Bleeding hydraulic brakes after 1 year - worthwhile?

[redbruce]

yep, assuming lid has sealed, 120ml sram dot container half empty, 20c degree air at 100% RH occupied the empty void of the bottle, a cubic meter of air can hold 17.3 grams of h2o at 20c, so 60cc of air can hold 0.001038 grams of h2o, thats going to be 0.0000173% of the fluids volume is h2o in your bottle

unknown, is the bottle actually a perfect seal, through the HDPE bottle itself or the cap seal. I suspect not.

this is where we need our resident chemist, REDBRUCE!!!!!

HDPE is impervious to moisture.

We store samples in it in fridge (very low RH) for months, even years with no contents loss/gain. Cap seal is weak link.

The only source of moisture will be in the air above the fluid. In Melbourne RH in summer is typically 40-50% (but last sat morning was 75%RH @24 degree after rain night before) and 50-70% in Winter so 100% would definitely be worst case here.

In any case the moisture in the air will eventually be partitioned between the liquid and vapour phase (not sure what the partition co-efficient is) so the amount of water in the fluid will be less than 0.001038 g in the 60ml.

2% moisture in DOT fluid is considered the point at which boiling point for MTB braking applications is critical so the amount of moisture in a left over half bottle is miniscule.

 

[link1896]

HDPE is impervious to moisture.

We store samples in it in fridge (very low RH) for months, even years with no contents loss/gain. Cap seal is weak link.

The only source of moisture will be in the air above the fluid. In Melbourne RH in summer is typically 40-50% (but last sat morning was 75%RH @24 degree after rain night before) and 50-70% in Winter so 100% would definitely be worst case here.

In any case the moisture in the air will eventually be partitioned between the liquid and vapour phase (not sure what the partition co-efficient is) so the amount of water in the fluid will be less than 0.001038 g in the 60ml.

2% moisture in DOT fluid is considered the point at which boiling point for MTB braking applications is critical so the amount of moisture in a left over half bottle is miniscule.

Thank you.

Can you make this a 4th year students research project?

 

[redbruce]

Conductivity is a reliable measure of water contamination in glycol-ether based brake fluids.

Cheap checkers are available

https://www.ebay.com.au/itm/5-Indic...e=STRK:MEBIDX:IT&_trksid=p2060353.m1438.l2649

 

[wkkie]

I bled a mates (previously mine) Shimano Saint M800 tonight.

The rear had a few partial bleeds in the last few years due to frame routing, and there was a fair bit of crap in the lines that came out with the flush.

The fronts haven't been touched in probably well over 5 years and he complained of them being spongy on a recent Buller trip.

This was what came out in the flush. Looked like poodle had been at the brakes with his baby oil, really dull fluid colour, and no, I didn't wee in the bag!

Here's the comparison with the new fluid that was going into them.... Brakes are rock hard again too, so peoples get bleeding!

 

[born-again-biker]

Semi-relevant thread hijack....

I am very fussy about brake performance & lever feel so I check, adjust & bleed often.

I can confidently say I have my XT/SLX brakes working to best potential - they usually haul my near 100 kilos up pretty well.
I'm running 180mm rotors front & rear & I recently added new finned pads (resin).

But....
All this talk about Maydena & the strain on brakes has me thinking I might be bringing a knife to a gun fight when I break the seal on my shiny new maydena collective membership...?

So, are Zee brakes any good?

(I've read mixed feedback here & there )
Are they good bang-for-the-buck? Value for money is my priority....not bling for blings sake.

Alternatively, I could add a 203mm disc to the front & switch to metallic pads (with fins) & I might be OK with the M675's....?
I'm no Richie Rude....and maybe the Zee's would be overkill for all the other days I'm riding regular trails...?

Bike is a modded 140mm Trance
that needs to be jack-of-all trades....





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[rangersac]

So, are Zee brakes any good?

(I've read mixed feedback here & there )
Are they good bang-for-the-buck? Value for money is my priority....not bling for blings sake.

