Brake Bleeding. Is it as easy as sounds?

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Ray Young
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Brake Bleeding. Is it as easy as sounds?

Post by Ray Young » Sat Aug 15, 2020 4:20 pm

I've just bought a brake bleed kit for Shimano brakes. Is it as easy as they make it sound? The reason I ask is because in my motorcycling youth I attempted to bleed brakes without success. I believe I am a bit less cack handed now than I was on those days though.

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Re: Brake Bleeding. Is it as easy as sounds?

Post by redefined_cycles » Sat Aug 15, 2020 4:35 pm

Yes.. it is. But.... :lol:

Lazarus
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Re: Brake Bleeding. Is it as easy as sounds?

Post by Lazarus » Sat Aug 15, 2020 4:37 pm

Almost always as easy as it sounds
Its like tubeless its usually easy but if it becomes faff the faff can last a long long long time

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Ray Young
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Re: Brake Bleeding. Is it as easy as sounds?

Post by Ray Young » Sat Aug 15, 2020 5:23 pm

Lazarus wrote:
Sat Aug 15, 2020 4:37 pm
but if it becomes faff the faff can last a long long long time
That'll be me then, :wink: .

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ScotRoutes
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Re: Brake Bleeding. Is it as easy as sounds?

Post by ScotRoutes » Sat Aug 15, 2020 5:26 pm

Aye, pretty simple. Just be sure you do a lot of tapping and flicking.

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Re: Brake Bleeding. Is it as easy as sounds?

Post by middleagedmadness » Sat Aug 15, 2020 5:28 pm

As Colin says When you push the syringe just flick the hose at the same time , it’s normally at matter of mins to do both

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Ray Young
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Re: Brake Bleeding. Is it as easy as sounds?

Post by Ray Young » Sat Aug 15, 2020 5:34 pm

Thanks guys. The rear brake has needed doing for a while and on the last trip started coming back to the bar without any noticeable retardation of forward momentum. I'll get on it tomorrow.

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Re: Brake Bleeding. Is it as easy as sounds?

Post by pistonbroke » Sat Aug 15, 2020 6:10 pm

Rears are trickier than fronts due to the ups and downs of the hose path. Try to make sure the hose runs totally uphill in every section from caliper to master cylinder. Also do everything slowly especially retracting the pistons so as not to risk air ingress. Air is much easier to get out if it's not there in the first place. Bottom to top bleeding usually works better than gravity, even with Shimano.

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Re: Brake Bleeding. Is it as easy as sounds?

Post by Fat tyre kicker » Sat Aug 15, 2020 6:39 pm

Normally when I /we are doing it, we do it exactly the same as doing a car
Motorbike etc, we have the kit but only use the hose for the bleed nipple,
Usual brake bleeding protocol applies I.e " hold, pump, top up etc "


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Re: Brake Bleeding. Is it as easy as sounds?

Post by jay91 » Sat Aug 15, 2020 8:48 pm

Do they need a bleed or can they be burped?
https://youtu.be/zckHR3-MMnY
Trying to ride bikes.

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Re: Brake Bleeding. Is it as easy as sounds?

Post by BigdummySteve » Sat Aug 15, 2020 11:12 pm

I’ve got the Avid pro bleed kit, possibly not needed for Shimano as they use mineral oil. If you use brakes that use dot fluid I think it’s essential, you can put proper negative pressure by pulling up in the syringe. This had the effect of making air bubbles expand hugely, you then tap it to get them to float to the top. It’s surprising how much air is trapped in even bottle fresh fluid.

When you have got your fresh fluid in set the bike up so it’s all up hill, if it’s the rear set it up in a stand as vertical as possible, you will need to rotate to lever to stop spilling it out of the res. Then tap, tap flick the hose, rapidly flicking the lever can also help bubbles to the top.
One area where bubbles can hide is the pistons, pump individual pistons out a little then with the nipple open push the pistons back in expelling any air.

Shimano MTB brakes are pretty easy to get a good bleed on, SRAM dropbar brakes are a faff. As others have mentioned take your time, it can make a huge difference to feel and power.
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Re: Brake Bleeding. Is it as easy as sounds?

Post by Ray Young » Sun Aug 16, 2020 7:25 am

htrider wrote:
Sat Aug 15, 2020 8:38 pm
viewtopic.php?f=7&t=14444&start=500
There you go!
Thanks Phil. Funnily enough I bought the same kit and also bought the Shimano screw in reservoir as it seemed it would make things easier.

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Re: Brake Bleeding. Is it as easy as sounds?

Post by Ray Young » Sun Aug 16, 2020 7:29 am

jay91 wrote:
Sat Aug 15, 2020 8:48 pm
Do they need a bleed or can they be burped?
https://youtu.be/zckHR3-MMnY
Thanks, I'll give that a go first.

