HELP; my rear brake is grabbing.

[kneescraper]

Hey all,

After a quick clean and rebuild-ish, my rear caliper seems to be grabbing the disc at all times. I did bleed the system with new DOT 4 fluid.

I rode the bike down the road for 5mtrs and the brake disc was so hot you could cook ya dinner on it.

Any suggestions.

[kneescraper]

Thought so....:)

[MSTRS]

Thought so....:)

What? It's settled down with use?

[imdying]

After a quick clean and rebuild-ishWhat does that mean? And what did you clean it with?

[kneescraper]

Nar it hasnt settled down.

I cleaned it using CRC 5.56 penertation fluid. I took the caliper apart and clean it as it was guncked up.

[imdying]

Oh dear, you've knackered it :(

I'll find a link for you in a minute :)

/edit: Linkzorz!
http://www.kiwibiker.co.nz/forums/showthread.php?t=52017
http://www.kiwibiker.co.nz/forums/showthread.php?t=52180

If you were in Chch, I'd fix it tomorrow for you :(

/edit2: I'm willing to bet there's people who've read that and thought my figure of over 100 calipers was an idle boast... it ain't :no:

[kneescraper]

Oh no!..if you could fix it tomorrow could you inform me out to fix mine..

[imdying]

You'll need to pop the piston out, use teh mcyl. Then clean the whole thing in meths, give it a big scrub up. Then clean the piston with some 600+ grit sand paper, just get it all shiney again. Then hot soapy water the whole lot. Then whack your new seal in, and you're off. Caliper piston seals are measured by the outside diameter of the piston, shouldn't be too hard to get a seal locally (Apex in Hamilton at a pinch). You might have to do without the dust seal (no real biggy if you clean your caliper with hot soapy water every 3-4000kms), as that'll most likely be an OEM part. Reassemble with RUBBER grease or brakefluid, bleed, and you're done :yes:

[The Stranger]

After changing the rear wheel bearings on my GSXR I had a similar problem. I hadn't done anything to the caliper other than remove it a re-install it.
I reasoned it must be sitting a little askew, so tried standing quite frimly on the brake lever, that didn't work so I whacked it a couple of times with a large rubber mallot. After that, no problems.

[kneescraper]

So no WOF for me tomorrow. Dam!...fuck I can be a dork sometimes. Thanks for the help

[kneescraper]

After changing the rear wheel bearings on my GSXR I had a similar problem. I hadn't done anything to the caliper other than remove it a re-install it.
I reasoned it must be sitting a little askew, so tried standing quite frimly on the brake lever, that didn't work so I whacked it a couple of times with a large rubber mallot. After that, no problems.


Thanks for that, I thought the same thing but no amount of wacking helped. I think imdying is onto it....makes perfect sense to me.

[imdying]

If you've all the parts, and some fresh fluid, you could do it in an hour, still time for a warrant :)

[imdying]

I reasoned it must be sitting a little askew, so tried standing quite frimly on the brake lever, that didn't work so I whacked it a couple of times with a large rubber mallot. After that, no problems.You worry me :lol:

Give it a good inspection, given that all the parts a good snug fit, that should be a pretty difficult thing to replicate. Just make sure you caliper bolts etc are tight, and that you've got the spacer between the caliper carrier and the wheel/swingarm still there :)

[The Stranger]

You worry me :lol:



Aww nice of you to care.

On the GSXR 1000 the caliper is not directly fixed to the swing arm. It has a separate floating carrier. A little grit/shit between the carrier and swingarm or had I not seated the carrier correctly would be enough cant the carrier out of alignment.

[kneescraper]

This is Gisborne.....the parts with take around a week to get here. :)

[imdying]

This is Gisborne.....the parts with take around a week to get here. :)No freakin way, NZC overnight, for two seals, from Christchurch, would be <$3.

[kneescraper]

Where is CHCH can I get parts for a RF400...it might be a shit load easer to deal with some one that already knows the parts and where to get them from

[imdying]

There are no parts listings for motorcycle seals, so we work off size. All you need is to measure the outside diameter of the piston. Don't try doing it with the piston in the caliper, it never works out too good. Best way is with some vernier calipers, even if they're $5 plastic ones :yes:

The seals will be about $5 each.

[kneescraper]

Oh awesome! I have mitutoyo (sp) cailpers so they should do the job.

[imdying]

If you have a local BNT, they might have them in stock, if you can tell them the sizes.

[kneescraper]

We do have a BNT so I'll check em out!

[kneescraper]

Well I popped the pistons out today, used a air compressor when the calipers were off the bike. So easy to do...had the cailper apart and pistons popped out in 5mins. Im so glad I did this, there was this sticky bright orange crap behind the pistons..I've cleaned that out and at the moment they are sitting in warm soapy water. I will get the new seals on Money...I'll up date once they are back in.

[kneescraper]

After fitting new seals its still doing it, its like the brake fluid isnt retracting from behind the pistons.

Any other suggestions?

[imdying]

Did you clean the master cylinder with anything?

Can you jiggle the rear brake lever at rest? i.e. Has it got obvious play between it and the mcyl pushrod?

Suspend the rear wheel off of the ground. I assume it doesn't spin at all? If that is the case, what happens if you crack the bleeder? Is there any evidence that the system is under pressure? (i.e. fluid comes out at any rate above a dribble) If there is pressure there, by cracking the bleeder open, does that let the wheel spin more freely?

Does is have a constant binding, or does it appear to have particular places it binds?

Is there more to the story that what you've told us? What was your motivation to rebleed it in the first place?

Was the fluid new from a sealed bottle? Any chance you've recontaminated it with something like auto trans fluid?

Went to bleed a friends brakes the other day, he couldn't get a lever no matter how he tried. Looked to me that the caliper mounts were bent... the lever travel was taking the flex is in the system... it was fled, it just would never have worked :(

[accel_unlimited]

Hey all,


I rode the bike down the road for 5mtrs and the brake disc was so hot you could cook ya dinner on it.

Any suggestions.

Dude, my ovens stuffed. Could i come round and fry up some sausages or something?

[moT]

Hey all,

After a quick clean and rebuild-ish, my rear caliper seems to be grabbing the disc at all times. I did bleed the system with new DOT 4 fluid.

I rode the bike down the road for 5mtrs and the brake disc was so hot you could cook ya dinner on it.

Any suggestions.

yell abuse at it! if that fails attack it with an axe