Hydraulic brakes mineral oil

[Bobbo_SA]

I dont want to speak on behalf of wyatt but for me, I only bleed with shimano mineral. Why, well shimano says I should...maybe its mass produced somewhere, maybe shimano knows something about the internals of the brake and there is something special in their red oil....who knows. I bought a liter of the shimano oil when buycycle(was like 200 rond I think) was running a special. Gonna take a while to get through it since I only bleed maybe once a year.

 

See if something goes on the brake I won't have this thought in the back of my mind that it could have been because I was taking shortcuts

 

The only exception i make here is the Tektro bleed kit is about half the price and also has a "red"-ish mineral oil that comes with it, reckon it looks similar to Shimano's option and also mineral oil so it should be safe, :-)

[Wyatt Earp]

After reading this thread yesterday, I decided to take a look at my XT-brakes last night as they kept on getting air in the system. I bought the bike 2nd hand in March this year and only started having trouble with the brakes about 2 weeks ago and didn't get round to looking at it till last night. Front brake has yellow fluid in and the rear brake has clear fluid inside? Seem to be leaking oil from the lever of the rear brake as there is a oily/muddy buildup where the lever goes into the housing (don't know how to describe it in any other way).

 

My question is, is there a way to determine what the fluid is inside the brakes and would you advise me to get the Shimano mineral oil? Where can I get Shimano mineral oil as the bike shops here and in Polokwane say they have in stock but don't sell it. They want to charge me to bleed the brakes themselves, and I don't have the time to drive the 65km and wait around till they get to my bike to solve the issue.

 

Any advise will be appreciated. 

Your fluid has boiled and it's lost all the viscosity it should have.

When it goes yellow or clear it means at some point the brakes got way too hot.

 

The guild you see form the lever could also just be excess from someone over filling the system previously by bleeding them with the pads in, and now when you push the pistons back or the lever very hard, some of it escapes (as I said, this is just one possibility)

 

You need to flush the system and replace all that fluid with fresh stuff.

Depending on your brakes, you will need two syringes, surgical hoses and a plastic packet with an elastic band and a bleed block.

If they are the newer brakes you need the bleeding funnel for ONE WAY bleeding.

And of course a 7 mm. spanner .

[fanievb]

Your fluid has boiled and it's lost all the viscosity it should have.

When it goes yellow or clear it means at some point the brakes got way too hot.

 

The guild you see form the lever could also just be excess from someone over filling the system previously by bleeding them with the pads in, and now when you push the pistons back or the lever very hard, some of it escapes (as I said, this is just one possibility)

 

You need to flush the system and replace all that fluid with fresh stuff.

Depending on your brakes, you will need two syringes, surgical hoses and a plastic packet with an elastic band and a bleed block.

If they are the newer brakes you need the bleeding funnel for ONE WAY bleeding.

And of course a 7 mm. spanner .

 

sheriff, what do you mean by one way? Top down gravity bleed?

 

I recall someone (patches??) posting a while ago that the recommended way as per shimano manual can blow the seals.

 

also what's the general opinion on burping brakes? Or should one rather do a complete bleed?

 

[Boerklong]

Lucky I didnt market baby oil for the gospel truth...phew

[Wyatt Earp]

sheriff, what do you mean by one way? Top down gravity bleed?

 

I recall someone (patches??) posting a while ago that the recommended way as per shimano manual can blow the seals.

 

also what's the general opinion on burping brakes? Or should one rather do a complete bleed?

 

Nope, not really gravity ,but almost that principle.

Now if it was patches ????? or whoever it was, they might have confused the different Shimano models.

 

The brake in your video is the older system and that is the system that you remove the top cap and bladder to bleed them, that system works with two syringes top to bottom and bottom to top if you have the old bleed kit that straps over the reservoir and burping works really well on the older system.

 

Some guys bleed the new one direction bleeding brakes the same as the old style and end up pushing the seals in the calliper beyond what they were designed to do..

So yes ,essentially that manner of bleeding for Shimano is incorrect, but only for the newer models where you will need the funnel.

 

With the funnel system you can still burp the brakes to an extent.

The fluid used in the video is Magura blood, as I said it's a very good mineral oil for brakes that use mineral oil.

 

Just a note for some, Avid recommend Dot 5.1 

Edited November 4, 2014 by Wyatt Earp

[fanievb]

Nope, not really gravity ,but almost that principle.

Now if it was patches ????? or whoever it was, they might have confused the different Shimano models.

 

The brake in your video is the older system and that is the system that you remove the top cap and bladder to bleed them, that system works with two syringes top to bottom and bottom to top and burping works really well on the older system.

 

Some guys bleed the new one direction bleeding brakes the same as the old style and end up pushing the seals in the calliper beyond what they were designed to do..

So yes ,essentially that manner of bleeding for Shimano is incorrect, but only for the newer models where you will need the funnel.

 

With the funnel system you can still burp the brakes to an extent.

The fluid used in the video is Magura blood, as I said it's a very good mineral oil for brakes that use mineral oil.

 

Just a note for some, Avid recommend Dot 5.1 

 

apologies I was referring to the new system which requires the funnel.

 

and I went and searched   it was Eldron that posted (https://community.bikehub.co.za/topic/138147-funnel-for-bleeding-shimano-disc-brakes/?do=findComment&comment=2266495)

 

 

 

[GerrieTruter]

Your fluid has boiled and it's lost all the viscosity it should have.

When it goes yellow or clear it means at some point the brakes got way too hot.

