HarleyTechTalk

Dual front calibers on bike.Brake lever has over 3/4 travel when applied, brakes work OK but a lot of travel in lever.I have bleed both calibers and no more air is left or will come out.
Used1/2 a bottle of fluid but lever is still almost all the way in to stop the bike?
MVI safety check says to much play in front brake lever!!
Any help would be appreciated.    Thanks E.T.

Try this.  Take the cover off the master cylinder and collapse the pistons all the way in; you may want to take the calipers off to make that easier.   Then bleed the brakes with the pistons collapsed.  It's a trick that will often help with lever travel.

Back in the day there was discussion about air trapped in the calipers.

ET, had same problem with dual disc brakes on 2000 SuperGlide Sport. Replaced stock rubber lines with stainless and solved problem. What a difference it makes. Oh, and make sure you're using the right fluid!  Good luck.

et! try this it absolutely works and is easy to do!.............................................make sure you have the m/c cover on correctly so it doesn't leak and cover the tank and surrounding areas just in case it does!......................then  rotate the bars full left and then apply light pressure to bottom out the front brake lever.once bottomed out take a small bungee cord or string and wrap it around the lever so it will stay in this position and let it set lightly bottomed out overnight. next morning release the lever and reapply a few times to work the master cylinder plunger.you should notice an improvement. repeat tying the lever down overnight a couple more times if necessary. it helps to use the bike between tying off the lever each night because doing so will facilitate any trapped bubbles in the lines etc to work to the top of the sytem which then purges into the mastercylinder resevour. i completely changed out the brake fluid on my 2005 eglide and had the same soft lever your describing.i tried to bleed it to no avail and eventually got about a 1/2 lever that was spongy.by doing the above after 3 nights it was the best it ever was. the biggest factor is to turn the bars and use the brakes to dislodge any trapped bubbles. it also helps before releasing the lever to lightly tap the master cylinder a few times in case any bubbles are near the purge vent.........next time i do brake fluids i will absolutely use this method! i also  use vacumn to suck the fluid out of the master cylinder,add new fluid and then let gravity drain the new fluid thru the lines and out the bleeders at the slave cylinders on the forks. there's lots of ways to change brake fluid and this was the easiest for me.

First off, I personally saw vast improvement after I did the piston cleaning that is shown on the Lyndall Brake website. http://www.lyndallbrakes.com/service-tech/

My bike, a 2005 FLHTC was going almost all the way to the throttle but had very poor stopping power.  Pads were still decent, but lever travel was way too far.  Before I did anything I did the piston cleaning and found 2 things.  First, the pistons would hardly move even with the caliper off the rotor and second, it took quite a while of cycling them before all four pistons reacted equally.  Once they did, the brakes worked great.

One thing, I would suggest if you have the master cylinder filled.  Suck some fluid off before you start the cleaning process, because if the caliper is full now you won't be able to push the pads all the way back, and they do need to go all the way back so you can watch the actual travel.

Quote from: Rags722 on March 26, 2013, 10:26:34 AM
First off, I personally saw vast improvement after I did the piston cleaning that is shown on the Lyndall Brake website. http://www.lyndallbrakes.com/service-tech/

My bike, a 2005 FLHTC was going almost all the way to the throttle but had very poor stopping power.  Pads were still decent, but lever travel was way too far.  Before I did anything I did the piston cleaning and found 2 things.  First, the pistons would hardly move even with the caliper off the rotor and second, it took quite a while of cycling them before all four pistons reacted equally.  Once they did, the brakes worked great.

One thing, I would suggest if you have the master cylinder filled.  Suck some fluid off before you start the cleaning process, because if the caliper is full now you won't be able to push the pads all the way back, and they do need to go all the way back so you can watch the actual travel.

  Make sure your pistons are clean and free first.  When I do a tire change I clean the pistons and always get a nice tall lever.  You have 8 pistons on a dual disc bike,  they all need to be free.

The other suggestions are good but if your pistons aren't clean/free you won't get a tall lever or if you do it will only be short lived.   Rick

What Rags said I clean mine twice a year

Quote from: 04 SE DEUCE on March 26, 2013, 11:25:23 AM

Quote from: Rags722 on March 26, 2013, 10:26:34 AM
First off, I personally saw vast improvement after I did the piston cleaning that is shown on the Lyndall Brake website. http://www.lyndallbrakes.com/service-tech/

My bike, a 2005 FLHTC was going almost all the way to the throttle but had very poor stopping power.  Pads were still decent, but lever travel was way too far.  Before I did anything I did the piston cleaning and found 2 things.  First, the pistons would hardly move even with the caliper off the rotor and second, it took quite a while of cycling them before all four pistons reacted equally.  Once they did, the brakes worked great.

