What did you do to your EBike this week?

[steve_sordy]

What brakes are they and what fluid, mineral oil or DOT? Have you pulled the rubber shroud back at the lever hose connection and checked for weeps and the rear hose to caliper entry and the rear bleed port also for small weeps?

Shimano XT brakes and resin finned pads. I use Shimano branded mineral oil.

I have not checked any of those places. Not that I had even thought to do so but decided not to, it just never occurred to me. My (maybe foolish) assumption was that any leaks would show up as spongy brakes, brakes that improve when pumped, lots of bubbles when bleeding, and signs of seepage.

Anyway, the LBS has it now. When I took it in, he had a good look at it and, after a few of the usual tests he was as puzzled as I was. Let's see.

I thought of something last night as I was drifting off to sleep. If the most apparent symptom is that apparently there is not enough fluid in the system, then why not remove the wheel, so that the disc is not there, press the lever until the pads close up, and then bleed the brakes from the top end. This will charge the system that has marginally more capacity. Then when I refit the wheel (assuming I can get the disc in!) let's see what happens.

EDIT: What gave me the idea was that I had remembered when I replaced the pads on the rear brake out on the trail. With the new pads in, the disc wouldn't fit in between. So, I loosened the lever reservoir bleed screw and levered the pads apart until the disc went in. Tightened the bleed screw, cleaned up and away I went. It occurred to me that if there could be too much fluid in the system (with no air), then maybe there could be too little fluid in the system (again with no air). It was when I renewed the pads that my problems began, so maybe I did something wrong? Never happened before, so it must be something subtle.

 

[steve_sordy]

I fitted the new Knog Oi Prima bell. (1st pic) They claim to have fixed the previous problem, that the previous coil spring design just didn't work. (2nd pic)

The tone is lovely; clear, penetrating and sustained.

View attachment 167004


View attachment 167005

I got my first feedback from a walker on Sunday. He didn't leap out of the way or act in any way startled, he just glanced, moved over and said "nice bell" as I passed. There was nothing for him to see, so it must have been the tone he was reacting to.

 

[VWsurfbum]

Shimano XT brakes and resin finned pads. I use Shimano branded mineral oil.

I have not checked any of those places. Not that I had even thought to do so but decided not to, it just never occurred to me. My (maybe foolish) assumption was that any leaks would show up as spongy brakes, brakes that improve when pumped, lots of bubbles when bleeding, and signs of seepage.

Anyway, the LBS has it now. When I took it in, he had a good look at it and, after a few of the usual tests he was as puzzled as I was. Let's see.

I thought of something last night as I was drifting off to sleep. If the most apparent symptom is that apparently there is not enough fluid in the system, then why not remove the wheel, so that the disc is not there, press the lever until the pads close up, and then bleed the brakes from the top end. This will charge the system that has marginally more capacity. Then when I refit the wheel (assuming I can get the disc in!) let's see what happens.

EDIT: What gave me the idea was that I had remembered when I replaced the pads on the rear brake out on the trail. With the new pads in, the disc wouldn't fit in between. So, I loosened the lever reservoir bleed screw and levered the pads apart until the disc went in. Tightened the bleed screw, cleaned up and away I went. It occurred to me that if there could be too much fluid in the system (with no air), then maybe there could be too little fluid in the system (again with no air). It was when I renewed the pads that my problems began, so maybe I did something wrong? Never happened before, so it must be something subtle.

Sounds like too little fluid.

 

[skizzian]

Shimano XT brakes and resin finned pads. I use Shimano branded mineral oil.

I have not checked any of those places. Not that I had even thought to do so but decided not to, it just never occurred to me. My (maybe foolish) assumption was that any leaks would show up as spongy brakes, brakes that improve when pumped, lots of bubbles when bleeding, and signs of seepage.

Anyway, the LBS has it now. When I took it in, he had a good look at it and, after a few of the usual tests he was as puzzled as I was. Let's see.

