I do often hear that Mr. Honda did things for a reason...

On the other hand: interestingly, the factory service manual doesn't specify any brake fluid change interval at all - only "checking" and topping up... so directly from Honda, it's either "every two years," or "never"...  ;D

Offline MrDavo

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Re: Renewing brake hydraulic oil
« Reply #16 on: December 27, 2019, 03:52:10 PM »
Re the use of smoking requisites to maintain motorcycles:

I used to be able to time a BSA pre-unit twin using a pencil and a Rizla. If I remember it correctly:

Shove the pencil in the plughole, and mark where TDC is. Find out the distance BTDC where it was meant to spark, (it was given in inches, not just degrees) mark the pencil that distance above the TDC mark, turn engine back to there. When you have done it once just keep the pencil in your toolbox, you won't need to measure and mark next time.

Set the magneto so it is just letting go of the fag paper placed between the points (ie points just opening). Tighten up the magneto sprocket, which was on a taper.

Done, two minute job. Five if you include taking the timing cover off and putting it back on again.

Regarding brake fluid (best post something on topic) I've sometimes spotted blobs of water running around in the bottom of master cylinders (it doesn't mix), that's a good sign it needs changing!





1969 Honda CL450 'Scrambler'
1974 Kawasaki Z1A
2005 Harley XL1200R Sportster
1985 Porsche 911 3.2 Carrera Sport
1978 VW Bay Window camper van

Offline K2-K6

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Re: Renewing brake hydraulic oil
« Reply #17 on: December 27, 2019, 05:30:43 PM »
Regarding longevity of fluid,  the Japanese original fit flexible brake hoses have always been very good quality and far less risk ( moisture migrates inwards through the hose to contaminate the fluid) than other automotive supply materials.  In addition,  the bike's mastercylinders generally have the flexible bladder under the cap which makes the biggest difference to moisture ingress,  which cars don't normally use.

These don't normally need to schedule a change with anything like the frequency of cars,  but if you do then all the fluid should be pushed through the system as it will all have the same moisture density dispersed right throughout it.

Offline mattsz

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Re: Renewing brake hydraulic oil
« Reply #18 on: December 27, 2019, 05:43:27 PM »
While we're here, I guess...

I've dumped way more brake fluid than I've put into brakes - "they" say not to save open bottles of fluid for later use as it will absorb atmospheric moisture and be ruined.  If you could open a bottle, use whatever you needed, then could positively seal the bottle against further exposure - at least until the next time you open it - can you save an open bottle on the shelf for later use?

For example, what if I open a bottle, use about 1/4 of the fluid over about 15-minute interval, then close the bottle and vacuum-seal it in a plastic bag which can't let air in...

Offline K2-K6

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Re: Renewing brake hydraulic oil
« Reply #19 on: December 27, 2019, 06:09:40 PM »
If it's in a flexible bottle,  just squeeze the bottle until liquid is at the top and put the cap back on to exclude air and it'll last longer.  Probably a year or two.

Nitrogen fill is used in lab situations to help things like this.  Probably cost more than the fluid to do it though,  although they do nitrogen fill tires in racing to prevent pressure changes due to heat build up in critical application.  Some tire fit places offer that to general consumers here.

Offline Bradders

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Re: Renewing brake hydraulic oil
« Reply #20 on: December 27, 2019, 07:19:01 PM »
Thanks all for your advice. Sounds to me I might leave it another couple of years yet. The oil in the reservoir is quite a clear colour and it seems that maybe it doesn’t need doing just yet.

Offline Nurse Julie

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Re: Renewing brake hydraulic oil
« Reply #21 on: December 27, 2019, 08:19:21 PM »
Thanks all for your advice. Sounds to me I might leave it another couple of years yet. The oil in the reservoir is quite a clear colour and it seems that maybe it doesn’t need doing just yet.
Good. If the brakes are working well and stopping the bike in time ( As well as 400/4 brakes have ever worked that is 😊😊😊) leave it for now and do it when you change the pads next.
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Offline Bradders

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Re: Renewing brake hydraulic oil
« Reply #22 on: December 27, 2019, 09:13:26 PM »
Great advice Julie thanks. My pads have always looked Like there’s less thickness on the inside pad than the outside one. Is that normal?

Offline Bryanj

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Re: Renewing brake hydraulic oil
« Reply #23 on: December 27, 2019, 09:51:17 PM »
Yes, original pads had a line/groove around them painted red and were ok till the line was worn into. Outer pad wears morn as it touches disc first before pulling caliper over for inner pad to touch, at least that is what i was i was told years ago

Offline Bradders

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Re: Renewing brake hydraulic oil
« Reply #24 on: December 27, 2019, 10:02:49 PM »
Thanks Bryanj.  That makes sense.

 

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