Mechanics Quick Question Thread [Ask Questions Here]

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Mechanics Quick Question Thread [Ask Questions Here]
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Posted: Mar 28, 2020 at 15:36 Quote
cyberoptixs wrote:
KUBBY wrote:
Hey, I'm having some brake troubles.

Got my brakes bled and pads changed by the shop. I don't think they bed them in though. My front brake is working perfect. But my rear doesn't grab and just squeals horribly. Any advice on how I can troubleshoot this and get my rear brake working again? Thanks.

you asked and answered your own question

clean the disk with iso and sand the pads so they are clean and bed them in

Posted: Mar 28, 2020 at 15:39 Quote
cyberoptixs wrote:
clean the disk with iso and sand the pads so they are clean and bed them in

Always a good first step. Just want to note acetone works better than isopropanol ... and we should probably conserve our isopropanol for use as hand sanitizer! Big Grin

Posted: Mar 28, 2020 at 15:44 Quote
R-M-R wrote:
reverend27 wrote:
The cups are part of the frame.

Then let's really hope they're straight! Something is sitting off-axis.

The saving grace is it wasn't doing this and now it is. I had the Shout on there and it wasn't doing it. I also had a Mrp Ribbon on it with no issue.

I'm just a stickler for a quiet bike.

I did notice I don't have the washer that goes under the compression ring.

Posted: Mar 28, 2020 at 15:46 Quote
cyberoptixs wrote:
KUBBY wrote:
Hey, I'm having some brake troubles.

Got my brakes bled and pads changed by the shop. I don't think they bed them in though. My front brake is working perfect. But my rear doesn't grab and just squeals horribly. Any advice on how I can troubleshoot this and get my rear brake working again? Thanks.

you asked and answered your own question

I tried bedding the rear in again but no dice.

Posted: Mar 28, 2020 at 15:51 Quote
KUBBY wrote:
cyberoptixs wrote:
KUBBY wrote:
Hey, I'm having some brake troubles.

Got my brakes bled and pads changed by the shop. I don't think they bed them in though. My front brake is working perfect. But my rear doesn't grab and just squeals horribly. Any advice on how I can troubleshoot this and get my rear brake working again? Thanks.

you asked and answered your own question

I tried bedding the rear in again but no dice.

Everytime I've had no bite and a squealing rotor it's been from brake fluid contamination.
If it got soaked bad you'll have to burn it off.
If is a metal or hybrid that'll work but resin tend to fall off the backing plate.

Trust me I have been absolutely cursed with rear brake contamination.

Posted: Mar 28, 2020 at 16:04 Quote
R-M-R wrote:
cyberoptixs wrote:
clean the disk with iso and sand the pads so they are clean and bed them in

Always a good first step. Just want to note acetone works better than isopropanol ... and we should probably conserve our isopropanol for use as hand sanitizer! Big Grin

why acetone i thought it left a residue that was bad for the pads?

Posted: Mar 28, 2020 at 16:15 Quote
cyberoptixs wrote:
why acetone i thought it left a residue that was bad for the pads?

It's a more effective solvent. Everything isopropanol can do for brake pads, acetone can do better.

Commercial brake cleaners are either acetone or tetracholorethylene, plus propellants. Tetracholorethylene is more toxic, so stick to acetone.

Posted: Mar 28, 2020 at 16:26 Quote
R-M-R wrote:
cyberoptixs wrote:
why acetone i thought it left a residue that was bad for the pads?

It's a more effective solvent. Everything isopropanol can do for brake pads, acetone can do better.

Commercial brake cleaners are either acetone or tetracholorethylene, plus propellants. Tetracholorethylene is more toxic, so stick to acetone.

The few times I have used acetone brake cleaners it seemed worse initially.... perhaps something else in the cleaner... who knows. Fire is my primary go to for brake contamination, with huge success... although, taking a few precautions before I begin messing around with fluid and preventing the contamination is probably the best solution.

After they run out alcohol, maybe they can use acetone as hand cleaner ... if people are sewing home made cotton masks to replace properly fit N95’s, ya never know.

Posted: Mar 28, 2020 at 16:30 Quote
reverend27 wrote:
The saving grace is it wasn't doing this and now it is. I had the Shout on there and it wasn't doing it. I also had a Mrp Ribbon on it with no issue.

I'm just a stickler for a quiet bike.

I did notice I don't have the washer that goes under the compression ring.

I've encountered this a few times due to crooked spacers. Once it was an aluminum spacer with a huge burr and twice it was poorly cut carbon spacers. Add it to your list if everything else checks out!

