[Closed] Shimano zee brakes - anyone had similar?

Sounds like micro leaking seals. Is it in warranty still?

sounds like classic shitmano brake issue. Had this with a set of zee brakes- levers just failed completely afer not being used for 3 months. Working OK, needed bled every other month, then a gap of riding at lockdown then boom levers just failed completely. Both of them. At the same time.

I have a pile of failed shimano brake levers. and some callipers. So poor. They are the new Avids unfortunately in my recent experience

Ah man I was hoping that it was something less sh1t than that.

Brakes bought in May last year so I believe two year warranty Joe?

Never had an issue with other shimano or Sram / Hayes brakes😞

Had a few sets of Zees on various bikes. Rears have always felt underpowered compared to fronts. Have always put it down to poor bleeding by me and the longer hose run.

Had a rear lever seal go on an XT setup previously. Felt totally different - nothing there at all.

Slightly different to the above, I've had a set of Zees for a few years and they have been great since day 1.

Very powerful, almost too much braking force with big grippy plus tyres when I'm tired. Always a comedy moment pulling them on and nearly making contact with the stem.

Had a fair few sets of XT, Deore and some really cheap Shimano that have all developed leaky pistons but touch wood these have been perfect.

I have Zees on both my bikes. Cracking brakes, and Ive not had any trouble from mine so far (eldest set is 4 years)

Its always a bit harder to bleed the rear due to the longer, mostly horizontal line - vertical bleed and a bit more attention usually deals with this nicely, but what you have there is a shimano micro leak.

Warranty.

I had a micro leak on my front deores a few years back. Found they squealed horribly when contaminated. Sounds like you have the same as new pads temporarily resolve the issue.

Mine started happening after I hadn't used the bike for a few weeks, when it usually got used a couple of times a week. Were replaced under warranty via On-One after they were reminded that Shimano provide a 2 year warranty.

If they're still in warranty send them back, it's not worth the grief of trying to make them work. If they work they're great, if they don't they're impossible. Sounds like you've got one of each.

Shimano brakes are a disgrace and they don't seem to be doing anything about it.

Thanks everyone

Shimano brakes are a disgrace and they don’t seem to be doing anything about it.

It's weird, cos they were so trouble free, right up to the Mn000 series. That's when it all seemed to go wrong. I wonder what they changed, apart from adding an extra digit to the series no!

It’s weird, cos they were so trouble free, right up to the Mn000 series. That’s when it all seemed to go wrong

I’ve always used them and never had any issues. Had some older two pot deore that didn’t miss a beat in seven years. These have cost me loads in unnecessary pad changes when it looks like I missed the obvious known issue.

Sounds like the issue I have on my M785's, if I don't ride for a few weeks they have no power and require the pad bedding in procedure to get them biting properly again. It must be a micro leak as it's not enough to ever need more fluid adding to the system.

I don't believe it's a micro leak if there are no signs of contamination on the pads/caliper. I do however get similar on mine when they're left for a while. If you're using Shimano pads, especially their organic ones, I believe they react to moisture in the air when unused for a period of time.

I find that if I know I'm going to be using my bike, and it's been idle for a couple of weeks, then I normally just blast the pads in the oven for ten minutes on high heat, a quick piece of sandpaper ran over the top to remove any glazing and they're good to go again.

I find that if I know I’m going to be using my bike, and it’s been idle for a couple of weeks, then I normally just blast the pads in the oven for ten minutes on high heat, a quick piece of sandpaper ran over the top to remove any glazing and they’re good to go again.

That sounds convenient 🤣

I think I’d just rather buy a brand of brakes that doesn’t have whatever this problem is.

I’ve had this issue on some slightly older deores (replaced them with guide R’s and then Code R’s) and my road bike’s shimano rear brake has just succumbed to the same problem. I have a Hope RX4 waiting to replace it when I have the time to mess about with funnels and syringes etc.

That sounds convenient 🤣

Ha, forgot to mention I only do it when the pads are howling ... quick up/down the drive to confirm. Doesn't do it all the time. Couple of times a year maybe.

Prezet- bike is used regularly (once a week minimum), and issue now occurs every time. Pads I have changed after every ride recently (costing a fortune) and mixing up - gorilla, Uber bike etc.

Convinced it is a faulty seal from the other comments and a bit more research. Would also explain why one is fine but one isn’t.

They are in warranty, just waiting to hear from the shop. Tempted to switch for something else albeit stock of everything is so low!

