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Discussion Starter · #1 ·
Team,

I changed over my rear brake pads last night without too much trouble. Had to release a little of the fluid to allow me to open the calipers (not sure if I'm supposed to do that) but otherwise no trouble.

Problem is that there is very little stopping power on the rear and the rotor disk seems to be collecting a lot of the pad material stuck to it..??

Is there something else I should do or just wait and allow them to bed in ? :???:
 

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Well, if by "release some fluid" you mean you opened up the bleeder valve, you will need to bleed the brake line. Doesn't have anything to do with bedding in the pads (but bedding them in properly is also a very good idea). Have someone help you pump the pedal while you bleed, should fix the issue. Don't be afrad to pump hard.
 

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Discussion Starter · #3 ·
Al, I was careful not to let any air back into the line, forced it back under pressure and sealed the nipple before releasing. I am fairly confident that the issue is not air in the lines.

I have noticed that they are becoming better as I use them so may be just a bedding in issue. I am more concerned about the amount of debris off the pads that seems embedded into the surface of the rotor disk..

I considered polishing the disk with something but wanted someone to give advice before I delved deeper..... :???:

Also the disk gets abnormally hot after a run round the block testing the brake... maybe I just haven't noticed that before??

[ This message was edited by: Binnsy on 2007-01-02 21:09 ]
 

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take it back apart.
when you put new pads on, you re-set the pistons in the fully retracted position. if you don't change brake fluid every now and then, it collects water out of the atmosphere and deposits it at the piston seal...corrodes the cylinder wall and makes the piston stick in the partially compressed position...this (from a distance it's impossible to know for sure) is what I suspect here.

the pedal is a spring return, but the pistons are floaters with allowance for expansion...there should be a brake pedal clearance spec listed somewhere...that's what that means.

clean the new pad surfaces and the rotor pristine, retract the pistons, checking for "stuck"...then do a proper bleed.

if you have air in the line, it will heat and expand...may be putting friction on the surfaces and compromising brakes at the same time. I also know folks who intentionally put air in the rear line to diminish rear sensitivity...makes a hydraulic system a partial pneumatic (air brakes found on big trucks)...but I don't subscribe to that myself.

new brakes take a while to seat on rotor surfaces...and brakes are the one thing you don't want to fudge.
 

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realize that when you crack the bleeder, you then need to bleed the system.
you can retract the pistons without opening the bleeder, but once you open it you should bleed the system.
G
 

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Binnsy, an 05 should not have any corrosion issues or the need to change out your brake fluid as yet and cracking the bleeder and squeezing out fluid while NOT releasing the lever while open should be fine and not require bleeding. You will feel it in the lever anyway. The rotors WILL run hot during breakin cause of the drag on bed-in so vary speed and distance so as not to over heat and warp them. The material sticking to the rotors is strange. Is the material in the rotor holes or on the surface ? What brand of pads ? Is the pad coming apart on the surface (heat glazed) ? How many K's did you go on the new pads ?
 

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Discussion Starter · #7 ·
On 2007-01-03 10:24, Normandy wrote:
Binnsy, an 05 should not have any corrosion issues or the need to change out your brake fluid as yet and cracking the bleeder and squeezing out fluid while NOT releasing the lever while open should be fine and not require bleeding. You will feel it in the lever anyway. The rotors WILL run hot during breakin cause of the drag on bed-in so vary speed and distance so as not to over heat and warp them. The material sticking to the rotors is strange. Is the material in the rotor holes or on the surface ? What brand of pads ? Is the pad coming apart on the surface (heat glazed) ? How many K's did you go on the new pads ?
Normandy, I did exactly that, only just cracked open the bleeder nipple enough to squeeze the pistons back sufficient to get the pads in. The "feel" of the pedal (rear brake) is as good as normal, only the pads don't seem to be biting hard onto the disk.

The pads are Ferodo from the local Triumph dealer.

The material is on the surface of the disk, the disk now looks like it is made from the same material as the pads? It does look like a "glaze" on the disk.

Only done a few k's and did use the brake a fair bit on purpose to test them out after the maintenance.

The brakes are getting better each day so I guess this is a break in thing, but I still want to get that pad material off the disk so may pull them off soon and clean the disk up....Binnsy :???:
 

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Wow, never heard of or seen pads coming off and sticking to a rotor face but it could be part of breakin for those pads ??
In future when pushing in your caliper pistons, just remove your master cyl cover, wrap a rag around it and you don't have to "open" the brake system. I wouldn't worry about removing the material as it will be worn off by your pads. You will have reduced break capacity during breakin. Let us know how you make out.
 

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Your rotor should not have gotten that hot. You must have glazed your pads. I'd take a scotchbrite pad to the disc. Rough up the pads with some sandpaper just enough to cut the glaze.

For bedding in pads my routine has been:
Take the bike up to 10 mph and slowly stop with the new pads but release the brake before coming to a complete stop.
Repeat this process by increasing the bike speed in 5 mph increments. I do this up to about 50 mph (takes a long road). You don't want to come to a complete stop as this builds too much heat in the rotor. This heat cycles the new pads properly. Always bed in new pads with an old rotor. Conversely, never bed in a new rotor with new pads.
 

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On 2007-01-05 10:17, Normandy wrote:
ssjones, if you have a new bike, the pads and rotors are new together. How can you have old rotor and new pads ?
Good point, but I've always read to bed in pads first, than put on the new rotor. I suspect they may heat cycle the rotors at the factory as part of the final build prep. Be interesting to confirm that.
 

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Discussion Starter · #12 ·
Follow up:

Brakes now have plenty of grip, I cleaned some of the gunk off the disk with a scotchbrite pad like Normandy suggested. Scotchbrite pad now deceased. Went for a 250km ride yesterday and they feel fine until I am almost stopped and then they shudder and squeal a bit??

I have a service due this week so I will get the Tech to have a look for me.

Thanks for the help team.... :wink:
 
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