Gtechniq – Chris Vine – Restoration of NNF 10H

Wiper Rack

Oct 112012

Wiper arm spline drive The general consensus from people who have gone through a full rebuild is that one of the first tasks is to fit the various pipes and components within the bulkhead, before access becomes too restricted. So I set to work on the wiper rack. It was working fine but had started to show signs of rust so I decided to smarten it up. Yet again, in my enthusiasm to press on, I forgot to take some decent before photos. The only difficult part during the dismantling was the removal of the rear brackets from the three splined drive assemblies, which needed to be pressed off. The rest of the parts were simply secured by nuts or circlips.

Splined wiper blade drives - the central drive (uppermost) has a spacer between the drive and the rear bracket The wiper arm splines on each of the three splined drives weren’t in the best of shape but were still serviceable. Which is just as well as the only replacement I could find was for a fully remanufacturer rack. Due to the shape of the rack, the central drive has a longer shaft than the outer two and so has a spacer fitted between the drive and the rear bracket.

With the exception of the angled bezels and chromed parts, the individual parts followed the now standard cleaning process: immersion in a citric based rust remover overnight, wire brushing, zinc plating/passivation and finally coated with Gtechniq S1. Meanwhile the outer bezels and retaining nuts had been sent off to be chrome plated.

The synchronisation of the rotation of the three splined drives is achieved by two connecting rods, with the central drive also having a connecting rod to the wiper motor to provide the drive. At each rod end is a ball-joint fitting which is secured by a small, horseshoe shaped, snap-lock clip shown below. Unfortunately one of the tiny snap-lock ‘ears’ made a break for freedom and, despite a hands and knees search of the living room carpet, was never to be seen again! The only option available was to purchase a complete socket unit which included the clip and the inevitable robbing by the E-Type parts suppliers!!

Original & new snap-locks	Wiper rack components	Reassembled splined drives

The connecting rods are connected to the central wiper drive by a series of spring washers, nylon guides and secured with a circlip. All very straight forward. All that remains is to fit the rack and connect the central drive to the wiper motor. I think it will be necessary to fit the washer jets and tubing before the rack as there’s not a lot of room in the bulkhead.

Refitting parts order	Connecting Rods refitted	Completed wiper rack

Rebuilding the cooling fans

Cooling Fans No Responses »

Jul 262012

Cooling on the original Series 1 cars was provided by a thin single two bladed cooling fan. This was uprated for the Series 2 with the introduction of twin four bladed fans. One of the popular upgrades is to improve the cooling by installing kits from Kenlowe or Coolcat, which are probably more suited to the stop-starting of today’s congested roads. I’m not sure if this upgrade is more targeted for the S1, so my aim is to restore all three fans, pick the better two for the rebuild and keep the third as a spare. I will then re-evaluate once I’ve driven the car for a period of time.

Motor body prior to shot-blasting The alloy end plates were sent off to be ultrasonically cleaned while I renovated the motor body and internals. The renovation of the motor bodies ended up being a bit of a palaver and took several goes before I was happy with the end result. They were quite heavily rusted and after shot-blasting revealed quite heavy pitting. Rather optimistically, I thought this would be hidden when they were painted with silver Hammerite. What I soon learnt was that paint is not a good filler as the pitting was still clearly visible through the paint. Also I wasn’t happy with the colour of the silver Hammerite compared with the original finish which was a dark silver grey. All the bodies were quite badly pitted

Unfortunately Hammerite have stopped making the dark silver paint and it took quite a while before I managed to find a suitable equivalent, Rust-oleum paint code 7388.0.4. In the meantime the motor bodies had been shot-blasted again and the pitting filled with Isopon Metalik filler. The first attempt with the Rust-oleum was a disaster. The paint seemed to effervesce on contact, presumably to obtain the hammered effect, but the bubbles created remained in the final finish.

Colour difference between the Hammerite and Rust-oleum ... the wiper motor will now be re-painted to match! I finally managed to get a reasonable result by heating the spray can in hot water and the motor body in a low oven. This reduced the viscosity of the paint sufficiently to allow the bubbles to burst and then the paint to level sufficiently before it started to ‘skin’.

The photo to the left shows the motor body painted with Rust-oleum compared with the wiper motor painted in silver hammerite. I’ll now re-paint the wiper motor body in the darker grey.

The armatures were next to be tackled. The rusted iron parts forming the electromagnet were carefully wire brushed before being polished. Then Gtechniq S1 Smartmetal was applied to give a hydrophobic coating which hopefully might delay the onset of rusting in future. Finally the copper contacts were polished with good old Brasso, the gaps between the contacts cleaned out and new brush sets obtained, Lucas part BR1 743171.

Before …	and after	New brush sets

The stator and the various bolts, washers and screws where then zinc-nickel plated using a kit purchased from Gateros Plating. The electroplating is surprisingly simple and good results can easily be achieved. The components were finally ready for the rebuild.

The rebuild process is, to use the overused terminology from Haynes manual, the ‘reverse sequence’ of the dismantling … but in this case it is as simple as that!

Plated stator	Armature refitted	Completed fan motor

The fan mounting brackets and the radiator cowl were originally a black, crinkle finish. Suitable crinkle paint spray cans are readily available but, while researching it, I found out that it’s possible to get a powder coating with a crinkle finish. After the disaster with the Rust-oleum hammered paint, I decided to go down the powder coated route.

However, it appears that the crinkle finish look must have fallen out of favour as I’d contacted almost all the local powder coating firms and none of them stocked it. I was about to give up when I found a small firm who had a small supply tucked away. A few days later and the parts were returned. I do hope that, after all this effort, the fans are up to the job!!

When the cars left the factory there were two plastic shields which covered the opening in the rear end plate for the electrical connections but these were missing. Fortunately SNG Barratt now remanufacturer these but I’m not convinced how effective they will be at keeping water out. I guess they’re better than nothing.

Cooling Fan with plastic shroud	Cooling fans – ready to fit	Before shot of the cooling fans

Rebuilding the Lucas 15W wiper motor

Wiper Rack, Wipers No Responses »

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 shrinking The 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 colour Next 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 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

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 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 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.