[Superbike Racer]

Howdy,

I rebuilt my front brake calipers. I cleaned (and kept) the pistons and replaced the seals. Then I put them back on the bike, used a vacuum tool to get the brake fluid flowing again through the lines, and ever since then I've been using the zip-tie-on-the-brake-lever-overnight trick to get residual air out. So far, so good. The problem is the bubbles keep coming out! Big bubbles. I've gone through about 20 zip ties this way. All I can think of is I let the reservoir get too low (I thought I was being careful) and it sucked major air into the lines. But I've been bleeding air for so long that any residual air should have been long gone. Has anyone had this happen before? Any suggestions?

 

[le skid]

Salut mon ami
Any chance there is a similar cause as the other stuck caliper thread you just commented-on? IE where did you guy the rebuild kit? Is it from the land of Lo-Mein? I assume you know what you're doing and the more of these stories I read or hear, it's shocking how often it's manufacturing related.

Unrelated but related: I just did front brakes on my car. NEW, not refurbished calipers from the dealer were $213 (with no core charge) which tells me 'Chinese'. Honda OEM calipers used to be 500-700 for new, less for remanufactured so something has changed.

So I went to Canadian Tire (canuck Harbor Freight) and they were $140 ea with lifetime DIY replacement???? I asked where they're made and the guy said it's ALL from China now.

Anyway, if the rebuild kit is from China, please let us know!

 

[Superbike Racer]

Salut mon ami
Any chance there is a similar cause as the other stuck caliper thread you just commented-on? IE where did you guy the rebuild kit? Is it from the land of Lo-Mein? I assume you know what you're doing and the more of these stories I read or hear, it's shocking how often it's manufacturing related.

Unrelated but related: I just did front brakes on my car. NEW, not refurbished calipers from the dealer were $213 (with no core charge) which tells me 'Chinese'. Honda OEM calipers used to be 500-700 for new, less for remanufactured so something has changed.

So I went to Canadian Tire (canuck Harbor Freight) and they were $140 ea with lifetime DIY replacement???? I asked where they're made and the guy said it's ALL from China now.

Anyway, if the rebuild kit is from China, please let us know!

Stock Suzuki seals only, my friend. I tried to delete that other post but couldn't figure out how.

 

[Superbike Racer]

I discovered that one of the banjo bolts was on backwards. Some lines are angled at the banjo bolt so that it doesn't bind against the caliper or another line. This one was angled TOWARDS the caliper so I reversed it. I think it helped, but it's still taking a LOT of zip ties to get more and more bubbles out of the lines. The line that used to have the backwards banjo has the most air bubbles coming out. I've pumped so much brake fluid through it though. I guess there are pockets of air that come out slowly with the zip ties. I'm expecting it to work but it's not there yet. Sheesh.

 

[Mb1500]

Shouldn’t constantly be getting bubbles. It’s possible that the bubbles are being introduced at your bleed hose, line could actually be clear. I’ve seen that before. Double check for anything that could be introducing air.

Maybe try a vacuum pump Mightyvac or similar.

 

[craigfer63]

When you disassemble the brake system lots of air gets trapped in. The bubbles you are seeing could be coming in past the threads on your bleed nipples. Copper grease on the bleed nipples threads, seals them up. Push brake fluid in through the top nipple, with a syringe and drain out the caliper nipples. Or reverse from calipers up to top.
I use these Drain bags to save on the mess. But I still manage to make a mess anyway. 😁

https://store.independenceaustralia.com/simpla-drain-bag-s2-2000ml-100cm-12140030

 

[Superbike Racer]

I think I got it. Thanks for all the tips, guys. I'll remember them for the next time I screw things up in a new and interesting way. For starters, I solved the mystery of the Backwards Banjo Bolt. I'm sure it was leaking air. Next, it took me a long time and many zip ties but the brake lever is getting much stiffer even though bubbles are still coming out. I don't know if this is really necessary, but here's what I'm doing: (1) Put a zip tie on the brake lever and leave it there for a few hours, (2) put the hose on the bleed screw and open/close it very quickly (about a half second) -- I'm not pumping the lever with my hand, just using the built-up pressure from the zip tie, so only a couple of centimeters of fluid comes out, complete with air bubble, (3) check the fluid level in the master cylinder, and (4) put another zip tie on. Wash, rinse, repeat. Sounds painstaking but I know no air is leaking in through the hose.

 

[craigfer63]

This zip tie, on and wait a few hours, could not work in a race pit, scenario. Or if you need to get to work.
But, what ever it takes.

 

[Superbike Racer]

This zip tie, on and wait a few hours, could not work in a race pit, scenario. Or if you need to get to work.
But, what ever it takes.

True, but it's a race bike so I have time. Once it's done, it's done. Won't have to do it again for a long time.