Some of you will remember I had a rear brake failure due to overheating last summer. Recently, even after a lot of faffing about it, was still dragging a bit. Yesterday, after buying aseal kit from Ebay I bit the bullet and pulled the whole thing apart, pistons out, the whole job.
It turns out there where two issues; the first was (Clive's right again... :icon_rolleyes:) the rubber grommet and rubber tube on the caliper sliders had swollen due to me using the wrong grease. Can't remember what I used but it should have been RED rubber grease. The second issue was - embarassingly - lack of maintenance in that I hadn't changed the dust seals for a long time. Corrosion had built up behind the seal in the groove, to the extent that there was hardly any groove and the seal was jamming between the piston and the bore :icon_redface:
It's all nicely cleaned out and new dust and piston seals fitted, re-assembled using RED grease supplied in the kit, and now works as advertised.
I shall be doing the fronts as a precautionary measure as soon as the kit arrives.
I can recommend this lot:
http://www.ebay.co.uk/itm/151278833937?_trksid=p2060353.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT
Everything you need is in the kit: new rubber parts, dust and piston seals, new bleed nipple and rubber cover, copper washers for the banjo and a small pack of red grease.
Did the same job myself this weekend, all three callipers though, they were all dragging slightly. Seem to be doing this a lot as the winter riding takes its toll and the Nissin brakes do not seem to take well to a lack of care/cleaning.
Now the callipers are moving freely, its new discs for the front!
Did you use the same Ebay parts?
No, I do this job so often (am doing about 25k miles annually) that I bought a load of seals a while back on ebay and a dozen of each of the rubber boots and grommets for the sliders from a Honda dealer. I like to always have them in the garage so I am not held up waiting for a delivery while my bike is apart.
I have found a good site online where you can buy these bits in bulk, will post a link when I get a minute.
That's about 60 quid too late :icon_lol: but better late than never....
Got round to doing the front brakes today. I'd forgotten how much I hate doing the fronts :BangHead :BangHead
Once there's air in the lines it's an absolute t*at to get rid of; I've been on effing ages with it and it's still not as good as it was before I started although, to be fair, it's as good as it is most of the time.
When I changed the fluid last summer I got lucky just for once and had the firmest lever I've ever had, even from purchase at 4k miles. Now I'm back to where I was before; there's a very tiny bit of air somewhere and I've yet to find it.
I'll tie the lever back tonight, then tomorrow take the calipers off, raise them, bash them and then bleed them again. Fingers crossed... :icon_rolleyes:
I don't bother busting a gut any more just get it something like and put and elastic band on over night and sometimes for a couple days it'll sort it.
Quote from: Bixxer Bob on February 11, 2016, 03:42:35 PM
Once there's air in the lines it's an absolute t*at to get rid of; I've been on effing ages with it and it's still not as good as it was before I started although, to be fair, it's as good as it is most of the time.
Do they recommend the "take the caliper off and bleed it with the nipple guaranteed to be up right" method??
Got one of those vacuum pump things from Frosts, it was well worth the £30 I paid. Makes bleeding the fronts a doddle.
I believe temperature has a lot to do with it, viscosity mostly. Which is why I try to do it in the summer, that'll be the two days window then :icon_rolleyes: I'd suggest trying to warm things up if you can, I realise that's not so easy at this time of year :new_xmas
Quote from: Chris Canning on February 11, 2016, 03:52:16 PM
I don't bother busting a gut any more just get it something like and put and elastic band on over night and sometimes for a couple days it'll sort it.
Agreed Chris, I did that overnight and it worked. As Sin says, probably a job best left till it's warmer.
Had a good ride down to the Excel but that's for nother thread.
Quote from: Sin_Tiger on February 12, 2016, 12:39:30 AM
I believe temperature has a lot to do with it, viscosity mostly.
Next time use DOT5.1 brake fluid. One of the differences in specs between DOT4 and 5.1 is viscosity at low(er) temperatures. For non-abs bikes it doesn't matter very much, some/several abs-bikes need their fluid to be thin flowing so in the newer 5.1 specs there is a requirement for that.
:iagree however, if you do go 5.1 carry some spare as it's not very common and mixing with DOT 3 or 4 is not recommended.
Do NOT get mixed up with DOT 5 which is the synthetic fluid and CANNOT be mixed with ANYTHING else, in fact don't use it unless you do a complete system strip down and clean.
Another night with the lever tied back and it's good and solid again. :icon_biggrin:
Another observation is that now the pistons move freely again, the brake judder that was developing has gone. When I looked at the pads (while the calipers were in bits) the pads were wearing on one end and had judder marks across the pad ie radially from hub to rim. Those have gone and the pad wear is evening up.