MkIndy7
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| posted on 5/6/05 at 06:17 PM |
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Sticking Sierra Calipers
Erm.. i'm confued on this1 what exactly sticks? and what do you do to free them off?
Just remove the caliper and clean everything off? and if fitting the same pads do you have to bleed it again?
I presume its the sliders that get crudded up normally but they don't seem 2 bad.
The car wasn't pulling to 1 side or making much of a squeek but the disk was actually smoking when I stopped  and the wheel was pretty hot.
ahh such fun!
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theconrodkid
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| posted on 5/6/05 at 06:24 PM |
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both or just 1 side,if both could be no clearance on brake pedal,caliper slides do stick if they are dirty or been sitting around
who cares who wins
pass the pork pies
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britishtrident
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| posted on 5/6/05 at 06:29 PM |
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In normal operation the caliper piston gets pulled back a few hundredths of a mm by the internal rubber seal, if the caliper is sticking but not
seized either the piston is sticking slightly usually due to aging of the seals or the pad next to the piston is sticking in its channel (this was a
particularly common fault on Cortinas even when brand new).
If you have the problem on both front or all four wheels the cause could be master cylinder related --- usuallly the pushrod is too long or vent
hole master cylinder lid is blocked.
Normal treartment is to pull out the pads clean the channel they/it slides in, clean the piston with silicone spray (nb not WD40 as it mainly a
kerosene type hydrocarbon) and work the pistons in an out a few mm, if that dosen't work renew the seals.
[Edited on 5/6/05 by britishtrident]
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MkIndy7
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| posted on 5/6/05 at 06:29 PM |
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Just the right hand side (that i've noticed),
I've got grooved disks and the grooves were just full of brake pad, yet there looks loads of pad left.
I've left it all to cool down and could just about turn the hub but you could hear it scratching,
pressed the brake pedal a few times to see if that would relese anything and it sounded like air coming out under the bonnet for about 3 pumps of the
pedal V.strange
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britishtrident
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| posted on 5/6/05 at 06:32 PM |
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quote:
Originally posted by MkIndy7
snip
pressed the brake pedal a few times to see if that would relese anything and it sounded like air coming out under the bonnet for about 3 pumps of the
pedal V.strange
If you have a servo the noise is the servo exhausting-- after 3 pumps you have no vac left in it.
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MkIndy7
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| posted on 5/6/05 at 06:35 PM |
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Sorry to sound dumb but what does that mean/effect then, should it do that? or might I might have a problem on the servo side of things as well?
And from what I saw of the caliper dust it was on the outside as if the outside pad had been sticking agains the disk.
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britishtrident
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| posted on 5/6/05 at 07:04 PM |
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Not a problem just normal operation the servo works by letting atmospheric air pressure into one side (the pedal side) of its diaphragm when the
pedal is pushed, normally you get three pumps of the pedal before the vac resevoir is exhausted.
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MkIndy7
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| posted on 5/6/05 at 08:21 PM |
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Well i've got the caliper off the car and the slides didn't seem too bad,
other than general dirt the only thing i've found is a rubber that looks to have come out of place on the caliper any ideas how to get this
rubber back into place or do I have to take the brake cylinder out?
If so, how do you keep the fluid in if you have braided hoses as i presume you can't crimp them up the same as normal rubber hoses.
Oops thought the pics would ave uploaded with this, pics in my photo's bit (break rubber 1&2) cheers folks
[Edited on 5/6/05 by MkIndy7]
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rusty nuts
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| posted on 5/6/05 at 08:51 PM |
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To keep the fluid in with braided hoses try putting a piece of polyphene under the reservoir cap to create vacuum if fluid level drops. You may lose a
few drops of fluid but shouldnt lose too much., as Trident says check the pads are not siezed in the caliper mounting.
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MkIndy7
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| posted on 5/6/05 at 08:56 PM |
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The calipers and holders etc are painted everywhere but it's never caused a problem,
I wonder if now everythings worn a bit the paint needs stripping off the bits that move?.
I could really do with getting that rubber back on without loosing any fluid cos my Bleeding assistant has buggered off to Italy for a week!
(After already loosing the bonnet at XXmph!)
[Edited on 5/6/05 by MkIndy7]
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Danozeman
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| posted on 5/6/05 at 09:01 PM |
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I have known the brakes to stick if the calipers are painted. Id Clean the carrier and pads all up with a file and lube them with copper slip and try
it before u pull the caliper apart..
I believe u have to pull the piston out to put the dust cover back in BTW.
Dan
Built the purple peril!! Let the modifications begin!!
http://www.eastangliankitcars.co.uk
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MkIndy7
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| posted on 5/6/05 at 09:06 PM |
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Just my luck with the dust cover 
Obviousley its there 4 a reason, might just have to clean up the rest and put it back for now then, till my assistant gets back.
Thanks for your help all! 
Never know my luck it might even go back easier than it came off!
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rusty nuts
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| posted on 5/6/05 at 09:09 PM |
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Remove the caliper without disconnecting the hose, make sure the pads are free in the caliper mounting bracket, if not clean off rust/paint. apply
copperslip to backs of pads and surfaces that pads touch on mounting brackets. If caliper dust cover is not perished/split use polyphene under
reservoir cap , pump piston out from caliper using brake pedal , refit dust cover into caliper groove , refit piston fitting dust seal onto piston.
You will have to bleed thst caliper , but probably not the rest of the system. A Gunsons Eazibleed is a good investment for bleeding brakes .
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NS Dev
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| posted on 6/6/05 at 08:02 AM |
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do you have a servo??
If so, one other thing worth checking (after the caliper in question) is the oneway valve on the servo.
I have had one of these fail and it can then intermittently apply vacuum to the servo withoutmoving the brake pedal, causing the brakes to pull on.
Just a thought.
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MkIndy7
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| posted on 6/6/05 at 07:15 PM |
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Thanks for the servo Idea, might disconnect it and remeber to stomp hard for a short journey!
Well i've cleaned off all the calipers and sliders, greased it up and put it all back but.....
If ya let go fo the wheel and brake it stays perfectly str8 until you get to below 10mph and then pulls to the right a little (the ex sticky caliper)
Could this just be my weight in the car? (Talking bout my Fiesta rather than Mk)
Or does we thinks there may still be a problem?
P.S I had it all tracked about 3months ago.
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