So, like you I am pretty much in the 100kg kitted up riding bracket. I can't comment on Zee brakes, but having started out MTBing disc brake life on Shimano LXs (M580s) and having moved through several other models of single pot brakes, I can say without a doubt that the most confidence inspiring change to my riding in more gravity orientated situations has been the switch from single to double pot brakes. For the record I've gone Hope, and the modulation goodness is amazing, none of that on/off feeling of Shimano with the ability to haul up in almost any situation without locking up. I'm yet to ride Maydena (March 3rd, bring it on!), but have ridden Derby with single and double pot brakes and it was an out of sight better experience on the doubles.

 

[wkkie]

I'm a little heavier than you and I'm running Zee on my bigger bike with finned pads and 203mm rotors.

You're right about being over gunned on the majority of trails, but when the trail heads downwards for any length of time, I definitely notice the difference to the xt. I started running the xt when I first got the bike and I'll be sticking with the Zee for the big bike. Even if they are overkill for most of the trails you ride, they do provide that extra power for the shuttle days and if you have a collective membership you'll get your money's worth with the Zee.

Bling wise, they're not blingy but I would say they are good bang for buck and they do work!

 

[born-again-biker]

... I can say without a doubt that the most confidence inspiring change to my riding in more gravity orientated situations has been the switch from single to double pot brakes.
......but have ridden Derby with single and double pot brakes and it was an out of sight better experience on the doubles.

Hmm....I'm surprised by your praise for the change in brake hardware. I guess I thought dropper post or 36mm forks or carbon wheels etc would be the "game changer" for most. Although there's a good chance you ride faster than me!

I'm a little heavier than you and I'm running Zee on my bigger bike with finned pads and 203mm rotors......I definitely notice the difference to the xt.........I would say they are good bang for buck and they do work!

Righto, looks like I'm officially in the market for double piston brakes.
A full Hope set up is gonna be around $600 AUD yeah ? Are Ze Germans better than CRC for Hopes?
There's Zee calipers on FleaBay for about $100 each....which I could just add to my existing lever & hose set-up.
Anyone found brake deals on any particular website....?

 

[wkkie]

Hmm....I'm surprised by your praise for the change in brake hardware. I guess I thought dropper post or 36mm forks or carbon wheels etc would be the "game changer" for most. Although there's a good chance you ride faster than me!



Righto, looks like I'm officially in the market for double piston brakes.
A full Hope set up is gonna be around $600 AUD yeah ? Are Ze Germans better than CRC for Hopes?
There's Zee calipers on FleaBay for about $100 each....which I could just add to my existing lever & hose set-up.
Anyone found brake deals on any particular website....?

Do the calipers come with hoses? If so that'll be the easiest way, then just use your existing slx / xt levers.

 

[born-again-biker]

Do the calipers come with hoses? If so that'll be the easiest way, then just use your existing slx / xt levers.

Yeah that's kinda what I'm thinking....
I don't think the caliper-only listings include a hose...but I should be able to use my existing hoses with a different banjo (?)...maybe....

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[Oddjob]

Yeah that's kinda what I'm thinking....
I don't think the caliper-only listings include a hose...but I should be able to use my existing hoses with a different banjo (?)...maybe....

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Or you could treat yourself to Goodridge or Jagwire braided lines and fittings. Mmmm whiplash inducing brakes.

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[born-again-biker]

Or you could treat yourself to Goodridge or Jagwire braided lines and fittings. Mmmm whiplash inducing brakes.

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Hmm.....true...true....
(Rubs chin & ponders blingin brake lines)

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[rangersac]

Hmm....I'm surprised by your praise for the change in brake hardware. I guess I thought dropper post or 36mm forks or carbon wheels etc would be the "game changer" for most. Although there's a good chance you ride faster than me!

Well I've never ridden carbon wheels (too fat, and not enough $$) or 36mm forks (got Pikes which are 35mm and they seem stiff enough for me). Droppers are nice but I don't have the cojones for big jumps, drop offs etc, so I only really take advantage of them in steep stuff. Modern geometry is probably the biggest game changer, but that's apples and oranges. As for being fast, I'm a slightly better than average fat bastard, who can climb thanks to some solid commuting miles, and have a bike that makes me looks better than I am when it comes to descending!

