Brake Caliper Balls-Up

[Descolada]

I should have known it was going to end in tears. I spent the morning replacing the rear pads on my wee. It went pretty well, they were very low, but not quite as dangerous as I was expecting.

Just as I was finishing up I decided to check and clean the front pads - I have an MOT at the end of March and wanted to ensure that no nasty surprises were in store.

As always I started by checking the free movement of the caliper on the near side and realised with a shock that they were more worn that I had expected, it was a surprise because I had checked them in the Summer and they weren't bad at all.

In order to clean them properly I removed the caliper assembly and took a closer look. They were low, but more worryingly, they were worn irregularly. The top of the brake pad showed signs of being more warn than the lower.

This suggested a sticking piston and I really wasn't surprised when I saw the state of it, all encrusted with salt damage, muck and some signs of rust.

I started to clean the pistons and caliper and confirmed that while the lower caliper moved freely the top one seemed almost stuck and needed much more work.



Having spent 10 minutes trying to clean the pistons I was starting to get a little frustrated because I couldn't get into the crevices enough to clean them to my satisfaction and the top piston was not freeing up. In addition I could not see how to remove the (from the parts list) "Caliper Carrier" assembly (there seemed to be a rubber plug extending out of the caliper body, but the parts list shows that it is infact an end to the "Insulator") - it seemed to be fixed in place and it was blocking access to areas that needed cleaning badly.

You will be able to guess what's coming next no doubt.  :angry-nono:

I decided to try and clean the sticking piston by extending it a little farther. I cleaned it and then tried it again - still sticking.

About an hour earlier I posted a comment on this forum that included a caution not to extend the piston too far, so I was very cautious as I decided to extend the piston a little further. I cleaned the piston again and tried to press it back into the caliper, at which point I realised that I could see rubber at two different laces
around the piston - I had exposed the top seal.



No matter how hard I tried it would not go back into the caliper.

Idiot!  

Now, I could have become very annoyed by this, but I also realise that it may have failed the forthcoming MOT based on the limitations of the caliper performance. More than that it was something that needed to be repaired either way. Riding with defective brakes is an accident waiting to happen. I learnt much from extending the piston as far as I had, the piston was showing spots of rust and some build-ups of salt along the internal barrel.

So, how to repair this problem. Do you think that a caliper seal kit would be enough, or does this look like something more substantial?

I need some advice please, because spending the next week travelling to and from work on the bus is going to drive me mad.  :angry-screaming:

[KLV-Rider]

Strip, clean, polish pistons, replace seals, fresh fluid, bleed....job done!.    

[Juvecu]

The seals were probably already sticking out like that before you started, that would be a good reason for the piston to stick like that. From that picture the piston doesn't look all that bad, I'd take the callipers off the bike, take them apart and clean them well with brake fluid. Use a cloth and brake fluid to clean the pistons, the rust might just polish off with the cloth and the brake fluid. Don't use anything abrasive, the chrome on the pistons scratch rather easily. Rub some red rubber grease on new seals, stick them in and put the pistons back in, push them all the way in. At this point I usually cover the whole caliper in ACF-50 and let it sit for about half an hour before wiping off any excess. Put the rest of it back together, use red rubber grease on the sliding bracket, make sure nothing can get on the pads before you put them back in (and make sure your hands don't transfer ACF-50 to the pads, though it will burn off quickly if it does get on them.)

The short answer was: Yes, just a good clean and new seals

[Jacko]

That should just be a dust seal, if you needed to be back on the road again quickly you could just remove that and push the piston back in. More long term though a new seal kit and a full strip and clean is the way to go, as mentioned above.

[Descolada]

Ah the comfort of people who know. Thanks chaps  

Can you point me to anything that will show me the right way to strip the caliper - I still need to resolve the issue of not being able to take off the "Caliper Carrier" assembly?

Any suggestions for where to get the seal kit - I'd rather do this now rather than put it off.

[mr_diver]

wemoto for your seal kits

I've had problems getting the caliper carrier free before- I just hit it with a hammer until it came out  

make sure you clean the corrosion out of the seal seats or they will corrode quickly again and red rubber grease on the new seals and in the seat.

[Juvecu]

The caliper carrier should be a sliding assembly. If it's stuck then that's your real reason for the uneven wear. The one pin slides in a hole in the caliper body, that's the side that has the small concertina rubber on. The other side slides in a rubber that sticks through a bigger hole in the caliper body. The whole thing should just pull out quite easily. If it doesn't then the side with the pin that goes into the hole (rather than into the rubber) might have corroded enough to be stuck. Give it a tap in with a small hammer to see if it breaks the corrosion, otherwise a bit of Plusgas might do the trick. Don't use anything that will damage the concertina rubber boot, WD40 should be safe.

