Note: Additions have been made to this page in October 2006.
All pictures are expandable. Click to enlarge.
Some of the pictures show some tatty areas of the Car that still need working on, please ignore.
The design of the Wipers on a Scimitar was the same as most cars of the day. A motor sliding a cable with a course thread type exterior in a tube ( Bundy Type tube) and this cable connected to the Wiper Boxes ( The part that the Wiper arms connect to). As the cable was pushed and pulled in the outer tube it gave the movement for the Wipers. It did not take long for wear to show the problems of the design. It is possible to get the Wipers working good although they will never work as well as a modern setup. One of the things you will need to make sure is that you remove as much play as possible in all areas.
The problems are partly due to wear of the mechanism, partly due to the grease becoming stiff, partly due to the wiper boxes being seized and partly electrical. If the wipers are erratic and can be made to work by "wiggling" the wiper switch in the car it could well be the switch itself. These switches are easy to repair, see here. Also make sure that there is 12 volts getting to the wiper motor as no repair will correct problems due to lack of volts. As with all things electric make sure that the battery is disconnected before starting any work on the electrics.
Start by removing the wipers and arms from there spindles. They do come off but can be stiff. By using a screwdriver with the thick blade lever away from the spindles. Take care as it is very easy to damage the paintwork so place a rag or thin piece of wood around the area you are working. Once the wipers are off mark the spindle at the top. The reason for this is when you put back together you will want this mark to be 180 degrees opposite to where you started, this will ensure that worn teeth of the wiper boxes are no longer in contact with the inner cable and the unused teeth are. Now remove the electrical connection multiplug.
Undo the two nuts that hold the bracket around the motor.
Then remove the four screws that hold the cover on. There could be earthing straps to some of these screws.Note that the pictures show different Wiper Motors. This difference can be seen by the adjuster on the top of the case.
The piston arm will now need to be taken off. Remove the circlip that holds it onto the circular cam wheel.
You will have by now noticed how "Gungy" the grease is so make sure you have some old rags to wipe all the old grease off.
The tube that comes out of the motor and goes into the bulkhead can now be removed from the motor, the motor should now be able to be taken off the mounting screws. Place motor to one side as the first area to attack is the Rack/Cable and tube. Ensuring that you have marked the arm spindles pull the inner cable out, it could be hard to pull due to the wiper boxes being very stiff. If it proves to be very stiff try twisting the inner cable so you "Unscrew" the cable passed the wiper box cogs.
The picture below is of an old wiper rack. Note the plate over one of the wiper boxes. There should be one over both the wiper boxes, they are there to protect the boxes from water dripping in. It is possible that they are not fitted as it can be "Fun" putting them back when refitting the rack.
To get at the Wiper Boxes looks difficult as the position that they are in makes getting at them difficult. There is an easier way. Once the nuts are removed from the spindles disconnect the Cable from the wiper motor. You will now be able to pull the Cable through enough for the right wiper box to be accessible. See picture below.
You will see that you will have to remove the cover that is on the Engine Side of the bulkhead. To get at this cover may need (will need) to have the Air Cleaner removed. Once the right Wiper Box is removed slide off the small Outer Cable Tube and then then slide the Cable to the right, this will allow better access to the left Wiper Wheel Box. The access is not as easy as when doing the Right Wiper Box but it is not very difficult. Once both Wiper Boxes are removed the whole cable can be removed by pulling towards the Wiper Motor.
Below can be seen the inside of a wiper box. Note the inner rack and how it engages with the box wheel teeth. This is the reason why you marked the spindle to ensure when it all went back together it used the unused teeth that were at the top.
Once the inner cable is out you can now check how stiff the wiper box splinned shafts are. They should twist very easy. If not they will need to be well lubricated. One way is to drill a small hole in the outer part that the spindle goes through (Not the plastic sleeve) until you get to the spindle, this will allow you to get some oil well into the spindle. Ensure that the inner spindle rotates easy as any drag or resistance will load the motor. Clean off all grease from the inner rack and refit back into the tube by twisting/screwing into the tube. The reason for doing this is you want the inner cable to go through the old grease etc then you can pull the inner cable out and the old grease etc will come out with it. When you are happy that you have removed as much of the old grease as possible clean the inner cable and apply a small amount of grease to it. I do not like putting to much grease on the cable as all you need is some to make it slide in the outer tube, to much and the motor has to push/pull the excess grease forward and back with the cable, once again you are helping the motor as much as possible.
Now it's time to attack the motor. Start by removing the motor body by undoing the two screws at the bottom of the motor body. The outer case will now come off and due to the magnets inside they will pull the armature out as well. It would be a good idea if you could hold the armature by the worm drive as you pull off the outer case.
