Magura brakes + shimano fluid = fail?

[silk186]

I took my bike in a few months ago to get my magura julie hydraulic disc brakes. I bought the bike second hand and it needed it. The shop used shimano mineral oil. About a week ago the rear brake leaver started leaking mineral oil. Apparently Magura stopped selling parts (seal kit?) in 2012 and I'm SOL. Talking with a guy a my local bike club he suggested that it was because it was bled with shimano mineral oil instead of magura royal blood and that the manual states that using any other oil will result in catastrophic failure. Is this total BS or do I have a case for going back to the shop that bled them and demanding compensation?

 

[fossyant]

You need to research it. Is there any difference in the fluids that could damage seals ? Not sure myself, but the Shimano stuff is just a mineral oil

 

[Drago]

Pretty sure the Maguras use DOT type brake fluid. The Shimmy oil is liable to have damaged the seals.

 

[silk186]

I can confirm that my brakes say mineral oil on the cap.
The question is, is their a difference between magura and shimano mineral oil that could be responsible for my brake failure.

 

[fossyant]

The other option, the bike was second hand. If not looked after and stored properly then the seals could have gone. Happened to a mate of mine. Brought a cracking GT full suss round for a service, I did all the mechanicals and tool a look at the hydraulic brakes. Seals gone. It had been sat in a shed for a long time. Complete new levers, hoses and callipers were needed.

 

[Yellow Saddle]

There is no difference between Shimano and Magura oil other than the colour. The leak is caused by something else.

 

[Richard A Thackeray]

Out of curiosity

Do Magura still use the 'Citroen' mineral oil, as they used in their hydro-pneumatic suspension systems?

The brakes on my old Pace Reseach (when I had it), used it

 

[Yellow Saddle]

No, they've now created a house-brand of the same stuff. They dyed it blue, took the opportunity to call it Royal Blood and upped the price. The same mineral oil is used in some cars as power steering flood, others as you mention, in suspension systems and in large trucks such as Bells pit loaders, as brake fluid. Castrol makes a nice reasonably-priced mineral oil suitable to all mineral oil type bike brakes, called Castrol LHM.

 

[Levo-Lon]

Brake seals fail ,im with yellow saddle..any mineral oil in a mineral oil system would be fine..
seals can fail due to many things from oil contamination while cleaning and lubing to poor machining or wrong fluid used by accident ..or just time..annoying no spares are available as seals do have a shelf life when fitted to a brake system.

same as any dot 3,4 and 5.1 are in a dot system. Dot 5 also but id not use that on my formulas..

 

[silk186]

That is what I expected. However, the guy at my community bike club read that you must use royal blood or the brakes will fail in the online manual. He said he would never go against manufacturers recommendations and the my lbc may be responsible.
If I could pin it on the bike shop and get them to replace the brakes it would save a poor grad-student. Oh, well. I will just have to wait for a good clearance sale at CRC.

 

[Profpointy]

That is what I expected. However, the guy at my community bike club read that you must use royal blood or the brakes will fail in the online manual. He said he would never go against manufacturers recommendations and the my lbc may be responsible.
If I could pin it on the bike shop and get them to replace the brakes it would save a poor grad-student. Oh, well. I will just have to wait for a good clearance sale at CRC.

the seals are most probably a standard size / shape made by a seal company, rather than model-specific. Of course, the tricky bit is working out what they are in seal-catalogue part numbers, especially if you've not got much in the way of measuring equipment. It's a bit like bearings - I'd be astonished of Shimano or whoever make sealed bearings - they'd just look up SKS's catalogue for a spec & size and order them in (possibly stamped Shimano)

 

[Smurfy]

Most design and manufacture companies don't reinvent the wheel for the sake of it. Is there any chance that an off-the-shelf seal will fit.

The brakes are already knackered. No harm in stripping and measuring the seal is there?

 

[Mobytek]

Royal Blood is like no other fluid - best descibed as neither MO or DOT. If you get a MO seal and put DOT into it you will see the rubber crack, warp then go to a goey sticky bit-like-blu-tak substance - and same vice-versa.

And mixing DOT 3, 3.5 or 5 with DOT 4 is also a quick route back to the shop.

Same also goes for things like Fox Fluid when people want to use other fluids or oils. All of which do serious damage to your paintwork!!

 

[Yellow Saddle]

Royal Blood is like no other fluid - best descibed as neither MO or DOT. If you get a MO seal and put DOT into it you will see the rubber crack, warp then go to a goey sticky bit-like-blu-tak substance - and same vice-versa.

And mixing DOT 3, 3.5 or 5 with DOT 4 is also a quick route back to the shop.

Same also goes for things like Fox Fluid when people want to use other fluids or oils. All of which do serious damage to your paintwork!!

Nope. Royal blood is mineral oil and will NOT damage seals made for mineral oil. Fox Float fluid, likewise. It is a mineral oil and does no damage to the buna O-rings in fox or Rox forks.

I am yet to see a fluid that makes rubber crack. If you apply the wrong fluid to the wrong rubber, all you see is a swelling of the rubber and eventually it turns soft and sticky. It does not crack. It doesn't warp either. Once the rubber has swollen and gone jelly-like, you can physically warp it but it slowly returns to its default form. I've attached a photo of a various brake components dunked into the wrong fluid i.e. mineral oil in DOT and vice versa. Note how they all swell up, but never crack or warp. The first photo is Hope (DOT) dunked in mineral oil. The second is, I think Hayes (DOT) in mineral oil and the third is Tektro (Mineral oil) dunked in DOT. I would love to see evidence of cracking or warping. Please post such photos.

Finally, only DOT fluid damages paintwork. The mineral oils do absolutely nothing to paint.

 

[Yellow Saddle]

the seals are most probably a standard size / shape made by a seal company, rather than model-specific. Of course, the tricky bit is working out what they are in seal-catalogue part numbers, especially if you've not got much in the way of measuring equipment. It's a bit like bearings - I'd be astonished of Shimano or whoever make sealed bearings - they'd just look up SKS's catalogue for a spec & size and order them in (possibly stamped Shimano)

From my experience, the seals are mostly proprietary parts. If you look at the reservoir seals in my photos above, you'll see that each manufacturer has its own shape. The O-rings are obviously standard but then the piston seals proprietary.
As for bearings, Shimano makes each and every one of the bearings in its hubs itself. These are cup-and-cone bearings and proprietary, The bearings in its bottom brackets are cartridge bearings and at first glance standard. However, they're proprietary too, being 1mm narrower than the industry standard bearing with the same OD and ID. I don't know who makes those bearings for Shimano.