finlay
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| posted on 16/6/08 at 02:14 PM |
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help needed with sierra rear calipers
hello all
i m having a right nightmare with trying to bleed the rear calipers, they are sierra ones
at first i got them mounted but could not get them to function after bleeding them, definetly getting fluid through, i then took them off but still
had all pipes connected and tried functioning them again, it felt like very little movement in the piston, so i bled them again and this time still
very little movement but when i let off the pressure on the brake peddle the piston didnt retract so i pushed the pedal again and the piston kept on
pushing out,
i couldnt physically push the piston back so i disconnected the fluid pipe and opened the bleed nipple but still the piston stayed fully
compressed/out
i cant get it to budge
so now the calper is off and the piston is fully out so i cant get the pads in
anyone got a solution or have they had this problem before ?
any help would be much appriciated
cheers
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Howlor
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| posted on 16/6/08 at 02:22 PM |
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Wind them back in, then lever up the actuation lever, this I was told is the best way to reset them.
Steve
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procomp
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| posted on 16/6/08 at 02:22 PM |
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Hi not sure if it is your problem but. If you have worked the handbrake setup prior to bleeding the hydraulic side of the calipers that will cause
problems. There is usually a warning notice inside the box when brought as recon/new.
Assuming of course these are new/recon and not S/H of donor.
Cheers Matt
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Mr Whippy
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| posted on 16/6/08 at 02:44 PM |
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piston winds in, a g-clamp will hold in while you bleed the brakes. Try tapping them with a hammer to loosen any bubbles inside and do make sure the
bleed screw is at the top
Fame is when your old car is plastered all over the internet
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finlay
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| posted on 16/6/08 at 04:12 PM |
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thanks for the replys
i ve managed to wind in the piston
i ve refitted the calipers after re-bleeding them with the bleed nipple facing upwards but still no luck,
do you have to wind the piston out to "take up the slack" before you bleed them ?
cheers
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Howlor
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| posted on 16/6/08 at 05:04 PM |
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Try prizing up the handbrake lever actuator. Get a pry bar behind it and they should lever up by about 12mm. Then try bleeding them.
Steve
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adithorp
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| posted on 16/6/08 at 07:44 PM |
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Have you opperated the handbrake lever before pumping up the brake pedal? If so then the mechanism is probably FUBAR.
adrian
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Howlor
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| posted on 16/6/08 at 09:08 PM |
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quote:
Originally posted by adithorp
Have you opperated the handbrake lever before pumping up the brake pedal? If so then the mechanism is probably FUBAR.
adrian
I think though if you lift the actuation lever up this will reset them ok.
Steve
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finlay
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| posted on 17/6/08 at 08:33 AM |
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quote:
Originally posted by adithorp
Have you opperated the handbrake lever before pumping up the brake pedal? If so then the mechanism is probably FUBAR.
adrian
yea i have actually, doh, i didnt see any notes with them to say not to, i will try what steve suggests, fingers crossed
cheers guys
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mad-butcher
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| posted on 17/6/08 at 08:36 AM |
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Best thing I've used for winding the piston back in is the pinned spanner for tightening disks on a large angle grinder.
as said wind the piston in fit pads then using the handbrske operating arm to reset the pads.
you will see from the pic that the bleed nipple is halfway down the caliper it needs to be at the top otherwise you will get an airlock. the easy way
to do this is to remove your disc and g clamp a piece of wood to it so the disc will sit on the floor now put caliper with pads fitted onto disc with
nipple pointing upwards now bleed the caliper. if you set both discs up like this you can bleed both calipers at once. now fit calipers and disks to
car.
It should be noted that there have been issues of the rear system not bleeding by doing the down ,open, close, up method of bleeding the rears due to
the way some people have run the brake pipe over the dif the system airlocks (you can't build up enough pressure to blow the air over the diff).I
personally use a guyson pressure bleederImage deleted by owner
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finlay
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| posted on 17/6/08 at 10:28 AM |
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spot on
appriciate the info
i will give it a go and let you know how it goes
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mad-butcher
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| posted on 17/6/08 at 07:30 PM |
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just in case some-one hasn't seen a gunson eezibleed. one of the best £10 I've spent.
fill bottle with brake fluid fit plastic cap to to of reservoir black pipe to spare wheel ( I use my compressor set to 24psi open bleed nipple. close
nipple .jobs done same on other 3 wheels
[Edited on 17/6/08 by mad-butcher]
 
Rescued attachment gunson eezibleed.jpg
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