Disc brake question.

[Captain Stupido]

viewtopic.php?f=41&t=392182

I picked this up locally fairly cheap a few weeks ago. It's the most modern bike I've ever owned, I think. The front caliper was hanging off, seller said it just needed new pads and he hadn't got round to it. I wasn't convinced...but at the price thought I'd take a gamble. They are Avid Elixir 3 brakes...the only hydraulic brakes I've worked on before are in cars or on motorbikes.

Ordered pads and new bolts. Attempted to fit and first of all realised I'd need spacers/washers too... Had a go at fitting the pads anyway following online instructions. The trouble is that the pistons seem to not want to go back - I used a screwdriver with the old pads to push the pistons back but they didn't move much. When I fitted the new pads there was only a narrow gap - not wide enough to leave space for the disc. I tried removing the pad and using a tyre lever directly on the pistons but no improvement.

Other than that they seem to be working as they should. What next?

 

[mattr]

take the pads out and use the centre bar of a cone spanner or something similar, couple of MM thick and ~20mm wide.
Trying to push pads in with point loads (screwdrivers, tyre levers etc) just makes them jam up in the bore (it's a *very* tight clearance).
You'll need to push quite hard and square to the axis of the piston. You'll also need to make an effort to hold the other piston in place while you push!

If you still have issues, the system might have been over filled. Just crack the bleed nipple open 1/4 of a turn and try again.

If the caliper needs loads of washers, you probably need this
https://www.chainreactioncycles.com/se/ ... prod110395
Or, in a pinch you can use those conic washers you used to get on v brake pads.

BTW, avid elixirs are probably the single worst hydraulic disc brake out there, do not invest more than the ~7 quid for the bolts on them. You can get a pair of shimano non series brakes for ~100 quid.
I've taken brand new ones off and either sold them or thrown them away rather than deal with them.

 

[jimo746]

Re:

Sounds like the brakes might have been bled with part worn pads fitted, now the new pads are fitted the extra pad material has reduced the gap for the disc to fit in, as above try cracking open the bleed nipple slightly as the system may just have too much fluid in there to accommodate the new pads and the disc in the same space.
Follow mattr's advice re: pushing the pistons back in the caliper, but while the pistons are sticking out a little try lubricating them with a little brake fluid.
Good luck getting them to work 100%, newer Sram/Avid brakes seem to have improved, but I think every set of Elixirs I've ever had/touched/seen have had issues of one kind or another.

 

[rwm1962]

BTW, avid elixirs are probably the single worst hydraulic disc brake out there, do not invest more than the ~7 quid for the bolts on them. You can get a pair of shimano non series brakes for ~100 quid.
I've taken brand new ones off and either sold them or thrown them away rather than deal with them.

Ain't that the truth - done the same. Felt guilty giving them away! An Orange deserves better.

 

[Captain Stupido]

take the pads out and use the centre bar of a cone spanner or something similar, couple of MM thick and ~20mm wide.
Trying to push pads in with point loads (screwdrivers, tyre levers etc) just makes them jam up in the bore (it's a *very* tight clearance).
You'll need to push quite hard and square to the axis of the piston. You'll also need to make an effort to hold the other piston in place while you push!

If you still have issues, the system might have been over filled. Just crack the bleed nipple open 1/4 of a turn and try again.

If the caliper needs loads of washers, you probably need this
https://www.chainreactioncycles.com/se/ ... prod110395
Or, in a pinch you can use those conic washers you used to get on v brake pads.

BTW, avid elixirs are probably the single worst hydraulic disc brake out there, do not invest more than the ~7 quid for the bolts on them. You can get a pair of shimano non series brakes for ~100 quid.
I've taken brand new ones off and either sold them or thrown them away rather than deal with them.

Thanks all - brilliant advice.

I had a similar idea re using v-brake spacers. Funny... I used to keep a little jar of them for just in case, then one day having never used any of them I chucked them all away... I'm sure I have some spares somewhere though.

If the Avids are rubbish maybe I should just bin them though. Or stick them on eBay... This bike is meant to be for my wife, so I don't need to be constantly fiddling with it, nor do I need crappy brakes that scare the life out of her.

What would a cost effective upgrade be? Shimano BR-BL-M355 (Alivio?) are only £38 on eBay (https://www.ebay.co.uk/itm/SHIMANO-BR-B ... 2608838527)...presumably I can use the existing rotors? Or is it worth going to Deore? SLX? I'm assuming that new makes more sense than used - don't want to mess about too much...

She's a timid novice, reliability is important, and she deserves something pleasant to ride, but out and out performance is not likely to be an issue.

 

[mattr]

If it's just for pootling about, alivio will be a solid choice if you can't get the Elixirs working acceptably with minimal effort/expense.

 

[jimo746]

Re:

The Alivio brakes are pretty good, I have them (in white) on my 29er (180/160 rotors) , seen plenty of use and a couple of races and still working fine. Considered changing them for SLX or something but tbh they work well enough, I didn't see much point in laying out the money for not a huge increase in performance.

 

[Captain Stupido]

Nice one, thanks guys. I'll have a fiddle with it tomorrow. To be honest for the money I'm leaning towards replacing them but if I can fix them easily then great.

Quite a few options in terms of budget Shimano but probably all much of a muchness. I quite like the white ones.

M315 (Acera?) is even cheaper and the specs seem very similar... Also there seems to be a new replacement MT200 on the market. Main thing I'll be looking for I suppose is the length of the cables as this seems to be the one thing that does vary... How much of a ballache is it to shorten them?

 

[jimo746]

Re:

Easy to shorten a "cable"
Just need an olive. Can usually get away with not needing to bleed the brake too.

 

[Captain Stupido]

Re: Re:

Easy to shorten a "cable"
Just need an olive. Can usually get away with not needing to bleed the brake too.

Cool. Yeah I spose they're hoses really. New-fangled blimmin nonsense.

It's appealing that Shimanos are filled with mineral oil rather than paint stripping old brake fluid...horrid stuff...

Have been doing some further reading and it's not all that scary after all... thanks guys... I haven't fixed it yet but I'm already glad I didn't give up and take it to the LBS.