[theisland]

Hello everyone!

I have a question about the front brakes of my DL650 which i just picked up about a month or so ago. I have looked here and there about an issue like this but I have come up short.

Anyhow, it all started shortly after I bought the bike. I was beginning to hear a faint grinding sound coming from the front of the bike. I looked at the brakes, everything I thought checked out. It has beginning to get a touch louder (loud as in, I can hear the grinding when driving on the HWY) so I took the calliper off and again, felt as if they are doing ok. The performance hasn't changed as far as I can tell but I have noticed that perhaps the brakes seem as though they are sticking a touch… if that makes sense.

When I lift up the front of the bike and spin the tire, the sound is defiantly coming from the pads. Moreover, the sound 'seems' as if it's coming from the inside pad (the pad that is butt up to the inside of the rotors). So, my question is, judging by the pictures here, are my pads ready to be replaced? If not, then whats going on with the grinding sound? If so, I would assume that the grinding would go away once the pads have been replaced, but why though? I am not too sure why brakes would sound as if they are grinding just because they are a little low I mean, maybe once the brakes were applied, but not when the the brake is not applied.

Anyhow, any ideas would be really appreciated.
Thanks for the time in reading this fellow 650 riders!
Have a good one.
Grant.

 

[Yak]

The pads look fine. The pistons may be hanging up and dragging. They look a bit dirty? Is there mud or something in there?

 

[theisland]

I see, perhaps they are dirty. They defiantly are dragging, well the pads that face the inside of the rotor that is. Any idea why that is? Also, in the picture with the red arrow, that little notch is almost hitting the rotor. Anymore wear, that tab will be hitting the rotor.

Thanks.

 

[SittingDuck]

I see, perhaps they are dirty. They defiantly are dragging, well the pads that face the inside of the rotor that is. Any idea why that is? Also, in the picture with the red arrow, that little notch is almost hitting the rotor. Anymore wear, that tab will be hitting the rotor.

Thanks.

That tab will not touch the rotor; the pads come out of the caliper on that side; it's the other side that just rubs against the disk and slides along the guide pins when you brake.

Since you have the caliper out, why don't you clean everythign nicely and run some sandpaper on your pad's surface? I

 

[theisland]

Ok, ok, this makes sense. Ill try cleaning everything up. Maybe I will go and get some cleaner and douse the brakes and give them a good scrubbing.

 

[Guest]

Once you have them cleaned and reinstalled. Take them for a test ride then check the temperatures If one is noticeably warmer than the other then you will have found a dragging brake.
Likely they just need to be tiddlied up and they will be quiet again.

 

[richw]

It looks like it should slide on the mount rods which would cause them to retract

There could be a pebble press into 1 pad

On a 650 if the axle is clamped make sure you tighten brakes before clamp nut

ONLY weak little BS or rings rolling provide the retraction force and almost any grit or corrosion can over come it

The buttons holding the rotor need to be clean so that the rotor CAN float.

Lastly use brake clean on all friction areas before your finished

 

[jokermtb]

The Strom uses old-style calipers, where the pads actually slide on pins [which are exposed to the elements]. This is one of the reasons a swap to GSXR calipers is often desirable - no exposed sliding pins! These pins eventually get worn, and instead of being a smooth surface for the pads to slide on, they get pitted, grooved, etc.....throw in a little dirt + road salt corrosion, and it's no wonder your brake pads are not able to fully retract.

From your photos - it's clear to me that your pins are very dirty, and look a little salt corroded. Clean em up, sand them down with some emory cloth, and give it a go.

 

[greywolf]

The sliders also get a little hi-temp brake grease after cleaning.

 

[theisland]

Thanks everyone for your responses. After work today, I am going to stop off at 'Canadian Tire' and pick up some goods, and brake grease.

I still am not too sure whats happening inside these callipers that will allow for equal force on both sides of the rotor to happen. It would only appear that since the piston is applying pressure to one side, the pressure will only be coming from there - but thats only half the story. I know this is getting off topic but perhaps I can find some infos in the internet tubes somewhere.

Have a good one!

 

[jokermtb]

Yeah, the piston side pad will always touch first - it's unavoidable. The opposite/non-piston side pad relies on sliding on nice shiny smooth pins to allow it a fighting chance of contacting the rotor at the same relative time that the piston side pad contacts the rotor. Not the greatest system, but from a manufacturer's standpoint, it's CHEAPER than a caliper with two pistons, and it will still work, at least if it's kept in good condition.

Just the nature of the caliper beast............which is why many have ditched the stock Vstrom calipers to get GSXR or Honda CBR calipers that use opposing pistons and don't rely on sliding pin technology [Amish-style technology!]

SV Racing, one of this site's sponsors, does sell a kit that makes doin' the caliper upgrade/swap pretty simple.

 

[greywolf]

Floating calipers allow the entire caliper to slide on the pins so the forces on both sides are equal.

 

[bower100]

Your describing what happens when the floating caliper doesn't ...well, float smoothly. Under the two rubber boots of each caliper are the two pin, part of the caliper mounting bracket. Stretch the boots off their retaining lip and pull the caliper completly off the two pins .... part of the mounting bracket. Clean both of old grease AND any corrosion you see. ( Rubber boots must be intact... no tears). As a test of their function, reassemble them without the boots in place, pins lightly lubed. They must slide freely .... no binding AND also, ...without any slop/play either indicating worn bushings.

Look at the floating caliper assembly carefully for any marks in the black finish, a gouge,scrape or dent, ( I know, cast aluminum doesn't really "dent"). Especially on the side facing out. Why? Should the caliper have ever gotten hit by something like in an accident, a car tire, bumper whatever, that force can bend the caliper mount bracket and the pins on it. This will either cause the caliper to not float correctly, ( a dragging brake), or just simply cause the pair of pads to not be parallel to the disc. (Binding of the caliper to its mounting brackets pins... when hydraulic pressure forces the pads parallel to the disc).

Don't confuse the little pad reataining pins with whats explained above. They act only to keep the pads loosely in place within the calipers. Corrosion on these is not a big deal, though clean them since your there.

Of course on final assembly do grease, the mount bracket pins and the two holes in the caliper that recieve those pins, liberally with the high temp disc brake grease. Line the inside of the rubber boots with some grease too help seal out road grime.

dave

 

[PTRider]

Only the threaded plate that bolts to the fork is fixed in place. Everything else floats. When you apply the brakes, the pistons push the outer pad against the disc. They also push the cylinder part of the caliper away from the disc which pulls the inner pad against the disc.

 

[theisland]

Thanks all for the input. I cleaned everything up, sanded down the brakes (the looked rough when I looked at them) and sprayed the brakes with brake clean, ensuring NOT to hit anything rubber, yes indeed. I still hear slight grinding however, I would assume that little is normal however, I do not hear as much as I did before! It was pretty bad before. The pistons looked as if they had a layer, (or a ring if you will) of dirt around them. Furthermore, the pins seemed pretty dirty as well. I cleaned them off and put a little high temp lube on them.

Not too sure if I am ready to tackle a brake replacement just yet however, perhaps later on down the road as I can see how this can become a rather consistent trend for me.

I was able to hunt down an illustration of what exactly is happening with these brakes when they are applied. I was just unable to wrap my head around the idea and since nothing seemed to move when I applied the brake, I wanted to see something like this...

How disc brakes work - 2 (Pro/e animation) - YouTube

I still feel a little friction through the brake leaver though. I am not too sure if this is something that I would have payed attention to when I first got the bike so I cant really say if it's normal or not. Either way, everything is quiet and stopping me with no issues.

Again, thanks everybody.
-Grant.