Life with the Milano’s Antilock Brake System (ABS) has been bittersweet. Since we bought the car new in ’87 we’ve had one failure. The electropump, which supplies pressure for braking, failed catastrophically in ’92 after five years of faithful service. It failed about 100 miles from home on a Saturday leaving the car without power-assisted brakes, a very dangerous condition. After limping home I replaced the pump for $800 (rebuilt units are not available) and stopping ability returned to normal.
Well the pump is five years old again and the master cylinder ten (MCs go for around $1800--again rebuilt units are not available), so rather than wait for another ABS component failure, I decided to replace the ABS system now with a conventional braking system. That is, the “normal” master cylinder/vacuum booster arrangement as supplied on the GTV6 and Milano models Gold and Silver. (Milano Platinum and Verde models were fitted with ABS.) So when I heard of a Milano Gold being parted out, I bought the pedal box, vacuum booster, master cylinder, and brake pressure regulator. Actually, the only moderately difficult part to come by is the pedal box. The other parts can be purchased new or from a wrecked GTV6 or Milano Gold or Silver.
Parts Needed Pedal box from a Milano Gold or Silver Vacuum brake booster Brake master cylinder Brake pressure regulator Check valve (fits into intake plenum) Metric brake line male fittings, 9 (10mm x 1.0) Metric brake line couplings, 3 (should accept above fittings) Metric brake line, 5 ft (4.5mm Bundyflex imported car brake line) Special Tools ISO (bubble) flaring tool set, JC Whitney $50, or Eastwood $60 Tubing cutter, smaller is better 13mm universal socket, 3/8 inch drive 6 inch extension, 1/4 inch drive, 2
ABS System is Teves’ (ATE) Mark II.
1) Before disconnecting any components, with the ignition OFF dissipate brake pressure by depressing the pedal at least 20 times until the pedal sticks.
2) Disconnect the battery. This is important since the dash will be taken apart and wiring modified.
3) Remove windshield washer reservoir to gain access to ABS components. Remove two screws, two hoses and three electrical connections. When the hoses are disconnected, plug the two pump outlets, or washer fluid will spill out.
4) Drain the hydraulic fluid from the brake master cylinder (MC) by disconnecting the feed hose at the electropump. Collect the brake fluid in something like a quart milk container. The fluid is corrosive so keep it off the paint!
5) Disconnect the pawl from the accelerator control lever and slip out the cable complete with sheath from under the plenum chamber. Also, remove the retainer clip from the sheath fastener where the cable passes through the firewall.
6) Disconnect the clutch MC feed hose at the reservoir. Plug the hose to keep dirt out and rotate it out of the way.
7) Disconnect both fittings connecting the electropump to the brake MC. Be careful and have a rag ready as fluid may spray out when the first fitting is opened!
8) Disconnect all electrical connectors from the MC and electropump including the ground wires screwed to the side of the MC.
9) Remove the bolt that holds the front wheel sensor mounting bracket to the MC.
10) Disconnect the wheel sensor connectors (2), by squeezing the tabs on either side of the connector and pulling apart. Gather up the cabling and move it out of the way.
11) Remove the three brake line fittings from below the MC. Also remove the clutch MC fitting. Cover each open pipe with plastic wrap and a twist tie to prevent dirt from entering lines.
12) From within the car, disconnect the brake and clutch pedals from their MCs by removing cotter pins, washers, and clevis pins. To gain access to this area:
13) From under the hood remove the four 13mm nuts holding the brake MC to the pedal box. Remove the brake MC assembly from the pedal box. Now is a good time to clean up any spilled brake fluid.
14) From within the car remove five 13mm nuts holding pedal box to the firewall. Three at the bottom are relatively easy to remove, using a 13mm universal socket and a 12 inch long 1/4 inch drive extension. Gain access to the bottom center nut by releasing the steering wheel extension lever and pulling the wheel towards you. This opens up a small space and allows you to get the socket extension between the steering column mounting bracket.
The two upper 13mm nuts can be removed with some difficult by inserting the socket extension on either side of the steering column. The nuts can be seen, though not clearly, and removed. Also, the left upper nut can be viewed through the hole left after the small storage box left of the steering wheel is removed.
15) Remove the pedal box from the engine compartment. Easy to say, difficult to do. Get a friend (or spouse) to help, if possible. To extract the box, you have to pull straight up to avoid catching the pedals on the bottom of the dash, but you can’t pull straight up because of the bodywork.
It helps some to loosen the dash and pull it out some. The dash is held in place by five screws. To loosen the dash:
After about an hour of futzing with the box, I got it free.
Only the clutch MC is installed on the new pedal box when the box is put on the car. This is so the box can be easily manipulated.
16) Run a die over the studs of the new pedal box and vacuum booster to make sure the nuts go on easily. Once everything is in place, access to the nuts will be poor (big surprise), so it's important that they go on easily.
17) Transfer the clutch MC from the old pedal box to the new one. Now is a good time to replace the clutch MC, if needed. Also, It's a good idea to peel back the rubber boot on the clutch MC and grease the ball at the end of the actuator rod. This makes clutch operation smoother and quieter.
Another suggestion is to replace the socket-head bolt nearest the MC that holds down the valve cover with a normal hex head 7mm x 1.0 x 20mm bolt. Once the brake booster is in place it is very difficult to get a hex wrench into the bolt's socket, so replace the bolt now.
18) Pass the accelerator cable through the hole in the new pedal box. Then drop the pedals through the firewall and push the pedal box into place.
19) From within the car install and tighten the five 13mm nuts that hold the pedal box to the firewall. See 14) above for tips on gaining access to the studs.
