New tires now soft brakes

[Guest]

i just put on some new tires and now my brakes are a little soft. I bled the brake lines which helped but wasn't perfect. I was told sometimes after moving the tires the grooves that had formed on the disk and the ones that had formed on the pads won't line up and this can decrease braking. Not sure if there is any truth in that. I could use new back brake pads anyway so I'm going to replace those and see where I am at after that. Any other insight would be great. Thank you.

[gsrick]

i just put on some new tires and now my brakes are a little soft. I bled the brake lines which helped but wasn't perfect. I was told sometimes after moving the tires the grooves that had formed on the disk and the ones that had formed on the pads won't line up and this can decrease braking. Not sure if there is any truth in that. I could use new back brake pads anyway so I'm going to replace those and see where I am at after that. Any other insight would be great. Thank you.

In the three years as being a MC mechanic at a shop, I've never had a problem like that. It might be possible for some air to get in when you compress the pads to remove to caliper, but even then that's rare. The pads do move slightly but I would think they would naturally fall back into the place where they've been as soon as you apply the brakes when riding. The fronts do the majority of the braking. Until you get new pads you may want to knock off a little of the surface area in case the pads are glazed. You can do this on a concrete side walk or driveway in a figure eight motion and let new groves wear into the pad, but if you have grooves in the rotor, you should consider replacing them.

[Nessism]

What bike are we talking about and have the brakes been properly serviced in terms of replacing the brake lines and cleaning out the calipers and master cylinder? Suzuki calls for replacing brake lines at regular intervals which assures the brake fluid gets changed regularly. Reason for asking is because it sounds like the pistons in the calipers are binding up and not aligning themselves properly after the wheel came off. And crud inside the calipers and brake lines is pretty much a given on a 35 year old bike unless it's seen proper maintenance since day one.

[rushton75]

It is an 83 gs750e. Low miles 25k. I have had it about 3 years. It seems to be much better after spraying some brake cleaner on them and bleeding the line. I will take a look at giving the caliper and pistons a better clean when I put new pads on tomorrow also I will fully drain and replace the fluid.

[hillsy]

Did you accidentally get some grease on the disc by any chance when you were doing the tyre? If so this may now have transferred to your pads and it will take some time (or maybe never) to get rid of it and get good feel back in the brakes.

[rushton75]

should I put some grease (if so what kind) on the pistons after cleaning them or just a bit of brake fluid?

[mmattockx]

should I put some grease (if so what kind) on the pistons after cleaning them or just a bit of brake fluid?

After disassembling and cleaning out your calipers you should wash all the new/clean internal parts in fresh brake fluid and then reassemble the caliper. No grease anywhere except on the pins that the caliper body slides on.


Mark

[rushton75]

Thanks for your help.

[hjfisk]

Also remember that bike has brake assisted anti dive, which can trap air. Unless someone has already eliminated it.