Calipers That Will Not Adjust Straight

[Gionnirocket]

I checked my brakes again and took some pictures,..



It turns out that the caliper spacer is countersunk, so there is actually a flat surface that could do some sealing and accommodate an o-ring,..

View attachment 188384View attachment 188383




I don't think that's it?
The spacer hole is only a smidgen bigger than the bolt.
The caliper itself has slotted mounting holes to allow for alignment,..

View attachment 188385View attachment 188386



I'm figuring that the spacer hole has to be a smidgen bigger than the bolt to allow for a different alignment when using the spacer?

I installed new air forks that were built for 180 mm rotors, so I didn't need the spacer and had to buy shorter caliper bolts to mount my caliper to the new forks,..

View attachment 188387


The original caliper bolts have those saucer shaped cone washers to allow for a slightly different alignment angle caused by the spacer being taller at one end than the other,..



View attachment 188388


I remembered @m@Robertson talking to @Nvreloader about those things, and how shitty/stupid they are, so I deleted them from my front caliper figuring that things should line up fine without the spacer?



I think that's it?
They just hold the bolt, washers, caliper, and spacer together to keep things from falling apart when things are assembled.




The o-rings go here, and actually work to hold everything together.

View attachment 188390


When you unbolt the caliper, the bolt doesn't fall out so it's all held together.





I removed the o-rings from both calipers, but I think that I'm going to remove those cone/saucer washers too.

They cause more trouble than they're worth.

View attachment 188391


The regular flat washer should be enough.
My bolt alignment might be off by 0.001° or something, but it's still better than the alignment issues that the cup and cones cause.

My caliper bolts will thread in farther, but the threaded holes in the frame go all the way through,..


View attachment 188392

Ok.. I couldn't tell from your original photo if the O_ring was at the bottom of the stack, which it is.... And that there's a ledge/space for it to sit in... Which there is. So it's probably as @PedalUma said, it's to hold everything together.
If so there's no need to remove it... Just make sure it's seated so it can work as designed an not getting sandwiched between parts like your squashed one causing problems.
Again... End user not understanding what to check and do.

Your definition of self centering and mine are not the same. I am referring either to a floating caliper or disc.

The cone washers allow for machining or lack of machining tolerances.

Yes we do.
That said... I wouldnt hold my breathe as understanding the nuances solves all problems.
Not trying to be condescending as all don't enjoy working on a bike... but that's the difference between an experienced mechanic and a parts installer.

 

[PCeBiker]

If so there's no need to remove it...

Sure there is.

I hadn't ever removed my rear caliper or bolt. I had just loosened the bolts enough to adjust my caliper.
The O-ring was pinched up and binding when I got my e-bike.

@PedalUma mentioned how some O-rings were disintegrated on brand new e-bikes he worked on.

Interestingly, I remember fussing with that rear caliper a bunch of times. It kept going crooked on me, but not when I torqued it up.
Mine went out of alignment after I rode the e-bike and used the brakes.

I thought that it was because the caliper doesn't pull straight down on the bracket because the caliper mount is about an inch offset from the rotor. (the caliper reaches out sideways to the rotor)

I thought that the whole caliper was torquing over sideways and throwing off the alignment.
I couldn't get the brake pads to stay centered in the caliper. They both got pushed sideways, so the rotor wasn't centered in the caliper.

I just gave up trying to center the rotor in the caliper.
The brake pistons kept the pads centered on the rotor, with one piston extended further than the other. The pads were wearing evenly, but the rotor barely cleared the caliper opening on one side.

So, I'll give it another try and get everything centered and see if it stays that way.

Someday when they get tired of improving everything else and can’t figure out how to make sales, they’ll get around to improving the disc brake system with a self centering pad.

Your definition of self centering and mine are not the same. I am referring either to a floating caliper or disc.

The pads and pistons do float within the caliper, so it doesn't matter if the rotor is perfectly centered in the caliper.

