WILWOOD BRAKES TROUBLESHOOTING GUIDE

LOSE YOUR PEDAL DURING RACE

CAUSE

SOLUTION

Fluid boiling due to wet fluid or foot drag

Flush out entire system with fresh Wilwood Hi-Temp° 570 racing brake fluid. Install dashboard brake light reminder.

Undersize brake system

Refer to the caliper web pages to select the correct caliper/rotor combination for your application.

Wrong size residual pressure valve

Use no larger than 2 lb residual pressure valve.

Incorrect or faulty master cylinder

Repair or replace master cylinder.

Leak in caliper or hydraulic lines

Check for leaks in caliper and lines.

Inadequate ducting

Reposition air ducts to center of rotor and caliper. (refer to Wilwood air duct technical sheet)

Pedal linkage failure

Check pedal assembly.

Excessive spindle deflection in corners

Check spindles for warpage. Install 2 lb residual pressure valve.

BRAKE DRAG

CAUSE

SOLUTION

Bad master cylinder

Switch or replace master cylinder.

Incorrect residual pressure valve

Use no larger than 2 lb residual pressure valve.

Rotors warped

Replace rotors.

Calipers not square to rotor

Re-align brackets or shim calipers.

Tapered brake pads

Replace pads, check caliper alignment to rotor.

M/C has internal residual pressure

Remove residual pressure valve.

CAR WILL NOT STOP

CAUSE

SOLUTION

Glazed pads and/or rotors

Grind and/or sand glaze from rotors.

HAVE TO PUSH TOO HARD ON PEDAL

CAUSE

SOLUTION

Too large of a master cylinder

Refer to the master cylinder web pages to select the correct size unit for your application.

Not enough pedal ratio

Increase pedal ratio, see pedal web pages to select the correct pedal for your application.

Pedal mounted at bad angle

Master cylinder push rod should not be off more than 5° in any angle.

Wrong pad material for your applications

Pads must match rotor operating temperature range.
See pad web pages to select the correct pads.

Frozen pistons in calipers

Rebuild calipers.

CALIPER LEAKS

CAUSE

SOLUTION

Caliper seal old or dried out

Replace with new seals.

Nick or ding on piston or cut seal

Replace pistons and/or seals as necessary

SPONGY PEDAL OR BOTTOMS OUT

CAUSE

SOLUTION

Air in brake system

Re-bleed the system.

Calipers not bled with bleed screws straight up

Unbolt calipers and hold with bleed screws in the vertical position.

Wrong size master cylinder
(too small)

Refer to the master cylinder web pages to select the correct size for your application.

Faulty master cylinder

Replace master cylinder.

Calipers not mounted square to the rotor

Re-align brackets parallel to rotor, or shim caliper.

Calipers mounted equal to, or higher than master cylinder

Install 2 pound in-line residual pressure valve.

Calipers flex excessively

Check pressure. Do not exceed 1,200 P.S.I.

Pedal ratio too great

Reduce pedal ratio.

Excessive spindle deflection in corners causing piston knock-back

Install 2 pound in-line residual pressure valve. Check spindles for warpage.

OSCILLATION FEEDBACK IN PEDAL

CAUSE

SOLUTION

Excessive rotor runout

Shim between rotor and hub/hat.

Pad material buildup on rotors

Change pads, clean rotor face.

Calipers loose

Tighten caliper mounting bolts.

Rotor faces not parallel

Re-grind rotor faces, or replace rotors.

Cracked rotors

Replace rotors. Refer to rotor web pages to select the correct rotor for your application.

Excessive front bearing clearance

Check for proper bearing size, or tighten the spindle nut.