Tektro m275 lack of brake pad retaining screw, leaking hydraulic oil, fragile hub, brake issues

[newbiemtb121]

Hi all, first post here, sorry about the long list of problems in advance but i can't seem to find details about this particular brake.

So i got an MTB months ago, rear wheel fell off suddenly during transportation, no idea how the QR lever could have done that by itself, left rear brake pad suddenly kept contacting the rotor and wouldn't stay the hell away no matter how many times i tried to adjust the caliper body via the mounting screws, it's as if just leaving the bike standing does that. Also allowed hydraulic fluid to leak out from behind the pistons when i loosened the screws holding the caliper together. Since retightening it, oil still leaks when i try to refill from the bleed port. but oddly doesn't happen when actuating the brake lever. I can't find any manuals for this particular model and am reticent about bending that retaining pin that seems to be holding the brake pads in place, in addition to also holding the caliper together and which stops me from resetting the pistons for this problem. Does anyone have any experience with calipers like this that don't have retaining screws for the brake pads?

Also, just took a fall, me falling well clear of the bike, on flat asphalt at barely 13mph, and when i cranked the pedals again, the splines were evidently damaged! Am i just unlucky or are MTB's these days that useless? I suppose i'd have to replace the entire wheel now?

Apologies for the flurry of questions, not really happy about what seems to be a poor POS for the money right now, thanks in advance for any advice.

 

[Cycleops]

Hello and .to the forum

Sorry about your woes. A few pics might be useful in seeing what the damage is.
What splines were damaged?
What make/model is the bike?
Specialized?

 

[newbiemtb121]

Hi, thanks for your reply. The damage is not visible unless perhaps i open up the hub itself, tools for which i lack. It's a Polygon Xtrada 5 2021, not sure if it's even known in this forum, bought it because of the apparently premium parts for the money but... poor experience for a first MTB. I reckon a damaged hub from simply falling at low speeds on the road isn't normal though?

Ah and i meant ratchet, that clickity clackity thing as the wheel coasts, still pretty new to biking!

 

[Cycleops]

Still at a loss to understand your problem. The clickety thing you describe is the freehub, or do you mean the cassette sprocket that carries the chain? How the freehub splines/cassette got damaged from a fall I can’t understand. If it’s damaged beyond repair you’ll either need a replacement hub, which will need to be laced onto the existing rim or a replacement wheel. If you don’t have tools or know a wheel builder or shop that can do it for you the latter might be your best solution.
if the cassette is damaged it’s a simple job to replace, but you’ll need tools.
I say again a picture would help to understand.
If you have a bike shop nearby I would suggest that would be the best place to get it sorted if you don’t have tools.

Regarding the brakes if you’ve got oil on the pads that renders them useless so you’ll need new pads. Again a bike shop will sort this for you and property adjust the calipers and clean everything up.

 

[newbiemtb121]

It's definitely the freehub, cassettes are fine. Could it be a simple misalignment or is it probably damaged beyond repair from the sound of it? If it's already damaged i'd skip going to my LBS and just get a simpler bicycle for my workout needs and sell this to someone who knows how to deal with it, I'm afraid i might have just given too much importance to the quality level of the drivetrain for my needs. ..

would cleaning the pads with rubbing alcohol not help though?

 

[fossyant]

Sounds like you've damaged the caliper by splitting it apart (god knows why you did that). The retaining pin, called a split pin, needs one 'prong' to be bent when fitted, just bend straight when changing pads (when you pull the pin out. You've likely contaminated the pads and disc if you've had oil leaks. Only new pads and a well cleaned disc will work.

Have you followed the correct bleed procedure for the brakes - probably not if you can't find the details.

PS wheels will come off if you've not checked the tightness of the QR.

 

[fossyant]

https://www.tektro.com/upload/Product/F_20150915093971Rwrqel.PDF

 

[newbiemtb121]

Split pin! That's it, i was reluctant to bend it, expecting it to snap after repeated bending. I just inserted fluid from the caliper side but fluid kept spurting out at the pistons, don't have 2 syringes or a funnel that fits the threading on the master bleed port.

QR lever has been tightened since i realized that solving the rotor contacting the pad issue was as simple as loosening the caliper mount and shifting it, prior to that every time i tightened the QR to a point i was comfortable with the rotor wouldn't stop contacting the pad.

So, new pads, does it sound like my hub is toast too? The wheel does spin fine, spinning the cranks spins the wheel too, but perhaps it's a single ratchet that's damaged beyond repair?