[edwardatherton]

Similar thing with my wife's bike a few days ago. The hole where the rubber insulator goes through had some corrosion in which effectively closed up the hole, clamping the sliding pin in place!
I had to cut the rubber boot but got a seal kit off ebay which includes it.

[cpjs]

That caliper looks a mess, go on ebay and get another there are plenty for sale. One on there now for £25.00.
http://www.ebay.co.uk/itm/Suzuki-DL650- ... 2a31360b94

[Descolada]

Well, that was horrible.

After fighting me all the way the caliper carrier finally came off. It was free at the top end but entirely seized in the bottom pin. Crazy thing is that both pins were well covered in black (I assume Heavy) grease. There were no signs of rust or anything else that might have caused it to seize.



Strangely there were more wear marks on the shaft of the top pin than the bottom and yet the top was still moving freely. Thank god for my rubber mallet.

I have just realised that Cupar Suzuki is open from 12:00 today so I will give them a call and see if they have a seal kit. I am going to get two kits cause if this side is bad it follows that I may find the same on the off-side caliper. If not well, at least I will have a spare set.

My biggest worry right now is the fact that the work in cleaning off the carrier and pins will expose the metal to the elements potentially making a future nightmare for cleaning up again.



Can I use copper grease in here to help stop the corrosion and can I use copper grease on the pins when they go back or does it have to be the black heavy grease?

Is there anything else I can do to protect the metal other than a liberal soaking of ACF50 (avoiding drips that might contaminate the pads of course).

[Descolada]

That caliper looks a mess, go on ebay and get another there are plenty for sale. One on there now for £25.00.
http://www.ebay.co.uk/itm/Suzuki-DL650- ... 2a31360b94

Thanks for this. The Ebay item is for a rear caliper. I'm looking for a front on an AK9.

[Juvecu]

Dealers will likely charge you an arm and a leg for seals, get them off eBay unless it's super urgent. Suzuki SV650 use the same caliper seals. That rusted pin you have in the last pic needs a bit of sandpaper love. After this you can give it a coating of copper grease. One end of the pads slide over it and has to move freely, the grease won't get on the pads from there.

Use red rubber grease for everything else that needs to move, if you don't have any, buy some from eBay. Any brand will do really, you only need a small amount, 15g should last you for a very long time. If it's not rubber safe grease the seals and rubbers will swell, become soft and tear easily.

[Jacko]

Silicon grease is best for the sliders, copper will work but light clear silicon grease is recommended. Don't worry too much about things, this is all quite normal, the pad wear, caused by the sticking slider are symptoms of mild neglect, this is why we clean our brakes routinely. Sounds like you've been vigilant enough to catch it before it damaged a disc, so pat yourself on the back, clean it all up, reassemble and have a beer.

[Juvecu]

See here, Des, it's handy having a 2nd set, you can have them ready for a quick swap and then clean the other ones when you have time.

[Descolada]

Thanks Juv, PM sent.

Out of interest, and self preservation, are there any differences between the ABS version of the K9 and the non-ABS model with regards to the calipers?

[Descolada]

Just checked in the Man Cave. I have red rubber grease I purchased for just such an event, I also have a pot of Carlube lithium based LM2 grease - will this be sufficient for the pin sliders?

[kissofdeath]

if all else fails
viewtopic.php?f=7&t=21509

[Descolada]

Thanks Kodkod, have PM'ed him but the message is still sitting in the outbox. Sometimes it seems to take a moment to go out.

[Juvecu]

It will sit in your outbox until the recipient has read it, it's a nice way of knowing that they've seen it or not.

The lithium grease will likely wash off with the first rain. Copper/Silicone grease should stay on longer.

[Descolada]

I was reviewing this thread http://www.v-strom.co.uk/phpBB3/viewtopic.php?f=58&t=16173&p=141843&hilit=seal+kit#p141843 and am a little concerned about the comments about the pistons being different sizes. Maybe it's just my eyes, but mine look identical in size and depth - is that because it's an ABS version or does that have no bearing on the calipers?

Just heard back from the local Suzuki dealer. They don't have them in stock and even if they did it would still be 35.90 for the set. So I am just as well getting them off ebay or somesuch cause they aren't going to get here any faster.

I love the conversation on that thread about how little they cost and the internet mark-up for what is just a simple seal. Just wish I could find them for that kind of price but all the links seem to point to old and now redundant data.