Cleaning the Caliper pistons?

[Fred W]

Yesterday was ride around through the chilly New England glorious foliage day!! :yahoo:

So today was FJR maintenance in the garage day. :glare: Good thing since its f***ing snowing now!! What? :dribble:

Anyhow, I knew for some time now that my front left side brake pads have been wearing faster than on the right side, with the inboard left pad wearing the fastest, and I had already flipped the pads inboard and outboard on a prior maintenance, so I decided to just install a new set of OEM pads and do a general clean-up on the calipers today, and maybe see if'n I could see what was causing the uneven wear.

After removal. it was apparent that I could have just switched the left pair with the right pair and got another 10k of mileage (or likely more) out of this set, but what the hell... I had the new pads in hand (for quite a while now) and the calipers were off off, so...

Before shoving the pistons back into the calipers, as would be needed to install the new pads, I extended the caliper pistons out farther so that I could clean them up as best I could in situ. The problem (and the big PITA) is that the rear most pistons in the calipers is located in a curved cut-out in the body of the calipers. I cut strips of cloth and used brake cleaner spray the best I could, but to be perfectly honest, I don't really know if I got the back sides of those frigging pistons clean or not.

I guess I'm in better shape than if I had just jammed the dirty peckers back into the holes. But what do you other anal retentive maintenance-o-philes do when cleaning up those brake calipers? Remove the pistons completely from the calipers? Or just do the best you can like I did?

Oh, I could not see any good reason why the left inboard was wearing the fastest. But after I swapped inboard and outboard pads on the left side the wear evened up on the pair. However, the left pair was considerably more worn than the right pair.

Other extreme maintenance was performed today, but none was as stimulation or exciting as the brake pads...

 

[TownsendsFJR1300]

What I did to my 04 was remove each caliber from the bike. You can pump the brake lever until one of the piston pops out, now you have to deal with getting the 3 others out. You really don't want to grab them with a pliers and score them. I then removed the entire caliber to keep brake fluid away from the paint. Mine were pretty stiff, I cut a small piece of hose (maybe 1/4" ID) and where the brake fluid would pass thru the caliber(to a piston), insert the hose and use compressed air, thru the hose, to pop out the piston (my air compresssor nozzel wouldn't fit down in the very small recess). You might want to put a rag or something in front of it as a safety as it WILL POP out forcefully. Once all of em are out, clean up the pistons, I used the back side (green ) section of a sponge on the pistons (weren't that bad). The caliber, brake cleaner or such, then flush with brake fluid and blow out with compressed air. You can also remove the seals gently with a angled pick.

Once ready for re-assembly I used the grease included from Yamaha that came with the new seals. The stuff is designed for brake seals and brake pistons and eases re-assembly. I greased up the seals (not alot), and the pistons and gently psuhed them back in. It also seems to allow the brake pistons to move easier... Re-assemble and bleed. My brakes don't drag anymore and are considerably better with very, very little drag..(approx 3/4 to a full rotation when spun by hand with the front wheel rasied)

I've since purchased and used for my FZ6 the below listed product from Permatex. Its designed for brake caliber seals, pistons etc....

https://www.amazon.com/Permatex-24110-Calip...e/dp/B000HBNV6W

Hope this helps.., Scott

 

[dwhartwell]

Never had one apart. Automotive calipers have a dust/water boot that seals into the caliper and the end of the piston. FJR does not have this?

 

[TownsendsFJR1300]

Never had one apart. Automotive calipers have a dust/water boot that seals into the caliper and the end of the piston. FJR does not have this?

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Pretty much the same, an O ring seal with (square corners) is the main seal, then there's another dust seal (a bit lighter) towards the outside of the caliber body bore. It appeared to me that the clearances are a bit tighter on the FJR. The manual also calls for replacement of seals and brake lines every TWO YEARS... I replaced the seals in the front of my 04 about a year ago as they were dragging....

Scott

 

[Fred W]

No, there is no "boot" in the same sense that an auto caliper has. There are only o-rings (possibly multiples as pointed out) and basically exposed raw pistons. I always appreciated the sealed boots on an auto caliper's pistons as I didn't feel quite so negligent just jamming them back in for the new set of pads...

 

[Allnight]

As for left side wear more significant than the right side...Good On You for using the rear brake!

Remember, the "linked" brakes we have, is that one of the 4 front calipers compresses when the rear brake pedal is pushed.

I thought I was the only one who ever used the rear brake

 

[Fred W]

Bzzzzzt!!! wrong answer!

1st gens ain't got no linked brakes. But thanks for playing!!

But FWIW, I do use my rear brakes. On a group ride recently I was informed that my brake lights were sticking on. I recognized this as a common problem on FJRs of the rear brake pedal getting stuck (due to lack of maintenance on my part) so I hooked it with my toe and pulled it up. But tried NOT to use it for a while and found it very unnatural, my present habit being to use them both.

