My Fiance's Diversion failed it's MOT on binding front brakes.

So, took the callipers off the forks leaving the hoses connected.
Whipped the pads out and pumped the pistons out a fair way. That was
enough access to clean the pistons up in situ with a dry cloth which
seemed to get them pretty shiney. After this they didn’t seem to be
binding but I didn't really check as that's always been enough before.
I could push the pistons back into the calliper and pump them out ok.

As I wheeled it out of the Garage for re-test this morning they were
certainly binding again. Put the bike back in the garage un-retested.

Given I'm reluctant to do a complete overhaul what's the FOAK's advice
on perfect non-binding brake?

On Jun 8, 8:17*am, MarkFraser <markfra...@ymail.com> wrote:
> My Fiance's Diversion failed it's MOT on binding front brakes.
>
> So, took the callipers off the forks leaving the hoses connected.
> Whipped the pads out and pumped the pistons out a fair way. That was
> enough access to clean the pistons up in situ with a dry cloth which
> seemed to get them pretty shiney. After this they didn’t seem to be
> binding but I didn't really check as that's always been enough before.
> I could push the pistons back into the calliper and pump them out ok.
>
> As I wheeled it out of the Garage for re-test this morning they were
> certainly binding again. Put the bike back in the garage un-retested.
>
> Given I'm reluctant to do a complete overhaul what's the FOAK's advice
> on perfect non-binding brake?

IIRC there was something in the Haynes manual about lubing the pistons
on Diversions with something (could be Copaslip) because they were
liable to binding. But it could be the product of a duff memory so
take this advice with as much of a pinch of salt as you feel it
deserves.

--
Malc

On Jun 8, 8:45*am, Malc <crickley...@btinternet.com> wrote:
> On Jun 8, 8:17*am, MarkFraser <markfra...@ymail.com> wrote:
>
> > My Fiance's Diversion failed it's MOT on binding front brakes.
>
> > So, took the callipers off the forks leaving the hoses connected.
> > Whipped the pads out and pumped the pistons out a fair way. That was
> > enough access to clean the pistons up in situ with a dry cloth which
> > seemed to get them pretty shiney. After this they didn’t seem to be
> > binding but I didn't really check as that's always been enough before.
> > I could push the pistons back into the calliper and pump them out ok.
>
> > As I wheeled it out of the Garage for re-test this morning they were
> > certainly binding again. Put the bike back in the garage un-retested.
>
> > Given I'm reluctant to do a complete overhaul what's the FOAK's advice
> > on perfect non-binding brake?
>
> IIRC there was something in the Haynes manual about lubing the pistons
> on Diversions with something (could be Copaslip) because they were
> liable to binding. But it could be the product of a duff memory so
> take this advice with as much of a pinch of salt as you feel it
> deserves.

I've got a vague recollection that in the past I've used brake fluid
on the pistons as a cleaner. I think it would also lube their travel
over the dust seals a bit.

Can someone confirm that the master cylinder is not a likely candidate
and cleaning the pistons is highly likely to sort it out?

On 08/06/2011 09:23, MarkFraser wrote:

>>
>> IIRC there was something in the Haynes manual about lubing the pistons
>> on Diversions with something (could be Copaslip) because they were
>> liable to binding. But it could be the product of a duff memory so
>> take this advice with as much of a pinch of salt as you feel it
>> deserves.
>
> I've got a vague recollection that in the past I've used brake fluid
> on the pistons as a cleaner. I think it would also lube their travel
> over the dust seals a bit.
>
> Can someone confirm that the master cylinder is not a likely candidate
> and cleaning the pistons is highly likely to sort it out?

DON'T use Copaslip - it can make rubber things swell and make it worse.

Unlikely to be the master cylinder.

The problem is likely to be caused by corrosion crud build up behind the
piston seals. It does need a total strip, remove the seals, clean out
with a dremel brush and then put it all back together. No need for new
seals ime - they seem to last a long time.

--
/Simon

MarkFraser wrote:

> Can someone confirm that the master cylinder is not a likely candidate
> and cleaning the pistons is highly likely to sort it out?

Dunno about how likely it was, but I've had a master cylinder
return hole get plugged by old crudded up fluid, which nearly
locked the front caliper solid as it heated up. In my defence
it was on the way home from picking up the SOB. Check the
reservoir and poke a soft wire through the return port.

Simon Wilson escribió:

> DON'T use Copaslip - it can make rubber things swell and make it worse.

When I was a car mechanic, it was standard practice to spread the stuff over
just about everything.

Copaslip and WD40 - all anyone needs for anything. Oh, and maybe oxy-
acetylene.

--
Paul.
CBR1100XX SuperBlackbird (Buen mueble de patio), Orbea Dakar, Legs
BOTAFOT #4 BOTAFOF #30 MRO #24 OMF #15 UKRMMA #30
http://paulc.es/ (content pending)

Thanks to all, I think I'll give the pistons a good clean with brake
fluid in the hope that lubricates and gets every speck off.

On Jun 8, 1:08*pm, Paul Carmichael <wibbleypa...@gmail.com> wrote:

> Copaslip and WD40 - all anyone needs for anything. Oh, and maybe oxy-
> acetylene.

And gaffrer tape. Don't forget gaffer tape.

Cue "if it moves and it shouldn't, Gaffer tape. If it doesn't and it
should WD40"

cheers

Spanners

On 08/06/2011 13:49, Spinning Spanners wrote:
> On Jun 8, 1:08 pm, Paul Carmichael<wibbleypa...@gmail.com> wrote:
>
>> Copaslip and WD40 - all anyone needs for anything. Oh, and maybe oxy-
>> acetylene.
>
> And gaffrer tape. Don't forget gaffer tape.
>
> Cue "if it moves and it shouldn't, Gaffer tape. If it doesn't and it
> should WD40"
>

Cable ties, don't forget cable ties. "If you see one, snip it".

--
/Simon

On 08/06/2011 14:02, Simon Wilson wrote:
> On 08/06/2011 13:49, Spinning Spanners wrote:
>> On Jun 8, 1:08 pm, Paul Carmichael<wibbleypa...@gmail.com> wrote:
>>
>>> Copaslip and WD40 - all anyone needs for anything. Oh, and maybe oxy-
>>> acetylene.
>>
>> And gaffrer tape. Don't forget gaffer tape.
>>
>> Cue "if it moves and it shouldn't, Gaffer tape. If it doesn't and it
>> should WD40"
>>
>
> Cable ties, don't forget cable ties. "If you see one, snip it".
>

Dangerous game.

--
Catman MIB#14 SKoGA#6 TEAR#4 BOTAFOF#38 Apostle#21 COSOC#3
Tyger, Tyger Burning Bright (Remove rust to reply)
116 Giulietta 3.0l Sprint 1.7 GTV TS GT 3.2 V6
Triumph Sprint ST 1050: It's blue, see.
#www.cuore-sportivo.co.uk