I've also had the issue with multiple pad brands so can rule that one out

A timely thread actually. Since my last post, the oldest rear brake has just developed a micro leak.

Dismantled it to find the transfer port seal is characteristically flattened. Ordered 5 new seals from the 'Bay and popped the pistons at the same time and did a full de-gunge.

The jury is out on the piston seals, but I know the transfer port seal does fail and I've had good success on a number of old M785 calipers with replacements.

Once the seals are here I will rebuild and report back. Cost of the seals was about 3 quid for 5.

Where do you get the seals from?

Ebay.

I can't find piston seals in the correct dimensions, but I haven't tried very hard because I don't think they're leaking.

@superstu - is there any indication that the seals are leaking? At the very least I'd expect to have some kind of oil residue on the back of the pads where they meet the pistons, or around the piston seals themselves.

In your original post you said it happens when you leave the bike for a week, but you then go on to say it's used every week minimum.

I guess if you're trying other brands of pads you can rule our the Shimano pad issue.

Have you tried a new rear rotor? Maybe that is knackered and is somehow glazing your pads. What size rotors do you use?

Prezet - thanks for the further comment. Sorry, not being clever or contradictory on the use - it’s used once a week most weeks, occasionally more but occasionally may be a two week gap. Never longer and rare to go over a week idle, so weekly use 90% of the time.

Rotor is 180 (front which is fine is 200) and was new with the brakes so only 12 months old and c. 500 miles of use. Both are shimano rotors.

More developments on this.

Seals arrived and were duly replaced and red-bled. My wondering bite point and weak breaking continued, together with noise. No 9bvious oil contamination.

Quite by chance I looked into the lever above the pivot, since I'd left it pressurised all night using a cable tie as part of a thorough approach to bleeding the line.

The lever was oily and had accumulated debris. I flushed out all out with IPA, re-bled it again and left it pressurised again over night, to find oil back in the morning- so, I actually have a leaking master piston.

Again, seals are on the 'Bay, and I'm currently waiting for them to arrive.

I have had this with my Zees. The older set I have I replaced the levers with some SLX ones I had and they have been great. The rear on the new set have gone the same way and the oil seeping from the lever was pretty obvious. I have now bought a new lever from Bikester in Germany for about £35. This has fixed the issue for the time being.

Reading this with interest as I have a spare, rarely used, bike with Zee brakes that howl like a strangled goose and have very little power (front and rear). They're out of warranty now so I'm not sure whether to try and fix or just replace with another brand (Clarks?).
No signs of leaks at the calipers (I guess that there could be leak between the two halves - never had much joy trying to fix these on gravel bike). Can it really be lever? Why would that cause the caliper to howl and shudder?

By way of an update the online shop I purchased them from have said their supplier wants them to check so they are in a box waiting to be sent back for inspection. Will report back when they do (they state a three week gap! Thank goodness for N+1!!)

FYI for anyone interested, sent them back to the online retailer who in turn sent them back to shimano and they’ve confirmed it’s a warranty job, now to decide whether to get a replacement or credit and get something else…hmmm

This was a weird thread to find as a couple of weeks ago my rear zee started howling. I tried cleaning the rotor and pad, then sanding the pad and cleaning more.
After sanding the face of the pad it worked a little better for a while but started honking soon after and felt spongier too.
Next resort is a full clean out, bleeding it and new brake pads. Front still works great though but it's really off-putting on some trails knowing I can't rely on the back brake's inconsistent stopping power.

How old are they Arcadian? Sounds like similar to me. Micro leak so not like they were dripping oil, but there would be howling and then lack of power. If yours are less than two years I’d consider if they’ve gone and save your hassle and get them looked at for warranty

They're quite old Stu, like 6 years at a guess! The last 3 years saw the bike get used less, had a baby to look after, then when he was in nursery enough to have free days the pandemic hit (was unlucky enough to catch covid at the start of the pandemic which mooshed my asthma for a good few months after) so only really been out the last 4 months with regularity.

Thing was they were doing well until about a month ago and it feels like chasing my tail trying to nail down what will sort it. Will give everything I've seen on here a go - fortunate enough to have moved next to a forest with trails a minute's cycle away so easy to give it shakedown runs!

Shimano brakes - it’s endless tales of woe with leaky lever, leaky pistons and inconsistent bite point. I don’t get why Shimano can’t just fix this - they didn’t used to have these problems many years back.