My car has only one brake piston on the brakes, so the caliper needs to float along the slider pins to get brake pad pressure to the outer brake pad.

Almost all e-bike calipers are dual piston (some have 4) so the caliper doesn't need to float.
The only issue comes from when one of the pistons is binding, then most of the brake pressure and pad wear goes to the opposite piston and pad on the other side.

 

[Gionnirocket]

Sure there is.

I hadn't ever removed my rear caliper or bolt. I had just loosened the bolts enough to adjust my caliper.
The O-ring was pinched up and binding when I got my e-bike.

@PedalUma mentioned how some O-rings were disintegrated on brand new e-bikes he worked on.

Interestingly, I remember fussing with that rear caliper a bunch of times. It kept going crooked on me, but not when I torqued it up.
Mine went out of alignment after I rode the e-bike and used the brakes.

I thought that it was because the caliper doesn't pull straight down on the bracket because the caliper mount is about an inch offset from the rotor. (the caliper reaches out sideways to the rotor)

I thought that the whole caliper was torquing over sideways and throwing off the alignment.
I couldn't get the brake pads to stay centered in the caliper. They both got pushed sideways, so the rotor wasn't centered in the caliper.

I just gave up trying to center the rotor in the caliper.
The brake pistons kept the pads centered on the rotor, with one piston extended further than the other. The pads were wearing evenly, but the rotor barely cleared the caliper opening on one side.

So, I'll give it another try and get everything centered and see if it stays that way.




The pads and pistons do float within the caliper, so it doesn't matter if the rotor is perfectly centered in the caliper.

My car has only one brake piston on the brakes, so the caliper needs to float along the slider pins to get brake pad pressure to the outer brake pad.

Almost all e-bike calipers are dual piston (some have 4) so the caliper doesn't need to float.
The only issue comes from when one of the pistons is binding, then most of the brake pressure and pad wear goes to the opposite piston and pad on the other side.

Removing them is just fine as well... My point was if the O_ring is sitting in it's designated area it won't affect the alignment.
That said getting it to stay there during installations and adjustments might be more trouble than it's worth.
So again... I've never seen this and I've recently worked on new TRP and another Tektro set of calipers with various spacers used.

 

[PedalUma]

This is why I flat sand off the paint, so the surfaces are smooth.

 

[Gionnirocket]

This is why I flat sand off the paint, so the surfaces are smooth.

Yeah my fork and chainstay mounts have no paint on the mounting surface... as it should be.

 

[PedalUma]

Bike manufactures buy forks in bulk. These are not quite on par with aftermarket forks and they often have paint on the posts. Because it is faster to make that way. If so, it has to go.

 

[PCeBiker]

Well, this is what I've got going on with my rear brake,..

I've got aftermarket air forks on the front but I'm not 100% sure what's going on with the caliper and bolts ?

I'm almost positive that I went to transfer the O-rings to the shorter caliper bolts and they broke, so I just said F-it and didn't bother replacing them while not knowing what they were supposed to do ?

This is why I flat sand off the paint, so the surfaces are smooth.

How do you manage to flat sand the flats squarely?

I'm worried that my flats will look more like this,..

Instead of this,..

 

[PCeBiker]

These are not quite on par with aftermarket forks and they often have paint on the posts.

The original forks were RST Guide forks with Tektro hydraulic brakes and 180 mm rotors, so both calipers had spacers.

The forks were supposed to be entry level spring suspension forks for fat bikes, and a pretty good bang for your buck, and they are not proprietary,..

The same forks came on both my ebikes. They are quite commonly used.

