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RSRBOB, Technician
Category: Motorcycle
Satisfied Customers: 1078
Experience:  Former Factory Service Rep, Dlr Line Tech, Service Manager, General Manager, Store Owner
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I have a 1999 Dyna Wide Glide that I am having rear brake

Customer Question

Hi Pearl, I have a 1999 Dyna Wide Glide that I am having rear brake problems with. I just rebuilt the master cylinder and it pumped up fine, the next day when I got it out the rear brake worked. When I got on it later the pedal bottomed out and the brake didn't engage.
JA: Have you checked the fluids recently?
Customer: There is still plenty of fluid in the reservoir and there are no leaks under the bike
JA: What is the model of your '99 motorcycle?
Customer: FXD wide glide
JA: Are you fixing your bike yourself? What have you tried so far?
Customer: I rebuilt the master cylinder to try and solve the problem, I don't know what else it could be.
JA: Anything else you want the mechanic to know before I connect you?
Customer: No
Submitted: 16 days ago.
Category: Motorcycle
Expert:  RSRBOB replied 16 days ago.

Hi and thank you for your question. I am happy to help you but would need a bit more input from you. My first question is, when you lost hydraulic pressure this last time, had the bike been sitting or did you ride/roll it somewhere then hit the brakes to find no resistance? You stated that you rebuilt the rear master cylinder. Was that rebuild intended to repair a pre-existing problem or did the problems happen as a result of the rebuild? If you rebuilt it to fix another problem, was there any service work or repair work done to the bike prior to the rear brake problem the very first time?


Customer: replied 16 days ago.
I bought the bike about 2 months ago and everything was fine until about 2 weeks ago. I took my wife for a ride and when I pushed the brake pedal it went all the way down without engaging the brakes. When we got home I checked the fluid and it was full which made me think there might be air in the brake line so I bled it and the pedal came up and the brake worked fine. The next day it was going all the way to the bottom again with no brakes engaging. I checked the fluid level again and it was full so I figured it had to be the plunger in the master cylinder so I ordered the rebuild kit and fixed that last week. When I bled the brake line it was fine again, the next day I got it out of the shed and the brake worked, but when I took off down the road it bottomed out again with no brake engaging. The fluid is still full and there are no leaks that I can find on the master cylinder, the caliper nor the brake line itself. There is no fluid on the shed floor where I keep the bike.Thank you,
Expert:  RSRBOB replied 16 days ago.

Thank you for the additional information.

One last question. Have you tried pumping the rear brake pedal repeatedly to see if the hydraulic pressure comes back? I am not suggesting this as a solution, but this is a diagnostic question that is helping us pin point the repairs needed. It sounds like as long as the bike doesn't roll, it retains hydraulic pressure. Essentially, if it sat in your shed for a week, and you had breaks when you parked it, you could come back a week later and hit the brake pedal before doing anything else and it would still have brakes, is that correct? Again, these are diagnostic questions not proposed solutions so please bare with me.

Customer: replied 16 days ago.
I understand you need to ask these questions. Yes, I have tried pumping the brake pedal and it won't come back up unless I bleed it again. When I do bleed the system I can get the pedal back to normal and engaging the brakes, before I replaced the plunger the brakes went down over night, after I replaced it the brakes were good the next day, until I moved the bike. I am not the best mechanic in the world, but I have worked on a lot of different machines and I have never had this problem. I have never considered the fact that moving the bike might do something to have an effect on the brakes.Michael
Expert:  RSRBOB replied 16 days ago.

Thank you for the additional information.

Where I was going with the rolling was a warped or bent disc pushes the pads back into the caliper and would give the symptoms of loss of breaks. Where that would differ from your symptoms is they would eventually come back from pumping them as the pistons slowly came back out of the caliper. Believe I certainly have no intentions of discounting your mechanical experience or abilities.

Out of curiosity, are you bleeding the brakes with some sort of vacuum pump or pumping the pedal, holding it, and cracking the bleeder valve at the caliper?

Customer: replied 16 days ago.
Pumping and cracking the bleeder, I use a clear plastic hose over the bleeder run the fluid into a pan. I have my wife pump the pedal and hold it down until I close the valve and then have her pump it up again. I do this until I am sure there are no air bubbles in the line. What confuses me is that it is a closed system and this shouldn't be able to happen, at least in my mind. That is why I am contacting someone with more knowledge than I have.
Customer: replied 16 days ago.
No ideas?
Expert:  RSRBOB replied 16 days ago.

