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I used to have problems with my calipers pistons getting sticky and not retracting when using Citroen LHM from Halfords. YMMV.
I haven't tested it but maybe Magura's mineral oil would be a better stand in for the Shimano stuff.
Having had a number of the droppers I ended up with quite a lot of Reverb fluid and have used that in Shimano brakes for the last few years - I can't tell any difference. The Morgan Blue oil referred to earlier is sold by plenty of shops as specifically suitable for use in Shimano brakes. I'll probably try that when current stocks run out, just because it's a different colour!
Though air still gets past seals and they need bleeding eventually.
Just for context, what is "eventually" in this scenario? I mean, we're measuring it in years right? For instance none of my current bikes have needed re-bled/flushed and the Ragley I sold in the Spring still had perfect braking despite the brake system having been set up over a decade previously.
How does magura royal blood compare
if air gets past seals the seals have failed. Its microscopic wear particles generated internally and dust getting dragged past the seals
Scotroutes - it depends on usage not time really. the buildup of dirt and wear particles will accelerate wear unless bled thru with new fluid
Just for context, what is “eventually” in this scenario? I mean, we’re measuring it in years right?
Again with TJ.... crap seems to get in at the bottom .. timing is whatever. Usually "years" but I've seen <1 yr. Once the crap is behind the piston its probably scored the seal and then causes sticking.
Ive pulled out master pistons and cleaning the black gunk can sorta get them working except for the scratched piston seals...but way more hassle than just doing a full bleed every so often when it starts discolouring.
Re: using water
BITD there was a vogue in the trials community for bleeding Magura HS33s (also spec'd with mineral oil) with water. Mainly because we were all teenagers with no money and plenty of time for tinkering. You can also completely submerge the system (E.g. in a bath) for the best bubble-free bleed.
I can confirm it worked just fine - pretty well in fact. The lower viscosity gave a lighter lever feel. Cold weather / freezing was a genuine problem, though! Veg oil also worked well in a bind.
Anyway, now I'm all grown up I'll probably spend the extra few quid on proper fluid.
I would only ever bleed brakes if they needed it. Not as 'preventative maintenance' where I'm sure I'd do more harm than good.
would only ever bleed brakes if they needed it. Not as ‘preventative maintenance’
this echos my view, although everyone’s experience is different, and I bow before TJs experience of keeping things going waaaay beyond their expected lifespan. I’ve only ever bled brakes after swapping levers, shortening hoses etc.
Because I'm a retard and why I try and bleed brakes myself I spill a lot and use a lot more than I have to and it sometimes takes me multiple attempts to bleed my brakes. 100ml wouldn't last long!!!
I guess the solution is to buy the 100ml for £10 and wait until March when it will hopefully be cheap to buy 1 litre again, or take the bike to a mechanic for bleeding.
270 to 400% inflation on mineral oil in a year - ABSOLUTELY DISGRACEFUL
I also have 3 bikes with Shimano brakes (Deore/SLX/Zee respectively) and I do 5000 miles a year off road (most of that is on an E Bike - the Turbo Levo) I'm not like some of the haters on here who hardly ride at all by comparison
nickc - I have the need to make stuff last ( econutterism) - but I don't use shimano at all because of the lack of spares for brakes and because the japanese turn albatrosses gay ( long story)
I expect never to buy any more brakes despite all my hopes being obsolete as all are interchangable and I have rebuild kits stashed
I also have 3 bikes with Shimano brakes (Deore/SLX/Zee respectively) and I do 5000 miles a year off road (most of that is on an E Bike – the Turbo Levo) I’m not like some of the haters on here who hardly ride at all by comparison
Still, once they are set up, they shouldn't need re-bled for several years.
Last bleed was in April on one system of brakes. Needed to do them again last week already.
scotroutes - in my book a dot fluid brake should have a fluid change annually and a mineral oil one every two years. thats to get rid of old contaminated fluid. I do not understand why people need to bleed so often - again if bled properly there is no way for air to get into the system so a rebleed should not be needed.
I haven't bled a brake apart from fluid changes for years
if air gets past seals the seals have failed
Is this true? I thought I'd read that nothing is *completely* airtight - hose, joins, seals etc all leak *tiny* amounts of air which builds up over time. Stuff gets hot, expands, gets cold, contracts.
With brakes I think it very much depends on the use you're giving them - if you're riding in the UK and you're longest, steepest hill is a few hundred metres vertical then you will get years out of them. We'd had trips out to La Palma and Pyrenees with uplifted riding and super steep 1000m++ descents. I completely cooked all the seals on my Hope E4's on the same trips.
Years ago I had to bleed a set of Hopes that had been completely fine in the south of the UK but the old man of Coniston was enough to lock them on (I seem to remember it was a steep tarmac road that did it)
But the SRAM guides on my hardtail needed bleeding after the summer and they've never done anything rad. One of the Shimano\s on my commuter bike really needs a bleed (but might have been shit from Canyon's assembly).
