Brakes keep cooking?

[Marke]

Hi Guys,

I have a trek powerfly lt 2018 and with around 3500 km's on it. I seem to be replacing my brakes (calipers and levers) about once a year. My rear brake has just started playing up and not bleeding properly. I suspect they are getting hot when I got downhill riding which i do for maybe ten days a year. I'm not the fastest but carry a little speed - I've done a bit of motocross racing in the past. At the moment I have a 2 pot deore on the rear and a 4 pot deore xt on the front. I do a full bleed a couple of times a year and the fluid is darker than fresh but not completely black.

The novelty of buying and installing brakes has worn off. Does my cooking theory holdup? If so should i just go shimano 4 pot saints all round? I think saints have banjo connectors - can i use my existing hoses with new ends or do i need to replace the hoses - this requires a motor removal?

Thanks in advance

Regards

Mark

 

[Mteam]

when you say its not bleeding properly, exactly what is wrong with it? is it leaking air into the system, ie seal failure, or something else?

You shouldnt be buying new calipers and definitely not levers every year, they should last way longer than that even with repeated overheat events.

If you are overheating them ,and you really would know if you were overheating them because their performance would drop off massively the moment they overheat - if you're not experiencing this then you're not overheating them, If you are then it may be worth investigating bigger rotors, or if you are already on 200mm rotors, then a better braking system like saints may be in order.

I suspect you could reuse the existing hoses if the banjos ar ethe same sizes.

 

[KenX]

Bigger rotors should help, also is it mainly the rear that's cooking? If so you need to brake more with the front, I was guilty of this when I started DH, boiling the fluid, blue discs, always the rear, learnt how to use the front brake and bingo, no more problems.....

 

[Marke]

when you say its not bleeding properly, exactly what is wrong with it? is it leaking air into the system, ie seal failure, or something else?

You shouldnt be buying new calipers and definitely not levers every year, they should last way longer than that even with repeated overheat events.

If you are overheating them ,and you really would know if you were overheating them because their performance would drop off massively the moment they overheat - if you're not experiencing this then you're not overheating them, then it may be worth investigating bigger rotors, or if you are already on 200mm rotors, then a better braking system like saints may be in order.

I suspect you could reuse the existing hoses if the banjos ar ethe same sizes.

Thanks for that, the brakes just seem to be sucking in air. They work fine when new but as they get older and after several bleeds they seem to get spongy faster. I replace them when i loose confidence. I don't want a days riding ruined through brake failure. I do get brake fade and the disks are a bit discoloured. The bike came with 200mm rotors as stock. My theory is I'm cooking the seals.

 

[Mteam]

Thanks for that, the brakes just seem to be sucking in air. They work fine when new but as they get older and after several bleeds they seem to get spongy faster. I replace them when i loose confidence. I don't want a days riding ruined through brake failure. I do get brake fade and the disks are a bit discoloured. The bike came with 200mm rotors as stock. My theory is I'm cooking the seals.

Sounds like a leaking seal . I had a set of hayes brakes years ago where the thread that the bleed nipple screwed into became a little worn after a few bleeds and wouldnt seal up properly , a bit of teflon tape round the thread fixed that, but its a bit risky on a safety critical item like a brake.

From what you say and the fact that you're on 200mm rotors already then yes I'd be looking to get something more suited to what you need that wont overheat , something like Saints or the current XT 4 pots should be fine. I've got the current model XT 4 pots on my ebike, sram code rsc on my normal bike and magura mt5 on my other normal bike.

They all work fine, and all have never overheated, but I prefer the sram code rsc overall.