Removing and Servicing the Lucas 5SJ Wash Wipe Pump

Figure 1

Lucas5SG Wash Wipe Pump

Removing Lucas 5SJ Screen Wash-wipe Pump

The screenwash reservoir, motor and pump are an integrated unit situated in the engine compartment on the lower nearside of the bulkhead. Removal is straightforward. Disconnect the battery and remove the two wires connected to the motor, then pull the clear plastic tubing from the pump outlet. Withdraw the reservior bottle upwards from the mounting bracket. If the car is old and was purchased second hand, the original wiring may have been changed and may not have been replaced by the correct colour coded wire. If this is the case, use a meter to check and label the wire which is connected to the ignition auxiliary fuse. When reinstalling the wash-wipe pump it is essential to connect the wires the correct way round. Polarity is important when using permanent magnet motors as they run in the opposite direction when the leads are reversed. The original wiring loom connects a dark green wire between the positive terminal of the motor and the auxiliary fuse, whilst a black wire with light green tracer connects the negative wire to terminal 2 on the switch. Terminal 1 is earthed by a black wire.

Three small bolts secure the mounting bracket to the bulkhead. These bolts will most probably be rusty, making removal a little difficult. It's worth replacing the bolts with stainless steel ones. The rubber strap is pop-riveted to the mounting bracket and will most probably be perished, but replacement ones can usually be found on the internet. If the 5SJ screen-wash unit is malfunctioning, modern units provide a cheap and reliable alternative.The washer nozzle is mounted on the scuttle and is secured by two countersunk screws. The plastic transparent tubing connecting the pump to the washer nozzle has an internal diameter of 3mm with 1.2mm thick walls and is available in most car accessory outlets.

Figure 2

Lucas5SG Wash Wipe Pump

Servicing 5SJ Screen Wash-wipe Motor and Pump

If you wish to restore a car to concours condition, the ancillary equipment should be the same as when the car left the factory. A Lucas 5SJ unit was the original equipment fitted during the 1970's and should be able to be renovated. Alternatively, second hand 5SJ's can often be found on e-bay as they were fitted to many other cars of the period. Replacements are also available from classic car companies like Holden. Renovating a 5SJ is straightforward. They are really simple, although you wouldn't think so when you see the price of the replicas or fully restored ones.

The motor is a permanent magnet type with a three pole armature as illustrated in Figure 2. To gain access to the inside of the motor, remove the securing allen bolt and lift the motor housing clear of the pump assembly. Be careful not to lose the coupling sleeve that locks the motor and pump couplings together. Slide the motor coupling off the shaft. The paxolin base of the motor housing can now be removed to expose the inside of the motor. The brushes should be examined. Hopefully they will not be worn down, as they are most probably no longer obtainable. Considering the relative short run time of the screen-wash motor, wear on the brushes should be low. They can be released by removing the two bolts securing the terminal nuts. The armature can then be lifted free, but be careful not to lose the nylon bush on the motor shaft. It acts as a spacer between the bronze bearing in the paxolin base of the motor housing and prevents the upper part of the motor shaft from slipping out of its upper bearing. Clean the commutator with methylated spirit, but avoid getting it on the armature windings, as it may attack the insulating lacquer. The copper segments should be smooth and stand proud of the insulators between them. If the insulators stand proud, they will need cutting down below the level of the copper segments.Carbon build up between segments can short them out, so clean the insulation gaps with a fine blade, but be careful not to burr the edges of the copper segments. Correcting a scored commutator is usually carried out using a lath to prevent distortion. I mounted the armature in a Dremel drill and used a strip of 1500 wet and dry paper to polish the commutator. Although this may be considered bad practice, I have not had a problem with this method. However, the commutator and segments must be thoroughly cleaned after this treatment.

The paxolin base is not shown in the illustrations. It contains a bronze bush which acts as the lower motor shaft bearing. It should not require lubrication. The use of oil in electric motors can prove troublesome as it can cause the carbon dust from the brushes to gum up the commutator. Two holes in the paxolin base, line up with the location pegs on the pump housing. The motor housing is secured to the pump body by a 3 x 45mm allen bolt. Unfortunately, the thread in the top of the plastic pump housing often get stripped where the allen bolt screws into the pump body.

Figure 3

Lucas5SG Wash Wipe Pump housing modification

A classic car is a part of motoring history and for some owners, the accessories on it should remain as close to original as possible. Of course the accessory should still function, so renovation of components should involve as little modification as possible. A simple fix to the stripped plastic thread problem, is to make and insert a metal one. All that is required is a drill and a 5 x 12mm pop rivet. The 5 stages are illustrated in Figure 3.

1 Support the rivet in a vice with the pin facing up. Protect the aluminium rivet and do not over tighten the vice. 2 Tap the pin out. 3 Enlarge the hole in the rivet with a 3mm drill. Enlarge the hole again with a 3.5mm, then 4mm drill. 4 Lubricate the original allen bolt. Insert the bolt into the rivet and carefully turn it back and forth with a little, but firm pressure, to cut a thread. The first few threads may strip, but as you continue a good thread should develop. 5 Having cut a thread through the entire length of the rivet, remove the allen bolt and cut the rivet in half. Discard the top of the rivet with the flange.

You may have to practice on a few rivets before you are satisfied with the result, but it will be worth the effort. The old worn threaded hole on top of the pump housing will have to be enlarged to 5mm diameter to take the new insert. Take care to keep the hole central. Thoroughly clean and remove all traces of lubricant from the outside of the insert. Screw the insert onto the end of the allen bolt and press it into the pump housing. You should find that although the diameter of the pop rivet was originally only 4.9mm, it will have stretched and form an interference fit with the 5mm housing hole. If the insert tends to rotate in the hole, fix it with superglue or epoxy adhesive.