Hard Brakes (ran search)

Both amber and red brake lights came on a week ago. Thay seemed to work fine until yesterday the brake pedal was really hard. I ran a code test from the ABS computer and recieved 2 flashes pause then 1 flash and then the light stays on. I guess this is a 21. I don't know what code that is. I here the motor pressurizing when I turn the key on. According to the post in the FAQ's I removed the relay and jumped T/Y with GY/R and the pump came on. I put the relay back in turned the key on and pumped the brake pedal a few times and didn't here anything. Then I grounded out the PK/LB wire with key on and the pump came on. On the other relay I'm gettin a constant 12v on the T/R wire and with key on I'm gettin 12v to the ABS computer. I went ahead and changed the relay furthest from the firewall due to all the post suggesting that so I said what the hell I'll just try it. $12 @ Autozone. when I put the relay in and turned the key on both lights went out immediately but, when I took it for a test drive as soon as I hit the brakes both lights came on and the brake pedal is still hard. And the lights won't go away anymore. Any suggestions would be greatly appreciated.

The electro-hydraulic power assist is 100% independant of the ABS part of the system, and therefore running the ABS self test will not give you any info on the hard pedal. 99% of the time, the problem is a bad hyd. pump relay, located under the vac tree. See the FAQ page.... there is an article on diagnosing the pump relay.

Are you sure you changed the pump relay and not the ABS power relay?

Could also be a blown accumulator, or failed pressure switch.

With car off, pump brake pedal several times. TUrn key to run. Do you hear the pump motor run for 10 to 15 seconds? You should.

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Jeff Korn

88 Turbo Coupe: Intake and exhaust mods, T3 turbo at 21 psi, forced air intercooler, water injection, bypass valve, Ranger roller cam, subframes, etc., etc.. // 86 Tbird 5.0 (original owner): intake, exhaust, valvetrain mods, 100 HP nitrous, ignition, gears, suspension, etc., etc.... // 91 Escort: Bone stock winter car // 02 Taurus Vulcan(wifes car)

[This message has been edited by Jeff K (edited 04-10-2004).]

I troubleshooted the relay acoording the your FAQ instructions. When i jump the plug i here the pump motor kick on. When i turn the key on and pump the brake a few times i don't here it even thought the brake is still very hard. I grounded out the PK/BL wire and the motor kicks on. The rekay i changed was the brown relay furthest from the firewall. This happened to me On my last T-bird and it was my accumalator. How do I troubleshoot the pressure switch and the accumalator. Thanks, Dice

Accumulator going bad usually results in the pump cycling on/off rapidly, the ABS and BRAKE lights flickering on/off as the pressure changes rapidly.

If grounding the PK/LB wire ran the pump, the problem is not the relay. Next likely thing to check is the pressure switch.

Pressure switch: located on the MC, sticking out parallel to the pump motor. Has a 5 terminal connector on it. Remove the connector, and with key on, jumper the PK/LB and GY (goes to ground) terminals in the connector. Pump should run. If it does, wiring to switch is intact. Key off. Pump pedal a bunch of times. Measure resistance between the 2 terminals on the switch that the GY and PK/LB wires go to. Should be zero ohms, i.e., the switch should be calling for the pump to run because pressure is low. Yes, it is a PITA to get to the switch terminals. If those 2 terminals indicate open circuit, replace the switch. I THINK (hope) that they are available seperately. If the switch reads closed circuit, my next guess would be a blown accumulator. BTW, if the problem is intermittant (like works fine for a day and then goes bad again) the problem is not the accumulator.... when they go bad, they stay bad.



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Jeff Korn

88 Turbo Coupe: Intake and exhaust mods, T3 turbo at 21 psi, forced air intercooler, water injection, bypass valve, Ranger roller cam, subframes, etc., etc.. // 86 Tbird 5.0 (original owner): intake, exhaust, valvetrain mods, 100 HP nitrous, ignition, gears, suspension, etc., etc.... // 91 Escort: Bone stock winter car // 02 Taurus Vulcan(wifes car)