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Slingshot
9th September 2004, 12:22
Hi all, need some advise.

The rear pads on my wife's bike need to be replaced (CBR 250R hurricane).


The problem is I can't get the piston to retract so that I can get the pad out. Do I need to do something like bleeding the brakes? Anyone know if there's a guide to this anywhere??

Thanks in advance.

Blakamin
9th September 2004, 12:24
Hi all, need some advise.

The rear pads on my wife's bike need to be replaced (CBR 250R hurricane).


The problem is I can't get the piston to retract so that I can get the pad out. Do I need to do something like bleeding the brakes? Anyone know if there's a guide to this anywhere??

Thanks in advance.
Could send you a copy of the cbr250 manual on CD-rom if you like?

pm me if you want it!

riffer
9th September 2004, 12:37
Hi all, need some advise.

The rear pads on my wife's bike need to be replaced (CBR 250R hurricane).


The problem is I can't get the piston to retract so that I can get the pad out. Do I need to do something like bleeding the brakes? Anyone know if there's a guide to this anywhere??

Thanks in advance.
Here's what I do. I know this sounds dodgy (and probably is) but it works for me and I've never had a problem.

Use some mole grips. Then (and this is the important bit) Set them so that they will JUST close over the caliper if you pushed them all the way in.

Gently put them over the caliper and the piston. And then just squeeeeze slowly and they will pop back inside the caliper.

Don't try and do this fast and brutal as you will wreck the piston. Nice and gentle and they will just pop back in.

Mr Skid
9th September 2004, 12:38
Had a quick squiz through the service manual, it doesn't outline any particular procedure for removal..

Have you got the assembly removed from the disc yet? Or are the pads biting too hard for you to remove it? I usually use a large screwdriver across the caliper to lever the piston back in when reassembling the whole affair. Not sure if that'd work for taking it apart.

If you want I'll go disassemble my rear brake and see if there is a trick to it.

Paul in NZ
9th September 2004, 12:39
The piston?

Probably has 2? One each side.. Sometimes brake dust and shit jams them but a good squirt with a can (not the whole can fer gawds sake) of brake cleaner will help. I use a wooden wedge thing to ease the pad back a little, pull em out, repeat (clean and push back) before dropping the new pads in.

Watch the fluid level in the master cylinder does not spill over and you will have NO brakes until the pistons pump back out to the disk.

If this makes no sense...

Read the manual!!!!!

Paul N

riffer
9th September 2004, 12:41
Actually, having read your original post again, you seem to have trouble just getting the pads out full stop.

You could try bleeding the fluid out but that won't push the pads back in.

What you will possibly have to do is:

Put a small host over the bleed valve on the brake, and undo the valve.
Try to push the pad backways slowly with a screwdriver or suchlike wedged between pad and disk.

I don't really like giving this advice cause its so easy to get it wrong. But if you have the pressure off the pad should go back easily enough that you can then take it out.

After you've done this you might as well drain the brakes completely and replace the fluid.

Of course, my advice could be completely wrong and someone else could have a better idea.... :mellow:

Blackbird
9th September 2004, 12:42
I don't know how the setup of the Slingshot is, but if you can get a fine screwdriver between the disc itself and the backing plade of the disc pad, then give it a gentle turn, that should drive the cylinder back. I'm a bit surprised that you can't extract the pad though even if the clearances are small. Sometimes the spring retainer clip means that the backing pad needs a firm tap. Dumb question, but has to be asked.... Is there a pin through the caliper which holds your pad in place, and if so, has it been removed? (sorry to ask, but covering all eventualities!)

Geoff

Slingshot
9th September 2004, 13:08
Firstly thanks for the replies (what a great site this is)!!!

Now, my first post wasn't quite clear (and I actually did this a couple of weeks ago and it's all coming back now).

I'm able to move the caliper up, it pivots on the bolt at the front of the caliper. I can get both pads out but when I put the new ones in the gap between the pads is out of alignment. If I only replace the new outer pad and left the old inner pad in then it's no problem.

So I guess my real question is...should I be able to lever the pistons without having to undo bleed screws etc.

Mr Skid
9th September 2004, 13:31
Firstly thanks for the replies (what a great site this is)!!!

Now, my first post wasn't quite clear (and I actually did this a couple of weeks ago and it's all coming back now).

I'm able to move the caliper up, it pivots on the bolt at the front of the caliper. I can get both pads out but when I put the new ones in the gap between the pads is out of alignment. If I only replace the new outer pad and left the old inner pad in then it's no problem.

So I guess my real question is...should I be able to lever the pistons without having to undo bleed screws etc.


So the problem is fitting the caliper back on with new pads?

Sounds like an easy one, there will be more meat on the new pads than the old ones, and the piston(s) will be extended far enough to make the old thin pads contact the disc.

