Calipers That Will Not Adjust Straight

[PedalUma]

Most disc brake bikes come with calipers that will never adjust right and stay that way. There are a few reasons for this. Did you ever give caliper screws that final torque for tightness and then they always go sideways? The problem is chiefly caused by O-rings. In a bike factory assembly line individual items of nuts, bolts, washers.. are preassembled as components. The caliper component is held together with an O-ring at the bottom of the stack of washers and spacers on the hex cap screw. When tightened part of it gets caught in the threads and the rest protrudes to one side. The cap screws must be pulled and the O-rings worked off for the bike's brakes to ever work right. I can give more. That is a good place to start. I will invite @m@Robertson to kick this thread off.

 

[m@Robertson]

huh?



I have been called a brake whisperer when it comes to adjusting people's brakes for them, and the secret has always been to NOT tighten the crap out of the caliper into the mount. As you say, the caliper can be aligned just perfectly, and that final torque-down ruins it. I don't have any o rings on my caliper mounts, or any others I have had to fiddle with. Its just that cranking down on that mounting bolt with even moderate torque is enough to make it shift (OR to change the caliper's orientation now that it is pressed hard into the surface of the adapter).

So I eyeball it carefully to get the caliper lined up so it has room on both sides of the pad (assuming hydraulic brakes where both pistons move). Then with the wheel spinning I verrry gently torque one caliper bolt so it is barely snug (only!). Spin the wheel again and see if the caliper has shifted. If it has, the other caliper bolt is not snugged yet. Using thumb and forefinger to move the other side of the caliper just a hair until no more rubbing. If necessary start over, loosen the first side and try again. Once one side is aligned and snug, use thumb and forefinger to hold the caliper (while the wheel is spinning) and barely snug the other caliper bolt.

Now you have a caliper aligned perfectly, but its only snug-tight. Alternate back to the original caliper bolt and only BARELY give it some torque. Move to the other bolt and do the same. Maybe go two rounds of this.

In the end you have a brake caliper that rubs nothing but is held in place by only mild torque. Which is fine. Worst case in a few weeks it will come loose and you repeat the process. I also usually use extra long caliper bolts into the adapter so I get engagement on ALL threads in the adapter. So the caliper can not fall off. And really nothing bad can happen since the caliper will still clamp the rotor just fine even if its freely moving and a bit loose.

 

[PCeBiker]

Look what I just found on my rear caliper mount,..

The other side looks fine, but I think that I'll just remove all the O-rings?

I'll just cake it up good with Anti-Seize instead to stop any corrosion.

I don't see much of a purpose to those O-rings? They just keep water out of the bolt threads I guess?
It's not like any water is going to get inside the caliper through the caliper bolts.

 

[Slaphappygamer]

So I eyeball it carefully to get the caliper lined up so it has room on both sides of the pad (assuming hydraulic brakes where both pistons move). Then with the wheel spinning I verrry gently torque one caliper bolt so it is barely snug (only!).

This is the best method! Worked for me each time.

 

[PedalUma]

Look what I just found on my rear caliper mount,..

@PCeBiker,
I Love It!!! Exactly. Now you can torque it down.

If I do not remove all the O-rings, I get fired from my livelihood. I get paid to ride eBikes in a beautiful little Nor Cal town. It was 75F here today. I do not want to give that up. I have to sand the posts, grease them with the wheel out, and use silicone oil on each of the mounting parts including washers, then clean the exteriors with 99% isopropyl, before reassembly. Then I strap the lever with the wheel in and torque to 6-8Nm so they never move. I used to do stuff like eyeball and not tighten that last extra bit. Anyone can tell if they have O-rings if when extracting the hex cap screws all the way out seems stiff. More photos please of retired O-rings..

They are useless to us. But the O-rings make pre-assembly easy so brake parts stay together in a fast factory setting. Oil the threads too.

 

[Marcela]

I compress the brake caliper on the rotor then tighten. Usually doesn't center the best as the rotor is warped or the caliper mating surfaces are not square. Then take a feeler gauge of about .002 or .003 and put it on the side that is rubbing and squeeze, tighten the caliper and see where it is at. Especially on new pads as there is not much clearance, as they wear the clearance opens up.

 

[PedalUma]

I compress the brake caliper on the rotor then tighten. Usually doesn't center the best as the rotor is warped or the caliper mating surfaces are not square. Then take a feeler gauge of about .002 or .003 and put it on the side that is rubbing and squeeze, tighten the caliper and see where it is at. Especially on new pads as there is not much clearance, as they wear the clearance opens up.

I have done the same for years. If it pulled to one side I would often insert a business card or two on that side. I could still never tighten it down all the way, so it would end up shifting because of the O-rings. Extracting them is the answer.

 

[Marcela]

I've never seen the O ring on any of my bikes. Have to keep an eye out for them.

 

[PedalUma]

I've never seen the O ring on any of my bikes. Have to keep an eye out for them.

