Skip to content

USCA Sidecar Forum

For some extra information about navigating the forum you can go to Forum Tips

Please to create posts and topics.

Excessive Rear brake travel to bike and sidecar

Hello. I am new to this forum and I am hoping someone can solve my problem. I have a 1996 Harley Super Glide with a Hannigan Classic Sidecar. It was installed in 2017. The sidecar brake is connected to the rear motorcycle brake line via a double banjo bolt on the rear motorcycle caliper with a brake line to the Brembo disc brake on the sidecar. There is a quick disconnect which was installed by Hannigan also. Things seemed to work okay until this year. Instead of normal brake travel I had to just about point my foot vertical to get the rear brake to work. I replaced the rear master cylinder on the bike and bled the system, sidecar and bike. Initially it worked but after riding a few miles it was back to the same problem. I have bled the system three times and it always turns out the same. I trailered  it 600 miles back to Hannigan a couple weeks ago. They bled the system again and did not find any other brake problems. I got it home and rode it for a few miles and the same problem of excessive brake pedal travel happened again. I am at my wits end. Is there a fix? Is it a problem with the quick disconnect? Should I just take off the quick disconnect and run a brake line to the sidecar? Any help would be greatly appreciated. Thank You!

Uploaded files:
  • You need to login to have access to uploads.
FlyingMonkeys has reacted to this post.

Thomas, what you don't say...did anyone check the actual brake pads on the bike's rear caliper, and on the sidecar caliper, to see how much pad is left, or if the pads are still good, or if the pads all need to be replaced.

"IF" the brake pads are well worn, then bleeding the brakes....til the cows come home....will not make it any better, as the calipers are pushing the pistons out farther to compensate for the worn brake pads.

So....that question needs to be answered. And given that you trailered it all the way to Hannigan, and they also worked on it, I would think that someone out there in the world has looked at, and inspected the brake pads at all the wheels.

Next, is there a brake rod adjustment on the bike itself?  Yes, I know, it has hydraulic disc brakes on the bike, but some models of bikes have a brake ROD that is actuated when pushing on the rear brake pedal. The brake pedal would actuate that brake rod, which in turn pushes on the brake master cylinder, and that pushed the brake fluid through the hose, and actuates the brakes at the calipers.

My point, sometimes that brake ROD can be adjusted, to allow freeplay, or take up freeplay, and anything that can be adjusted, also means it can come out of adjustment, especially on a shaker like an H-D.  Inspect the bike's rear brake pedal....manually with your hand push on that rear brake the actuation of that rear brake pedal, and SEE what is being actuated.....SEE how that brake pedal interacts with the rear brake master cylinder.

Then, report back to me.

CCjon, Thane Lewis and Thomas Fogarty have reacted to this post.
CCjonThane LewisThomas Fogarty
Two Million Miles, and All 7 Continents

  The quick disconnect is one of those things it works or it don't .  Most likely not the issue. A 1996 used used DOT 5 brake fluid.  DOT 5 will not mix with any other fluid. If Any of the others DOT 3,4 or 5.1 were mixed with the DOT 5 it will cause issues.

  1996 There is a good chance the rear brake master CYL is gone bad on you.  It sound like Air is getting in some where.

Disconnect sidecar brake line.   Bleed the bike If it feels right but latter goes soft on you the issue is a rear caliper or the master cyl.

I own and ride a 1996 HD for the record.

CCjon, Thane Lewis and 2 other users have reacted to this post.
CCjonThane LewisFlyingMonkeysThomas Fogarty

Thank You FlyingMonkeys and Smitty 901! Great suggestions all around. I have only used Dot 5 so that should not be a problem. The rear brake on the bike has 5.5 mm of pad left and the caliper appears to be operating properly. However, when I checked the sidecar pad it was completely gone! I  have about 8600 miles on those pads and I had not looked at the thickness remaining before the suggestion. That was my mistake.  Thanks for the suggestion, FlyingMonkeys! The rotors are scored since the pads were shot. Hannigan uses a small Brembo caliper on the sidecar. I don't know what Brembo model caliper it is or what pad I would need. Not sure who makes the rotor or if it has enough thickness to be turned. I will let you know my progress on this. Thanks again for the great advice!