I do agree with you it is confusing and frustrating. I must say it sounds like you are doing everything correctly so I have no issues with anything you have done. The first thing that comes to my mind is if there are tiny air bubbles, very tiny, still trapped and the vibrations from the engine and road and riding are moving them around and allowing them to congregate and create one air bubble that is big enough to cause the symptoms. I would suggest using either the handle of a screw driver or a small hammer to tap on the line and simulate the vibrations encountered while riding to see if you can release the rest of the trapped air. As you said, it is a sealed system so normally air would enter the system in the same place that fluid would leak out. Since that is not the case, I don't suspect it is continuing to draw air into the system. Also, did you happen to rebuild the caliper as well?

Customer: replied 15 days ago.
I did not do the caliper because I saw no leaks and when I was bleeding the system I could feel it gripping the disk very well. The other reason is because there is no fluid leaking from it. I don't to rebuild brake parts and only did the master cylinder because it was impossible to find a new one for that bike. I can try replacing the caliper, I have thought about replacing both it and the brake line if I can't get the system to stay pumped up. I am wondering why you think it might be the caliper?
Expert:  RSRBOB replied 15 days ago.

The reason I had asked about the caliper was because I was wondering if the pads were being retracted too far. I have seen situations where the seals stick to the piston and when you let off the brakes, it tends to pull the pistons back into the caliper and cause the pads to be too far from the disc and make the pedal spongy to non-existent. You can check for this by touching the edge of the brake pad and the brake disc and depress the brake pedal, You should feel slight movement of the pads squeezing on the disc, but when you let off the pedal, they should not be any significant movement to pull them away from the caliper.

I am not a fan of shot gunning the whole system either. This does not sound like any one component has failed, therefore I would consider it a waste of money to do that. If you were determined to replace one thing, my first suggestion would be the M/C.

Customer: replied 14 days ago.
Sorry I didn't get back to you sooner, yesterday I had to replace a sliding glass patio door at my house and a couple of friends were off work and able to help me. When I do bleed the brakes I can see and feel the caliper working, and as we have discussed the brakes seem to work fine after being bled, it is after the bike sits overnight that the problem seems to start again. I have rebuilt the master cylinder because I can't seem to find a new one anywhere for this bike I know it is possible that the replacement parts were bad, but I am thinking that would be unusual, however I know it is possible, once I had to go through 2 pressure plates for on old van I had to fix it right. I can order another rebuild kit if you think that is the way to go.
Expert:  RSRBOB replied 14 days ago.

Hey, not a problem on the time frame. Do what you need to do, I will be here.

First, I need to confirm some things we mentioned in passing previously, but since we still don't have it resolved, they move up the importance ladder.

First, Has the rear wheel or brake caliper been off between the time you got the bike and the time the problem showed up?

Is it correct that you re-built the MC to address this very problem, and the re-build did not fix it? If that is not correct, please explain what prompted the MC rebuild.

OK, now some new questions...........

Are you using DOT 5 brake fluid?

Is it doing it every time you ride now?

Does it have to be 2 up for it to happen, or has it happened when you were by yourself too?

How many times has it happened since the MC rebuild?

Now, some new suggestions,

Check the run out of the rear wheel bearings and rear disc run out.

Check the cap for the M/C to make sure the atmospheric vent is not clogged.

Make sure the rubber diaphragm inside the M/C is fully retracted when installed. It should be flat across the bottom.

Let me know!


We WILL get this beat!

Customer: replied 13 days ago.
I always use DOT 5 on my bikes so that answer is yes. I have not had the caliper off since I bought this bike. I did put saddle bags on the bike and this problem started right after I did that, but I'm not sure why that would have an effect on the brakes. The bags were made to fit this bike and all I did was remove 2 bolts from the rear fender and replace them with the new bolts for the bags. I don't think I even touched the caliper and if I did it was just brushing it with the bags. I bought this bike for pleasure and my wife loves to ride with me so at this point I've only had it out 2 or 3 times solo, does it make a difference if you have someone riding with you? I have only taken the bike out once since I did the rebuild and that was both of us.
Expert:  RSRBOB replied 13 days ago.

Thank you for the additional information.

This really sounds like something is going on with the caliper, pushing on the brake pads causing the pistons to be pushed back into the caliper. In addition to the possibility of it being bad (loose) wheel bearings, the disc could have excessive run out or the caliper was assembled incorrectly at one time. The 99's had a crazy wire above the pads that can cause them to get pushed apart. When that happens, it takes multiple strokes of the brake pedal to extend the pistons again so the pads can exert pressure on the disc and create the brake pedal feel of pressure and resistance to bottoming. In your chronology, you said you had the bike 2 mos.

