I think my gas mileage just increased !!

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Noticed yesterday that my rear brake was dragging slightly - not too bad but the wheel wasn't spinning as easily as it usually does. BTW, I replaced the rear tire a few weeks ago and the wheel seemed to spin OK after I replaced the wheel after the tire change.

Well, even 120 psi of air wouldn't budge one of the caliper pistons !! I finally got it out and had a good used spare to replace it with. After removing and cleaning the piston seals and dust seals and cleaning out the seal grooves, I re-assembled and re-installed the caliper and bled the rear brake. What a difference !! The rear wheel spins without hardly any drag. The bike seems to have more pep now, too. I did a 55 to 100 mph pull and it ran great.

When I got the bike about 25K miles ago, the rear brake was dragging and the caliper was rebuilt at that time, too. So, I just ordered a used caliper from EBay and plan to rebuild it and then every time I replace the rear tire, I'll swap out the caliper for the rebuilt spare. I'm definitely not a member of the " If it's not broken, don't fix it " club.
 

ST1100Y

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You can't go wrong with a little preventative maintenance to keep things working correctly.
Amen to that...
And I would have replaced those piston seals... those are "cent-items" vs roadworthy safety...
 
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Jim Van
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Amen to that...
And I would have replaced those piston seals... those are "cent-items" vs roadworthy safety...
+1 on your quote , I will rebuild the EBay spare with new seals ( about $14 w/shipping ) and even new pistons, if the old ones need replacement ( but they must be made of S.S. because they show no sign of corrosion ).

But I have an IBA long distance ride planned for this week and there was no time to order and receive the seals before I start the ride. However, I must report the old seals after cleaning looked like new - no wear whatsoever. I think the "white" corrosion in the seal grooves ( mostly the dust seal groove ) was causing the dragging problem.
 

ST1100Y

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...new pistons, if the old ones need replacement ( but they must be made of S.S. because they show no sign of corrosion ).
AFAIK are they coated, which is why I don't advocate "polishing" them... it might thin/damage the corrosion protection...

But I have an IBA long distance ride planned for this week and there was no time to order and receive the seals before I start the ride.
I had no offence intended, and still don't...
But if regular checks and maintenance work get scheduled more frequent (like at least once a year...) most issues (or aftermath) wouldn't establish at all...
And when longer trips dawn I try (yes, I too know the crux of packing on the last minute ;-) ), to start the pre-flights like 2~3 months ahead...

I think the "white" corrosion in the seal grooves ( mostly the dust seal groove ) was causing the dragging problem.
Definitely the begin of this: humidity/water from the outside meets with traces of brake fluid seeping from the inside...
If this crystal-growth keeps going unattended, the rings will jam so much, that the piston movement can actually cut rubber chips off them, and then their really stuck...
Also pitting-corrosion (small black spots), burrs or deformation (gorilla mechs removing pistons with water pump-pliers or vice-grips... :( ) can shave off rubber particles, which start to accumulate/block the clearance between cylinder and bore...
I've grown quite "anal" on those stoppers... yes, the bloke a "contracted workshop" might "do it" in 1/2 the time... BUT! :cool:
 

moddy

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Well done, I just did a caliper rebuild x 3 due to the brakes clamping a little hard on the front rotors. Really, If I would have known you could extract the pistons while on the bike and what is actually going on inside a caliper, I would have done it all sooner. It's what this forum is all about.

Looking forward to what my mileage will increase to. Hoping for at least 2 points.
 
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Jim Van
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Got my Ebay calipers yesterday ( rear & fronts ) and removed the pistons. They were all a little sticky, but came out fairly easily with compressed air. All pistons are like new since I "de-grunged" them. The dust seal grooves in these caliper's look much better than the grooves in my original calipers.

I ordered 12 seal kits yesterday also. So I will rebuild these calipers and after I swap them with the ones I'm running now, will rebuild the ones currently on the bike. Plan to do that every time I replace the tires. I'm also going to coat the dust seal grooves with silicone grease when I install them. Hopefully that will reduce the amount of corrosion in those outermost grooves.

BTW, after cleaning up the binding rear caliper, yesterday on a 350 mile ride, it looks like my mileage increased 3 mpg.
 

ST1100Y

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I'm also going to coat the dust seal grooves with silicone grease when I install them.
Just see that its not going to contaminate the brake fluid... (IIRC: silicone + brake fluid = bad...)
I use specified brake assembly paste instead, which won't interact when getting in contact with the precious DOT 4.
A slight smear on the rings before installing them, then a slight smear on the pistons, with that they'll glide right in...