Righto, looks like I'm officially in the market for double piston brakes.
A full Hope set up is gonna be around $600 AUD yeah ? Are Ze Germans better than CRC for Hopes?

Merlin is as good as anyone when it comes to Hopes.

 

[Delazy]

Maydena...amazing place...but horrible for brakes! Like many of the above I'm tipping the 100kg mark kitted up on my Norco Sight

I'm rocking near enough new hope E4s with the standard resin pads and 203/180mm hope sawtooth rotors...

On both occasions I've ridden at Maydena now I've suffered from brake fade (lever to the bars kind of stuff)...usually within 2 runs down the hill...for the moment I've put it down to lack of confidence given I've spent some 6-8 months not riding and overusing the brakes...

Plenty of other people seemed to be in the same situation also...

Personally I'll be taking a full kit of brake related spares on any future trip given the Maydena mechanic only seems to keep shimano spares...

Beyond keeping everything fresh and using the brakes less I don't really see any worthwhile upgrade options...

 

[rangersac]

On both occasions I've ridden at Maydena now I've suffered from brake fade (lever to the bars kind of stuff)...usually within 2 runs down the hill...for the moment I've put it down to lack of confidence given I've spent some 6-8 months not riding and overusing the brakes...

Interesting (and slightly scary!). I run 180/180 and have never felt under gunned brake wise at Derby, South Hobart, Meehan, North/South etc. Only difference is I run sintered instead of resin pads. When was the last time you bled your brakes and check the pistons were even? I did this before a fairly recent N.Z. adventure ride, and it definitely improved things.

 

[Delazy]

Interesting (and slightly scary!). I run 180/180 and have never felt under gunned brake wise at Derby, South Hobart, Meehan, North/South etc. Only difference is I run sintered instead of resin pads. When was the last time you bled your brakes and check the pistons were even? I did this before a fairly recent N.Z. adventure ride, and it definitely improved things.

the bike went to Ride Bellerive for a complete clean/service and i did request they pay particular attention to the brakes in between the muddy collective ride day and opening day... likewise ive never felt under braked before and it certainly took me by surprise... my day mostly consisted of green/blue trails which is the more scary part of it

like i said im putting it down to me being abit harsh on the brakes, still adjusting to the vertical drop of maydena and 8 months off the bike... but im definitely not the only one that had issues with a decent set of brakes...

 

[c3024446]

Every year would be overkill for me for the amount I ride. Have bled several sets of M785's with black sludge in them, anyone knows what causes that?

 

[rstim]

Hmm....I'm surprised by your praise for the change in brake hardware. I guess I thought dropper post or 36mm forks or carbon wheels etc would be the "game changer" for most. Although there's a good chance you ride faster than me!



Righto, looks like I'm officially in the market for double piston brakes.
A full Hope set up is gonna be around $600 AUD yeah ? Are Ze Germans better than CRC for Hopes?
There's Zee calipers on FleaBay for about $100 each....which I could just add to my existing lever & hose set-up.
Anyone found brake deals on any particular website....?

Another option I've been looking at before I make the trip to Maydena are Magura MT5 or the trail sports these are supposed to have good power and modulation and looks like you can get a set for about $250. I'm sure I've read a thread on here with a couple of people using them that really like them.

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[tkdbboy]

These go on special for $150 an end. I grabbed a set and couldn't be happier. Old brakes were Elixir R.

http://www.chainreactioncycles.com/au/en/hope-tech-3-v4-disc-brake/rp-prod112987

I say just keep your eyes peeled for it to drop again.

 

[born-again-biker]

These go on special for $150 an end. I grabbed a set and couldn't be happier. Old brakes were Elixir R.

http://www.chainreactioncycles.com/au/en/hope-tech-3-v4-disc-brake/rp-prod112987

I say just keep your eyes peeled for it to drop again.

Purple ano FTW!

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