mntbiker_ken

I have a re-occuring issue involving the front brake on 3 different bikes now and can't figure out what is causing it or a definite way to fix it.

To transport my bike(s) I take off the front tire and lay it in the trunk, disc side up.
I put the rest of the bike in the back seat area...it has plenty of room....it bumps around a bit getting it in there...but no certainly no worse of a beating than it would take on a trail.

Then, when I get to my destination, I take my bike out, go to put the front tire in the forks and find that I can't get the front tire to go in because the distance between the brake pads have narrowed substantially and not enough room for the disc rotor to fit between. I don't know what is causing this!

With 2 of the bikes that use cables/mechanical disc brakes I had been able to pump the brake a few times and/or jiggle things around and it seems to get back to normal. One time I adjusted the cable to compensate.

But today, with a different bike that has hydraulic juicy 5 brakes......same thing. Went to go put the tire in and initially couldn't get it in due to the brake pads. I finally jiggled it in there.....but it was tight and the tire would not spin freely. I rode on it, thinking it would eventually work itself back....but it never really did.

Anyone know what could be causing this (in laymens terms please) and what I can do to adjust that when it happens?

Thanks much!
Ken

BCRider

The only thing I can see is that since you're laying the bike on its side perhaps the front brake lever is being worked by the bike moving around and it's pumping the pads inwards? That wouldn't even come close to doing anything to the mechanical brakes but with the hydraulic ones it could be an issue. Either lay the bike on the right hand side or get the packing slips that come with brake systems and hold the pads apart.

I don't really believe what I wrote since all the systems have return springs but it's all I can think of that might be the issue.

mntbiker_ken

Thanks for the reply. Actually, the bike is upright in the car....so not sure thats doing it.
BUt I like the packing spacer idea.
Any thoughts on what do to as far as adjusting after it happens is welcome too.

mntbiker_ken

ok......I think I pretty much know now what is going on. Pretty much what BC rider said. The brake lever probably was getting pumped a few times getting the bike in and out of the car. WIth no wheel in place, apparently the pads close together..........I did not know this!!

So, like BC-rider said, I need to get the spacers that go in between the pads.

In the meantime, I understand you use a 10mm box wrench to push the pistons back in.
Anyone want to shed a little more light on this part? I don't have a 10mm wrench handy so tried using a screwdriver but the pistons don't seem to budge! Does the 10mm wrench make a lot more difference than using a screwdriver to push them back in? Are they supposed to be so hard to push back in?

Just to be sure.....the piston is that whole circular unit on each side and not just the little square shaft in the center right?

Thanks for the help!

Torchy McFlux

When you buy aftermarket hydraulic disc brakes, a plastic wedge/spacer is included. Hayes used to sell them separately. Not sure if they still do. It's just a simple plastic thing with a taper on one edge so you can just jam it in there without removing or damaging the pads.

DannoXYZ 

I usually use a BIG 18" screwdriver to separate the pads. The thing is about 10mm wide and I just push the tip straight in centered between the pads to not gouge it. The taper of the blade spreads out the pads as I push it in.

But yea, it's even easier to not let the pads squeeze together in the 1st place.

jsharr

I wonder if you could just use plastic door shims from HomeDepot of Lowes to hold the pads apart during transport? A pack of them is just a few bucks.