 

The guild you see form the lever could also just be excess from someone over filling the system previously by bleeding them with the pads in, and now when you push the pistons back or the lever very hard, some of it escapes (as I said, this is just one possibility)

 

You need to flush the system and replace all that fluid with fresh stuff.

Depending on your brakes, you will need two syringes, surgical hoses and a plastic packet with an elastic band and a bleed block.

If they are the newer brakes you need the bleeding funnel for ONE WAY bleeding.

And of course a 7 mm. spanner .

Thanks Wyatt

 

The brakes are the BR-M775 XT's so older type. Still has the reservoir cap that you have to remove to get fluid in. By flushing, do I have to add the new fluid and bleed as normal till the fluid that's coming out is the same as top or bleed it dry and start from beginning? Or is there something I have to run through the system to clean it?

[GerrieTruter]

Sorry for the questions but I'm used to working on car brakes and the only way I know how is to get pressure up by pumping the brake and opening the nipple to release the air. Can that method be used for MTB brakes?

[Wyatt Earp]

Sorry for the questions but I'm used to working on car brakes and the only way I know how is to get pressure up by pumping the brake and opening the nipple to release the air. Can that method be used for MTB brakes?

If you have the older model and those 775's are, then you are in luck, get a syringe and a surgical hose ,fill the syringe with fluid.

Take the brake lever and turn it horizontal to the ground with the bike on a stand.

Get the wife, girlfriend or boss to suck fluid from the reservoir as you pump fluid to the top from the bleed nipple at the back, loosen the bleed nipple with a 7 mm. spanner before you attempt this and be sure to have the pads removed with a bleeding block between the pistons.

 

Once all the fluid in the reservoir looks like the right colour, close the bleeding nut with the 7 mm. spanner.

Take the surgical hose and detach it from the syringe, attach a small plastic bag over the hose and make it fit snug and secure with an elastic band.

Now attach that to the bleed nipple and open the nipple a three quarter turn form tight, now pump the lever and keep filling the reservoir till you see no more bubbles.

The minute you see bubbles in the hose , you close the bleed nipple and then open it again till the bubbles move in to the packet.

 

Once you see no more bubbles you burp the brake as in the video posted here.

Remove the bleed block and install the pads ,loosen the brake mounts and put your wheel in the bike, spin the wheel and pull the brake till it feels firm, centre calliper and tighten the mooting screws.

 

I hope that explains in more detail.

Edited November 4, 2014 by Wyatt Earp

[James Mulholland]

First off.

I love, wait I adore home mechanics, they do everything so right and so by the book.

I have seen some of these guys come and gone, they look for a holiday job, tell the LBS they know everything and within the first two weeks they drop rocks in their rods because they have never seen so many tools and then they walk around red faced all day because they have come to the realisation they actually know very little.

 

Shimano

What a great innovative yet very underrated company, too often they get accused of wanting to monopolise .

They almost perfected bicycle hydraulic brakes whilst everyone else were still trying to develop disc brakes for bicycles.

 

I recall around 2001 my mate Wes called me as he wanted his XT four pod piston brakes bled .

His dad was one of the importers back then and the set he had was already pretty ragged and took some abuse, they were a demo set and besides that, Wes did not play with his bicycle.

The brakes had four pistons per calliper and they came out with a 2 finger lever and wait for it, braided hoses.

 

Get your hands on a set of these and you have gold .

I paid at that stage, the most I have ever payed for any two little bottles of fluid, an expensive bottle of cognac would have been cheaper.

 

I bled the brakes for him, I was at his dads office last week, that same set of brakes is still on a bike and doing a sterling job.

What is the point I am trying to make ?

Shimano as a company are exceptional at what they do, everything they do gets done with massive amounts of engineering and design around it.

When they develop a particular fluid for their brakes, then we need to know that there is just no alternative, regardless of the cost.

 

These mega companies have always and will always know better than any layman out there.

James, sorry if this bored you ,but I just had to get that off my chest

 

Now back to your original question.

Magura blood is a great alternative, but horrible expensive too.

In an absolute case of emergency, cooking oil or olive oil will also do the job, but bear in mind that a complete system flush will be required after that .

Much appreciated. you make a good point about how low the cost really is given the price of the equipment and how long a good bleed can potentially last.

[Pipsqueak]

apologies I was referring to the new system which requires the funnel.

 

and I went and searched   it was Eldron that posted (https://community.bikehub.co.za/topic/138147-funnel-for-bleeding-shimano-disc-brakes/?do=findComment&comment=2266495)

 

 

That funnel is the bomb. You just run a tube to a jar at the calliper and let gravity flush your whole system out. I just shuttle fluid from the jar to the funnel as it seeps down.

[Morwa]

I've been to four LBS's in Pretoria......nobody has stock of the Shimano Mineral Oil. 

 

Yes, I can order from CWC or Evobikes....but I need the oil now.

[Pipsqueak]

I've been to four LBS's in Pretoria......nobody has stock of the Shimano Mineral Oil. 

 

Yes, I can order from CWC or Evobikes....but I need the oil now.

I've seen good hydraulic brake oil in fancy motor bike shops - KTM and such like.

[Wyatt Earp]

I've been to four LBS's in Pretoria......nobody has stock of the Shimano Mineral Oil. 

 

Yes, I can order from CWC or Evobikes....but I need the oil now.

How much do you need/want ?

[Bobbo_SA]

I've been to four LBS's in Pretoria......nobody has stock of the Shimano Mineral Oil. 

 

Yes, I can order from CWC or Evobikes....but I need the oil now.

 

Also ask or Tektro, "same" stuff

[Morwa]

How much do you need/want ?

Hi.... enough for front and rear. So 150ml would do.