CCjon and FlyingMonkeys have reacted to this post.

Thomas, those Brembo brake PADS are very easy to find, and not expensive at all. I may actually have a set of them in my shop, so I will look tomorrow morning, and if I still have them, I will send them to you.

IF you find the need to replace that disc brake rotor, I'd bet you can easily source it from Texas Sidecar Company/DMC, as they use that same rotor on most of their rigs. If not from them, then Hannigan will have a metric ton of them. That's better than chasing an odd disc brake rotor all over the country.

Glad that my suggestion of LOOKING at the brake pads worked out for you. But don't discount what @smitty901 suggested to check out on the rear brake master cylinder. Once the sidecar brake pads have been replaced, and the disc brake rotor either turned, or replaced....make sure it ALL still works right, and if not...go directly to that rear brake master cylinder.

AND...given that those sidecar brake pads wore away in less than 8600 miles...check to make sure that sidecar wheel is not dragging via the brake. All sidecar rigs are different, but mine has over 11,000 miles on the sidecar brakes, and the pads have more than 50% of the braking pad something isn't right on yours.

SwampFox, Craig and Thomas Fogarty have reacted to this post.
SwampFoxCraigThomas Fogarty
Two Million Miles, and All 7 Continents

FlyingMonkeys, Thanks again for the advice. And, yes, Thanks to Smitty901 also for the advice on checking the master cylinder. That is what I thought was causing the problem initially a couple months ago so I did install a new master cylinder back then. Thanks for the offer of the Brembo pads. I don't want to use up your private stock but if you could advise me on a part number that would be great! I will contact Texas Sidecar Company or Hannigan for the rotor if it cannot be turned and used again. It has 11 mm of thickness remaining so I am guessing it can be turned. I will update you both on my progress on getting things back to running order. Thanks Again for the great advice!

FlyingMonkeys has reacted to this post.

  Just some info. The rotor on my Hannigan twin classic has 70,000 miles on it. And that has been some spirited riding.

This would be a good time to swap bleeders for sped bleeders. They make things easier.

FlyingMonkeys and Thomas Fogarty have reacted to this post.
FlyingMonkeysThomas Fogarty

Thanks Smitty901! I guess I should be able to get many more miles on my rotor after turning. I will have to look into speed bleeders. Have never used them. From what I can see of your rig it looks very nice! Thanks Again, Tom

smitty901 and FlyingMonkeys have reacted to this post.

Thanks to all of you for your suggestions. I finally fixed the brake problem. The rear brake caliper piston was getting stuck after the brake was applied. I did not notice it until I went for an hour and a half ride. When I got home I could not move the bike in neutral by pushing it. The rear wheel would not move. The rotor was extremely hot and warped. I let it cool down and removed the rear caliper and rotor. The caliper piston had gotten stuck against the rotor due to debris build up on the piston due to not changing the brake fluid every two years as required. I cleaned the piston and caliper, installed new seals, installed a speed bleeder, new caliper, bled the brakes again. Everything works fine now. Rear brake works, sidecar brake works. Thanks again for all your help!

SwampFox, DirtyDR and 3 other users have reacted to this post.

Glad you figured out that there was a deeper problem.  I didn't hear anyone suggest that the lines themselves might be failing.  I have seen brake lines degrade and bulge as they age which would cause the same issue as described.


FlyingMonkeys, Thomas Fogarty and Brstr have reacted to this post.
FlyingMonkeysThomas FogartyBrstr

Thane, good point. I could see debris when I changed the master cylinder and rear brake line as the first step in trying to resolve the problem. They had deteriorated. I should have known that the debris had already made its way to the caliper piston and gradually coated it so that it could not move freely. Lesson learned!

FlyingMonkeys and Brstr have reacted to this post.