This 1994 FXR, like all carburetor Harley Davidsons without abs, uses Dot 5 Silicone brake fluid,
which does not corrode paint, does not absorb moisture, has a long service life, and has a high boiling point both dry and wet
On motorcycles with ABS, DOT5 is not used because bubbles form in it when the valves of the ABS unit are operating
DOT 5 should not be mixed with any other brake fluids,
but the owner of this motorcycle added a glycolic DOT 4 to the rear brake system
As a result, the caliper piston is jammed,
brake pads are worn down to the metal,
the brake disc is damaged.
Now it is difficult to determine the cause.
Perhaps the oil seal was swollen or the fluid corroded the paint on the fittings, which formed a slag due to which the piston did not slide well
So, the brake disc with pads and brake line must be replaced,
the caliper must be rebuilt, the master cylinder must be flushed.
As you can see, due to the worn pads the piston sticks out too much and jammed,
it can be released with an air compressor.
The dust seal is squeezed out
The caliper can be perfectly cleaned with a dishwashing cleaner
For caliper rebuild, I will use a repair kit and new pads.
On the old piston, there are scuffs and traces of impacts,
apparently, someone tried to knock it back into the caliper
First, the rubber ring is installed in the groove.
The rubbing surfaces are lubricated with the brake fluid
After a new piston is inserted
The piston must be squeezed out so that the groove for the dust seal is accessible
The dust seal is fixed with a snap ring, which must sit in the groove completely
The old rubber brake line has expired.
It has an integrated brake light sensor and requires an inch thread banjo bolts and special washers with rubber seals.
The paint on the fitting was corroded by the dot 4 brake fluid
I'll make a new brake line from HEL components,
we are official dealers with number 129, which is on all our sleeves
Instead of the original brake sensor, I use a banjo bolt with an integrated brake sensor
The HEL stainless steel fittings can be bent at an angle and rotated after assembling,
Which eliminates a hose rotational tension and makes installation easier.
The sleeve is crimped in a radial press and provides a reliable triple sealing of the fitting in the hose
I use new stainless banjo bolts with new copper washers
Next, I will install a new brake disc.
Bolt threads are easy to clean with a thread cleaning nut.
Apply a thread lock and tighten brake rotor bolts to 45Nm opposite each other
Before removing the wheel, I checked the chain slack,
it was about 5 cm with the hanged rear wheel
The axle nut is tightened to 88Nm
I am using the new shims that come with the pads.
The outer brake pad is fixed with the clip.
The Brake caliper mounting bolts are tightened to 27Nm
The brake sensor is plugged into the original connector
The fitting with the yellow HEL tag goes to the caliper
When bleeding, I drained some brake fluid to flush the brake master cylinder: which releases air automatically
At this moment, you can see exactly how the DOT 5 is bubbling.
Now the rear brake system is not just repaired
but also improved with the steel braided brake line
which does not expand under the pressure
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