I'd grab a piece of wood (bit nicer and more uniform pressure than my dodgy screwdriver method) and stick it in on the piston without the pads in place, then apply pressure to it to force the piston back far enough to accomidate the new pads.

Maybe have a quick look at the resevoir, to check that it's not topped up to MAX before you do this though, and be careful not to push it too far and squish the seals on the piston.

F5 Dave
9th September 2004, 13:31
Don’t have much time but will add. Don’t use brake clean anywhere near the seals. It is fine on the disk, or to clean the calliper when you have stripped the seals out, but will damage/swell the seals.

If you pump the pistons out a smidge you can clean around them with thin bits of rag. I push the pistons back with a small sashclamp (for holding wood together ($4 from guess where). Check level in MC, you may need to take some out if some extra has been added at some stage, but easier to open the bleed on the calliper (with a hose).

Don’t use the disc to lever against anything, use may well bend it.

riffer
9th September 2004, 13:39
So the problem is fitting the caliper back on with new pads?

Sounds like an easy one, there will be more meat on the new pads than the old ones, and the piston(s) will be extended far enough to make the old thin pads contact the disc.

I'd grab a piece of wood (bit nicer and more uniform pressure than my dodgy screwdriver method) and stick it in on the piston without the pads in place, then apply pressure to it to force the piston back far enough to accomidate the new pads.
Trust me Slingshot. My method works better. :msn-wink:

vifferman
9th September 2004, 13:42
I'm able to move the caliper up, it pivots on the bolt at the front of the caliper. I can get both pads out but when I put the new ones in the gap between the pads is out of alignment. If I only replace the new outer pad and left the old inner pad in then it's no problem.

So I guess my real question is...should I be able to lever the pistons without having to undo bleed screws etc.I have a feeling that the caliper may have only one piston. Regardless of that, you should be able to lever the piston(s) in, but clean them first as Paul said, otherise any crud that's present will stuff your seals. You can lever them in however you want: mole grips, vice grips, your thumbs, or a small G-clamp. Just do it slowly, and watch the level of the brake reservoir to make sure it doesn't get too high.
When my front pads were replaced a couple of weeks ago, they were VERY worn, and despite the reservoir being at the full mark, and there being a total of 8 pistons, the reservoir didn't overflow.
If everything is clean, and anything that's supposed to be lubed is lubed (like the caliper pin) with high-temp grease or copperslip, then everything should end up straight when you're finished.

Slingshot
9th September 2004, 14:02
Thanks for the replies everyone...I'll have another look tonight when I get home.

I might even take some photos if I can get it sorted.

Mr Skid
9th September 2004, 14:03
Trust me Slingshot. My method works better. :msn-wink:
Judging by my (lack of) mechanical skills I'd tend to agree!

Hoon
9th September 2004, 14:31
Just shove a big screw driver in between and lever them back....or get some vice grips on them.

Posh Tourer :P
10th September 2004, 10:13
If you have only one piston and the thing is floating ie one side fixed and piston on the other, it may be gummed up so it is no longer floating. Look at where the caliper is attached in this case, and spray it with CRC/take it apart and put some grease in. If, as I suspect, it has a piston on both sides and is in a fixed position, get some wood and a clamp and gently squeeze back in. Also, the pistons will self adjust to the right distance after squeezing the brakes a few times, so the distance immediately after putting pads in may not be important. Remember to check the master cylinder level during this process so you arent too low/trying to blow fluid out the top of it...

Slingshot
10th September 2004, 12:49
Didn't get a chance to look at the brakes again last night, I decided to buy a new bike instead :niceone: :Punk: :) :P

I've now got some movation to get it sorted as I need to sell the bike and wouldn't feel good about selling a bike with questionable brakes. Also considering I don't pick the new bike up until early next week I've got some time to kill.

Blakamin
10th September 2004, 12:54
Didn't get a chance to look at the brakes again last night, I decided to buy a new bike instead :niceone: :Punk: :) :P

I've now got some movation to get it sorted as I need to sell the bike and wouldn't feel good about selling a bike with questionable brakes. Also considering I don't pick the new bike up until early next week I've got some time to kill.

What did you buy?

Mr Skid
10th September 2004, 12:59
Didn't get a chance to look at the brakes again last night, I decided to buy a new bike instead :niceone: :Punk: :) :P

Do you sell your car when the ash tray gets full as well? :bleh:

Slingshot
10th September 2004, 13:02
Brought a 97 CBR600F3.

Doing my full test on the 20th so I'm just jumping the gun a little. We're now a three bike household (3x insurance,3x rego, 3x WOF0).

Blakamin
10th September 2004, 13:16
Brought a 97 CBR600F3.