 

[Roadstar]

I did a set of 2 piston calipers on a goldwing & there were just 2 o-rings (no dust boots) I questioned this & found out the bottom o-ring is for the seal for the fluid & the top ones is infact a seal to keep dirt from getting in (kind of like a wiper.) There is 2 ways to clean the caliper (once the pistons are out & caliper is cleaned), first is using a brake hone (just enough to make things shinny again if you can get it to work) , 2nd believe it or not , but aluminum foil (my method i just used on my 76 goldwing calipers on the rebuild) & also used it on the pistons & smoothed them out . Put new o-rings in, soaked everything in fresh brake fluid & piston went right in. Look hear & go between 1/2 & 3/4 down & you will get the picture. https://www.nakedgoldwings.com/forum/viewto...afa75db846cdbba

 

[madmike2]

Great post, Fred. It's a dirty tedious job (If I still swore my garage would now be permanently blue.). I did mine before the CFR trip and used the same technique with strips of cloth soaked in WD-40 to clean the pistons blocked by the close proximity to the caliper machining.

My brakes are wearing evenly now. Good for you for doing the job and sharing.

 

[Andyfjr]

I found a very effective method of cleaning the calipers and pistons. Unbolt the calipers from the mounts remove pads and move away from the disc. Use an old tooth brush(stiff bristle) and soapy water to loosen the grime from the caliper and pistons. Then use brake cleaner spray to wash away the dirty water from the caliper/pistons. This method qiuckly cleans everything up. I then ease the pistons out a little, by applying the brake lever, any pistons that stick, I use a small block of wood to hold the free pistons until the stiff piston moves. I use a cloth to clean away the grime or the soapy water/tooth brush if stubborn, then re-apply brake cleaner. Gently push the pistons back to allow refit of pads. Apply a small amount of copper grease to rear of pads.

This method only takes 15 mins per side to achieve a good clean up.

Note, this is only for calipers which are functioning normally prior to service. If pistons are seized then a further strip down and clean will be necessary to replace damaged pistons, seals etc.

Andy

 

[Fred W]

Thanks for the toothbrush tip, Andy. That is basically what I did, but without the toothbrush and water.

But the tricky part isn't extending the pistons or scrubbing the parts of the piston that you can see and get at easily. It's the back side of the two rearmost pistons that are wedged up tight to the side of the caliper body that is the PITA. That's where I had to use the strips of cloth to get at, and because you really can't see it's kind of a leap of faith that they are all nice and clean back there when you are done.

And yeah, I guess I could have popped the pistons out completely, cleaned them, replaced the seals, reinstalled, bled the brakes...

Whew! Sounds like way too much work. I can't see replacing seals every 2 years on brakes that are working normally. :blink:

 

[Geezer]

Is there any reason you can't turn the pistons in the bore to clean the back side?

 

[Fred W]

Is there any reason you can't turn the pistons in the bore to clean the back side?

That right there is a good (not excellent) question.

The only difference between a good question and an excellent question, is that an excellent question is one I know the answer to...

I did try to rotate the piston by hand to no avail. I didn't want to force it or grab the piston with tools that might mar it. I assume it was just the seal friction I couldn't overcome by hand.

 

[ionbeam]

I'm a toothbrush & brake cleaner guy. I've leave one caliper on the bike then insert my Finely Calibrated Pine Board inside the removed caliper and press the brake lever so the pistons extend just slightly past where they normally sit when on the rotor. This usually extends the pistons to where there is a clean ring just past the seals so I can get them completely clean.

To rotate the pistons in the bore I have had some success using my internal/external snap ring pliers set for internal, then use them inside the piston cup. My snap ring pliers have interchangeable tips that come both straight and angled so I can usually find some combination that works.

It makes me feel faint and weak to hear that someone uses water with pressure and force around the piston seals. I can just hear the hydrophilic brake fluid slurping up the water :Snorkle:

 

[Zorlac]

Same as it does with driven rain?

 

[Fred W]

Another good tip, using the internal snap ring pliers, ion.

Thanks

 

[ionbeam]

Same as it does with driven rain?

Let's see, riding in the rain the calipers are on the fork tubes, the pads are in place, the rotor is between pads, the pistons are mostly retracted into the caliper and to some extent the caliper will be warm enough to assist in drying off a light film of water. Even in a heavy downpour there is very little room for a hose job directly on the piston seals.

During cleaning you have to pop the pistons quite a ways out, cover them with water, perhaps 40-60 psi water, and a surfactant agent (soap) then get in with a fairly stiff brush and scrub, scrub, scrub.

In the end, it may be fine to scrub the piston and seal area with water and a brush. A cloth would be less aggressive around the seals. I will opt out on the H2O cleaning method and I flush my brake system regularly. I just thought I would mention that water may not be the first choice as a cleaning solvent for brake systems.

 

[Zorlac]

Yes 60PSI water right at the seals would be over the top, but remember, the seals themselves are capable of holding IN a few PSI of brake fluid.

I just dust mine off dry and call it a day.