Yamaha YBR Front Brake Stuck

PsychoPigeon · 18 Oct 2020 at 16:17

Hi, just want to get a second opinion on what to do next after an issue with my front brake.

For the last couple of weeks I've heard a slight scraping sound coming from the front of the bike and it's started to become more noticeable. I've had no issues while riding, steering is great and brakes work as they always have done. I put the bike on the centre stand and got the front wheel off the ground and spun it and could hear the scraping while the wheel moved freely. I used the front brake then released and the wheel struggled to move freely after that, the piston in the caliper did not pull back all the way. Eventually it freed itself but I took off the caliper to rule out any other issues, the sound is definitely being generated by the caliper.

I wanted to clean the pads or see if anything was wrong with them, the bolt that has the 2 pins through it seems to have seized I cannot get this thing off. I thought ok I will clean what little I can see of the piston but it refuses to retract at all and has bitten down on the brake pads so I can't even get it back on the bike. Would anyone have any advice for that?!

Piston: https://i.ibb.co/zScL98Q/2222.jpg
Seized bolt holding the pads: https://i.ibb.co/P4gg4Qp/111.png

Should I look around for a new caliper, if so what would your procedure be for fitting it, should I take apart the new one and grease parts before fitting, drain brake fluid etc? What would your workflow be like?

PsychoPigeon · 18 Oct 2020 at 17:49

Ok thank you that's pretty clear. Is there a way to get the piston to ease off and relieve pressure as I cannot get underneath it. Would bleeding while it in its current state work? Either way, I'll probably have to get a new caliper because of this seized bolt that prevents from getting anything loose

PsychoPigeon · 19 Oct 2020 at 21:35

It's not threaded just seized up, I will give it a go with a hammer (ordered some PlusGas for it.) Bit worried how I'm going to get the piston back in, seems like the only way is with a clamp. I ordered some chrome polish and grease will try and lube it up.

PsychoPigeon · 20 Oct 2020 at 00:17

There's a lot new calipers available that come with break pads that fit the YBR 2016 model, but they're from China (the gold ones spammed all over Ebay and Amazon.) I wasn't sure if I should take my chances with one of them.

If I buy a second hand unit am I not going to run into this problem later on and still have to service the caliper? (or maybe you're just referring to me having to be rough with the current one?)

PsychoPigeon · 20 Oct 2020 at 12:24

I found one on Ebay that looks legit from VMP motorcycle parts, it's £50 with new brake pads and post included. I'll go with that and rebuild the old one as a side project and let you know if I need help fitting. I'll be draining the brake fluid for the first time too.

PsychoPigeon · 21 Oct 2020 at 13:28

The YBR doesn't have ABS, it's a pretty basic learner bike. As far as I understand I'll only need to pump the brake fluid through the new caliper to push out all the air right, then top it up? I won't need to drain the entire reservoir (it had a fluid change recently during MOT.)

PsychoPigeon · 21 Oct 2020 at 18:00

Ok got it, I should only use the red rubber grease if it's coming into contact with the rubber seals. I have been reading but the problem is that people do different things, there's some using white grease to try and ease the piston back in saying that the seals block any contamination to the brake fluid so that's not an issue, others saying anything other than rubber grease erodes the seals faster. But it's good to learn, no one ever told me about the front brake eventually having to be serviced I know it's in the manual but I expected the MOT to pick it up if it showed signs of serious wear, I'm just glad it happened while the bike was stationary and didn't get stuck while riding.

PsychoPigeon · 26 Oct 2020 at 15:12

New caliper and pads installed ok, drained the brake fluid reservoir 3 times (while topping it up before reaching the bottom) just to make sure there was no air left in the system and topped up the reservoir to the maximum since it's new pads.

I'm noticing the pads are dragging but from what I understand that's expected until they wear in? And the brake disc is lukewarm after a 30 minute ride not overly hot.

The brake itself feels like it has a little less resistance when pressing it than previously, could this be down to new caliper replacing a 5 year old one? But other than that the front brake works great.