Front caliper seizing

[Throttled]

My KLE is the winter bike and it comes out when the roads get gritted or I get to go off road. It gets cleaned once a week and I do look after it. It does about 4000 miles a year.

I find the front caliper gets really mucky and seizes far more than any other bike I have owned or come across. It tends to be the smaller of the two pistons that goes first. This time it has seized solid, neither piston will come out and have scored the smaller one trying. They are both very rusted even though they are only a year old as I replaced them last winter due to seizing.

I found a ER500 front caliper in very good condition and corrosion free on ebay for £30 and will replace the old one. It will definitely fit the KLE, the part numbers are the same and they look identical.

I am just wondering, will this just happen again, or have I been unlucky?

[Warin]

Originally Posted by Throttled

I find the front caliper gets really mucky and seizes far more than any other bike I have owned or come across.

They are both very rusted even though they are only a year old as I replaced them last winter due to seizing.

What are you cleaning with? And where do they rust first? Piston face or along the barrel?

I'd expect the pistons are coated to prevent corrosion. Either the coating is ineffective (and there would be a lot of failures) or your 'cleaning ' is too aggressive?

-------------- Unlucky
Unlucky would be one piston rusting .. not all of them.

[mollydog]

Good you found another caliper for not too much money!
If riding salted roads, hose bike off everyday to prevent this sort of damage.

Can you fit some sort of front disc guard to your KLE? May reduce exposure to Salt/chemicals.

Also, more frequent caliper service will help. Lubricate pistons well with Brake Fluid, coat caliper slider pins/mechanism with Cooper grease. Do not get brake fluid or Cooper grease on brake pads.

Also, Bleed brakes. Work pistons IN and OUT ... hopefully without popping them out ... but if you do, just force them back in place. Or take them out and POLISH THEM with a Green scrubby thingy.

Rubber caliper piston seals need to be in good condition and sealing well against elements. Keeping them lubed with Brake fluid and clean and polished helps preserve them. Using harsh chemical sprays on caliper pistons will KILL the rubber seals quickly, promote corrosion.

Wash with warm mild soapy water, rinse, blow dry or ride.

Best of luck, hope new caliper lasts a bit longer!

[Throttled]

The bike is cleaned once a week with muck off and car shampoo and rinsed with water. the brakes get a blast of brake cleaner. A deep clean meant also taking out the brake pads, WD40 round the pistons (I could see it seep in to help lubricate the rings) and grease the sliders.

Both pistons were corroding around the edges. I think this time I will give them a wipe with ACF50.

I take it neither of you have had such problems, but are your roads as heavily gritted as Scotland's?

[mollydog]

No Salt on roads here in California but I spent time in UK (Oxford) with my buddy who commuted through Winter. A wealth of knowledge on keeping a bike going on Salted roads and an expert on brake maintenance.
I learned A LOT!

I would not use Brake Clean, harsh chemical that is hard on the rubber seals that surround the caliper pistons. Soap and water only. Brake Clean is good for flushing out brake dust but not GREAT for rubber bits. Soap/Water just as good.

WD40 is OK but washes away in minutes in rain, but it will NOT harm rubber seals. Don't get WD on brake pads.

I've heard of ACF50, but never used it. (not sold here, far as I know) I hear it's good. But for brake pistons, plain old brake fluid is best I know of if area is kept clean.

I had my Nissin radial mount type calipers seize on my '07 Triumph 1050 Tiger (14K miles) The brakes got weak, took them apart, found very uneven pad wear ... as one piston was working, the other stuck.

Just slight corrosion on pistons. Shined up pistons, new fluid and pads
but for some reason these caliper are prone to seizing up ... so like you, I have to keep after them way more than I like to.

Uneven pad wear is a sure sign at least one caliper piston is stuck or dragging. Both must slide in and out freely.

When polished and shiny they operate well. When I change tires I clean them up and dab a bit of brake fluid on pistons and run them IN and OUT a few times to make sure they moving smoothly. (PITA)

Good luck, hope you can solve this!!!

[backofbeyond]

Brake Pistons seizing through salt corrosion is so common if you ride a bike through the average British winter. I've no idea whether things have improved over the years (my current winter bike used drum brakes) but with Jap stuff there used to be a brake seizing pecking order with Yamaha at the bottom. You'd think a good wash would get rid of the salt but where it collects in the gap between the piston and calliper and behind the pads is hard to get clean water into. Plus it's warm in there - just perfect for corrosion.

The only real way to avoid it is for the manufacturers to put rubber bellows over the pistons - that's what cars do. There may be some bikes with brakes like that but I'm not aware of any and I've never owned a bike with them. Failing that it's going to be a regular strip down and clean - particularly if you've got pistons that already have some salt damage.

ACF50 is good and if you applied it carefully it might work for a while but it won't be an apply once and leave until spring regime like it is on other parts of the bike. It does wash off if it's in direct road spray and it certainly burns off if it gets hot. Ifyou're a bit slapdash applying it you won't have any brakes at all next time out until you burn it off the disc.

[trackdayrider]

The KLE/ER5 calipers (also used on the Z750 and Versys) do seem more susceptible to seizure.

I have stripped and rebuilt them on a Z750 and an ER5.

I don't know if its a bad design issue or not, but buying second hand is ok, so long as you know you might be buying something that is not a lot better than you already have - well worth investing in a repair kit a refurbishing the caliper before fitting

[Throttled]

I did buy new pistons and rings last winter and they have lasted a winter and a half. New pistons and rings were about the same as the whole caliper, which arrived today and is in very good condition.

[Throttled]

The ER5 caliper from a 2000 bike fits fine and is working a treat. Look out for the number 125 next to the nut for the brake line. The part number is KA049380.