Rear disc brake issue

[Jakkals.]

Hi Gents, need some help here from the tech guys.

 

Okay, first, I'll admit, I also own a mtb, for those who didn't know.

 

Long story short, I cant get the rear brakes to center.

 

The bike stock comes with 140mm rotors, however when I bought it it had 160mm rotors and the caliper was bolted onto one of those 140->160 thingies.

 

I've taken the calipers completely off, tighten them again but as soon as I do that, the whole bracket underneath the screw moves the caliper against the rotor, with a half a turn back it rectifies itself, however it moves again when I ride. and I have constant friction between pad and rotor.

 

I've given up riding with my 29er for now, and riding my trusty 26er without issues.

 

So please advise what else there is I could do.

 

Thanks, have a great Friday and an absolute brilliant weekend.

Edited June 20, 2014 by antonj

[yetiboy]

If I understand the problem correctly, loosen the centering bolts on the calliper, pull and hold the brake lever firmly and while doing this tighten the bolts. Should be fine after that.

[Vangar]

Couple of things I can suggest.

 

1.) Make sure nothing is broken(Sure you've done this)

2.) The plastic bushes that go up against the spacers, take them completely off and the bolts apart, or try swapping them around. This makes no sense but was the only thing that worked for me.

3.) Manually center the caliper using your fingers and tighten it down, or pull that brake like there's no tomorrow and tighten it down.

[shaper]

Take a look at the post mount bracket, in particular where the 2 points connect to the frame. check to see if is flat or whether has a raised part which does not seat properly against the frame.

 

I had a similar issue where a part of one of the screw points did not sit flush with the frame and as soon as I tightened it, it moved and had a similar problem with the caliper not centering on the rotor.

 

I replaced the post mount bracket which solved the problem

Edited June 20, 2014 by shaper

[openmind]

Clean and grease the shoulders of the bolts that hold the calliper to the brake mount. Loosen both bolts slightly so that the calliper can move side-to-side. Walk the bike forward while pulling the brake lever to centre the calliper. Stop the bike, hold the brake lever in hard and carefully tighten the calliper bolts each a little at a time, alternating between them until they're tight. If the calliper moves, start again and tighten the bolts even less each time. Release the brake and spin the wheel to check alignment.

[Guest CHRIS001]

Good day

What brakes are they

[Vangar]

Take a look at the post mount bracket, in particular where the 2 points connect to the frame. check to see if is flat or whether has a raised part which does not seat properly against the frame.

 

I had a similar issue where a part of one of the screw points did not sit flush with the frame and as soon as I tightened it, it moved and had a similar problem with the caliper not centering on the rotor.

 

I replaced the post mount bracket which solved the problem

Couple of things I can suggest.

 

1.) Make sure nothing is broken(Sure you've done this)

2.) The plastic bushes that go up against the spacers, take them completely off and the bolts apart, or try swapping them around. This makes no sense but was the only thing that worked for me.

3.) Manually center the caliper using your fingers and tighten it down, or pull that brake like there's no tomorrow and tighten it down.

Clean and grease the shoulders of the bolts that hold the calliper to the brake mount. Loosen both bolts slightly so that the calliper can move side-to-side. Walk the bike forward while pulling the brake lever to centre the calliper. Stop the bike, hold the brake lever in hard and carefully tighten the calliper bolts each a little at a time, alternating between them until they're tight. If the calliper moves, start again and tighten the bolts even less each time. Release the brake and spin the wheel to check alignment.

 

So to rephrase:

 

Step 0.1: Obtain at least six beers and open one....going to take a while

Edited June 20, 2014 by Vangar

[Jakkals.]

Couple of things I can suggest.

 

1.) Make sure nothing is broken(Sure you've done this)

2.) The plastic bushes that go up against the spacers, take them completely off and the bolts apart, or try swapping them around. This makes no sense but was the only thing that worked for me.

3.) Manually center the caliper using your fingers and tighten it down, or pull that brake like there's no tomorrow and tighten it down.

 

I've pulled that brake with a bobejaan spanner boet, not working.

I dont have any bushes or spacers either, I have tried using my fingers and tighten but still this doesnt help, because at first, when I press the caliper, it moves the rotor a bit and secondly, when I tighten the bolts, it still moves on the bracket.

[Jakkals.]

Good day

What brakes are they

 

y did you have to ask this question?

 

they are avid XX

[Jakkals.]

Not sure how to word it, but when tightening the bolts, clockwise, it moves the caliper on the bracket(caliper towards the rear wheel) and I can hold that brake in as hard as I like, it still moves, as if there is a groove that the screw wants to go into.

[Zaskar09]

I've pulled that brake with a bobejaan spanner boet, not working.

I dont have any bushes or spacers either, I have tried using my fingers and tighten but still this doesnt help, because at first, when I press the caliper, it moves the rotor a bit and secondly, when I tighten the bolts, it still moves on the bracket.

 

There's your problem

[G00SE]

y did you have to ask this question?

 

they are avid XX

 

I think you've found your problem....

[Jakkals.]

There's your problem

 

Makes sense, but how do I go about this now?

 

The caliper will be standing in the air if I put anything underneath it.

[Vangar]

There's your problem

 

Agreed, swap out the spacer and the bolts. They are'nt really expensive,

[Jakkals.]

I think you've found your problem....

 

Hahah, I'm from the avid appreciation club

[missionS]

Check and see if you have a washers between the bolt head and brake calliper?

 

In the picture the little conical washer has a small plain flat washer on top and this is the one I'm referring too.

Edited June 20, 2014 by missionS