Posted: Mar 28, 2020 at 18:05 Quote
R-M-R wrote:
reverend27 wrote:
The saving grace is it wasn't doing this and now it is. I had the Shout on there and it wasn't doing it. I also had a Mrp Ribbon on it with no issue.

I'm just a stickler for a quiet bike.

I did notice I don't have the washer that goes under the compression ring.

I've encountered this a few times due to crooked spacers. Once it was an aluminum spacer with a huge burr and twice it was poorly cut carbon spacers. Add it to your list if everything else checks out!

Thanks for being so helpful.

Since my last post I cut the steerer and now have my stem slammed and one spacer on top per Trust instructions. Still creaked.

So I disassembled again had a bearing sitting in my box don't know where it came from.
But the chamfper was much more pronounced more slant bigger bevel. So my thinking was it sits deeper in the cup and makes more contact.

Took it up on Oklahoma State campus and hit some stair drops ran it into curbs etc. No creaking or popping. Though I think it still loosened on me a tiny bit but not a peep out of it.

That was a 20 min ride though. Tomorrow I'm out for a 30 mile trail loop so we'll see how it holds up.

Posted: Mar 28, 2020 at 18:18 Quote
Hey guys, I'm curious wether or not the Oneup EDC tool will fit in a rockshox boxxer. I don't see why not as the tool is the same diameter throughout. Note: I don't care if i'm "not supposed to do it" nor do I care if its a safety hazard. I just want to know if it would fit.

Posted: Mar 28, 2020 at 18:25 Quote
reverend27 wrote:
chamfper was much more pronounced more slant bigger bevel.

There are two "standard" angles for the interface at the inner surfaces of integrated headset bearings. 45° is most common and 36° has also been used.

Is it possible you had a spare bearing with the incorrect angle and accidentally switched them?

Posted: Mar 28, 2020 at 19:18 Quote
R-M-R wrote:
reverend27 wrote:
chamfper was much more pronounced more slant bigger bevel.

There are two "standard" angles for the interface at the inner surfaces of integrated headset bearings. 45° is most common and 36° has also been used.

Is it possible you had a spare bearing with the incorrect angle and accidentally switched them?

No I don't think so. I just dropped the fork because I wanted to run longer brake line and longer di2 wire. I only had 2 bottom bearings the one I was using first and the one with the bigger angle. The one with the bigger angle was in my catch all bin.

Now the bottom bearing has a completely different angle then the bottom bearing.
The crown race I'm using is from a cane creek angle set I was using on my Intense. I noticed when playing with the crown race from the Giant headset that the bearings wanted to slide around on it. So I thought maybe thats where its happening.
This could all be from lack of torque. But from what I'm reading it seems 5nm should be plenty.

Posted: Mar 28, 2020 at 19:22 Quote
reverend27 wrote:
R-M-R wrote:
reverend27 wrote:
chamfper was much more pronounced more slant bigger bevel.

There are two "standard" angles for the interface at the inner surfaces of integrated headset bearings. 45° is most common and 36° has also been used.

Is it possible you had a spare bearing with the incorrect angle and accidentally switched them?

No I don't think so. I just dropped the fork because I wanted to run longer brake line and longer di2 wire. I only had 2 bottom bearings the one I was using first and the one with the bigger angle. The one with the bigger angle was in my catch all bin.

Now the bottom bearing has a completely different angle then the bottom bearing.
The crown race I'm using is from a cane creek angle set I was using on my Intense. I noticed when playing with the crown race from the Giant headset that the bearings wanted to slide around on it. So I thought maybe thats where its happening.
This could all be from lack of torque. But from what I'm reading it seems 5nm should be plenty.
Forget torque, property bearing preload is the only thing that really matters.

Posted: Mar 28, 2020 at 23:40 Quote
reverend27 wrote:
R-M-R wrote:
reverend27 wrote:
It does it when I turn the handlebars from side to side and im not on it.

I think something is off-axis and is being forced to shift as it turns. Best case: tap down all the cups, races, etc. Worst case: pull the headset and face the head-tube.

The cups are part of the frame.

So it's doing it again it was tight when I left the house. Now when I hold the the front brake push it I can feel the
I don't have a 5nm torque key so I am guessing..but I had it so tight yesterday that I broke one of the stem bolts.

I'll mess with it again tomorrow. I may take pictures of my assembly in chronological order for you to look at.
It sucks cause my lbs is only doing emergency repairs right now.

Have you got those super thin spacers between the compression washer an the top cover? Some times they help


 
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