 

[PedalUma]

I get to give away another bike today. Well half a bike. I knew that my friend's kid needed a 24" up from a 20". I researched and found a 21 speed 24" flatbar gravel bike with cable discs, all through frame at a holiday price. I offered to buy it and dial it in if she paid half. The kid's 6th birthday was last week but they were out of the country. I applied black reflective tape over the ugly logo and on the top tube so it looks like carbon gloss. And I stripped a gold chain in the ultrasonic washer and hot melt paraffined it. And added a matching brass bell. It looks badass, with tanwalls.
To answer the question, just back your emery cloth with something hard and flat. Remove the paint and lightly grease all mating surfaces so they do not pull when being locked down. I like to strap on the lever. Please pass the strap on.

 

[PCeBiker]

To answer the question, just back your emery cloth with something hard and flat.

OK, I'm thinking of gluing the cloth to a chisel. It's got some weight to it and if I choke up on the handle, I can keep my hand pressure directly on top of the sanding area to help reduce the wobble/torque affect from not being on top of the sanding area.

And on a related note, (Vado induced Segway) I just bought a new knife sharpener that Kicks Ass !!

I've got two other sharpeners that I can't work worth a s*it,..

I find the single edged sharpener way too difficult to consistently hold at the proper angle and one off stroke takes off the entire edge.

The other one isn't much better and when you're pulling the knife through to the end, your hand is too far from the cutting blades to keep things lined up properly.

My new one works Awesomely, because you are pushing down directly above the cutting blades and pulling the sharpener along the knife blade instead, so it's Easy to keep everything square. No torque affect.
You just have to hold the knife square and you Easily end up with a sharp knife.

I clamped a Vise-Grip on the knife handle to hold it square and steady and add some weight.

It's still not a Chef Quality cutting edge, but I'm not interested in all the Specialized tools and techniques needed for a perfect edge.
That all gets completely carried away.

The edge is a little rough and ends up kinda serrated like any sharpener that scrapes the metal off, but I finally have sharp knives even if there is a bit of sawing going on when I cut.

 

[Gionnirocket]

OK, I'm thinking of gluing the cloth to a chisel. It's got some weight to it and if I choke up on the handle, I can keep my hand pressure directly on top of the sanding area to help reduce the wobble/torque affect from not being on top of the sanding area.

And on a related note, (Vado induced Segway) I just bought a new knife sharpener that Kicks Ass !!

View attachment 188426

I've got two other sharpeners that I can't work worth a s*it,..

View attachment 188427


I find the single edged sharpener way too difficult to consistently hold at the proper angle and one off stroke takes off the entire edge.

The other one isn't much better and when you're pulling the knife through to the end, your hand is too far from the cutting blades to keep things lined up properly.

My new one works Awesomely, because you are pushing down directly above the cutting blades and pulling the sharpener along the knife blade instead, so it's Easy to keep everything square. No torque affect.
You just have to hold the knife square and you Easily end up with a sharp knife.

I clamped a Vise-Grip on the knife handle to hold it square and steady and add some weight.

View attachment 188428



It's still not a Chef Quality cutting edge, but I'm not interested in all the Specialized tools and techniques needed for a perfect edge.
That all gets completely carried away.

The edge is a little rough and ends up kinda serrated like any sharpener that scrapes the metal off, but I finally have sharp knives even if there is a bit of sawing going on when I cut.

I have one of those ACCU-... and it works great.
I use very light pressure and only do 1 to 2 strokes on the blade every few weeks and they stay razor sharp.
I only cut on a board with my favorite knives

I picked up the garden version for my lawn mower blade and it's super fast and easy.

 

[Marcela]

If the pads and pistons did actually float, they wouldn't rub the disc and we wouldn't be having this chat. Is that not correct? I know if my pads and pistons were floating, they would be a set it and forget it.

 

[PCeBiker]

If the pads and pistons did actually float, they wouldn't rub the disc and we wouldn't be having this chat.
Is that not correct?

If the pads are rubbing, you might have a warped rotor or the pads and pistons aren't floating properly.

My brakes (and I think all hydraulic brakes) have a spring on the pads to retract them away from the rotor after the brake lever is released.

I took some pictures of my brakes,..