Give the armature a good clean and using a sharp blade clean between the armature contacts as shown above. Only gentle pressure with the blade is required.
Now remove the center cam wheel and park switch. The switch pushes off in the direction shown below, there is a small locating tab on the switch. Take care sliding the switch off as there is a small plunger that could be damaged.
When the circlip is removed the cam wheel can be removed. It may have difficulty sliding out, if so it is because a "burr" has been made on the spindle where the circlip was. Gentle use of a file will remove this burr. Once burr removed the cam wheel will come out easily. Note, In one of the pictures it can be seen that one of the bearings has come out with the cam wheel. Not a problem, easy to push back in.
I have advised to remove the switch first to prevent it getting damaged but if the cam wheel is removed first you will see the clip that holds the switch on, see above.
Camwheel looks like this. Note the "Bump" that is used for the park switch.
Once switch off it can be taken apart, see below,
Hopefully the picture explains all, the contacts can be removed easily. I recommend doing this as you will be able to clean all contacts thoroughly. Take carefull note of how they come off. They can be taken off one at a time and refitted before removing the next contact so helping to prevent errors.
Next give the brush assembly a good clean, check the brushes by refitting the armature and seeing if they are making a good contact. If not they can be replaced. I believe Lucas can supply the brush assembly although my local Lucas depot ( Plymouth ) were unable to supply. They should be available ( Click Here ) or at at one of the Scimitar Dealers but another solution could be is to take the brush assembly into a shop that does Washing Machine Parts. They could have something close that can be filed to size. Brushes are soft and easy shaped.
As always reassembly is the reverse of the above. Apply some grease, no need to go mad with it, all you need to do is to make sure moving parts are slippery. The motor only wants to push the cable, not pushing lots of grease. Fit the armature through the brush assembly (Gently pushing the brushes back) and into the main cam cog, hold in place while you fit the motor body as the magnets in the body will pull at the armature. When all assembled check freeplay of Motor Armature. This is done by loosening the lock nut on the adjustment that is at the top of the unit when mounted in bracket. When nut loosened turn screw downwards until resistance just felt, then tighten lock nut. If you have a later type of Wiper Motor there will only be a screw. Now slide the Cable Tube ( the bent bit ) through the Bulkhead and attach to the Left Wheel Box. If you loosely assemble the Wheel Box (Fit the nuts) you should be able to get the Outer Tube into the Wheel Box. Before tightening the nuts make sure that the Outer Tube to the Right Wheel Box is in place. Now you can fit the Right Wheel Box. When fitting the Wheel Boxes you will be able to push/pull the Outer Tube where it goes through the Bulkhead to help get at the Wheel boxes easier. Refitting the Wheel Boxes is not difficult, just fiddley. Now all you need to do is to get the Spindles through the Scuttle Panel (This is the panel below the Windscreen). One of the main areas of slop and play is where these Spindles go through the Scuttle Panel. To ensure that the spindles are held in place better make up a long plate, about 2 inches wide and 21 inches long. Now make two holes 17 inches ( 17 inches form the center of each hole ) apart. These holes need to be big enough to allow the Spindles to pass through. If possible use stainless steel as this is an area that is open to the elements and something like mild steel will be vulnerable to rust etc. Now this plate will fit over each Wiper Box before putting the Spindles through the Scuttle Panel. The plate goes flat against the Wiper Boxes and under the Angled Spacers. This plate will hold each Wiper Box firmly in place without movement. To get the Wipers working as good as possible you want to remove as much slop and play as possible. The plate can be seen in the picture below. I have shown it above the Scuttle Panel, it of course is fitted below the Scuttle Panel.
Once all refitted check the operation of the wipers before fitting the Wiper Blades and Arms ensuring that the park switch is working OK, that is they stop when the Wiper Arms would be over to the left. When you are happy that all is OK fit the Wiper Arms and Blades. Do not push the Arms too tight onto the Spindles as you may need to remove them to get them in the correct position, that is when they have been switched off they park in the correct position. Remember that when checking the Wiper Arms will not go completely to the Park Position if the Windscreen is dry. This is because the Wiper Blades will "drag". Best when adjusting is to make sure that the windscreen is always wet, this will also ensure that you do not scratch the Windscreen.
If you have done all of the above you will now find that the Wipers work very well. Being the " Sad Old Fart " that I am at each stage I checked the operation of the Wipers and found that there was small improvements and all together they made a big difference, although the biggest difference was the fitting of the Plate between the Wiper Boxes. You will never get all of the play in the mechanism due to the bend in the Outer Tube that passes through the Bulkhead and bends to the Wiper Boxes. Due to this bend the Inner Cable will have a play of about one eighth to one quarter of an inch if you wiggle one of the Wiper Arms but this play does not make a lot of difference during Wiper operation.
Good luck. I hope this has been of use.