Front brake not working on a Honda XR125 L3

Hi there,

We've had problems recently with the front disc being semi-locked on. The bike would be suddenly hard to wheel, and then it would sometimes be fine, mostly after riding, Today, the bike would'nt go past 20-30mph even in 4th when it should be doing 60+ after a 2 minute ride (literally) you could hold your hand 5-10cm from the disc and it was HOT.

Today, we drained all the old fluid and put some new Dot4 in the Resivior or w/e it's called. and now when we tried to bleed/drain the liquid ot just stayed in the resiviour thing, and the brake lever has no restrain on it AT ALL! as like a mountain bike brake was unclipped, hard to explain, and obviously the brake doesn't work, When riding it today the acceleration was ALOT better, using only the gearbox and rear brake to slow down so when the bike was first bought it was obviously locked on now and again.

Has anyone got an idea what this could be?

Info:

Bike: Honda XR125 L3
Year: 2003
Mileage: 44,000km :yahoo:

 

Befour anything,check the piston and bore for scoreing and corrosion.It should be a nice silver colour with no corrosion.As to bleeding do as Minor says.If that dosent work then lock the bleed nipple off,make sure theres enough level in the resovior and pump the brake til pressure is felt,hold the brake in and open the nipple(you will feel the lever go slack,thats normal)keep the lever down and lock off the nipple.then repeat.If it still dosent pressure up then the master cyl is goosed or you have a leak.

Paul

 

No pressure is building up and nothing is coming out of the bleed valve or even the brake line at the caliper if disconnected so im guessing the master cylinder is a gonner?

 

Thanks for your info, sorted it now, Squirted aload of WD40 in the Caliper piston thing (Behind the pads) but alll back together and seems all good. :yahoo:

 

You still need to dismantel the piston and clean it,the problem will reoccur.

Paul

 

The thing was a barn find, was sitting in a barn for a few years, was the Vauxhall garage owner W.J Kings bike. If its working which it is, we'll leave it for the time being, no point trying to rectify a problem if its all a-okay. When it comes back we'll strip it :good:

 

as said, it needs a total strip. Once the piston is out remove the piston seal and give the recess a proper clean behind the seal. Usually grime accumulates behind the seal and pushes the piston out. Over time it stops the piston returning a bit at a time and slowly makes the piston bind on the disk....slowly getting worse.
AND if the discs been as hot as you say due to binding (reduced speed), theres a good chance that the disc may be slightly warped. You'll feel this as a pulsing when you feather the lever after the calipers been rebuilt. Thats one that'll need replacing

 

Whilst your at it get a master cylinder repair kit, get the caliper seals and pistons, new disc and new pads.

It's probably scored to shit and half way throught he caliper.