May 202014

The fitting of the windscreen was one of those tasks that I thought would be best left to a professional. One of the forum members had given a good feedback when their screen was installed by Howard of Merlin Motorscreens, based in Surrey.

Unfortunately I couldn’t arrange economic transportation of the rolling chassis to their workshop so it would have to be done in situ. As each car is different, I was warned that the installation may need to span over two days and that he may need to use his own supply of the rubber seals, depending on the quality of the SNG seals.

My only contribution to the whole process was to periodically returning to monitor progress and take a few photos of the various stages. On the positive side the SNG seals were useable. The whole area was protected with a generous covering of masking tape, the seals quickly trimmed to length and fitted to the windscreen flange using a bonding sealant.

In no time at all, the rubber seal had been lubricated with a soapy detergent allowing the screen to be eased into position from one side. A screwdriver was then used to get the final edge of the screen correctly seated into the seal. The next task was to tape the packing rubber strip to the top edge of the screen which sits between the screen and the top chrome finisher.

Windscreen slotted into rubber seal Taping the rubber strip Top chrome tapped into position

Re-chroming the top finisher can lead to distortion problems due to the heat created by the polishing process. Luckily my now banana shaped chrome finisher wasn’t too bad and he managed to tap it home with a rubber mallet.

At this stage you get the impression that the job is almost complete, but there was a lot more fiddly bits to do. There was much trial fitting of the A-post caps and chrome finisher to determine if and where additional packing rubber was required. The cavity under the rubber seal can be generous in places so additional rubber is pushed into these areas to avoid the screen dropping away from A-post caps later on.

Trial fitting A-post chrome Clamping the bonded chrome Completed A-post chrome

A beading strip could now be inserted into the rubber seal. Its purpose is to push the external side of the seal hard against the windscreen and mounting flange, locking the screen in position.

The chrome finisher, running along the base of the screen to conceal the beading, slides into slots moulded in the screen seal. Although contact adhesive is also needed to keep it in place in the long term.

The A-post chromes are also bonded into place although they are also fixed by screws along their rear edge and slotted under the A-post cap at the top. The interior trim also slots under the cap and therefore needs to be fitted at the same time. The bottom of the interior trims are secured by the same clips used to fix the door cards.

This leads to the logistics conundrum of what should be fitted first …. the final adjusting of the wiper linkages needs the windscreen in but the dash top off, to provide access the linkages. Putting the windscreen in, included the fitting of the A-post trims. However with the A-post trims in situ, it’s then not possible to fit the dash top!!

All that remained was to trim back the top rubber strip inside and out and remove any excess adhesive with white spirits. From start to finish it took just over 5 hours. If anyone in the South East is looking for their screen to be fitted, I would thoroughly recommend contacting Merlin Motorscreens.

Completed screen Interior A-post trim
May 092013

There’s little worth noting regarding the fitting of the windscreen washer and jets. Fortunately the chromed jets were the first thing I’d decided to install before the bulkhead pipes and wiper rack, which made it possible to fish out dropped washers and wing nuts.

The washer plumbing was left until all the heater and vacuum pipes were in place to avoid it getting in the way.

I managed to succeed in making life hard for myself by putting the washer jets in place and then attempting to fit the washer and wing nut one handed from underneath.

I’d lost count of the number of times I’d dropped either the washer, the nut or both. Finally common sense prevailed.

They could easily be moved and held in position by placing the wings of the nut between the forefingers and balancing the washer on top. The washer jet can then be screwed in from above until it had engaged with the nut, then finally tightened up from below.

My decision to insulate the internal bulkhead heater pipes also caused problems with the routing of the washer piping through into the bulkhead. The heater pipe passes very close to the hole for the washer piping and so the insulation was blocking the way.

Finally, to keep the tubing neat and tidy and away from the moving parts of the wiper rack, it was zip tied to the wiper rack frame.

Apr 242012

As with all the other electrical units, the alloy parts were was ultrasonically cleaned and then sprayed with Gtechniq S1 SmartMetal while the other steel parts were zinc-nickel plated. The next two tasks were to sort out the gearbox lid which had been distorted and also to strip and paint the yoke.

The offending motor gearbox lid after several attempts at heat shrinkingThe centre area of the gearbox lid has been stretched at some point. Therefore its outer perimeter no longer made a continuous seal and so would allow water into the gearbox housing.

The suggested solution was to heat shrink the centre section of the lid to reverse the deformation – heating the centre of the lid to near red heat and then rapidly cooling. After several attempts of heating the lid with a gas blow torch and cooling using a can of compressed CO2, all I succeeded in doing was to work harden it in exactly the same shape as before. Aaaaaaargh!

