Spongy Front Brakes

[Fazer]

Just changed the pads on the front brakes and now they feel spongy.  Only ridden a few miles, but should be able to get on 'er this weekend for more riding.  I can predict that bleeding will be suggested, and I plan to do this, but where would air have been introduced that was not there before changing the pads?

Another question--they are mildly dragging.  I attribute this to being new, fresh and greater depth than the old,  and that they will "run in" with a little use.  Am I correct in this assumption?  After all not much can go wrong in re-assembly if the pad pin is in and bolts are properly torqued.

Any comments are welcome.

[98valk]

disk brakes Always drag, they are designed that way. with bike/car raised, spin wheel, spins by itself 1 1/2 to 2 rotations, they are good.

ambient temp changes can change feel of brakes. colder temps give softer feel.

[hubcapsc]

Just changed the pads on the front brakes and now they feel spongy.  Only ridden a few miles, but should be able to get on 'er this weekend for more riding.  I can predict that bleeding will be suggested, and I plan to do this, but where would air have been introduced that was not there before changing the pads?

Another question--they are mildly dragging.  I attribute this to being new, fresh and greater depth than the old,  and that they will "run in" with a little use.  Am I correct in this assumption?  After all not much can go wrong in re-assembly if the pad pin is in and bolts are properly torqued.

Any comments are welcome.

Mashing the pistons back in for the new thicker pads without cleaning the
pistons first (assuming you didn't clean them first) means that that icky
crusty part of the pistons that  were previously exposed are now inside
your calipers.

The pin your pads slide on gets icky everywhere except where it
passes through the pads, so if you didn't clean the pin, your pads
are now trying to slide on a grungy part of the pin.

I learned this the hard way, and my "mildly hanging" quickly turned
into "I can't even roll my bike back and forth in this parking slot"
by the time I got to work.

Some people (I'd probably make a mess of this) take their pads out
and gently mash on the brake lever to cause the pistons to extend
enough that you can clean them nicely... I'd probably mash the
lever too hard and the pistons would pop out and fluid would go
everywhere  

When I change my pads now, I remove the calipers, pop out the pistons,
clean them all up, put in new seals, and put it all back together with
great results. It was intimidating at first, but there's nothing inside
the calipers other than the pistons, the seals.



Here's a before/after picture of the time I found out that not cleaning the pin
caused the brakes to drag a little... you can see the cleanish place where the old
pads sat in the top picture, the whole pin is clean in the next picture...



-Mike

[Fazer]

Thanks 98 Valk and Hubcap.  I did clean the pisotns as best I could before forcing them back in.  I used wd40 and a rag.  But I did nothing with the pin.  Should not be too hard to pull and clean--probably won't even have to remove the caliper.  Any lubrication on the pin?  If they still hang, I will do as you suggest and extend and clean the pistons.

[hubcapsc]

Thanks 98 Valk and Hubcap.  I did clean the pisotns as best I could before forcing them back in.  I used wd40 and a rag.  But I did nothing with the pin.  Should not be too hard to pull and clean--probably won't even have to remove the caliper.  Any lubrication on the pin?  If they still hang, I will do as you suggest and extend and clean the pistons.

I wouldn't lube the pin, that would probably end up being
like lubing your pads 

You might already be pretty much good to go, given that you did
the most important thing: clean the pistons... I bet almost nobody
cleans the pin, and I bet any stickyness caused by that would take
care of itself as the pads scrub in their own "clean place"...

About cleaning the pistons... if you clean the part you can see without
pushing them out some, there's still some ick on them...

To make this picture, I cleaned the exposed part of the pistons, jambed
a board in where the rotor goes, and used compressed air to push
the pistons out some... you can see that the ick on the pistons extends down into
about where the seals are...



-Mike

[Fazer]

Mike--I read your post about using air to remove the pistons.  If this doesn't get better, I will do as you recommend.

Greg

[Leathel]

Also as well as cleaning the pad retainer pins check the slides that allow the caliper the move are moving freely as they can cause brake drag

[hubcapsc]

Also as well as cleaning the pad retainer pins check the slides that allow the caliper the move are moving freely as they can cause brake drag

Yeah, those sliders are in the rubber booties... lube does go in there...
If the booties were to get holes in them, they'd need replaced, but I've
never seen a holed bootie...

-Mike

[Chrisj CMA]

Thanks 98 Valk and Hubcap.  I did clean the pisotns as best I could before forcing them back in.  I used wd40 and a rag.  But I did nothing with the pin.  Should not be too hard to pull and clean--probably won't even have to remove the caliper.  Any lubrication on the pin?  If they still hang, I will do as you suggest and extend and clean the pistons.

Next time don't use WD40 and a rag, that's very inefficient and introduces a foreign substance into the system, bad!

What works best is a shoelace dipped in brake fluid then wrap it around the piston 360 degree turn and then pull it back and forth. That piston will shine

[hubcapsc]

introduces a foreign substance into the system, bad!

Yeah... there's even a place in the valkyrie manual (pg 15-21) that
says to put silicone grease on your new caliper seals when
installing them... blegg... I "lube them up" with brake fluid
when installing them instead...

-Mike

[sandy]

If you pushed the pistons back in without bleeding some fluid out, you might have some pressure built up. Do a short bleed and see if the dragging goes away.

[Fazer]

Removed the calipers and discovered that I had misaligned one of the front clips that hold the pad in place.  I had actually bent over a small ear on the brass clip and the pad was not seated properly.  I was able to bend it back into shape with a pair of needle nose pliers, re-assemble, and all is well.

Thanks to all that offered help.

Fazer

[baird4444]

Also as well as cleaning the pad retainer pins check the slides that allow the caliper the move are moving freely as they can cause brake drag

Yeah, those sliders are in the rubber booties... lube does go in there...
If the booties were to get holes in them, they'd need replaced, but I've
never seen a holed bootie...
Mike

            DUDE.......