It is a drag, front brake that is.

[Rsteen]

Put the front tire back on and it was very hard to get the pads onto,the rotor. Major drag now. Sure a dumb way to have a stud on the caliper that requires you to put the caliper on the fork leg before before you mount the wheel. I note some arrows on the back of the pads and wonder if I got the pads on the wrong side. It did not drag before I took it all apart. Suggestions?

 

[gggGary]

New pads? New or overhauled caliper? If not that's the place to start. There are (supposed to be) 1/2 shims between the pads and pistons. With the wheel out of the way the pistons should retract with gentle prying on the pads. Like with a screwdriver.

 

[XSLeo]

What year is your bike. The early two piston calipers can be tricky. The later single piston calipers are a breeze.
Leo

 

[Rsteen]

It is a 1975 year. I did not see any shims that went between pads and pistons. No new pads. It rolled fine prior to putting fork seals in

 

[XSLeo]

Can you push the pistons back into the calipers? How old are the lines?
Old lines break down from the inside out. Bits of the rubber break off and float around till they find a place to get stuck and block the fluid flow.
The master cylinder can be dirty enough so the fluid won't return and this can stop the pistons from pushing back in.
When was the last time you changed the brake fluid?
When was the last time you tore down the calipers and the master cylinder to clean them?
Leo

 

[Rsteen]

Well the outside piston was stuck. Had a heck of a time getting it out. Inboard piston would move when air was applied. Finall put it back on the bike and bled brakes and used hydrolic pressure to get the stuck one to move. Cleaned then up and now everything great. I think we are back on schedule.

 

[payaso13]

Didn't want to start a new thread but I rebuilt caliper with kit all new rings,seals new piston also. With new ss hose(single) and new master. Fresh fluid...to...with the front wheel off ground I spin it with very small drag and squeeze brakes it stops. It still spins as hard as I can get it going but just unsure if I should worry or normal til I get new pads seated to rotor

 

[payaso13]

Also I did take caliper apart already to make sure everything was good. Looked good. Used new crush washers on all banjos no leaks detected. I'm thinking I need to brake new pads in like a car? Just not do an endo

 

[gggGary]

I think I am unclear on what you are saying. With pressure on the lever it should not be possible to turn the front wheel by hand. Where did you get the MC? Is the lever stopping before it hits the handlebars?

 

[payaso13]

Sorry I rambled on. Mc is from Hugh(slimline) I have great brake pressure. It start to grab a lot easier than the original set up with two piece hose...anyway calipers rebuilt but spinning the wheel brake pads are very slightly rubbing on rotor. Not enough to just stop wheel but barely. With new pads was wondering if its normal. Just need to brake pads in on rotor...give it some time?

 

[gggGary]

Yes "a bit" of brake drag is normal. Ride it a bit and check that the drag does not increase and that the shoes, rotor aren't getting hot. You should be good. An old "stuck" caliper can be very free turning and require "too much" pressure.

 

[payaso13]

Not squeezing lever at all... just spinning wheel. When I squeeze lever it stops as it should. But released and spinning wheel there is slight contact with new pads and rotor

 

[payaso13]

Ok thanks I took it all apart just to make sure I didn't miss anything and all looks good.

 

[XSLeo]

Ok, on disc brakes the piston slides through the piston seal as things wear, or when first assembled. The seal flexes a bit as the piston moves. This flex is all that pulls the piston back. This lets the pads drag a bit
In the early factory repair manuals it lists a spec for brake drag. You lift the front wheel, hook a scale to a spoke out near the rim, turn the wheel with the scale, if it takes more than 2-4 m-kgs there is too much drag. I think that's about 15 to 30 lbs.
So a bit of drag is normal.
Leo

 

[payaso13]

Thanks Leo I did rebuild everything and I had front wheel off ground and spin wheel it just barley touches and the wheel still spins for quite a while. So this was my first time rebuilding caliper and wasn't sure if with new pads it should touch rotor until using brake. Thanks for info

 

[mjpchief]

Just put a new caliper on my '75. Going to rebuild and sell old caliper. Just a little help on removing the caliper. I noticed you said you had to remove the wheel to remove the caliper. If you remove the brake line and the bottom mounting bolt and remove the top acorn nut you can rotate the caliper up and remove it without removing the front wheel. Saves a lot of time and work. Also helps to remove the front fender brace.