20) Attach the retainer clip previously removed from the sheath fastener where the accelerator cable passes through the pedal box. Then pass the sheath under the plenum chamber and reconnect the pawl to the accelerator control lever.
With the pedal box in place, it's time to modify the three brake lines so they'll attach to the new MC. The procedure will be to cut the existing lines and fit a brake line coupling. Then after the MC is in place, we'll make three short connecting lines.
Trial fit the vacuum booster and MC and mark the brake lines for cutting. Mark the lines so the coupling won't interfere with anything and the connecting lines won't be too short.
21) The brake line from the rear calipers already has the proper fitting and a bubble flare, so it can be inserted and tightened into a brake line coupling directly. Unfortunately, the metric brake line couplings I bought locally did not quite accept the OEM fitting, so I had to use one I had from a parts car. Lacking a coupling that fits, just cut off the existing fitting and treat the line as described in the next step.
22) For each of the remaining "uncoupled" brake lines, cut at the mark with a tubing cutter and slip on a fitting. Next, ream out the tubing. During reaming try to prevent metal fragments from dropping into the tubing.
After the tubing is properly reamed, go into the wheel well and separate the metal brake line from the flexible hose and blast compressed air through the brake line to blow out any metal fragments that dropped into the brake line.
23) Make the bubble flare (be sure the fitting is on before flaring!) and screw on a coupling.
24) Slip the large coil spring over the rubber boot of the vacuum booster and insert the booster into the hole in the pedal box. Make sure the bracket at the end of the pushrod engages the brake pedal properly and that the spring is positioned correctly. Push the booster tightly against the pedal box. Because of the spring pushing against the brake pedal, you may need a brace or friend to hold the booster in place until it's attached.
25) From within the car:
26) Remove the blanking plug from the air plenum and install the check valve. Fit the hose between the check valve and the vacuum booster. Tighten the hose clamps.
27) Bolt on the brake master cylinder and brake pressure regulator (PR). Make sure the O-ring seal and the 3/8 inch tip on the vacuum booster pushrod are in place before mounting the MC. Also, put a small amount of grease on the tip of the booster pushrod.
28) Measure and construct the three short connecting lines that will run between the couplings and the MC/PR. See the diagram below for which lines go where.
1 Handbrake pad operating lever 13 Handbrake lever 2 Handbrake cable 14 Brake fluid low level and brake 3 Handbrake cable sheath pad wear warning light 4 Stop light bulb 15 Switch for handbrake warning light 5 Air bleed screw 16 Pressure switch 6 Friction pads 17 Vacuum booster 7 Pistons 18 Pedal 8 Discs (self-ventilating) 19 Stop light switch 9 Engine vacuum port 20 Handbrake pad push rods 10 Vacuum pipe 21 Adjuster 11 Tandem master cylinder 22 Handbrake warning light 12 Fluid reservoir with warning light switches
29) Reconnect the clutch MC hose to the brake fluid reservoir, make sure all the fittings are tightened, and fill the reservoir with brake fluid.
30) Bleed air from the clutch and brake lines in the normal way.
31) This pretty much concludes the heavy mechanical work, so the dash may be reassembled and the lower steering column cover put on.
32) The unused ABS connector plugs may be clipped or bundled and tucked out of the way. In either case, we need to connect the low fluid warning switch on the newly installed MC so it operates the AR control panel LED. To do this, find the five-pin plug connector that attached to the ABS brake MC reservoir. Peel back the protective boot and find the orange/black (OB) and black (B) wires attached to pins 3 and 4. Cut these wires at the plug connector and then remove the wrap from the wire bundle back to about where the bundle passes the power steering fluid reservoir. Free the OB and B wires to this point and then connect them to the low fluid level switch at the rear top of the newly installed brake MC reservoir.
Connecting the wires to the low fluid level switch can be difficult if you don't have the two rather odd circular connectors. I had the proper connectors from a parts car, so the installation looks pretty good. If you can't find the circular connectors, you can always wrap the wires around the pin connectors and then use heat shrink tubing to hold the wires in place.
33) If you decide to cut off the unused ABS connectors, be careful! Only cut a cable if it terminates in an unplugged ABS connector. After cutting off a connector, tape the wire bundle shut to prevent shorting and improve the appearance of the installation. Be careful not to cut the brake pad wear indicator wires. These are two thin black wires that pass thru a rubber grommet near the brake line.
34) If desired, remove the ABS electronic control unit (ABS ECU). The ABS ECU is bolted to the frame on the driver's side of the trunk over the wheel well. Remove the ABS ECU by pulling the side carpeting out of the way and removing the cardboard. Remove the two 10mm hex head nuts, disconnect the massive plug, and extract the ECU. Wrap the plug in plastic and tape to prevent it from rattling around.
35) If desired, remove the wheel sensors:
36) To prevent the "AntiLock" warning light from ever lighting again, remove the bulb behind the "AntiLock" warning message on the AR control panel (ARC). This is the second bulb from the left, top row. To gain access to the bulb, remove the ashtray and the two screws hidden by the ashtray.
To dislodge the ARC gently pry out the two legs at the bottom of the panel. There are two clips at the top of the panel that hold the panel in place. Pull out the "Antilock" bulb holder, pull the bulb, and then replace the holder. If you leave out the holder, stray light may give the impression the light is on. After spending the effort to remove the ABS, you don't want another reminder that ABS was once on the car.
The conversion from ABS to conventional brakes probably took about 12 hours to accomplish if we ignore the time wasted on problems unrelated to the swap.
The most difficult parts were:
Snags I ran into unrelated to the swap: