675 Pistons have arrived

[david_m]

The other thread has grown to 4 pages, so I decided to start a new thread. I need to ask a question, and I wanted to make sure it got noticed, and not buried on page 4 of the other thread.

So, the new brake pistons have arrived. The kit comes with pistons AND seals. Everything looks great. Here's my question:

When I remove the brake lines from the front calipers will all of the brake fluid drain out of the system? Is there any way to prevent the front system from draining all of its fluid while I replace the pistons and seals?

Normally I wouldn't be concerned, but my bike has ABS. A normal brake bleed is no big deal, but if the system runs dry and air gets back to the ABS unit, I must have the electronic Triumph service tool in order to bleed the whole system. I'm afraid if the removal of the calipers causes the brake fluid to drain I won't be able to perform the piston swap myself. I'll need to get it to the dealer (D'oh!) which will be added time and expense.

Someone please let me know if there's any way I can replace the pistons and seals on my calipers without draining the brake system of fluid.

Thanks,

David

[TRIUMF3]

I haven’t looked at the newer sprint, but if you remove all the clips holding the lines to the forks Ect, you should be able to disconnect the lines from the callipers. Then lift the lines so the open end is higher than the reservoir and secure them so they stay higher, you will lose a little fluid during the operation but once the open ends are above the reservoir you should be ok.

[NinjaRAT]

What TRIUMF3 said, though I think you'll get air into the line. Question is, will air get all the way up to the Master Cylinder (which would the problem with ABS, no?), is the question.

I don't know, as this is my first bike with ABS, and I never heard of any difficulties with bleeding ABS until I read about it on this forum.

[bluesjeans]

How about removing the caliper assembly from the bike first then holding them higher than the reservoir before removing the brake lines..?? You'd want to be sure to keep the cap on the reservoir during the whole operation or you'll surely have a mess everywhere.

[Airsick]

On 2006-08-04 06:32, bluesjeans wrote:
How about removing the caliper assembly from the bike first then holding them higher than the reservoir before removing the brake lines..?? You'd want to be sure to keep the cap on the reservoir during the whole operation or you'll surely have a mess everywhere.

That is a great suggestion. My ZX9R calipers should be here today and was wondering the same thing. Also, I know that you are aware how corrosive this fluid is so keep a tarp over your baby before removing those lines!!

[bluesjeans]

On 2006-08-04 08:11, Airsick wrote:
Also, I know that you are aware how corrosive this fluid is so keep a tarp over your baby before removing those lines!!

And to that I would add it might be smarter to have 4 hands while removing the brake lines. You wouldn't want them swinging wildly free flicking their corrosive fluids in every direction..

[kek]

As an '06 ABS owner with constant brake bleeding required to operate safely, I'm EXTREMELY interested in how/if the 675 piston swap works.

david_m, if you lived anywhere near me here in Texas, I would be happy to lend a pair of hands.

[Sport]

Why not just seal the line by tightening a bolt and nut through the brake line eye? You may consider larege area washers or even o-rings under the bolt and nut to prevent leaking.

Just a thought.


[ This message was edited by: Sport on 2006-08-04 09:20 ]

[david_m]

That's a GREAT idea. I'll hit the hardware store on the way home.

[david_m]

So, the 675 pistons were installed this week end.

Based on a suggestion from the board (Thanks Sport!!) I stopped by the hardware store Friday (on the way home from work) and bought some rubber, beveled washers; some long, thin screws and some wing nuts.

The beveled washers worked great for sealing up the brake lines while the caliper is off.

I had cleaned the calipers and pistons a few weeks ago, and everything was still very clean. But when I pumped up my brakes to get the pistons to move, only one piston in each caliper decided to move. ONE FREAKING PISTON!!! Ugh. I think it is absolutely ridiculous that repeated application of the brake lever will not move all four pistons.

I pulled the calipers off the bike, loosened the hex nuts and disassembled the calipers. I don't have an air compressor, so I couldn't blow the pistons out. I had to pull the pistons out with a pair of needle nose pliers (insane). Two of the pistons were so bound up I had to put the caliper under my foot and pull like crazy. How on earth are these things supposed to actuate when I can barely move them?!? So, the pistons are FINALLY removed. The seals and rings inside the calipers looked great, so I decided to keep them in there. This way, I can change ONLY the pistons and see what kind of difference I experience.

The original pistons are out. They're very shiny and clean, and, despite having to use needle nose pliers to extract them, they don't have a mark on them. They look brand new. Heck they are brand new (my bike only has 4,200 miles on it). They are the color of shiny copper and look like a brand new penny.

I placed the old pistons next to the 675 pistons. The 675 pistons are grey with a matte finish. They are definitely "slicker" to the touch than the original pistons, and there's no doubt that they are coated where the original pistons are not.

I grabbed the 675 pistons, rubbed some brake fluid around the outer side for lubricant, and slipped them into the calipers. The 675 pistons fit in snugly, but slid in SO MUCH EASIER than the original pistons extracted. Then, I reassembled the calipers, remounted them on the bike and reattached the brake lines.

During this whole ordeal I made sure that the reservoir always had brake fluid in it. There were some drips when I was reattaching the brake lines, but the reservoir never ran dry. Since my bike has ABS, I was very concerned about NOT letting any air into the ABS system.

After everything was reassemebled, I bled the brake lines. I'm pretty sure I got all the air, but without a vacuum bleeder it's hard to be POSITIVE. I pumped up the handle and everything seemed fine. Then I zip tied the brake lever back and let the bike sit over night.

The next day................................

I went out the next morning, cut the zip tie, and then inspected the calipers for any sign of leakage. I had placed a very clean pan under each caliper the previous evening, and figured if there was leakage I'd see it. The pans were dry, so it looks like everything was sealed up nice and tight. I'm going to keep my eye on things for a few more days. You can't be too paranoid about brake performance.

The brake lever felt like a Japanese bike brake lever. However, I had just bled the brakes the previous evening, so they SHOULD feel good. I rolled the bike forward and everything seemd to move smoothly. I applied the brake and the bike stopped. So far so good.

I fired it up and took it for a spin around the neighborhood. Everything seemd to be in order, so it was off to find an empty parking lot.

I pulled into an empty parking lot at a closed grocery store. I ran the bike up and down the lanes and practiced some panic stops. I got the ABS to kick in, and everything seemed to be working fine. The brake feel was FANTASTIC, and the performance was really good. This was on Saturday.

Today (Monday) I rode into work. So how are things after a couple of days? Well, the brake lever still feels really good. It's NOT as great as Saturday morning (the night after the bleed), but WORLD'S better than what I had before. There isn't ANY hesitation on brake application now. Before I would experience some initial hestation where I would have to pump the brakes up before I would start slowing down. Considering how bound up my pistons were, I'm not surprised.

Based on previous brake bleeds I really won't know if this is a fix until the end of the week. Initial results are VERY PROMISING. If nothing else, the difference I felt in removing the old pistons versus installing the new pistons inspires confidence that my brakes are going to perform more consistently.

We'll see how things progress.

David