Hi All:
My new sidecar has a disk brake and caliper system on the hack that I have spliced into the rear motorcycle master cylinder. Unfortunately, it seems that the OEM master cylinder is simply not upto the task.
Despite a riggorous bleeding and adjusting the actuator so that it plunges the piston as deep as possible into the master cylinder, my brakes are still not quite up to par.
Does anybody have any suggestions for sourcing an upgraded master cylinder? Its a rod-actuated remote resivior type. The largest that I can find anywhere is a 13mm bore and I suspect that is what's already on the bike.
Any suggestions are most welcome.
I wonder what make and model of motorcycle?
Originally written by gnm109 on 3/8/2009 7:51 PM
I wonder what make and model of motorcycle?
Hahaha ... thanks for the "subtle" hint. My apologies. It is a 2005 Triumph Rocket III.
I've talked to a couple of different folks and they have strongly suggested that need to re-do my brake bleeding job. Fair enough. I'll re-bleed them and see if that firms them up.
Still though, if anybody has input regarding a larger master cylinder I wouldn't mind having a larger piston given that I'm now pushing two calipers rather than two.
I'd go over the brake bleeding, very little fluid actually moves in a brake system although more moves with disc brakes than drums. What do the brakes actually do, (or don't)?. I have a 2004 Harley with a sidecar. I don't believe they replace the master cyl, just relocate the reservoir. The back brake and sidecar brake are hooked together, of course I don't know how they compare in size with what you have. It does stop straight though. Hannigan didn't recommend any upgrade?
Originally written by bluehdmc on 3/8/2009 10:55 PM
I'd go over the brake bleeding, very little fluid actually moves in a brake system although more moves with disc brakes than drums. What do the brakes actually do, (or don't)?. I have a 2004 Harley with a sidecar. I don't believe they replace the master cyl, just relocate the reservoir. The back brake and sidecar brake are hooked together, of course I don't know how they compare in size with what you have. It does stop straight though. Hannigan didn't recommend any upgrade?
Hannigan didn't have a specific recommendation for my specific bike, but I gathered that they do sometimes upgrade the units and sometimes not.
The bike slows hard with the rear brake and does so straight, but the pedal hits the floor before the the rear tire(s) are at their full stopping potential (they will not lock up, even in the rained on wet roads).
By way of update however, I took the sidecar to the painters today and dropped it off. Thus, I unhooked the hack brake line via the disconnect, and the bike tire will not lock up either. It stops hard, but won't lock up.
This has me nearly convinced that I must have air in the lines still. I think I'm taking a simple problem and looking for a complex solution. Before I buy a new mastercylinder, I'm going to re-bleed the system (that will be the third time) and see if I don't just have air still in the lines.
If, under any circumstances the pedal goes all the way to the floor, there is definitely air in the system. An ordinary bleeding using the master cylinder is not very effective on a motorcycle, where the master cylinders are usually rather small to begin with.
I use a Mity-Vac. That's the type of unit that draws the hydraulic fluid through the lines to the wheel cylinders and expels the air into a container. It's a very positive method of bleeding the air out. I learned about the Mity-Vac from my Gold Wing riding friends. They are popular with them.
To draw a parallel, the Harley system has a small master cylinder that is still big enough when the sidecar is connected. The pedal on my Harley is very firm.
Once you get a good bleed job, you will be able to tell whether the master cylinder is sufficient. My guess is that it will be OK. Just get all of the air out and you should be fine. Get a Mity-Vac.
Regards.
Thanks for the tip! Never heard of a "mighty vac" but I'll certainly check that out!
I'm always up for a new tool/toy.
Originally written by geek_law on 3/9/2009 12:51 AM
Thanks for the tip! Never heard of a "mighty vac" but I'll certainly check that out!
I'm always up for a new tool/toy.