Doing my full test on the 20th so I'm just jumping the gun a little. We're now a three bike household (3x insurance,3x rego, 3x WOF0).
COOOOOL!!!!

toads
10th September 2004, 16:36
Could send you a copy of the cbr250 manual on CD-rom if you like?

pm me if you want it!

hey would it be possible for you to send me a copy of the cbr250 manual on cd rom too????, please????, We have one and it would be good to read up on it, especially when there are so many things we seem to find out after we've done something the hard way!! cheers Lucy

Blakamin
10th September 2004, 17:37
hey would it be possible for you to send me a copy of the cbr250 manual on cd rom too????, please????, We have one and it would be good to read up on it, especially when there are so many things we seem to find out after we've done something the hard way!! cheers Lucy

No Probs!.... pm me your address and i'll get it in the mail monday! (heaps of blank discs at work) :niceone:

Slingshot
23rd September 2004, 20:34
I finally decided to give the brake pads another go...still can't figure out what the hell is going on.

I've attached a photo of the problem, I can get the main piston back it which makes heaps of room for the outside pad but the it looks like the whole calliper mechanism needs to move inwards to create room for the inside pad.

Does anyone know how to do this?

Blakamin
23rd September 2004, 20:42
I finally decided to give the brake pads another go...still can't figure out what the hell is going on.

I've attached a photo of the problem, I can get the main piston back it which makes heaps of room for the outside pad but the it looks like the whole calliper mechanism needs to move inwards to create room for the inside pad.

Does anyone know how to do this?
doesnt look like its sitting in the caliper correctly... you 100% sure its the right pad???

Slingshot
23rd September 2004, 20:48
Yeah...it's definalty the right pad...I'm gonna take another photo...hang on

Slingshot
23rd September 2004, 20:53
The bit that I've circled is the part the the calliper pivots up on to change the pads...to me it seems that the whole calliper should slide back in on this pivot point.

Blakamin
23rd September 2004, 20:53
sweet...from slightly further away?

Slingshot
23rd September 2004, 20:55
Yeah...I've had a big screw driver in there and I've tryed to level the calliper back in but it doesn't want to move...do I need to be bleeding the brakes while I'm trying to level the calliper back?

Blakamin
23rd September 2004, 20:58
Here's mine

Blakamin
23rd September 2004, 21:02
looks like this bit is not moving....(marked "not moving")

ben444
23rd September 2004, 21:06
The caliper should move freely on its mounting bracket in and out(floating caliper).
Undo the bolt that the caliper is held onto the mounting bracket, the caliper shold be able to pivot up now so you can put the pads in, now align the caliper so the disc slides between the pads (maybe a bit tight, fresh pads) making sure the pads sit right on the mountting bracket(i think, long time since I played on a CBR250), then do up the mounting bracket bolt. Sounds to easy... mmmm... maybe your sliding rod and mounting bracket bolt need abit of grease on them

Slingshot
23rd September 2004, 21:07
I think that bit does actually move...It's bolted on solid but there's a sleeve that slides in and out.

I suspect that the calliper moves across to "auto" adjust as teh pads wear down. Because there's no piston on the back side this is the only way that it looks like it could have the inside pad be of any use.
Otherwise all it would be doing would be pushing the outside pad against the disk.

I'm starting to think it may be easier to take the bike into the shop.

Blakamin
23rd September 2004, 21:09
can you get a photo from the same angle as mine?

Slingshot
23rd September 2004, 21:11
The caliper should move freely on its mounting bracket in and out(floating caliper).
Undo the bolt that the caliper is held onto the mounting bracket, the caliper shold be able to pivot up now so you can put the pads in, now align the caliper so the disc slides between the pads (maybe a bit tight, fresh pads) making sure the pads sit right on the mountting bracket(i think, long time since I played on a CBR250), then do up the mounting bracket bolt. Sounds to easy... mmmm... maybe your sliding rod and mounting bracket bolt need abit of grease on them

Thanks...I suspect that you're right about the grease.

It's all starting to make sense now...the outside pad was totally worn, yet the inside pad still had a bit of meat on it, I guess the reason for that could be that the calliper floatie bit is siezed...hence why I can't get the calliper to move back in and therefore make room for the new meaty pad.

I wonder if a big hammer would do the trick.

Slingshot
23rd September 2004, 21:14
can you get a photo from the same angle as mine?

The first photo I posted is bacisally the same angle...just a little closer.

The second photo I posted is the pivot thingie that sounds like it may have seized.

F*** It...I'm going to bed to watch TV.

Blakamin
23rd September 2004, 21:16
The first photo I posted is bacisally the same angle...just a little closer.

The second photo I posted is the pivot thingie that sounds like it may have seized.

F*** It...I'm going to bed to watch TV.
fairy nuf.... i'm goin t'garage to pull forks off!

F5 Dave
24th September 2004, 08:43
Is it just me or does that pic make it look like the calliper is not straight compared with the disc? Prob just perspective.

Take the calliper off & check that the sliding pins are lubed (pull the mounting plate away from the calliper) & you should be able to move the sliding bit back & forth with your fingers.

[edit] Opps I've missed a couple of posts,