Renewing brake hydraulic oil

[Bradders]

Afternoon all. I have some grungy stuff in the bottom of my brake Caliper reservoir and wanted to clean it out. I’m thinking it would be a good time to renew the brake fluid as well at the same time. I’ve looked on the internet and I think it’s within my mechanical capabilities ( famous last words). Any tips or advice would be greatly appreciated. Also it says to use DOT 3 but have not seen that around. Is DOT 4 ok to use? Regards, Chris.

[Nurse Julie]

You will be OK with DOT 4 or DOT 5 but do not use DOT 5.1 unless you are doing a complete overhaul and changing all rubbers etc as 5.1 is not compatible with DOT 3, 4 or 5.

[Bradders]

Thanks Julie. No just going to renew the oil.

[MrDavo]

Top tip, learned the hard way.

When pumping the new fluid through the system, don't be pulling the lever all the way to the bar, things will not go well, as you are taking the seals past their normal range of travel.

You can tape a matchbox or similar to the grip to stop this happening.

Ash will be along soon to point you at the appropriate service bulletin.

[mattsz]

Here's one (sorry Ash!)...

[Bradders]

Thanks MrDavo for that tip. This forum is so useful for tips like that.

[Johnwebley]

Be careful with the bleed nipple.it could be corroded shut.
After you made sure you can loosen the  nipple.I take apart the caliper. Remove sliding pad.and carefully press the piston into the caliper as far as it will go.

Suck old dirty oil from the master cylinder. Then partially fill with fresh oil  and start to flush the system.
Careful operating the brake lever. As oil will spurt out. And ruin your paint work.
Once fresh oil comes out.
Replace the pad.assemble the caliper and pump the brake lever. Checking the fluid level at all times.

Replace top.check all bolts are tight. Should work for another umpteen years

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[Nurse Julie]

Good point about the bleed nipple John, they can be a bit of a nightmare. Chris, if you want a new bleed nipple, I have them in stock and will pop one in the post to you.

[Bradders]

Thanks guys. Do you all change the oil every 2 years or is that a bit of overkill ?

[Johnwebley]

Thanks guys. Do you all change the oil every 2 years or is that a bit of overkill ?

Over kill.

It's worth while swapping the caliper seal every 10/15 years.

That retracts the piston. And makes the system work sweetly

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[Nurse Julie]

Thanks guys. Do you all change the oil every 2 years or is that a bit of overkill ?

Over kill.

It's worth while swapping the caliper seal every 10/15 years.

That retracts the piston. And makes the system work sweetly

Sent from my SM-A750FN using Tapatalk

Agree, we don't change ours until there are crispy bits in the bottom of the resovoir 😊. Saying that, most of our bikes have had the systems completely re furbed and rebuilt so we use DOT 5 silicone fluid.

[Bradders]

I think Peter the previous owner overhauled the whole lot about 3 years ago. The Caliper etc looks in very good condition. 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?

[SteveD CB500K0]

I was most amused by the use of “matchbox”. Are they still a thing?


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[MrDavo]

I was most amused by the use of “matchbox”. Are they still a thing?

I dare say modern smokers can substitute their electronic vapourising device for the matchbox.

[PatM]

I was most amused by the use of “matchbox”. Are they still a thing?


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Steve- Might not have any matchboxes left but i was glad Im still a smoken when a fuse I broke down a while back due to a cracked fuse. Out fwith the fag-paper and home I rode! (as for lighting them, the wife upgraded me to a Zippo about 25 years ago!)