I haven’t bled a brake apart from fluid changes for years
And I haven't bled a brake apart from fitting for years.
Shimano Brakes of Love (Copyright Jedi), all like a 1 minute lever bleed with the funnel every few months. That's all you need to do. Uses maybe 20ml of fluid.
i guess if it looks discoloured during this, that's the time for a full flush, refill and bleed.
Is this true? I thought I’d read that nothing is *completely* airtight – hose, joins, seals etc all leak *tiny* amounts of air which builds up over time. Stuff gets hot, expands, gets cold, contracts.
No - it's not. Just above TJ stated that tiny particles of dust can be dragged past the seals and this was perfectly normal and indeed a reason for bleeding brakes, but air - no, that's a "failed seal". In reality, applied braking forces can slightly move the piston and deform the seal enough to trap a particle of air as easily as a particle of dust, it will then be crushed by the seal moving back to its normal position and dragged into the caliper during retraction. This is entirely normal, but equally entirely tiny.
Because I’m a retard and why I try and bleed brakes myself I spill a lot and use a lot more than I have to and it sometimes takes me multiple attempts to bleed my brakes. 100ml wouldn’t last long!!!
You're not trying to pour it direct from the 1L container into the reservoir are you?! Decant a bit into something like a measuring cylinder or a small beaker with a pouring lip on it. Then from there into the reservoir - ideally via a funnel. Bet you can get a small beaker and a small funnel in some poundshop or hardware store for a few pence - it'll save you spilling all the expensive mineral oil everywhere!
Still not sure how your brakes need bleeding this regularly, I recall we've been here before with the maintenance threads...
Out of curiosity, how often do folk bleed the brakes on their motorbikes, cars and vans?
Out of curiosity, how often do folk bleed the brakes on their motorbikes, cars and vans?
When I replace a part. Only reason my MTBs see more frequent bleeds is because I swap stuff about more.
No – it’s not. Just above TJ stated that tiny particles of dust can be dragged past the seals
Regular-ish full bleeds just get rid of the crap and any sucked in air as well. I'm still using 2015 levers and calipers mainly.
i guess if it looks discoloured during this, that’s the time for a full flush, refill and bleed.
tends to be my criteria... it really only takes a minute to check (faster than oiling a chain)
Out of curiosity, how often do folk bleed the brakes on their motorbikes, cars and vans?
Every year when I had my motorcycle as recommended - well the BMW anyway - the BSA has cable drums 🙂
Its on the annual service schedule IIRC
Does it say "gravel specific" on the bottle?
I recon it's about time I bled my 15 year old avids. Although no idea what fluid they take but seeing as it's a fully sealed system no air has got in yet.
Shimano Brakes of Love (Copyright Jedi), all like a 1 minute lever bleed with the funnel every few months. That’s all you need to do. Uses maybe 20ml of fluid.
i guess if it looks discoloured during this, that’s the time for a full flush, refill and bleed.
I completely agree that a quick lever-only bleed is a great way to get rid of (most of) any bubbles in the system, but only if the brakes aren't working right - it shouldn't be necessary to do that routinely. If your brakes need bleeding that often, there's a problem. And if you're in the (daft, IMO) camp of bleeding brakes for 'preventative maintenance' then that method is useless since you're only replacing a fraction of the fluid.
I don't usually bother with a lever-only bleed any more, I find a proper caliper-up bleed the best way to get a solid result.
Need to do one of my Zees though, so maybe I'll give it a try first.
Weird how some Shimano brakes just never need touching though. I had a set of Deore from 2014 which I got on a used bike and only ever wanted new pads.
Sold them last year still in perfect working order.
The problem I have withe Caliper-up bleed is that I struggle to draw mineral oil out of the 1 litre container into the Syringe with no Bubbles. It takes me AGES to finally get it bubble free.
Draw fluid into syringe.
Invert syringe so that the tube is at the top.
Squirt a little fluid out, expelling the air (you might want to tap the sides of the syringe a little to free any bubbles).
Apply tube to bleed nipple.
If there is little fluid left in the 1L container and the tube struggles to reach, then just decant some of it into something smaller. Whatever you don't use can be poured back in.
I’ve had 3 leaky Shimano callipers over the last few years all using Shiamano oil.
Get an oil analysis done to see what magic ingredient is in it! Mineral oil for hydraulic brakes has been around for decades so I don’t think any manufacture would put anything in it that would damage brake seals - it would be easy for them to check and replace any problems ingredients.
LHM for me too
What is it with Shimano and leaky calipers ?
I've gone through countless with Shimano Deore.
SLX and upwards no problems yet, but I've not been using the high end stuff for even a year yet