Dual Tokico Rear brake setup leaking from switch

[toast]

Hey everybody, I've got a Fab Kevin-style dual rear Tokico brake setup on my shovel. To have a functional brake light switch, I used this hydraulic switch from Dennis Kirk (link) to go through the banjo bolt eyes on the brake line. Tried to bleed the brakes and all I got was brake fluid leaking from this switch. This is the second switch I've attempted to use, first one failed after the first use (rear brake seized up) and this one I can't even successfully bleed the brakes without it dripping. Does anybody have any better ideas?

I am at work right now but can get some pictures up this afternoon if that'll help. Also if anybody is in the Hampton Roads area of VA and would like to help out, let me know.

[usmc50lx]

I never use those banjo bolt switches for this very reason, I've heard too many horror stories. I always use the brake switch out of an early to mid 60s Ford car... 1/8npt male threads and 2 bullet connectors, then just run a 3/16inv to 1/8npt tee fitting and you are in business with a cheap reliable part that you can snag at most Autozone, NAPA, O'Reilly etc. in case shit breaks on the road but I haven't had one go yet.

[Tattooo]

Post a pic of what and where it's leaking...........

[toast]

I never use those banjo bolt switches for this very reason, I've heard too many horror stories. I always use the brake switch out of an early to mid 60s Ford car... 1/8npt male threads and 2 bullet connectors, then just run a 3/16inv to 1/8npt tee fitting and you are in business with a cheap reliable part that you can snag at most Autozone, NAPA, O'Reilly etc. in case shit breaks on the road but I haven't had one go yet.

So just run a Ford switch like this one (link) inline on the brake line, off of the tee? Then just a regular banjo bolt at the caliper? Sorry I'm a little dense.

Post a pic of what and where it's leaking...........

I'll have pictures this afternoon/early evening. Just wanted to get a jump start on the thread to get some ideas moving in my head.

[usmc50lx]

Yup that be the one, I sometimes dust some paint on it if I want to conceal it, Earls makes a Tee that has a Bolt hole to hold it down as well. On my pan I welded a stud on the frame under the trans to mount the tee and switch then hardlined to the master and back to the axle plate then a tab and flex line to the drum. But Adele clamps will work fine as well to hold the line in place and secure the switch from banging around.

[Cory]

It's a dual brake set-up? Are you stacking the two banjo bolts? Did you use a copper or aluminum washer in between? and on both sides? That will cause a leak for sure.

[toast]

Yep, dual caliper, single disc. It's a dual bleed banjo bolt/switch, so the line can split off and go to the second caliper. There is a washer between each piece of the fittings. You'll see when I can get a picture up.

[DocKnosBest]

Hey Brother... I use these ALL the time on our builds. They work great. But remember to use PERMATEX THREAD SEALANT on the threads. We use nothing else so maybe that's the ticket too (available at most auto parts stores). Also, there are different thread sizes available in these so make sure you got and have the correct thread size. Use a high quality of "crush washers" on both sides of it too. GOOD LUCK... Doc at Doc's Choppers in MN

[toast]

So, I haven't had time to do any wrenching on the bike because my son was born a month early at the end of September. So I've been a bit busy, needless to say... anyways, I've got some pictures now, as well as some more information after some troubleshooting and shaking down, but still no solution as of yet. I've got a few ideas, but I wanted to bounce them off the forum before I tried to do anything. So, pictures first:









Here's the setup that I'm running on the rear. So, I bought this whole kit second-hand, either from the classifieds here or using chopperswapper on IG. As far as I'm aware, the bracket is made by Fab Kevin and the calipers are from a GSX-R crotch rocket. I took the calipers apart and cleaned them out really good with brake parts cleaner and put them back together using the original seals since I don't know what year these calipers are off of to buy the proper rebuild seal kit.

The problem I'm experiencing is thus: my rear brakes work... for awhile. The banjo bolt leaks as noted before, but I haven't used any thread sealant as the last commenter mentioned I should (because I was worried about getting anything mixed into the brake fluid. I guess I can give it a shot if it'll stop the leaking though). The BIGGER problem, however, is that my rear brake will continually seize up. Let me give you an example of a ride. Kick the bike over (sometimes 3 kicks, sometimes 30), then go. Various accelerating, slowing, stopping, traffic, etc. You know the deal. Now, eventually, I will come to a stop at a stop sign or stop light, and I will inevitably let off the brakes and attempt to, ya know, GO... but I'm practically stuck. The rear brake will NOT disengage. The shoes are clamped tight on the disc, and if I do get going I can feel the motor fighting the brakes. So, I'll pull off the side, I'll discover my brakes are locked up yet again, and I'll loosen up the bleeder valve. Hot, steamy, boiling brake fluid will come shooting out of the valve and relieve the pressure to the calipers, which I can then pry off the disc with a flathead. Once I've got them disengaged and cooled down, they'll work fine... until the same thing happens.

So, I've got several theories, and several possible solutions... all of which I'll mention here for us to debate.

The first idea I had is that the master cylinder is not meant for pushing 4 cylinders in 2 calipers and is just being overworked; while the master cylinder can push enough fluid to engage the brakes, the fluid cannot return fast enough (due to a too-small return hole), thereby causing the shoe to not be able to fully disengage due to braking friction creating heat causing expansion of the fluid, thus keeping the cylinders pressed out. The solution for this would be to either remove one caliper assembly, leaving one on; OR to drill out the master cylinder to permit faster return flow.

The second idea that I had is that my rear brake pedal seems to maybe ever so slightly touch up against the foot peg when my foot is on the peg, which could theoretically be causing slight compression of the pedal and causing the brake to slightly engage at all times, leading to the same friction-heat-expansion problem mentioned earlier. This is why you can see in the picture that the last time I poked around on this thing I took the peg off to see what happened. Hard to ride with only one foot, by the way.

The third is that I shouldn't be using these damned jap parts on muh Harley because america #1, and I should switch out these TOKICO calipers for something a little more... domestic. I do have a pair of nearly brand new calipers and brake pads from a dual disc HD Road Glide, but I don't have a bracket to use or the fab tools/skill to hang those up properly.

Input? What do you think? Again, sorry for such a long delay, but as all you dads know, kids come first.

[tomsoftail]

- FabKevin in does make a bracket to use the new 11.8" rotors for our 11.5 inch setup.
- I would recommend a 5/8" matter cylinder too. I like your thought on the reservoir being too small on the return path for the fluid.
- get that pedal isolated. Maybe your bike will be faster too???!!!

[farmall]

The third is that I shouldn't be using these damned jap parts on muh Harley because america #1, and I should switch out these TOKICO calipers for something a little more... domestic.

You just don't like the Tokico logo but I understand.

A flap disc or a mill gets rid of those.

[Guest]

Fab Kevin is very helpful with master cyl specs, email him. The gsxr calipers he uses recommend 5/8 for a single rear, can't say I like the feel or it works great, but problem could be elsewhere.

Looks like a early 2000s sv650 caliper. Search that auction site for keywords like tokico and Suzuki or 650 or gsxr and you should be able to pinpoint what they are with little effort.

Make sure you have compatible fluid and make sure they are bled to the nines. Bleed screws 12clock, go broke on fluid. They are pretty hard to make happy.

If they've been overheated the Pistons can end up sticking and I'm not sure if they'll ever work.