I thought of something last night as I was drifting off to sleep. If the most apparent symptom is that apparently there is not enough fluid in the system, then why not remove the wheel, so that the disc is not there, press the lever until the pads close up, and then bleed the brakes from the top end. This will charge the system that has marginally more capacity. Then when I refit the wheel (assuming I can get the disc in!) let's see what happens.

EDIT: What gave me the idea was that I had remembered when I replaced the pads on the rear brake out on the trail. With the new pads in, the disc wouldn't fit in between. So, I loosened the lever reservoir bleed screw and levered the pads apart until the disc went in. Tightened the bleed screw, cleaned up and away I went. It occurred to me that if there could be too much fluid in the system (with no air), then maybe there could be too little fluid in the system (again with no air). It was when I renewed the pads that my problems began, so maybe I did something wrong? Never happened before, so it must be something subtle.

a random thought - but did you buy the Shimano mineral oil recently - as they now have 2 different viscosity oils on the market... a new lower one for the latest M8200 M8220 - not sure how much of a difference it would make - but worth checking....

 

[steve_sordy]

a random thought - but did you buy the Shimano mineral oil recently - as they now have 2 different viscosity oils on the market... a new lower one for the latest M8200 M8220 - not sure how much of a difference it would make - but worth checking....

No, it's not the latest LV mineral oil that is the problem.
https://www.bikeradar.com/features/tech/shimano-lv-mineral-oil-brake-fluid

I have put it to the LBS that it feels like I don't have enough oil in the system, but I can't work out how to get more in! In that, I agree with @VWsurfbum.

Thanks for the suggestion though.

 

[skizzian]

hopefully your LBS will work it out. I think winding out fully any adjustment and then doing a burp bleed at the levers would probably get it full again if not enough fluid is the problem...

 

[steve_sordy]

hopefully your LBS will work it out. I think winding out fully any adjustment and then doing a burp bleed at the levers would probably get it full again if not enough fluid is the problem...

Already tried that, hence my puzzlement!

 

[skizzian]

this vid is quite interesting
might be useful...
not done it myself before - but think I will...

 

[steve_sordy]

@skizzian Thanks for that I hadn't seen that particular one before.

I have Shimano XT brakes and they have a Free-Stroke-adjust feature. I have never ever been able to detect any benefit from the FSA. It makes no difference that I can detect whether it is fully in or fully out.

The content of the video makes perfect sense to me. I related in one of my previous posts in this thread the impact of more or less fluid in the brake system. But I haven't been able to make use of that knowledge on this occasion, hence the trip to the LBS.

 

[skizzian]

@skizzian Thanks for that I hadn't seen that particular one before.

I have Shimano XT brakes and they have a Free-Stroke-adjust feature. I have never ever been able to detect any benefit from the FSA. It makes no difference that I can detect whether it is fully in or fully out.

The content of the video makes perfect sense to me. I related in one of my previous posts in this thread the impact of more or less fluid in the brake system. But I haven't been able to make use of that knowledge on this occasion, hence the trip to the LBS.

the fact that he ignored the FSA and reach adjusters but still changed the effective reach with the system closed is interesting - I never open the system for the purpose of getting the pads apart - which does point back to your adjustment on the trail...
definitely a head scratcher

 

[ZR1]

I rode up a mountain, attempted to hop over a water bar whilst climbing and dinged the rim.

Also changed mavens over from my other bike as missed the power and consistency on long descents

 

[Mijo]

As a newbie I'm a long way behind the curve on mods and upgrades however I did go "tubeless" this weekend and I have to say it was so easy!

I also went tubeless this weekend. Shwalbe Big-Betty's, Muk-Off tape and Orange Stuff. No runs, drips or errors. Beat'm up on Tuesday and they worked great!

Rode the purple one at Staunton on trails, Enduro type riding with up, down, falls, glory and smiles.
Rode the Orange one to my house on a few trails/roads after dropping van off for servicing.

IMG_20240424_182850 by Steve Weeks, on Flickr

Thats an Impressive Stack of Wood! Ready for winter I'd say!

