Pulsing when squeezing front brakes
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Road Warrior
Joined: Jan 2010
Posts: 1,597
Likes: 136
OK thanks for all the advise. I have to get a new back rotor because the brake lock-up scored it, so when I have them put that new on one I will have them remove the front one and check it for being warped.
I've had a lot of work done to the bike and keep trying different shops after one shop after another screws up. My LED lights guy keeps telling me I need to take a few courses or watch a few fixmyhog videos so I can learn to do this stuff myself.
I'm handy with tools so maybe I can learn.
I've had a lot of work done to the bike and keep trying different shops after one shop after another screws up. My LED lights guy keeps telling me I need to take a few courses or watch a few fixmyhog videos so I can learn to do this stuff myself.
I'm handy with tools so maybe I can learn.
It is not necessarily the add on's that are making your problems but possibly who is putting them on (reference your other thread). It is difficult to find a good mechanic that is close by which is shy I learned to work on my own bikes early on. That way if something goes wrong I know it's my own fault.
Either way, your luck has been really bad. Rotors will usually warp from excessive heat however the stock softail calipers have not been well known to do this. The Brembo calipers on the newer baggers have been known to wrap rotors very easily as they create so much heat.
You might want to ask your shop to check the rotor runout. .008 or less is within Harley spec. Anything above that is our of spec. I have had customers who have had rotors that were in spec t hat still behaved as if they were warped. It could also be that your pads are lower now and wearing unevenly causing this although warpage is the most likely suspect.
Either way, your luck has been really bad. Rotors will usually warp from excessive heat however the stock softail calipers have not been well known to do this. The Brembo calipers on the newer baggers have been known to wrap rotors very easily as they create so much heat.
You might want to ask your shop to check the rotor runout. .008 or less is within Harley spec. Anything above that is our of spec. I have had customers who have had rotors that were in spec t hat still behaved as if they were warped. It could also be that your pads are lower now and wearing unevenly causing this although warpage is the most likely suspect.
May our Moderator Rest in Peace
Joined: Sep 2006
Posts: 11,386
Likes: 35
From: Rochester, NY
You can, we all had to at some point.
It would help if you can get someone to help explain some of the technical language, but overall a bike isn't all that complicated.
Overall its a collection of fairly simple machines put together to make it go and if someone figured out how to build it.
Anyone with a bit of common sense, a bit of patience and the manual can figure out how to take it apart and put it back together.
The really hard part is learning an entirely new language of curse words when your trying to figure out what the hell they were drinking when they put some of the parts together.
You'll eventually come to the same conclusion many of us have that not one of the engineers who designed the bike ever gave any consideration to the idea that someone might actually try to take it apart to fix or change something.
So go get a manual, READ IT, a decent set of tools, buy any you don't have or find you need, some rags and a bar or bottle of Lava or Go-Jo hand cleaner.
Come here and ask any questions you might come up with and there WILL be questions and have at it.
I would venture to guess that you probably can't do a lot worse than some of the so called mechanics that you have been relying on up till now, can you?
It would help if you can get someone to help explain some of the technical language, but overall a bike isn't all that complicated.
Overall its a collection of fairly simple machines put together to make it go and if someone figured out how to build it.
Anyone with a bit of common sense, a bit of patience and the manual can figure out how to take it apart and put it back together.
The really hard part is learning an entirely new language of curse words when your trying to figure out what the hell they were drinking when they put some of the parts together.
You'll eventually come to the same conclusion many of us have that not one of the engineers who designed the bike ever gave any consideration to the idea that someone might actually try to take it apart to fix or change something.
So go get a manual, READ IT, a decent set of tools, buy any you don't have or find you need, some rags and a bar or bottle of Lava or Go-Jo hand cleaner.
Come here and ask any questions you might come up with and there WILL be questions and have at it.
I would venture to guess that you probably can't do a lot worse than some of the so called mechanics that you have been relying on up till now, can you?
Grand HDF Member
Joined: May 2008
Posts: 4,624
Likes: 189
From: Newcastle, Ca.
Sounds like the caliper was not installed correctly. Either not centered with rotor or caliper/pistons were not pushed into caliper all the way creating too much drag on rotor, which in turn causes too much heat, which will warp rotor. Make sure the wheel spins over 1 turn with a good push after new caliper and rotor are installed.