It probably needs to be heated to a much higher temperature using oxy acetylene. In the end I cheated to avoid holding up the rebuild and obtained a replacement lid. When I get time I’ll give it a proper go at flattening the lid, as I would like to keep the original with the correct stampings.

The wiper motor yoke painted in silver hammerite .... at some point I'll repaint in the correct colourNext up was the yoke which contains the two permanent magnets. The magnets can be removed by lifting the retaining clips so the yoke could then be shot blasted before being painted in silver hammerite. I was quite pleased with the finished article even though the silver hammerite was not quite the correct colour.

During the refurbishing of the cooling fan motors I had found a dark silver hammered paint from Rust-oleum, which is very similar to the orginal colour. At some stage I will re-paint the round bodied yoke but decided to put it off for now. Mainly because of the difficulty I’d had getting a good finish with the Rust-oleum product.

Fortunately the armature wasn’t in such a bad state as those in the cooling fan motors and so all that was required was some light wire brushing and polishing before the S1 SmartMetal coating. I had investigated the availability of new brushes and parking switch units but these seemed to be rather difficult to get hold of. Therefore when I spotted a ‘new, old stock’ brush unit for sale I thought I’d get it as a spare for the future. However I’ve not yet found anyone who can supply the parking switch units.

Cleaned armature Triple Brushes Wiper Motor Parts

The armature was wired brushed to remove the worse of the rust. It was then polished and finally sprayed with Gtechniq S1

The armature brushes and parking switch unit

The wiper motor compentent ready for the rebuild, including the spare armature brushes unit

The rebuild starts with installing the armature brushes and parking switch unit, as these are wired together. The brushes are secured by three small setscrews and the connecting wiring passes through a notch in the motor gearbox housing.

The parking switch is secured by two setscrews from the inside of the gearbox compartment, as shown in the middle photo below. This also shows the protruding parking switch plunger which is activated by a cam on the underside of the gear wheel. The cam positioning is such that it operates the switch when the wiper blades return to their normal rest position.

First fit the brushes Parking switch attachment ACF50 applied to Yoke

The brushes and the parking switch unit are the first to be fitted

The parking switch is attached by two setscrews from inside the gearbox housing. Note the switch plunge which operates when the wipers return to their normal rest position

The interior of the yoke was sprayed with ACF50 which provides a good protection from moisture

After several attempts at fitting the armature and yoke, I found it easier to first fit the armature into the brushes and motor gearbox and then fit the yoke. With this approach its was necessary to hold the armature’s worm drive from within the gearbox so that, when fitting the yoke, the yoke’s magnets didn’t pull the armature out of the brushes. Also don’t do what I did and forget to fit the plain washer between the armature and motor gearbox housing!

Care was also needed in making sure that the thrust and fibre washers were correctly seated in the yoke bearing housing. The easiest way to do this was to join the two with yoke positioned so the ‘bearing’ housing was facing downwards.

Initially I tried to put the armature into the yoke and then attach them both to the motor gearbox. However the problem was it was then difficult to withdraw the three sprung brushes at the same time as inserting the armature, because the yoke restricted access to the brushes.

The middle photo below shows the arrow head marking on the motor gearbox and a corresponding line on the yoke. These need to be aligned when refitting. Also shown is the threaded armature stop. This was then screwed into the gearbox housing until it touched the nylon cap on the armature shaft, before being backed off a 1/4 of a turn.

Next fit the armature Alignment markings Belleville washer goes here

The brushes were then withdrawn to allow the armature to be inserted

The markings on the motor gearbox housing and the yoke must be aligned when re-fitting

The Belleville washer provides pre-load for the armature shaft

The Belleville washers is then positioned within the gearbox before inserting the geared output shaft. The rest of the gearbox was then filled with grease before the output rotatry link and gearbox lid were refitted. The rubber moulding sealing the output shaft area had hardened and split.

At the time I dismantled the motor, it was one of the few parts that wasn’t being remanufactured. Probably because it was only used on the Series 2. However by the time I has started the rebuild, one of the suppliers had made a small batch so I decided to grab one while still available.

Re-packed with grease Output rotary link Motor rebuild completed!

The geared output shaft (just about visible) was inserted and then the remaining space packed with grease

The output rotry link was refitted which also secures the geared output shaft. Although I'd forgotten to insert the rubber seal first .... so I'll have to refit it

The completed wiper motor

The only thing that remains is to adjust the various wiper motor & rack linkages which can only be done once they’re installed in the car. People usually leave the installation of the windscreen until the latter stages of a rebuild. I guess this is because it would restrict access to dash area. However I’m tempted to install the windscreen as soon as the dash wiring looms and dash panels are in place. Therefore I’ll be able to adjust the linkages before the bulkhead access become restricted.