Author Topic: Front disc brake issue  (Read 242 times)

bus4@207

Front disc brake issue
« on: September 12, 2026, 05:51:05 AM »
I thought I would stick this here rather then the Mondince 336 dedicated thread.

When I try and centre my front caliper I cant get it to point where the pads and disc is not rubbing.
New disc and new pads  are the worst combo. Old disc and new pads is the best I can get but still get a 'ping'.
After about an hour of messing around I noticed that the bottom part of the caliper is being sitting inwards ie the bottom screw hole in the frame is not in line with the top hole.
Now if I pull the bracket at the bottom to make it level the pad makes contact with the inside of the disc evenly. As soon as I open the bottom nut to centre the caliper and pads the bottom jump inwards towards the inside of the frame making centreing impossible.
I wanted to ask here to see if its me before I touch base with Mondince about it!
In the picture maybe you can see how the bottom of the bracket is moving inwards.
« Last Edit: September 12, 2026, 05:52:40 AM by bus4@207 »

bus4@207

Re: Front disc brake issue
« Reply #1 on: September 12, 2026, 06:07:48 AM »
I manage to get where it rolling without 'pinging'.
I had to open each bolt a fraction and adjust the top and bottom of the bracket seperatley to get clearance.
It was like having to make small pivots of the top and bottom without one interfering with the other.

ZacItaly15

Re: Front disc brake issue
« Reply #2 on: September 14, 2026, 04:24:34 AM »
new brake pad are not parallel each other.
Brand new rotor are always with some micro "chip" in the machining
I always suffer a little when using new brake pads so I try to aling as better as I can than...the downhill let the brake pads bed by themself
 

That's why professional teams and advanced shop use this bedding machine
https://trpcycling.com/products/trp-sinter-smart-bedding-machine?srsltid=AfmBOopc75Q44CrfqVS1ftUjLfk4Y9MnWGXbAstxFcM5v6YgVbzXFhEA

Serge_K

Re: Front disc brake issue
« Reply #3 on: September 14, 2026, 05:04:56 AM »
new brake pad are not parallel each other.
Brand new rotor are always with some micro "chip" in the machining
I always suffer a little when using new brake pads so I try to aling as better as I can than...the downhill let the brake pads bed by themself
 

That's why professional teams and advanced shop use this bedding machine
https://trpcycling.com/products/trp-sinter-smart-bedding-machine?srsltid=AfmBOopc75Q44CrfqVS1ftUjLfk4Y9MnWGXbAstxFcM5v6YgVbzXFhEA

+1 on the importance of bedding in these things. Perfection on the bike stand at day zero doesnt matter, the bike needs a fair bit of shake down before it's worth worrying about the slightest noise or misalignment. True for rotors, headsets, gears, pretty much everything, really.

MarioCanario

Re: Front disc brake issue
« Reply #4 on: September 15, 2026, 08:51:26 AM »
getting brakes right is sometimes a bit of a task. is the disc true in all directions? maybe brake mounts need some slight facing? there is often a little correction needed

i got myself a wheel truing stand and a brake mount facing tool from alix. 150 $ well spent.
« Last Edit: September 15, 2026, 08:54:26 AM by MarioCanario »

frewster

Re: Front disc brake issue
« Reply #5 on: September 15, 2026, 10:15:17 AM »
Take the caliper off and look at the mounting posts. I could not get the front brake on my FM336 to not rub despite spending an hour trying to get it aligned. Turned out the threaded inserts weren't flush with the mounting posts. I ordered the brake mount facing tool discussed in this post (https://chinertown.com/index.php/topic,4812.msg113399.html#msg113399) and after carefully facing the posts on the fork I was finally able to tighten down the caliper without rubbing on the disc.