How many miles did you put on the bike since you owned it until the brake problem showed up?

Did you ever ride it without the saddle bags without a problem and if yes, how many miles?

How far had you ridden when you lost the brakes on the 1st trip out with your wife?

Also, the time you had bled the brakes and got them to come back, then was it like the next morning, and the bike had never moved, that the pedal was gone again?

If that is the case, we definitely have a problem in the caliper, and probably that wire is installed incorrectly.

Here is a link to a diagram of the rear caliper, and it shows the wire that I am referring to. It is reference #2

This wire can push the pads back and then the hydraulics will take an exceptionally long time to recover because it is pushing the pistons back out thousandths of an inch at a time. If you haven't taken the bags back off since the problem happened, I suggest taking them off and looking for any evidence that the bags might be hitting the caliper too.


Customer: replied 13 days ago.
I had put about 30 miles on the bike before I bought and installed the bags, these were solo miles and miles with a rider. The problems started right after I put the bags on, I had ridden about 2 miles and when I pushed the brake pedal there was no engagement of the brake, even after pumping it. (my wife was with me on this trip) The first time I bled the brakes they were fine when I bled them, but the next day just backing it out of the shed they were gone again. After I replaced the MC and bled the brakes they were fine when I took it down the road and they were good when I got the bike out of the shed the next morning. I was taking my wife out to lunch that day and noticed right after we started the brake was not working again. The bags are about 4 inches above the caliper so I don't think they are touching it at any given time, from what I can see the pads look okay, the bike has about 22,000.00 original miles on it. I am thinking if I do replace the caliper maybe I should do the pads at the same time anyway. I can pump the brake pedal a hundred times and it doesn't engage the brake. I am just confused as to why I can't find the fluid leaking anywhere. I have been told, that this engine only has about 500 miles on it, the 99 engines on these bikes came with plastic cams and they chipped and destroyed the engine so Harley rebuilt the engine with different cams. I did call the factory and they verified that problem was real on these engines.
Expert:  RSRBOB replied 13 days ago.

Again, thank you for the additional information.

What I believe is happening is the pads are being pushed back into the caliper. It could either be that wire or it could be a problem with the disc being warped or the wheel bearings (loose). The fact that there is no fluid leak reinforces this theory to me. I would recommend checking the disc and wheel bearings before ordering a caliper. If they are the root cause of the problem, a new caliper is going to do the same thing. While you are at it, I would also suggest taking the current caliper off the disc and inspecting it for any abnormalities, including the brake pads.

Customer: replied 13 days ago.
What is the easiest way to check the wheel bearing? I'm not sure I have what I need to lift the rear wheel off the ground. I guess I could run a strap around the frame and use my tractor with the loader to lift it. I would rather do it some other way though.
Expert:  RSRBOB replied 13 days ago.

We usually use a flat jack under the rear of the frame just in front of the rear wheel. I understand about being leery of using your tractor with the loader. I suppose it would work, if push comes to shove. I am just an advocate of not spending money on parts, especially big money, until I am convinced it is money well spent.

Customer: replied 12 days ago.
Hi again,
I pumped the brake pedal and the brakes started to work. I took the bike down the road a mile or so and the pedal stayed pumped up, I went down a road that has very little traffic and tried the brake about ever 200 yds and it worked fine. I came back to the house and got my wife and before I got out of the driveway the pedal was bottoming out again. I took her down the same road and after I pumped the pedal 10-12 times the brake started to engage again, but after about 50 ft it would bottom out again and I had to pump it back up. I am guessing that since the pedal didn't go down with just me on the bike that the rear wheel bearing is good and the caliper not warped. I'm not sure how to get a jack under the bike to lift the rear wheel up, the belt is lower than the frame on one side and the exhaust pipes are lower than the frame on the other side and I don't want to damage either one. I really don't understand why my wife getting on the back seat would make the brake not work?
I have thought along the lines of bleeding the system again tapping the line with a screwdriver handle as you suggested but I wanted to get your opinion on what is happening now. Before I rebuilt the M/C it would not pump back up at all unless I bled the system, now at least it is pumping up which makes me think the M/C is okay.Thank you,
Customer: replied 12 days ago.
Here we go. I bled the system out very good, filled the reservoir 3 times and it was all brake fluid in the hose I used to drain it from the bleeder. I took the bike down the road alone about 5 miles and the brakes worked fine, I came home and got my wife to get on and the pedal went all the way down before we got to the end of the driveway. I was curious so I pumped the pedal until it came up again and then went down the road by myself and the brakes worked fine, the pedal stayed pumped up. I came back and my wife got on and the pedal bottomed out again right away. I have never had anything like this happen before on any vehicle, what do you recommend I try now? Replace the caliper? I did get the bike in the air and the wheel bearing has no plat and I put a strait edge on the rotor and couldn't find where it was warped in any spots, I also turned the wheel by hand and eyeballed the rotor as it went through the caliper and couldn't see where it was warped that way either.Thanks,
Expert:  RSRBOB replied 12 days ago.

