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Author Topic: brake seized on  (Read 658 times)

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Offline scooby puppy

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brake seized on
on: 21 Sep 20, 09:53:26
hi, I've been doing up my late sons sx and whilst doing it changed the pads all round,

both the front calipers where a right pain in the arse to push the pistons back,

it's been off road a year and half now but its now at a point where I could have ago, i did a few laps round our estate and the front brakes locked on, front right caliper, I'm fairly sure it's the calliper so going to order a rebuild kit new seals etc so I can pop the pistons out and use the parts washer at work, I'm also going to do both sides

is there anything else it could be like a pressure relief valve anywhere

thank you


Offline Scotty001

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Re: brake seized on
Reply #1 on: 21 Sep 20, 04:01:35
No, no pressure relief valve, it is likely the piston pots have corroded brake dust stuck on them and need a through clean. also check for pitting on the piston pots, if they are pitted they will also need replacing. (as you now won't have a perfect seal which could cause substantial issues, also the rough edges of the pitting may tear the new rubber seals, again resulting what could be a substantial issue)

If doing at home and not using the parts washer at work, order up a can or two of brake cleaner, a new tooth brush and red rubber Grease. (a tooth brush is good for rubbing away caked in brake dust / road grime on a piston pot sprayed with brake cleaner without scoring or damaging the surface of the piston pot.) also good for cleaning off the crud  around the calliper and piston ports. ( if you don't clean the callipers using the works parts cleaner)

The red rubber grease is good for the seals and lubes them up for when you put the pistons back in.

Small g clamps and cardboard / thin slice of wood are good for pushing pistons back in to the calliper.

Undo the fluid reservoir, syphon out the fluid in it, (as you know taking care not to get any on the bike / paint work).

Put a piece of cardboard / slice of wood on the rear of the calliper and another piece / slice over the front / piston pot, slide a g clamp over them and start to tighten the clamp down gently (pushing the piston back into the calliper) do it slowly and keep an eye on the fluid resivour so it doesn't spill over. Once done throughly bleed the braking system.
Last Edit: 21 Sep 20, 04:05:08 by Scotty001


Offline scooby puppy

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Re: brake seized on
Reply #2 on: 21 Sep 20, 07:00:42
cheers already got all off that stuff anyway but I'll definitely use the parts washer, might as well if I can 👍👍


Offline Peterbennetive

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Re: brake seized on
Reply #3 on: 26 Sep 20, 10:57:27
When l stripped my calipers l found it very hard to bleed until l  found this great way. Before you put the pistons back in. Connect the brake lines and then tip new brake fluid into the caliper piston holes. Fill as high as you can just leaving room to replace the pistons without pushing them in. When you now push all the pistons in, it will push the new fluid up through the lines and into the reservoir. Then rebleed as normal.