Back Bleed Squishy Brakes

We have run into this problem from time to time.  Most people assume just bleeding the brakes cures all your squishy problems but here is another trick that will help you out when dealing with squishy front brakes on Harley Davidson Motorcycles.

We are working on a 2004 FLHR dual disc front brake setup. Pic#1 Shows how far the lever pulls back. This brake system has already been properly bled out and flushed with fresh fluid. As you can see the brakes will grab but the lever will pull almost to the grip before they do.

Pic #2 Shows the reason why. Dirt in the caliper. Also notice how the pistons don't protrude equally from their bores. Brake dust and road grime over time gets into the piston bores in the caliper and gums up the o-rings. This causes the pistons to stick in their bores and the hydraulic pressure (feedback at the lever) to fade. This results in a squishy lever and can also cause the pads to wear unevenly.

Pic#3 Shows dirt on the pistons.

Heres how we fix it. Start by removing the caliper and pumping the brakes repeatedly until the pistons come out of their bores. Then we spray them down with brake cleaner.

Then blow them dry with compressed air.

Pry the pads apart with a pry bar or big flathead screwdriver. (Notice if you are replacing the pads you will want to do this process with the old pads installed so as not to damage a new set of pads.)

You might have to hold one side of the pads while pumping the brake lever to get the opposite side pistons to come loose.

Repeat the process of cleaning, drying, prying and pumping 3-4 times. What you want to end up with is pistons that are clean and shiny and that all come out of their bores at the same rate like the below pic.

Install your new pads.

Reinstall the caliper and torque all fasteners to spec as per the service manual. Repeat this process for the other side caliper.

Notice the difference in pull between where our lever started.

And where our lever is now. We have a lot more lever available than we did before.

Always remember to recheck the fluid level in the master cylinder when you are done. Hopefully this helps you out next time you deal with squishy front brakes on your Harley Davidson V-Twin.
You can always hit us up at www.BlueCollarBikeWerks.com if you have any problems or questions. And feedback is always appreciated. --Aaron