 

[Mijo]

I also went tubeless this weekend. Shwalbe Big-Betty's, Muk-Off tape and Orange Stuff. No runs, drips or errors. Beat'm up on Tuesday and they worked great!

 

[Amber Valley Guy]

Looking at my bike today (was out on it yesterday) I noticed my rear brake rotor was wearing strangely. By strangely I mean the rear brake pad sweep on the disk wasn't a mil or mil and and a half from the edge but a good 3mm (1/8") down from the perimeter. And the rotor 'spokes' had a corresponding 3mm (approx) wear mark on them below the pad sweep area.

Hmmm, it's a 203mm disk, plus 23mm TRP adapter on rear 180 post mounts with TRP brakes on 6 bolt Shimano 203mm disks. Something isn't right, a quick calculation said I'm losing about 15% rear braking capacity as the lower part of the pads is squeezing fresh air until it hits a spoke. So I've shimmed the caliper up 1.5mm (thickest flat M6 washers I had) and noticeable improvement, bar the squealing. Yes I probably need a new rear rotor, no biggy, but what the hell, the only thing I can think of is the post mounts are short from the factory, everything else measures up . A few pics

 

[steve_sordy]

Nice fix. Cheap, quick and effective!

 

[VWsurfbum]

Looking at my bike today (was out on it yesterday) I noticed my rear brake rotor was wearing strangely. By strangely I mean the rear brake pad sweep on the disk wasn't a mil or mil and and a half from the edge but a good 3mm (1/8") down from the perimeter. And the rotor 'spokes' had a corresponding 3mm (approx) wear mark on them below the pad sweep area.

Hmmm, it's a 203mm disk, plus 23mm TRP adapter on rear 180 post mounts with TRP brakes on 6 bolt Shimano 203mm disks. Something isn't right, a quick calculation said I'm losing about 15% rear braking capacity as the lower part of the pads is squeezing fresh air until it hits a spoke. So I've shimmed the caliper up 1.5mm (thickest flat M6 washers I had) and noticeable improvement, bar the squealing. Yes I probably need a new rear rotor, no biggy, but what the hell, the only thing I can think of is the post mounts are short from the factory, everything else measures up . A few pics

View attachment 167571 View attachment 167572 View attachment 167573

Kind of a standard thing that, I think all my bikes are running a 1.5mm washer between adapters.

 

[Amber Valley Guy]

Kind of a standard thing that, I think all my bikes are running a 1.5mm washer between adapters.

Can honestly say I've never seen it before and the front post mounts with the same TRP plus 23mm adapters are perfect. Is it a rear brake caliper thing? Anyway I've ordered a new rear disk.

 

[VWsurfbum]

Can honestly say I've never seen it before and the front post mounts with the same TRP plus 23mm adapters are perfect. Is it a rear brake caliper thing? Anyway I've ordered a new rear disk.

if a mount is for 160/180/200mm and adding a 20/40mm adapter but using a 203 rotor you need a 1.5mm spacer.

 

[skizzian]

if a mount is for 160/180/200mm and adding a 20/40mm adapter but using a 203 rotor you need a 1.5mm spacer.

that makes sense - but he had a 23mm extender...

 

[Amber Valley Guy]

if a mount is for 160/180/200mm and adding a 20/40mm adapter but using a 203 rotor you need a 1.5mm spacer.

????, it's 23mm spacer as I've stated in my posts.

 

[steve_sordy]

Ref my previous post #1018 on 1st Sep'25. About an unusual rear brake problem.

The LBS guy believes it is the lever assembly piston seal, leaking into the bladder, therefore no fluid leaking externally to see. I had a spare lever assembly (from 4 years ago when I broke the lever, since fixed). So I took that in for him to try. Worked perfectly! Problem solved.

He had come across this before with his own road bike. He had taken apart the lever assembly and found the problem, so he was aware it could happen.

 

[skizzian]

Ref my previous post #1018 on 1st Sep'25. About an unusual rear brake problem.

The LBS guy believes it is the lever assembly piston seal, leaking into the bladder, therefore no fluid leaking externally to see. I had a spare lever assembly (from 4 years ago when I broke the lever, since fixed). So I took that in for him to try. Worked perfectly! Problem solved.