One thing, I would suggest if you have the master cylinder filled.  Suck some fluid off before you start the cleaning process, because if the caliper is full now you won't be able to push the pads all the way back, and they do need to go all the way back so you can watch the actual travel.

  Make sure your pistons are clean and free first.  When I do a tire change I clean the pistons and always get a nice tall lever.  You have 8 pistons on a dual disc bike,  they all need to be free.

The other suggestions are good but if your pistons aren't clean/free you won't get a tall lever or if you do it will only be short lived.   Rick

+10 on cleaning the pistons,they must be thoroughly cleaned, I use a rope style shoe string,sprayed with brake clean, to get at the back side of the pistons,after you are sure they are clean, I spray them with a silicone lube..
  I learned this lesson the hard way, I beat my head against the wall for a while before I finally listened

ok i'm following this thread pretty close trying to learn something here!  on my 2005 eglide there is two pistons to each rotor on the front. do you remove each caliper one at a time and pump the brakes to expose as much of the pistons as you can with the pads still in place? once they are exposed the pistons and boots are thoroughly cleaned with brake cleaner and then pushed back into the caliper so they can be mounted back on the fork. with the pads still in place can the pistons come all the way out when pumping the brake lever? i know you don't want to get any brake fluid on the painted surfaces but are there any other tricks or hints when doing this maintenance?

MKD...  on an 05 touring, there are FOUR pistons per caliper, 2 calipers for a total of 8 pistons.

Here is how I did it, others may have different methods, but this is about as easy as you can get.

First off, check your front brake master cylinder and see if it is topped off.  Keep in mind, you will be pushing the pads all the way in with my method, and if the master is already full you may need to draw a little off ( only if you have added fluid) to make room in the master for the stuff you will be pushing back.

Pop the 2 bolts off that hold the caliper to the fork leg
Edit added Remove caliper from bike It will come off without removing tire or fender, but some blue painters tape on the fender for protection can't hurt.
Spray the pistons good with brake cleaner ( I just leave the pads in place because I use the pads to pry on to retract everything
Use a shoelace soaked in brake cleaner and clean the piston as good as you can. A small stiff artist paint brush works too

Now, at this point, some people may just call it good enough but the next few steps make all the difference in the world.
Find something about the thickness of the brake rotor and keep it handy
Using a screwdriver or pry bar, force the pistons (evenly) all the way back in the caliper.
Slip the tool ( hunk of metal about the thickness of a rotor ) between the pads ( this will keep the pistons from coming all the way out )
Squeeze the lever and watch the piston action  You want, and can get all 4 pistons traveling at the same rate
If they didn't travel at the same rate, clean again and push the pistons all the way back
Repeat until they work at the same rate
Put caliper back on bike

At this point, you still have another full caliper to do, but if your bike is like mine you will have a lever that feels like it did when the bike was new.
Now go on and do the second caliper and follow the instructions above.  Be sure to top off the master cylinder when you are done, and you will have a much nicer front lever feel.  The bad news is the rear brake needs the tire pulled to get in there and do it right, but it's probably even more filthy than the fronts.  Depending on your level of excitement for work, you may want to leave that one for the next tire change.

I do pretty much the same thing,  except I don't unbolt the calipers.  With the wheel off at tire changes,  short pump the lever til the pads are together clean then retract and repeat til all the pistons move evenly when the lever is squeezed.  Rick

mkd,  there is no dust boots on these,  just a dust seal and a seal. 

If all the above stuff don't work check rotor runout.. If OK replace the brake pads..

Max

rags722 ! do the 1998 softail flsts springers have 2 pistons or 4?   i have one of those and maybe that's why i'm confused!

