Midsize LTD L4-140 2.3L SOHC (1986)
Vacuum Brake Booster: Service and Repair
1985-87 4-140
1.
Disconnect battery ground cable and remove air cleaner.
2.
Disconnect accelerator cable from throttle plate.
3.
Remove screw that secures accelerator cable to shaft bracket and remove cable from bracket.
4.
Remove two screws that secure accelerator shaft bracket to manifold and rotate bracket toward engine.
5.
On LTD and Marquis models, remove RPO horn.
6.
On Cougar and Thunderbird models, release fuel system pressure, then disconnect the two manifold injector connectors located near oil dipstick
retaining bracket. Disconnect two fuel lines to fuel supply manifold assembly.
7.
On all models, remove engine oil dipstick tube and bracket.
8.
Remove windshield wiper motor.
9.
Disconnect vacuum lines located over brake booster at dash panel vacuum tee.
10.
Remove bolt securing clutch cable stand, then move bracket to side rail at fender inner panel.
11.
On models equipped with speed control, move speed control cable to one side to clear booster.
12.
On all models, disconnect manifold booster line from booster check valve.
13.
Disconnect brake lines from master cylinder, then remove master cylinder attaching nuts and the master cylinder.
14.
Working under instrument panel, disconnect electrical connector from stop lamp switch.
15.
Remove hairpin type retainer and outer nylon washer from brake pedal pin, then slide stop lamp switch off brake pedal pin just enough for outer
arm to clear pin.
16.
On models equipped with speed control, unfasten control amplifier from lower outboard booster stud and position aside.
17.
On all models, slide booster pushrod link and nylon washers off brake pedal pin.
18.
Move booster forward in engine compartment until booster studs clear dash panel, then rotate front of booster toward engine and remove booster.
19.
Reverse procedure to install.
HYDRO-BOOST
1.
Disconnect stoplight switch wires at connector and remove hairpin retainer, then slide stoplight switch off brake pedal pin far enough for switch
outer hole to clear pin and remove pin from switch.
2.
Slide hydro-boost pushrod and nylon washers and bushing off brake pedal pin.
3.
Remove master cylinder and position to one side without disturbing hydraulic lines. It is not necessary to disconnect brake lines, but care
should be taken not to deform lines.
4.
Disconnect pressure, steering gear and return lines from booster, then plug lines and ports in hydro-boost to prevent entry of dirt.
5.
Remove hydro-boost retaining nuts, and remove assembly sliding pushrod link from engine side of dash panel.
6.
Reverse procedure to install. To purge system, disconnect coil wire so that engine will not start. Fill power steering pump reservoir, then while
engaging starter, pump brake pedal. Do not cycle steering wheel until all residual air has been purged from the hydro boost unit. Check fluid level,
then connect coil wire and start engine. Apply brakes with a pumping action and cycle steering wheel, then check system for leaks.