He had come across this before with his own road bike. He had taken apart the lever assembly and found the problem, so he was aware it could happen.

good to know

 

[BAh30]

Bought a orbea kemen suv for trekking duty. I removed the head light mounted to the stem b/c i couldnt use any kind of handlebar bag or a front rack w/o it being right in the way. Then i replaced all the internally routed cabling in the steertube spacers with traditional steertube spacers so the cabling is externally routed making it easier to lower the bars to fit racks/baskets. Also looks so much better..

 

[Amber Valley Guy]

Serviced the lower legs and fitted XT 4 pots to replace the TRP T4's. Had to drop the motor to get the rear brake hose in as it wouldn't get past the sharp bend at the bottom of the down tube battery space (thank god my bikes a front removal battery) easy enough now I know how to do it. Didn't expect it take 9 hours though.l, but I was giving everything a good clean as I dismantled everything. By the way anyone who has a an EP8 and I presume an EP801 the non drive side terminal cover is an absolute BITCH to align when replacing, I think a good hour or more of the 9 hours was just trying to get all three tiny screws to align.

 

[irie]

Was almost completely dried out so topped up sealant in tyres.

Tubeless sealant top up

Just topping my sealant up for the 4th time. I was just wondering if people just keep adding more until the tyre needs replacing or clean stuff out at some point. Not had a tyre off yet so not sure what to expect re solidified sealant. Before I went tubeless I had the tyre off on most rides.

www.emtbforums.com

 

[Amber Valley Guy]

Found the problem with the uneven rotor wear which I posted a few comments above. The aftermarket pads have the braking compound (semi metallic) placed on the backing pad about 2mm lower than a genuine pad. Which is a pity as the Sommet pads are great otherwise, and I have 3 more brand new pairs.
Anyway if you look in the picture you'll see a genuine pad on the left (TRP Blue) and a pair of the Sommets on the right, all aligned through the hole with the pad compound further down the pad. So if buying aftermarket pads, it may be worth checking that the braking compound lines up with the original set before you knacker your rotors.

 

[skizzian]

snapped me shimano mt500 dropper lever in a greasy root crash
also snapped my left butt cheek
time to buy a new i spec ev lever...

 

[steve_sordy]

Ref my previous post #1018 on 1st Sep'25. About an unusual rear brake problem.

The LBS guy believes it is the lever assembly piston seal, leaking into the bladder, therefore no fluid leaking externally to see. I had a spare lever assembly (from 4 years ago when I broke the lever, since fixed). So I took that in for him to try. Worked perfectly! Problem solved.

He had come across this before with his own road bike. He had taken apart the lever assembly and found the problem, so he was aware it could happen.

The lever felt great in the LBS. Felt great when I set off on my next ride. By the end of the ride, the travel adjust was back at the extreme, my 2nd finger was getting trapped, and this time, pumping the lever made it firmer (ie air in the system). What the hell is it?

Left message with the LBS (they tend to use the answerphone on Mondays to crack on with work). I will keep updating.

Looking on the bright side, that means that I don't have a scrap lever assembly after all!

 

[VWsurfbum]

The lever felt great in the LBS. Felt great when I set off on my next ride. By the end of the ride, the travel adjust was back at the extreme, my 2nd finger was getting trapped, and this time, pumping the lever made it firmer (ie air in the system). What the hell is it?

Left message with the LBS (they tend to use the answerphone on Mondays to crack on with work). I will keep updating.

Looking on the bright side, that means that I don't have a scrap lever assembly after all!

Leaky hose/caliper/union. It only needs to be a tiny amount.

 

[Tyjay]

Sent fox x2 factory off for warranty work due to some weird squishing sound
They fix or replace it for free as it was a silent recall
also sent back MT7 brakes under warranty as master reservoir burst again and they can’t be repaired
fully expect Magura to say it’s my fault but truth is they just failed on a trail

strategically sent off when I’ll be away for 2 weeks