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jimster |
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jimster Spanner Monkey
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Bhud |
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Bhud World Chat Champion
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Posted: 23:25 - 16 Aug 2021 Post subject: |
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The calipers need to be completely overhauled and cleaned, and the seals renewed. At the same time, the pads sound like they are in need of replacement.
Don't ride the bike, as they will get worse and worse when the brakes are applied.
With every project bike I've ever got my hands on, the brakes were a job that needed doing. I learned to do it through trial and error, and I have messed up a couple of calipers in my time, so watching videos and reading Hayes isn't the best way to do it. There are also serious safety considerations if you get this wrong.
The way to do this, ideally, is to get a bike mechanic over to you, to show you how to do the whole process step by step. You could buy brake fluid, seals sets, pads and pistons right now if you like, and then just watch him and ask him questions. He will probably use the master cylinder on the bike to pump out the old pistons first.
You can approach this however you like, but if the front brakes are seizing then there's nothing you can do with a bit of sandpaper to the pads that will change that. They are overdue servicing. |
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Robby |
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Robby Dirty Old Man
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jimster |
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jimster Spanner Monkey
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MCN |
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MCN Super Spammer
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Posted: 10:08 - 17 Aug 2021 Post subject: |
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I think certain makes or certain models suffer more or less from sticking pads.
My Yamaha Thundercat was very prone to binding brakes.
Triumph Sprint never any problems.
The 2 BMW GS bikes never had any issue.
BMW S1000RR never any problems (Other than munching it's way through front pads.).
BMW K1300 bastirt front brakes (breaks ) bind religiously if not used regularly. The Rona nonsense has me away at work for months so it's a strip-down job when I come home. (Need to show the Mrs. how to do that.)
'Normally' the steel backing rusts, combined with pad dust and road shite caking between the free-spaces around the backing and pad guides of the callipers. That free-space is there to let the pads 'float' and not bind.
Removing the callipers and digging out the pads, gouging out the cake, using a small file or an old flat screwdriver restores things.
Assemble, preferably with new pads.
I smear some brake paste on the 'contact' surfaces of the backing to help the pads slide. A few puddles later that shit gets displaced though.
Never had to open a callipers yet. Just cleaned out the hard kak.
A scoot of brake cleaner down their gullet when the bike is washed helps to wash out shite build up too.
Brake dust is corrosive and also tends to cake if not blown/washed out. ____________________ Disclaimer: The comments above may be predicted text and not necessarily the opinion of MCN. |
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bikenut |
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bikenut World Chat Champion
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bikenut |
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bikenut World Chat Champion
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jimster |
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jimster Spanner Monkey
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Posted: 15:51 - 17 Aug 2021 Post subject: |
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Thanks bikenut & all,
It's a 97 Yamaha Diversion 900 with about 65k miles (!) on the clock, twin front discs, each side having two pistons & single rear (which I think is OK, at least it's not binding).
Will post pictures later but am about to head off to wemoto to click-and-collect (it's handy that I'm in Brighton right now!) ____________________ Current: Yamaha Diversion XJ900
Previous: Yamaha Diversion 600cc, Piaggio Zip 50cc, Honda CG125-W, Siamoto Caddy 50cc moped |
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jimster |
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jimster Spanner Monkey
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MCN |
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MCN Super Spammer
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Posted: 10:20 - 18 Aug 2021 Post subject: |
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You probably need discs now. They can fail for surface pitting.
But you'll not need an MOT till this time next year. ____________________ Disclaimer: The comments above may be predicted text and not necessarily the opinion of MCN. |
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jimster |
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jimster Spanner Monkey
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jimster |
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jimster Spanner Monkey
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Posted: 01:19 - 19 Aug 2021 Post subject: |
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Fizzer Thou |
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Fizzer Thou World Chat Champion
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Kris |
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Kris World Chat Champion
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jimster |
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jimster Spanner Monkey
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Posted: 13:00 - 20 Aug 2021 Post subject: |
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Thanks Kris & Fizzer Thou,
Thanks for the feedback and the links also very helpful. I have all the bits for the callipers (hopefully) but it will take a couple of weeks to get the hose lines ordered and I'd like to get the bike through it's MOT next week.
I assume I can fully rebuild the callipers, repace the pads & bleed the brakes for the MOT, and then do the cylinder & hose at a later stage?
Thanks - really appreciate all the helpful feedback and support - am really enjoying figuring all this stuff out, it's like Lego for adults ____________________ Current: Yamaha Diversion XJ900
Previous: Yamaha Diversion 600cc, Piaggio Zip 50cc, Honda CG125-W, Siamoto Caddy 50cc moped |
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Fizzer Thou |
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Fizzer Thou World Chat Champion
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jimster |
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jimster Spanner Monkey
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Posted: 20:57 - 20 Aug 2021 Post subject: |
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So the job is underway. Photos attached.