May our Moderator Rest in Peace
Joined: Sep 2006
Posts: 11,386
Likes: 35
From: Rochester, NY
Larger diameter rotors give the calipers more leverage on the rotating wheel and allow it to stop the tire/wheel better faster for the same amount of lever pressure.
You generally only put a 13" rotor on the front because it does most of the stopping, and putting one on the rear would just make it that much easier to lock it up in a panic stop.
Another benefit of using a larger diameter rotors is that that it will dissipate heat better because of its greater surface area and give you a little better "feel" so you can get it that much closer to locking up without actually doing it.
If you think you would like to go for a larger diameter rotor many of them come with or can be ordered with a set of spacers to allow you to use your existing calipers.
One suggestion I would have is that if anyone is really interested in new or larger rotors, they should look into getting floating rotors.
They are a bit more expensive but they do offer better stopping power by dissipating heat more efficiently.
And even if they do warp they generally don't give you that ugly pulsing feel in the lever because not being fixed in position as a conventional rotor is it can move in the caliper where solid rotors push the brake pads around giving you that pulsing feel in the lever or pedal.
PS Just to put a point on bigger rotors being better.
Check out the front rotor on a Buell.
The perimeter type floating rotor they come with is so big they bolt it to the rim, not the hub.
And believe me it WORKS. You better be hanging on tight when you grab the lever on that thing.
If not it WILL make a believer out of you.
Its like running into a brick wall.
You generally only put a 13" rotor on the front because it does most of the stopping, and putting one on the rear would just make it that much easier to lock it up in a panic stop.
Another benefit of using a larger diameter rotors is that that it will dissipate heat better because of its greater surface area and give you a little better "feel" so you can get it that much closer to locking up without actually doing it.
If you think you would like to go for a larger diameter rotor many of them come with or can be ordered with a set of spacers to allow you to use your existing calipers.
One suggestion I would have is that if anyone is really interested in new or larger rotors, they should look into getting floating rotors.
They are a bit more expensive but they do offer better stopping power by dissipating heat more efficiently.
And even if they do warp they generally don't give you that ugly pulsing feel in the lever because not being fixed in position as a conventional rotor is it can move in the caliper where solid rotors push the brake pads around giving you that pulsing feel in the lever or pedal.
PS Just to put a point on bigger rotors being better.
Check out the front rotor on a Buell.
The perimeter type floating rotor they come with is so big they bolt it to the rim, not the hub.
And believe me it WORKS. You better be hanging on tight when you grab the lever on that thing.
If not it WILL make a believer out of you.
Its like running into a brick wall.
Last edited by In Memoriam Citoriplus; Jun 9, 2012 at 10:47 PM.
Stellar HDF Member
Joined: Mar 2006
Posts: 2,395
Likes: 153
From: Utah
Stop. There are a number of possible causes for pulsing that are not due to a warped rotor. If you want to learn about brakes (you probably don't really want to) there is an article a few months back in American Iron magazine that will explain most all of what you need to know.
You can check the runout to determine if the rotor is warped by putting a jack under the bike, hooking up a coat hanger to your bottom leg that has an end close to the rotor, and spinning the wheel to see if the rotor is warped. You may be able to see this with just watching the pads to see if they move back and forth when spinning the wheel. You may also notice that there are places where the wheel seems to drag and then free up but if the pads aren't moving then it's not due to a warped rotor.
You may have different composition pads than before that are more sensitive to the condition of the rotor. Pulsing can be due to air in the brake lines, master cylinder and/or caliper, hard spots in the rotor, or hot spots in the film on the rotor (part of how brakes work). Something as simple as cleaning the rotor with laquer thinner may help the hot spots. My first guess, however, would be air in the brake lines due to incomplete bleeding since you just got the caliper installed.
You can check the runout to determine if the rotor is warped by putting a jack under the bike, hooking up a coat hanger to your bottom leg that has an end close to the rotor, and spinning the wheel to see if the rotor is warped. You may be able to see this with just watching the pads to see if they move back and forth when spinning the wheel. You may also notice that there are places where the wheel seems to drag and then free up but if the pads aren't moving then it's not due to a warped rotor.
You may have different composition pads than before that are more sensitive to the condition of the rotor. Pulsing can be due to air in the brake lines, master cylinder and/or caliper, hard spots in the rotor, or hot spots in the film on the rotor (part of how brakes work). Something as simple as cleaning the rotor with laquer thinner may help the hot spots. My first guess, however, would be air in the brake lines due to incomplete bleeding since you just got the caliper installed.
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