Mity-Vacs are available from places ilke Harbor Freight. They come in two types, plastic or diecast metal. They also come in two kits, one with all of the fittings for bleeding and testing vacuum parts on cars and bikes and a smaller kit with fewer accessories if you only want to do bleeding of hydraulic systems.
I'm giving you a link to the one from Harbor Freight with all of the accessories. I think the ones sold at Harbor Freight are the plastic version. I prefer the die case metal version, however. I think Napa dealers have those for a little more money.
These are widely used in the automotive and motorcycle repair business.
http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=39522
Disclaimer: I have no stock in the Mity-Vac company but I wish I did. LOL
Very cool! Thanks again for the tip. I've never even heard of these. Here I was dripping fluid all over the side of my bike and tire :-{
Originally written by geek_law on 3/9/2009 12:31 AM
Very cool! Thanks again for the tip. I've never even heard of these. Here I was dripping fluid all over the side of my bike and tire :-{
Easy on the fluid! Dot 3/4 will eat your paint.
Let us know how it works.
Happy Trails.
Good on the use of the mity vac. They work well and are not very expensive. If you get the plastic one do not overdo it when pumping it up as you can crack the container. Great tool in either case.
It is a good idea to have the bleeders at the upper most part of the caliper when bleeding brakes. Not as critical with the mity vac but if you still have issues give it a try. To do this you may have to unbolt th ecaliper and rotate it on the rotor while bleeding.
Originally written by claude #3563 on 3/9/2009 11:31 AM
Good on the use of the mity vac. They work well and are not very expensive. If you get the plastic one do not overdo it when pumping it up as you can crack the container. Great tool in either case.
It is a good idea to have the bleeders at the upper most part of the caliper when bleeding brakes. Not as critical with the mity vac but if you still have issues give it a try. To do this you may have to unbolt th ecaliper and rotate it on the rotor while bleeding.
The more and more I talk to folks, the more convinced I am that my problem is not the mastercylinder, but simply that I failed to completely expunge the air from the line.
I'm going to pick up one of these mighty vacs and go to town on the brakes.
As for taking the caliper off, thanks for that tip too. That's no more difficult than changing the pads, so I'll try that as well, just in case any air has gotten trapped in upper pockets of the caliper itself.
I knew I came to the right place!!!
The only RIII I've seen with a hack on it was plumbed into the front master-cylinder not the rear.
When you are T'ing into the rear that cuts it's fluid supply in 1/2 for each. If you T into the front it only cuts it by 1/3. Of course all this depends on the associated slave piston diam's vs the master-cylinder. Just a thought.
As a side note:
Years ago with the GL1500's some used to tie into the rear but had to bore out the master-cylinder and put in a larger piston. Then along came the GL1800 and the plumbing was found to work just fine with the front master-cylinder with no mods needed. The only problem with the 1800's was getting the system to blead properly.
I prefer to use a seperate master-cylinder for the hack with a brake pedal next to the bike's so I can roll my foot left or right to aid steering as needed, but then I'm a little old school on that.
Originally written by JerryR on 3/9/2009 10:10 AM
I prefer to use a seperate master-cylinder for the hack with a brake pedal next to the bike's so I can roll my foot left or right to aid steering as needed, but then I'm a little old school on that.
Somebody else suggested this to me. That would be a very cool set up as it would allow my to use the hack brake to pivot the rig to the right or left simply by rolling my foot right or left onto the respective brakes.
Unfortunately, I'm not much of a fabricator and I doubt there are turnkey solutions (tell me if I'm wrong).
I'd love to have a separate brake though. Any tips on perhaps how to go about doing something like that?
Hmmmm ... maybe I should just look for a local welder or fabricator and see if they could work up a pedal for me. That would be a very very cool solution. Obviously I'd still bleed my brakes too.
A picture of your dual pedal set up would be great if you have one.
You might check with Motorvation or others and see if they will sell you one of their sidecar brake pedal/master cylinder assemblies. Some are bolt on accessory items.
Lonnie