I'm pretty sure the 98 STS had a SINGLE Piston floating brake on the front.  Keep in mind, the 05 Flht had a solid mount caliper and pistons for each brake pad.  The caliper never moved, only the pistons & pads on each side of the rotor moved.  The STS had a piston on one side of the caliper, the entire caliper floated on it's mounting bolts and the pad on the back (inside) was hard mounted on the caliper.

http://www.shopronniesharleydavidson.com/OEMpartfinder.htm#/Harley-Davidson%c2%ae/FLSTS_BRLW_Softail_Heritage_Springer_(1998)/FRONT_BRAKE_CALIPER/1H02280015/02280097

Rags is right on. Actually, from 1987 on up thru 1999, all HD calipers (both front and back) on big twins had only 1 piston. Not sure about sportsters.

" If all the above stuff don't work check rotor runout.. If OK replace the brake pads.. "

Especially if you do a quick double pull and the second time the travel is less...lol
The master cylinder stroke displacement is barely enough to handle 2 calipers.
Pads worn past 50% still look good but need more fluid to get in contact with the rotor.

There is a whole lot of talk about calipers on here, but if it were mine I would rebuild or replace the master cylinder. After bleeding the lines if I had too much travel, I would check the master cylinder as they can leak internally which will cause too much lever travel.

It is in the calipers! I have done dozens of these and when the pistons are dirty they do not slide in the o-ring and the natural pull of the o-ring on the piston causes piston to retract a few thousands causing the extended travel. Normal automotive technology uses a square cut seal, not a o-ring and uses a dust boot to keep clean. Mike

Quote from: Rodman on March 28, 2013, 02:14:30 AM
" If all the above stuff don't work check rotor runout.. If OK replace the brake pads.. "

Especially if you do a quick double pull and the second time the travel is less...lol
The master cylinder stroke displacement is barely enough to handle 2 calipers.
Pads worn past 50% still look good but need more fluid to get in contact with the rotor.

Excuse me? Perhaps I am confused!
As the pads wear the brake fluid fills in behind the pistons in the wheel cylinders. The pads travel the same distance whiether the pads are new or worn out as the brakes are applied. Now with worn pads there is more fluid capacity behind the wheel cylinder pistons and more room for air to get trapped and cause softer brake feel.

If you are doing a "double pull" to get the brakes to apply you have air in the lines or some other issue.

Greg, his point is about rotor runout.  If the rotor is warped, as it turns, it'll push the pistons back in the caliper more than one stroke of the lever can push them back out.

Good sign of a tweaked rotor is you get great lever in the garage, back the bike out and the lever sucks again.  Pump it up and the lever is back.  Roll forward a few turns of the wheel and the lever sucks again.  An almost sure sign the rotor is pushing the pistons back in.

Watch the pistons as you pump the lever. If the caliper needs cleaning you will see that only one or two of the pistons move freely. This is the cause of the soft lever on most dot5 2000 and up bikes. Point of least resistance sort of thing. You must free the 'sticky' pistons so that they all move evenly. Remove one caliper at a time leaving the pads in place pump, clean, free, and then fully compress the pucks into the bores. Install that caliper back on the bike and pump up the brake. Remove the other, if dual, and repeat.
Rotors must be true as stated and the system bled.

JB 

Quote from: PoorUB on March 30, 2013, 05:51:32 PM

Quote from: Rodman on March 28, 2013, 02:14:30 AM
" If all the above stuff don't work check rotor runout.. If OK replace the brake pads.. "

Especially if you do a quick double pull and the second time the travel is less...lol
The master cylinder stroke displacement is barely enough to handle 2 calipers.
Pads worn past 50% still look good but need more fluid to get in contact with the rotor.

Excuse me? Perhaps I am confused!
As the pads wear the brake fluid fills in behind the pistons in the wheel cylinders. The pads travel the same distance whiether the pads are new or worn out as the brakes are applied. Now with worn pads there is more fluid capacity behind the wheel cylinder pistons and more room for air to get trapped and cause softer brake feel.

If you are doing a "double pull" to get the brakes to apply you have air in the lines or some other issue.

You are confused....read the whole thing.
Rotor runout will push the pucks back.
You're excused!

After the problem is fixed will you let us know what fixed it?

 Thanks guys for all your help with my front brake problem...it is repaired.
I first tried the easy fix of tieing off the lever but it only gave me a little lever action.
Then took the calipers off and disassembled them, left first. 
Only one or two pistons moving,cleaned them and pushed them in and out until there was movement on all four and then did the right one.Checked and added fluid to reservoir, now I got me a Viagra lever,hard and lots of stopping power.
Again thanks to you great members for sharing your experience and knowledge with me!!
                                                                                                                                E.T.