Author Topic: Easing back rear brake pistons - without doing damage.  (Read 2385 times)

Offline Sprunghub

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Easing back rear brake pistons - without doing damage.
« on: May 21, 2009, 08:13:47 AM »
I can't imagine I'm the first to find this tricky. I'm about putting new pads in the rear brake on the F1.  I expected, because I knew no better ::) - that the 'contact face' of the piston would be flat......but as far as I can see in the dark recesses it's hollow ?? & it's just the outer "rim" which presses on the back of the pads ? either that or the pistons are stuck in the chambers & I can't see any piston  :o
The 'old' pads were pretty 'thin' & there was well short of the necessary gap to drop the new pads in.  I've been able to get the 'outer' of the two gaps increased - hopefully by retracting the piston rather than bending the disc, the piston did seem to "give" a bit but the inner one is a bu**er.
Just a matter of patience & application ???.......or is there a trick......the front one, which is now working took three elephants standing on it to retract it - I can't see me getting that sort of 'wellie' onto the back one & hope I haven't got to break the whole rear end down just to change a pad. :-\
Needless to say, the Manual says' "remove old pads & replace with new" - & I'm more used to brake shoes  ;)

N
The current stable,
76, CB750 F1
83, FT500
89, VTR250
78, CB125T

Offline Sprunghub

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Re: Easing back rear brake pistons - without doing damage.
« Reply #1 on: May 21, 2009, 09:31:29 AM »
....& the answer is.....take off the rear caliper assy, apply clamp, clean up & replace. 
Ho hum.
The current stable,
76, CB750 F1
83, FT500
89, VTR250
78, CB125T

Offline mick

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Re: Easing back rear brake pistons - without doing damage.
« Reply #2 on: May 21, 2009, 10:36:59 AM »
I was just about to say thats what i ended up doing  ::), they pick up all the dirt and crap in those rear calipers no wonder they stick and the only way to give them a proper clean is to strip 'em down,  ;) cheers Mick.

Offline Bryanj

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Re: Easing back rear brake pistons - without doing damage.
« Reply #3 on: May 21, 2009, 12:37:51 PM »
If they are that tight you would be better pumping them out and fitting new seals after cleaning out the caliper especialy the seal grooves

Offline Sprunghub

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Re: Easing back rear brake pistons - without doing damage.
« Reply #4 on: May 21, 2009, 01:19:29 PM »
Cheers both, re-fitted & bled through.  I need to get her in 'test' so I can road run her & tweak her whilst managing the tidying up....otherwise she'll sit in the garden & that's not much good :-[

Have managed to get a late notice appointment for this afternoon....fingers x'd ;)
The current stable,
76, CB750 F1
83, FT500
89, VTR250
78, CB125T

Offline mick

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Re: Easing back rear brake pistons - without doing damage.
« Reply #5 on: May 21, 2009, 04:08:40 PM »
Good luck  ;)

Offline Sprunghub

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Re: Easing back rear brake pistons - without doing damage.
« Reply #6 on: May 21, 2009, 06:25:46 PM »
1) Right hand 'tell-tale' indicatior light not working. :-[

2) Brand new, fitted by renowned bike Garage, front tyre not correctly seated on rim ???

Failed.

Ho diddly dee....hopefully back in again tomorrow.  Worth the hassle for the "first" proper ride.  Did think it was bit pogo'ish at the front, but then again, new to the bike & my old side valve does that anyway !  Hadn't noticed the t/t light.....more interested i whether the actual indicators worked !......live & learn.

Engine ran very well - which is the main thing.....well pleased, clutch as smooth as silk. ;D 
The current stable,
76, CB750 F1
83, FT500
89, VTR250
78, CB125T

 

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