,.. I like to strap on the lever. Please pass the strap on.

I like to remove the pads and pump my lever a bunch of times.

 

[PCeBiker]

I have one of those ACCU-... and it works great.
I use very light pressure and only do 1 to 2 strokes on the blade every few weeks and they stay razor sharp.

Even with the light pressure, you can hear it cutting so you know it's working.
The other ones take way more pressure to hear them cut, then they just rip into the metal.

I only cut on a board with my favorite knives

I had no favorite knives.
They were all dull AF.

I picked up the garden version for my lawn mower blade and it's super fast and easy.

I use my grinder to sharpen my mower blade every year or so.

 

[PedalUma]

After all I have said, I did everything right today on a Aventon build including removing the O-rings and lubing all the adjustment surfaces, and still needed to use two business cards stacked to one side to get it locked down tight and right.

 

[Gionnirocket]

I use a Park Tool business card as I find them to be the most accurate

 

[Slaphappygamer]

I found that bleeding the brakes AFTER replacing the brake pads is best. I bled my brakes BEFORE changing the brake pads and had a heck of a time getting the caliper back over the rotor. The newly bled brake line had new pressure and I had to release the pressure by removing the reservoir screw at the brake lever and then I could move the piston back in to fit the caliper over the rotor.

 

[PCeBiker]

I found that bleeding the brakes AFTER replacing the brake pads is best.

Yeah, that's what I'm going to do.

I was pumping the brake lever with my ebike standing upside down, and I'm pretty sure that that can introduce bubbles in the system?

Hydraulic brakes are fine to be upside-down but I shouldn't be pumping the brake levers like that.


The brake fluid feeds into the master cylinder through a hole at the bottom of the reservoir,..

When the reservoir is upside down, any bubbles in the reservoir will rise up to that port and get drawn into the master cylinder if you pull the brake lever.

There's a bellow/gasket that fits inside the reservoir that seals the fluid underneath it and has an air pocket above to help keep the reservoir from becoming pressurized so that the fluid doesn't get pushed out of, or sucked into the reservoir due to a pressure difference.

The reservoir has two chambers with ports between the two, to help feed and keep bubbles in the chamber where the bleeder screw is.

I may very well have put bubbles in my brake line, so I'm going to slowly roll the bike upright to work any bubbles back up to the reservoir, starting at the caliper, then do an easy lever bleed when I'm done.

The rear brake line has lots of hills and valleys along it's path to the handlebars that can trap an air bubble, so I going to roll the bike around to get the bubbles to rise back up to the top.

The wheels and battery are removed so the frame is light and easy to deal with.

The caliper is disconnected from the frame too, so I can angle it around and flick it to hopefully get any bubbles that may be behind the brake pistons, to rise up into the brake line.

 

[PedalUma]

I pull the pads and the wheel when doing a bleed and insert a spacer. I do not want any oil near the rotor or pads. It is amazing how much dissolved air is in brake fluid. If it is kept in a vacuum it will bubble like a soft drink for an hour. One of Gionni's suction pumps works great for this. It is true that the Park Tool business cards work best.

 

[spokewrench]

Most disc brake bikes come with calipers that will never adjust right and stay that way.

In 4 years I've had 6 mechanical calipers and 2 hydraulic calipers. They may come from the factory misaligned. Otherwise I haven't had any trouble. Am I doing it wrong?

With mounting bolts slightly loose, I use a boot lace with a clove hitch to lash the lever to the handlebar so that the caliper is clamped to the disc and the disc keeps it aligned. Before torquing, I get both bolts fairly tight, maybe 1/4 turn from fully tight. That way, when I torque the first one, the friction under the other one and the stiffness of the disc will stabilize the caliper against misalignment. Nowadays, I use an ISO Allen key to give me the right torque.

I love those little O rings, but they're often missing. A dab of RTV makes a good substitute. It will keep stuff from sliding off the bolt but won't complicate tightening.