Silicone grease only on outside parts, like the rubber grommets and caps for the sleeves/pins the callipers "float" on. The pins themselves get some of that white ceramics grease.
 
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Jim Van
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I use specified brake assembly paste instead, which won't interact when getting in contact with the precious DOT 4.
What brand ( who makes it ) is the brake assembly paste ?? And where do you get it at ??

I have some ( A really really old plastic bottle - about 30 years old !! Doesn't take much when re-assebling a caliper ) Raybestos brake assembly fluid that I use to re-assemble. It's basically very thick brake fluid. I haven't seen any of this stuff on the auto parts shelves in years !!

EDIT : Looks like it's still around , but they changed the bottle - Raybestos BAF12 Brake Assmbly Fluid
 
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ST1100Y

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Grabbed a tube of ATE brake assembly lube at a local auto-store... (ATE is OEM supplier for many automotive MFGs)
Compliant with DOT 3, 4 and 5.1, also avail on Amazon, Ebay, etc...
Yes, one doesn't need much, the 180g tube will be sufficient for many, many brake overhauls...

Some nice tips shown here:

https://www.youtube.com/watch?v=tUyGTvLDrt4

Spraying copper-slip on the outside of the calliper pistons is debatable though...
But the idea of protecting the outer surface from the elements is advisable...

On the "float pins" (the ones that go into the rubber grommets/tubes) I use Ceramic Paste (white, sticky stuff, nasty to get off your pawns)
But anything like waterproof grease, yet even Moly is good as long as those parts actually receive some service...
 

moddy

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Looking forward to what my mileage will increase to. Hoping for at least 2 points.
I've ridden 199 miles, 70 of it was 2up and the needle is at a half tank, now how exciting does that sound so far? I didn't ride too crazy slow for the mileage either. 70 of those 199 is blasting down I-65 at 75 to 80mph. How warm were my rotors when I stopped, you ask? Probably 10 degrees warmer than it was outside. Kind of nice they're not touching when I'm not braking.
 
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Jim Van
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Received my seal kits Saturday and all three spare calipers are now re-built. I'll be needing a new front tire before spring, so will be swapping the front calipers when I install the new tire this winter.

Since the brake fluid should be flushed & replaced about every 10K miles, swapping calipers will coincide with tire replacements.

My front brakes don't seem to be dragging now, but I'm curious to see how easily the caliper pistons will come out when I rebuild them. And if my mileage increases again after I install the rebuilt front calipers, I will be very pleased, indeed.
 

moddy

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6.61 gallons for 302 miles = 45.41 mpg. 1/3 2up 55-60mph, 1/3 70-75mph, 1/3 solo 55 to 60mph
 

gmast1100

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I just filled up my 03 1100P and figured out to 48.4. Not too bad for many periods of excessive speed. I had to remove the carbs and clean them as I couldn't get an idle. Must have done sumpin right?
 
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Jim Van
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Last 234 miles ; 234 miles / 5.13 gal = 45.6 mpg

I'm happy with that, considering my weight and mostly @ 75 MPH.
 

moddy

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43.7, less than last time, but an improvement over 40.5 to 41.5 before. That 2mpg doesn't seem like much, over time it will pay for the maintenance you put into your machine to improve mileage.
 
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Jim Van
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Received my seal kits Saturday and all three spare calipers are now re-built. I'll be needing a new front tire before spring, so will be swapping the front calipers when I install the new tire this winter.

Since the brake fluid should be flushed & replaced about every 10K miles, swapping calipers will coincide with tire replacements.

My front brakes don't seem to be dragging now, but I'm curious to see how easily the caliper pistons will come out when I rebuild them. And if my mileage increases again after I install the rebuilt front calipers, I will be very pleased, indeed.
I decided to install the rebuilt front calipers today since I have the forks off for flushing & re-filling and getting ready to replace the timing belt. 3 out of 4 pistons were nice & free , but one was getting sticky. It took a bit more compressed air to remove than the other three. It wasn't really stuck bad because I could see no difference in wear comparing the left & right caliper brake pads. So , I'm curious to see if my gas mileage increases after I'm back on the road. It's been about 28K miles since they were last rebuilt. Another PM item to be added to my list.
 
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