If the caliper's hex cap screws seem tight when backing them all the way out, you have them. They are very small and black so they blend in with the threads.

 

[Stefan Mikes]

I've never seen the O ring on any of my bikes. Have to keep an eye out for them.

Those guys seem to have never seen a quality bike
So, @PedalUma you say your Vado has O-rings on your hydraulic disk brakes. A photo or it has never happened
Because all I can see on mine are regular washers.

 

[Gionnirocket]

I compress the brake caliper on the rotor then tighten. Usually doesn't center the best as the rotor is warped or the caliper mating surfaces are not square. Then take a feeler gauge of about .002 or .003 and put it on the side that is rubbing and squeeze, tighten the caliper and see where it is at. Especially on new pads as there is not much clearance, as they wear the clearance opens up.

Squeeze the caliper to the rotor but not excessively hard that will distort alignment and also so that you can still spin the wheel with friction... After a few wheel rotations tighten the caliper alternating between bolts until snug... but again not excessively that will distort alignment.
This usually works... If not @m@Robertson method is my alternate method.

I've never seen O rings.. must be a California thang

 

[m@Robertson]

I compress the brake caliper on the rotor then ...

That is how I get my first working 'centered' result. One hand on the brake lever holding it closed. The other has a wrench in it and I stretch a little so I can tighten the caliper and clamp the lever at the same time. I may need a couple tries and I'll usually need to jigger it a touch afterwards. This is not the time to also have to worry about the bike falling over so I make sure its in a stand or somehow can stand on its own.

I've never seen O rings.. must be a California thang

Noop if it weren't for that pic posted above I would have never seen them either.

EDIT: I never bother but with the brake dust and dissimilar metals, the caliper bolts are good candidates for anti-seize.

 

[Gionnirocket]

That is how I get my first working 'centered' result. One hand on the brake lever holding it closed. The other has a wrench in it and I stretch a little so I can tighten the caliper and clamp the lever at the same time. I may need a couple tries and I'll usually need to jigger it a touch afterwards. This is not the time to also have to worry about the bike falling over so I make sure its in a stand or somehow can stand on its own.



Noop if it weren't for that pic posted above I would have never seen them either.

EDIT: I never bother but with the brake dust and dissimilar metals, the caliper bolts are good candidates for anti-seize.

I put the anti seize on the O_ring so it ceases to be a problem

 

[PedalUma]

I tape the O-rings to each build report. But sometimes they disintegrate when yanking the overly stiff screws. So, I report that they are dust, smoked. It only happens with bridge caliper adaptors. Like smoking Vados.

 

[Gionnirocket]

I don't see much of a purpose to those O-rings? They just keep water out of the bolt threads I guess?
It's not like any water is going to get inside the caliper through the caliper bolts.

An O_ring needs a flat surface to seal... so with the thread water would just wind its way past anyway.
Wonder if it's being used a spacer to keep a thinner bolt centered in an oversized spacer hole... a factory hack solution.
Is there a lip the O_ring is sitting on or is the hole in the spacer the same top to bottom?
... or as @PedalUma says just to hold the assembly together.. But even then wouldn't it be at the bottom of the spacer stack?

Again... Never seen this ever... and I recently disassembled a new bike and there were no O_ring nor the clearance for one as in your pic

 

[Marcela]

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.

 

[Gionnirocket]

It's self centering already...Some of the problem is poor quality control on the manufacturer end with things not being square and true... then add poor installation.
Then you top it off with the end user not understanding the nuances of maintenance and final adjustments when things begin to wear.
YBreakPadsMV

 

[PCeBiker]

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

An O_ring needs a flat surface to seal...

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,..

Wonder if it's being used a spacer to keep a thinner bolt centered in an oversized spacer hole... a factory hack solution.

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,..

Is there a lip the O_ring is sitting on or is the hole in the spacer the same top to bottom?

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,..

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,..

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?

... or as @PedalUma says just to hold the assembly together..

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.

But even then wouldn't it be at the bottom of the spacer stack?

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

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

Again... Never seen this ever... and I recently disassembled a new bike and there were no O_ring nor the clearance for one as in your pic

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.

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,..

 

[Marcela]

It's self centering already...Some of the problem is poor quality control on the manufacturer end with things not being square and true... then add poor installation.
Then you top it off with the end user not understanding the nuances of maintenance and final adjustments when things begin to wear.
YBreakPadsMV

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.

 

[PCeBiker]

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

The spacers and even the cone washers themselves have shitty tolerance.
They're all fricken sloppy and mangled.

I'll just delete them.

These are camber bolts for a car that work on the same idea, to adjust the bolt angle alignment, but they're made from proper hardened steel.

I guess with an ebike saving weight is paramount, even with such critical components as the brakes.

The only hardened steel I've found on my e-bike are the ball bearings, races, and bottom bracket.

I just replaced my freewheel with a hardened steel version,..

I don't care if it's a few grams heavier.
My ebike has a motor.