I ran into a really annoying problem; without an airline I planned to pump the pistons out with the brake lever once the calipers were loose. Unfortunately, the lever lost pressure after a single pump. So I used a grease gun to pump out the pistons - which worked well on one piston but unfortunately, not the second! So now I need to get a stronger g-clamp to jam the free piston in place and then give it some muscle to loosen the other one. I've also sprayed a lot of brake cleaner on it and gently tapped the piston with a hammer.
Getting the grease out of the caliper will I'm sure be a lot of fun...
PS The calipers, pads and master brake cylinder don't seem as bad as I thought (even the brake fluid looks OK) but I'll still replace the pads, fluid & seals. The pistons however are VERY rusty so I have a nasty feeling will need to be replaced, although I'll try to clean them up as best I can once they're out...
I haven't started on the second caliper as I don't want to release the grease gun until both pistons are out on the first caliper.
https://i.postimg.cc/jDzWVskd/1629488823568.jpg https://i.postimg.cc/gwmxmffy/1629488831681.jpg https://i.postimg.cc/d76L15Yb/1629488834675.jpg https://i.postimg.cc/CBKdfbMz/1629488838875.jpg https://i.postimg.cc/S2tRLjjV/1629488843641.jpg
Rusty calipers being freed by a grease gun, with the loose one being held in not tightly enough by a plastic g-clamp
https://i.postimg.cc/75VxMbW7/1629489333851.jpghttps://i.postimg.cc/CZxwvY32/1629489335711.jpg ____________________ Current: Yamaha Diversion XJ900
Previous: Yamaha Diversion 600cc, Piaggio Zip 50cc, Honda CG125-W, Siamoto Caddy 50cc moped |
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Bhud |
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Bhud World Chat Champion
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jimster Spanner Monkey
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Bhud |
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Bhud World Chat Champion
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Posted: 01:29 - 21 Aug 2021 Post subject: |
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jimster wrote: | Thanks Bhud! Do you have any recommendations for an alternative to Wemoto? |
Nah, as long as they're machined to the right size, they'll work. I bought a TRK kit for my latest project, and it was tarted up in a fancy box like a high end Swiss watch, which is a bit ridiculous, but it was fine at the end of the day. I said I'm a bit ambivalent about Wemoto because they've started selling a lot of useless Chinese stuff these days. I mean, really useless. But the brake pistons I got from them were fine.
Quote: | Since I still need to do the second caliper on the other side (and would prefer to avoid the horrific grease mess if possible) how would I solve the problem of the brake lever having zero pressure preventing me from driving the pistons out? |
Well, there will be a union banjo connection making the 2 brake lines (the ones that go to the individual calipers) go to one (the one that goes from the union to the master cylinder). All you've got to do is disconnect absolutely everything at that union. Then connect that single line from the master cylinder to that other brake caliper. Then pump away, use your G-clamp technique, top up with brake fluid at the reservoir as necessary, etc. The pistons will come out. |
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jimster Spanner Monkey
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bikenut |
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bikenut World Chat Champion
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Posted: 10:23 - 21 Aug 2021 Post subject: T |
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It's been wet all week here so the internet is more crap than usual.
How we say they are the best network is beyond me !
How they didn't manage to slit that guys throat in the advert, they must have had a direct link.
We at the moment and the internet is crap !
Spanners are for nuts and bolts, you have some old pads ?
Those pistons in the above pictures will be pitted and scrap.
Wemoto trk, expensive box ?
You have jumped the gun a but by not dealing with one caliper and one piston at a time.
Always "exercise" the piston by pumping it out as far as you dare, clean and lube then with g clamp and protective wood etc. Gently screw back in. Repeat until that piston Is free, then move onto the next, untill all pistons in that hydraulic system is free and will be easy to remove.
Do not open or disconnect hydraulics until all pistons are free in that system.
The pumping out, clean and lube ( brake fluid ) and screw back in via g clamp will help clear that tiny tiny tiny hole in the master cylinder floor, which you have now noticed ?
If that tiny hole is blocked, screwing the pistons back in general a g clamp will be very difficult.
Yes, brake jobs can be very messy !
Look at the caliper piston holes with seals out. Much "white crap" in the seal "slots" ?
The area between the hydraulic seal and dust seal, much white crap and pitting there ?
You can get small diameter rotory wire brushes for electric drills, and smaller ones for Dremel type drills, which are great for cleaning these areas.
When seal areas are de
crapped and the caliper outside clean including the bleed nipple hole and slide pin holes, the caliper can he finally cleaned with very soapy ( fairey liquid) water, well rinsed and dried, ready for painting and assembly.
Get everything clean and dried and painted etc. ready for reassembly, for one ( one ) caliper, then come back.
You where told at the begining to give yourself lots of time to do this job....
Ps m and p do brake stuff....
Do not wire brush the internal bore of the caliper below the hydraulic seal. ____________________ nuts about bikes |
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Fizzer Thou |
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Fizzer Thou World Chat Champion
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moezop |
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moezop L Plate Warrior
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Old Thread Alert!
The last post was made 2 years, 230 days ago. Instead of replying here, would creating a new thread be more useful? |
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