The Lazy Caliper Repair Question of the Day

Okay, so can I/how do I remove the caliper without draining the lines. Is it possible so that I can get the piston working but not have to do a full replacement/bleed? Thanks.

 

I find many times it's not the piston that's causing the problem, it's cheezed up sliding/pivot hardware.

On yours with the single pin pivot, they like to get so stuck (sleeve and pin) together that the caliper can't pivot and apply both pads when you squeeze...so you get terrible braking action from it.

You don't have to disconnect the line to deal with that, so it's worth a look....

 

I tried that a few weeks ago, didnt really have the desired result. I would pop the calliper off, pull the pistons dress them up, check your seals (mine was sticking due to loads of corrosion behind the seals making them too tight) and clean up and grease the sliding pin too, should be able to do that in a few hours and have it bled up again.

 

Thanks for the suggestions. Well, mine gave me the typical behavior for a gummed up piston - one ride home it got tighter and tighter, then the front wouldn't roll next morning. Pulled the pads, and could tell that the caliper pivot worked. But I couldn't push the piston back in at all. MC fine - and had new fluid last year.

 

Did you try a "C" clamp to force the piston back? using the pad that sets next to the piston in place and the other pad out, jack the piston back into the bore. The reason for using the pad is to help the piston go back in as straight as possible so it won't bind up. Once the piston is back in, say about half way then use the brake lever to force the piston all the way out. BTW an ever tightening brake could mean that there is a plugged orifice in the MC.

 

Crud builds up in the channels behind the seals.

"Lazy caliper repair" doesn't work. You will continue to have problems until properly addressed.

You need to carefully clean the channel seals, then REPLACE the seals if original. They were only supposed to have lasted 2 years.

You can take all the shortcuts you want. In the end, you'll spend MORE time than if you did it right the first time. Meanwhile, this is your front brake; upon which your life can often depend.

Shortcuts (or "laziness") is NOT a good philosophy when it comes to brakes.

 

Thanks LVSteve. Will that replace the compressed air method that lots of posts recommend?

I don't have the system to do it at home nor the balls to tell a brake repair guy that god told me he could do it for a donut and coffee.

And don't worry fitz, I just grabbed my new package of seals out of the mailbox an hour ago. My laziness is in preventing losing the air bubble-free environment in the lines that I have.
Taking the caliper apart entirely tomorrow. Just want to be able to reconnect and fill/bleed the caliper only - and top off mc. Maybe I'm SOL on that?

 

Well, once you pop that piston out, there goes your "air-free system." You can theoretically rebuild the caliper still attached to the lines, but it's not like doing the pads, if you take caliper apart you WILL have to do some bleeding.

 

I had similar problems with my bike which led to warping of my brake discs! (Talk about expensive!)

But I went all out, for my bike I had to get new pistons to get the seals.
And I used a grease gun to get the pistons out, and the grease was not too had to clean out since the residual brake fluid acted as a lubricant. I also used a dremel to clean the insides, and switched to stainless lines because the wallet was open anyways.

But I can't argue with the results. I have had to use these brakes and I'm glad they are strong!

 

Hi Dan, displacing the piston hydraulically is the preferred method, if you still have the brake lines attached, though I have used compressed air with success. As far as getting a bubble free bleed, I suggest that you use the vacuum bleeding method and have an assistant tap on the brake lines with a screwdriver handle while bleeding.

 

Here's the deal:

Bleeding Yamaha brakes is a PIA. It doesn't matter which of the many methods or tricks you try, it's a PIA.

No matter WHAT you do, the system likes to trap bubbles. Part of this is due to the extra fittings at the junction block; this can be dealt with by "cracking" each union and bleeding it, or by simply being patient.

A larger part of it is due, IMHO, to the rough machining on the inside of the caliper. All of those fine grooves trap tiny bubbles when the system is first refilled; and it takes a while for them to consolidate into larger bubbles and bleed out.

A lot of folks, including myself, seem to get better results by pulling the lever to the bar, and leaving it overnight.

I said "seem." I've discovered the KEY is the "leaving it overnight" not necessarily having the lever pulled to the bar.

You can bleed and bleed and bleed a freshly-filled system and it will still be spongy. Leave it alone for 12~14 hours and it will bleed much more effectively.

The lesson here is that you only want to go through it once. You DO have to empty and refill the system at some point.

So be sure you're replacing those 30-year old dangerous brake lines too.

 

Haha, PIA....
It took me over an hour and two days...

 

Exactly.

Wanna do it AGAIN???

I did one brake overhaul in "stages" and learned my lesson.

 

Thanks to all.

So really, even if I get the caliper disco'd and somehow clamp off the line just above caliper (did this once on 4WD with vicegrips to get down a crazy rugged mountain pass when a drum was oozing fluid. Eased down on 3 brakes and as slow as 4WD would go), I will have the air problem anyway MOSTLY due to the caliper interior when I refill it and bleed the system.

In that case, nevermind my question. In the garage now with coffee music...

 

You never wanna clamp an old brake hose shut. They can fall apart internally from it and cause no end of troubles...

 

All you really wanna do with old brake hoses is replace them with nice new braided stainless steel hoses.

That falling apart internally thing can happen even with no clamping.

 

So Rolf, the old tattooed German biker that runs the bike repair shop I rely on for the tough stuff, popped it out with air this week. Well his assistant did, and free of charge - although I'll drop back by with a six pack next time I need a favor.

So, the system is no longer sans air. I will be bleeding. And in reference to my other post, probably not use my mouth to assist, although maverickbr77 gave me hope...

 

Worried for no reason. Some of the other posts about this got me all in a fit about the difficulty of bleeding. I just used same bleed method I have done on any car that needed it.

Apply pressure and hold, open nipple, shut nipple, repeat. 15 minutes and I had pushed all the old fluid thru. And on a hunch I only closed the MC with the rubber cover/diaphragm and not the metal cover. That made it even quicker.

Per suggestions, I left the handle strapped to grip overnight. Two days later the braking is solid as a new sports car, and I didn't even need to add more fluid to the MC.