Getting Pistons Out of Front Calipers

[audiowize]

Is there any sage wisdom around here for how to get all the pistons out of the front calipers without struggling too much?

My weather seals are shot, so I'm going to attempt to yank out the pistons and renew all the seals, but once I pop one out, the rest won't be very motivated to leave the caliper.

 

[Mihalis fjr]

Install again the piston back in the caliper,put a thin piece of wood between the four pistons and try with low pressure compressed air in the hole for the brake hose.If the pistons are very stuck,try with more pressure compressed air.

I believe that is the only way when you have the caliper in your hand.

 

[Twigg]

^^^^^ This.

And if they are really stuck the other way, although messy, is to blank off the hole for the fluid pipe and fit a grease nipple to the bleed hole. With a decent grease gun and lots of grease, they WILL come out.

 

[audiowize]

Alright, I just wanted to make sure there wasn't some reason to try to remove the blue plugs or something. Does anybody have the measurements for the ID, OD, and thickness for the banjo bolt washers? I'd love to replace them, but I'd like to buy a bag of 100 from McMaster.

 

[03silverbullet]

Are they leaking?

268k miles and I have never had to replace those seals.

 

[Mihalis fjr]

Don't remove the blue plugs!Try that i wrote in my previous post and that's it!

I believe that the compressed air is the solution..!

 

[Donal]

Install again the piston back in the caliper,put a thin piece of wood between the four pistons and try with low pressure compressed air in the hole for the brake hose.If the pistons are very stuck,try with more pressure compressed air.I believe that is the only way when you have the caliper in your hand.

Agree with Michalis with one addition. When you have a piece of wood between the pistons - use it to move the pistons on both sides back and forth to make sure they are free.

If they are a bit stiff/tight try some light oil to get things moving, you are going to replace the seals so no harm done.

When they are really free you can just pop them out using your fingers.

 

[FJRay]

You have a perfectly good hydraulic system on board. More than once I have used the the bikes brake system to jack a stuck piston out. You generally only get one so clean it up and install with new seals. Clamp it in place and jack the other one out. It works fine just make sure to keep everything clean cause brake fluid is tough on painted stuff.

 

[audiowize]

If the seals will go hundreds of thousands of miles, should I just pick out the dust seals and replace them? I was able to get all the pistons to move freely when squeezing the brake lever, and they were all fairly clean. My motivation for pulling everything apart is so that I don't leave old, crusty dust seal chunks where they don't belong. Nothing, however is leaking.

 

[Donal]

For what they cost I would just replace all the seals, it's a pretty simple job, just a bit fiddly..............

 

[FJRay]

Well if it ain't broke don't fix it. go for a ride.

 

[wfooshee]

I will be less succinct than ^^^^:

The seals are not a maintenance item. The only reason to replace them is leaking or stuck pistons.

Leaking is obvious. You see brake fluid around the piston.

Stuck piston is less obvious. Best symptom is the front wheel doesn't freewheel like it should. Put the bike on the centerstand, have someone hold the back down so the front wheel is in the air, and spin the front wheel by hand. If it stops as soon as you let go, you need caliper seals, because the seals have stopped allowing the slight retracting of the pistons when the brakes are released.

The wheel won't spin freely even if the seals are good unless you actually press the pads back from the rotor, but it should complete at least most of a full revolution, if not more, with the brakes released. If it won't coast at all, then that's bad. Excess pad wear will be the result.

If you have no leaks, and the freewheel test is good, there is NO REASON to go through the hassle and expense of replacing the seals. Lck of leaks and good freewheeling are all the "peace of mind" you could possibly need.

 

[audiowize]

I'm a little disturbed that chunks of O-rings coming out of your caliper pistons isn't at all alarming.

 

[wheatonFJR]

If you have chunks of O-rings coming out...how is it not leaking?

 

[audiowize]

If you have chunks of O-rings coming out...how is it not leaking?

I believe they are the dust seals, not the main seals.

 

[Harald]

Not that this will help if your seals are already damaged, but I've found that cleaning the pistons whenever changing pads results in long seal life. The seals should last a long time unless you force crud into them, which is what happens when you push dirty pistons back into their bores.

I use a piece of wood that's the thickness of the rotor plus the thickness of 2 brake pad backing plates for the cleaning. Placing the wood between the pistons and then applying the brake results in all pistons extended, but not popped out of their bores. Then the pistons can be thoroughly cleaned with a brush and inspected before getting pushed all the way in to make room for new pads.

93,000 miles on my original seals with no problems (but knocking on wood just in case ). Getting ready to replace front pads yet again this weekend, so at least the front calipers will be clean. :yahoo: No comments on the lack of cleanliness for the rest of the bike.

 

[audiowize]

Yeah, my particular bike sat in eastern Washington for most of its life, which is a very dry climate, and at times very hot.

I do find it strange that these failed after a relatively short amount of time (11 years), but it was 2-3 of them on each side, so I guess it's just time.

 

[TownsendsFJR1300]

I had to replace the seals in my 04 FJR years ago when the front wheel wouldn't free spin more than 1/2 turn.. After new seals, easily 3.5 full spins..

Rubber seals with age, harden up and don't flex (and retract the piston) as would new seals. I didn't have any leakage...


I have the exact same calipers on my FZ6 as the Gen 1 FJR has. Same issue, with time, free spin was down to 1/2 to 3/4 a turn.

*Another easy way to check is to go for a ride, stop with the REAR BRAKE ONLY, and then touch the front rotors. If their dragging, the rotors will be hot (not good).


For my FZ6 (don't have the shop manual for the FJR anymore), seal replacement, by Yamaha is recommended EVERY TWO YEARS.
In real life, I've found 4-5 years more realistic.

Re popping out pistons. If you have access to even a small air compressor, a pointy blower tip WITH an angled cut of rubber hose on the end takes care of business. Simply put the hose on the tip, have it trimmed to an angle, then slip it in the bore(one piston is popped out hydralically). Add a shot of 100 PSI or so, it will come out. Put a rag in between the piston and the caliper to prevent damage/ flight and
definitly watch your fingers..

 

[Donal]

You might find something like this useful to get tight or reluctant pistons moving...........