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Ray Young
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Re: Brake Bleeding. Is it as easy as sounds?

Post by Ray Young » Sun Aug 16, 2020 7:31 am

One final question. Is it ok to mix different brands of mineral oil?

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Re: Brake Bleeding. Is it as easy as sounds?

Post by htrider » Sun Aug 16, 2020 5:30 pm

Yup, no issues as its all the same barring colour

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Re: Brake Bleeding. Is it as easy as sounds?

Post by ScotRoutes » Sun Aug 16, 2020 5:40 pm

Ray Young wrote:
Sun Aug 16, 2020 7:31 am
One final question. Is it ok to mix different brands of mineral oil?
No.

If it's Shimano brakes then use Shimano oil.

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htrider
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Re: Brake Bleeding. Is it as easy as sounds?

Post by htrider » Sun Aug 16, 2020 8:36 pm

ScotRoutes wrote:
Sun Aug 16, 2020 5:40 pm
Ray Young wrote:
Sun Aug 16, 2020 7:31 am
One final question. Is it ok to mix different brands of mineral oil?
No.

If it's Shimano brakes then use Shimano oil.
Nah - its all mineral oil. The only mistake is to mix Dot 5 with mineral oil.....
Fork oil is probably the cheapest alternative to the excessively price branded brake oil sold by the likes of shimano et al. Use 10 or 15 weight

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Re: Brake Bleeding. Is it as easy as sounds?

Post by Dean » Sun Aug 16, 2020 10:04 pm


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Re: Brake Bleeding. Is it as easy as sounds?

Post by thenorthwind » Mon Aug 17, 2020 8:37 am

htrider wrote:
Sun Aug 16, 2020 8:36 pm
Fork oil is probably the cheapest alternative to the excessively price branded brake oil sold by the likes of shimano et al. Use 10 or 15 weight
That's really useful to know, cheers. I was wondering what I was going to do with the rest of the litre of 15wt motorcycle fork oil I bought because it was cheaper than a thimbleful of SRAM's finest Snake Oil® after I'd serviced my fork.

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Re: Brake Bleeding. Is it as easy as sounds?

Post by Gummikuh » Mon Aug 17, 2020 10:48 am

Just double check your hose is firmly on the bleed nipple, its really easy for it to come off, spraying oil/DOT all over everywhere.

Done that a few times.

Once in the front room! I had the mother of clean up jobs before the boss got home.

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Re: Brake Bleeding. Is it as easy as sounds?

Post by Supernova » Mon Aug 17, 2020 11:19 am

I’m a big fan of a periodic 5 minute quick bleed for Shimano as described by Epicbleedsolutions, just to sharpen the brakes up again:

https://epicbleedsolutions.com/blogs/gu ... mini-bleed

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Re: Brake Bleeding. Is it as easy as sounds?

Post by Lazarus » Mon Aug 17, 2020 4:50 pm

Fork oil is probably the cheapest alternative to the excessively price branded brake oil sold by the likes of shimano et al.
Never heard this before - is it a well tested solution?
Secondly not not all fork oil is mineral some is synthetic ,some semi synthetic some petroleum and some mineral based - are you certain this would still work?

Finally it comes in different weights - which means viscosity so I assume that some are better than others - also worth noting that one 5w may not equal another brands 5W for viscosity

Seems a lot of factors to take into account when using it

https://transmoto.com.au/comparative-oil-weights-table/
Not sure its wroth t for what a tenner saving on your brakes - which are fairly important feature i would not like to fail

I have heard of folk using the citroen LHM but its apprently thicker and may cause pistons to stick/not retract but will probably be fine

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Re: Brake Bleeding. Is it as easy as sounds?

Post by ScotRoutes » Mon Aug 17, 2020 5:32 pm

A 1 litre container of Shimano Mineral Oil can be obtained for something like £15-20 and will last for years, especially if you don't go around bleeding your brakes just for the hell of it. I just sold a bike with XT775 brakes that hadn't been bled for 5 years or so. The only time mine are bled is if they are new/relocated and so have hose changes. Based on all of that, I don't see genuine Shimano Mineral Oil as at all expensive and therefore not something to save a few quid on.

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Re: Brake Bleeding. Is it as easy as sounds?

Post by rollindoughnut » Tue Aug 18, 2020 6:07 am

Don't use fork oil!
I speak from experience.
Just a few weeks ago I was bleeding a rear shimano slx brake and accidentally picked up the bottle of fork oil rather than brake oil. Spent about an hour trying to force oil into the system. The tube from the syringe blew off the nipple twice shooting oil all over myself and my surroundings. It was made worse in the fact that I was showing the neighbours son how to do it as I'd just given him the bike.
Suddenly I twigged what I'd done and secretly switched bottles muttering "there must be a blockage, let's try a different technique ". Of course with the right oil (much thinner) it flowed in smoothly and the job was done in seconds.

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