Front Brake Service

[NorcoT]

Hey All, yesterday i noticed by front pads are dragging a little when I pushed my FZ6 around so I put it onto its centre stand and checked it out. Now if i spin the wheel it rotates about 1 revolution and then stops, so its not a huge amount.. Does anyone know if this is an MOT fail in the UK?

I took the calipers off, pads out, and pumped the pistons out a bit, the part of the pistons that were within the caliper were good as new, a little dirt build up on the part outside of the caliper so I took some brake cleaner and shined them up. Now I greased it all up reassembled and its still dragging the same amount.

Right so my question!.. Should the pads drag slightly? Is this normal?

If not then do you think I could do a partial service on the calipers by just removing the pistons, cleaning any crap I find, grease it all back up and put the pistons back in? ie not buy new seals yet?

Thanks for any comments / help

 

[tanman]

Hi, my pads drag slightly but not that much. I find that if you take the bolts out that the calipers slide on clean and degrease then regrease, that helps. Also once you have taken the calipers off and refitted try doing a handful of really hard stops at low ish speed to help the calipers re set. That always worked for me pre mot time! Dan. Also the mot states that the wheels must be free to rotate without resistance and dragging I believe.

 

[NorcoT]

Thanks Tanman, will give that a go! Im just cautious as my previous bike failed for sticking brakes but they were a lot worse. I'll clean the sliding pin assembly and also the areas where the pads slide on the brake shoe and see if that helps.

Will try pumping out the pistons / pushing them back in repeatedly to see if that helps..

Anything to avoid having to pay the garage to do it for me!

 

[greg]

also check for crud in the sliding pin hole, pushing the pad against the disc

also give the pistons a clean with some brake cleaner and a tooth brush

 

[Marthy]

Make sure you clean up the piston very good before you push them in to not damage the seals. The pads should always lightly drag against the rotors. If not you will have to pump the brake before the pads grip the rotors.

Other than that does your pads are getting worn out? If you're pads are getting low maybe the piston is at a spot where it's not returning well? Clean everything up first and it the situation is the same change for new pads.

 

[NorcoT]

Thanks for all the comments, I cleaned the pistons up till they were sparkling using brake cleaner, reset them, pads are plentiful still, and I greased up the sliding joint. Reassembled but they still dragged, although I haven't had a chance to ride it and brake firmly a few times to help Reset the calipers so I will give that a go soon.

I think if this still doesn't work then I remove the pistons and clean it all out and rebuild and bleed the system. I have the service manual but just to clarify, on rebuilding the calipers do you need to grease the pistons at all or do you just lube them using brake fluid and push then back in? I'm aware some brakes use a lithium grease between the oil and dust seals, but no mention of any grease in the service manual. Thanks.

 

[Marthy]

Thanks for all the comments, I cleaned the pistons up till they were sparkling using brake cleaner, reset them, pads are plentiful still, and I greased up the sliding joint. Reassembled but they still dragged, although I haven't had a chance to ride it and brake firmly a few times to help Reset the calipers so I will give that a go soon.

I think if this still doesn't work then I remove the pistons and clean it all out and rebuild and bleed the system. I have the service manual but just to clarify, on rebuilding the calipers do you need to grease the pistons at all or do you just lube them using brake fluid and push then back in? I'm aware some brakes use a lithium grease between the oil and dust seals, but no mention of any grease in the service manual. Thanks.

If you're going to go through all this, get new seals and rebuild them. Using the special seal grease is always better but using a bit of brake fluid instead always work fine for me.

 

[TownsendsFJR1300]

One full turn is not bad. You don't mention what year bike you own but Yamaha recommends replacing the brake seals every TWO YEARS. My bike is an 07, so I got 5 years out of them..

I cleaned and greased (brake specific grease) my seals (4 seals on each caliper, 2007) about a year ago. It helped for awhile but started dragging again.

About two weeks ago, I rebuilt the calipers with ALL new seals. I did not use brake grease this time, just brake fluid upon re-assembly. No corrosion, several pistons were a b..ch to get out using an air compressor, that's after being apart and cleaned within a year..

BTW, some black came off the old seals but you couldn't tell the new ones from the old ones...

Anyway, once done, I'm getting at least 3 full spins on the front tire vs previous 1-1.5 full turns...Much less drag, brakes work great, especially with SS braided lines..

Make sure you have access to an air compressor, I don't believe it can be done without one. Some paint stirring sticks (stacked accordingly) also help as spacers to keep the pistons from flying out and get tham all out as far as possible. DO NOT put your fingers inbetween the pistons when using air, your fingers will get squashed.. If its an 07 or newer, there's two different size pistons in each pot (4 pistons for each caliper). If it 06 or earlier, two pistons for each pot... I found its not real hard to do (with an air compressor, even a small one but with at least 100 PSI output), bleeding a dry system takes more time than changing the seals...

Its new seal time!!