Rear Brake Issues.

[Phil_Norwich]

New pads and a good clean of the caliper seemed to have sorted the issues :)

[speedy231278]

I might get away with removing and cleaning the existing pistons, however they don't look very happy, and I figured if I didn't get new ones, they'd turn out to be shot when I tried to clean them up properly. Also, sod's law says there'd be a tiny pit somewhere that would catch the new seal and ruin it. I figure they've been on the bike almost 20 years, so £36 for another 20 years of pistons doesn't seem too bad!

[speedy231278]

Could someone explain to me the purpose of the joint that goes between the caliper and the brake hose? Does the caliper have a different thread size/pitch to a standard brake line fitting? Also, I don't really understand why there's only a crush washer between the joint and the caliper, and not between the joint and the hose as well.

[porndoguk]

Could someone explain to me the purpose of the joint that goes between the caliper and the brake hose? Does the caliper have a different thread size/pitch to a standard brake line fitting? Also, I don't really understand why there's only a crush washer between the joint and the caliper, and not between the joint and the hose as well.

Indeed its an adaptor for two different threads, also the hose has a rubber grommet in the back i beleive so no need for the washer whereas the caliper does,

[speedy231278]

Just as well seeing as I don't have a spare copper washer! Now, can I get the caliper down, pistons out, thoroughly clean it, new pistons, pads, bleed nipple and seals fitted, bled, road tested and make it in time for the pub? Last time I did a caliper with two pots it didn't take two hours, and I had no decent tools to do it with. This time I'm a little more prepared, although the pistons are pretty sticky, so fingers crossed!

[porndoguk]

Do you have a compressor?

[speedy231278]

No, I don't. The pistons aren't sufficiently sticky that they won't come out by pumping the pedal, and I've got a hefty pair of Sealey piston extracting pliers which I am hoping will be sufficient to take over when the pistons travel past the fluid seal. If not, it will be a long evening and no beer! Having said that, I know someone who does....

One last question, what size are the crush washers? Sod's law says if I have to disturb the line (I'm hoping not to have to disconnect the caliper, but that's out the window if serious effort is needed to remove the pistons) then being naughty and reusing the existing washer will cause it to leak!

[Morespeedvicar]

Remember to clean the seal grooves out, and put plenty of rubber/silicone grease in them when your rebuilding them.
I've always used the old washers never had one leak yet.
Cheers
Ian

[speedy231278]

All done. New seals lubed with brake fluid as per Haynes/Honda. Shedloads of shite under the old dust seals which were utterly shagged, fluid seals were near mint. Some animal has managed to chip bits out of the outer face of the caliper around both pistons, so the dust seal has slightly more exposure to nature than is ideal, I guess this is where the water has got in to set off the corrosion. I didn't need to remove the hose from the caliper, so the hose seals were not disturbed. However, I was not able to get quite all the crap out of the dust seal grooves as there was so much of it and it was very well set in, and while the damage does not seem to affect the operation of the caliper, I will be looking for a replacement item in due course as I do not believe the condition of the caliper to be sufficient to maintain acceptable long term life of the seals... No improvement on braking force, although I swear I had the rear wheel chattering, however there is now zero binding, and the bike is easier to push about than een when I considered the brake to not be binding. Fingers crosssed for tommorrow....

[speedy231278]

Pass. One advisory on the worn rear tyre, which I was having replaced anyway. For some reason if you book and MOT and tyre change, they have to do the MOT first. Sounds a bit odd to me! One of the fork seals has had a slight weep, so that will be kept a very close eye on, and I'm not very happy seeing as the forks haven't been on the bike very long and were allegedly almost/zero use since they were rebuilt!