It does sound like there is something going on when the rear suspension is more compressed. Check to see if the caliper has been hitting the fender. You should be able to see either chipped paint or some kind of contact mark on the top of the caliper. Do you know if it has been lowered in the back? You will need to either go back to stock height in the back or bump up the spring preload on the rear shocks so the suspension doesn't compress that much under normal conditions.

Again, I am not a fan of just ordering parts and throwing money at it. I would suggest taking the existing caliper off and inspecting it closely, although this seems to be more tied to the loading of the bike more than anything. Perhaps you have a friend that can sit in your place on the bike and you can observe what is happening from behind? Either that, or ride it without the bags and see what it does.

Customer: replied 11 days ago.
The caliper is not hitting the fender. If any of these suggestions you have given me turn out to be the cause, then what is the fix?
Expert:  RSRBOB replied 11 days ago.

That is totally dependent on which root cause you come up with. The fact that the problem only shows up when there are 2 people on the bike eliminates the possibility of the source of the problem being anything related to hydraulics.

Can you put someone else in your place on the bike with your wife on the back so you can get a look at the brake system components and see what is going on with them? The other option would be to ride it without the saddle bag too.

BTW, it actually would not have been the 1st 99 dyna to have the caliper hit the fender. In fact, it was fairly common when the bike was lowered or the spring preload on the shock softened up.

The other test I would suggest is put the wife on the back, being mentally prepared that the rear brakes will fail, ride it until they do, then using the front brakes, either go home or get to a safe space to stop, and inspect the brake pads to see if they have pushed away from the disc.

Customer: replied 10 days ago.
I have to wait until this afternoon before I can check what you have mentioned. If the bag or the fender are hitting the caliper what options do I have. I am pretty sure if anything is hitting it would be the bag and I need them for when we go for trips that last more than a couple of hours. My wife is a type 1 diabetic and we need to be able to keep her supplies cool so we put them in the bag with ice packs. The other thing I don't understand is that the calipers are bolted on and the bags are flexible so even if they touch the caliper why would the have an effect on it?
Expert:  RSRBOB replied 10 days ago.

If something is contacting the caliper when riding 2 up, you need to stiffen up the rear suspension so it isn't traveling as far under normal conditions. If the preload on the spring is backed off you can turn that up, or, if the springs are too soft for the 2 of you, put heavier springs on the shocks. This will have a double benefit of preventing a loss of rear brakes when riding 2 up but also giving a better ride as well. By keeping the shocks in the upper end of the travel, it will give them the normal stroke to soak up the bumps in the road without transmitting so much of them to the frame and rider.

The calipers are a solid mount but they are what are called floating calipers, In any disc brake system, something has to float. Either the caliper or the disc. Since yours is a solid disc, that means the caliper has to float. Float means the caliper is capable of sliding back and forth on pins so both the inside and outside brake pads contact the disc together and apply equal pressure to the disc so it doesn't get pushed out of shape if the pressure were to come from one side only. Since it floats, if anything contacts it, it is going to push it one way or the other and put a space between one of the brake pads. When you hit the brake pedal after that happens, it is not going to offer any resistance because it has to pump those pads back until they contact the disc.

If it is the bags, you could look at spacing the right side out farther so it doesn't hit, changing to a different style of bags, or getting a travel trunk or a soft luggage system that will allow you to do what you need to do to be able to travel longer distances.

Customer: replied 8 days ago.
I just wanted to thank you for your help and let you know I think the problem with the brakes is fixed. I cut some spacers and extended the bag on the caliper side so it can't touch the caliper when someone is riding behind me. So far it seems to be working.
Expert:  RSRBOB replied 8 days ago.

Excellent. I am glad that you have found what seems to be the problem. You did a great job hanging in with me to sort through a lot of confusing scenarios to get it resolved. It was a pleasure working with you and I hope your wife and you enjoy your bike for a good long time.


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