Anyone who has removed or replaced a rear bumper bar on a MK1, MK 2 , Daimler 250, Jaguar 240 and 340 series cars would be well aware of the problems of the 5/16 inch caged nut system used to secure the bumper bar to the mounting brackets. It is nearly a sheer impossibility to carry out this operation without the special caged nut which is a spring loaded boxed nut which sits in a slot in the bumper bar and to which the mounting brackets are bolted.
A club member in the country was in dire straits needing caged nuts to mount three rear bumper bars. He had tried every outlet to get these caged nuts but had been totally unsuccessful. It requires 8 of these nuts to mount a rear bumper
Back in 2001 I did some serious research into local sources and came up with a metric equivalent. It is an 8 mm caged nut and uses an 8X20 mm bolt to hold the bracket to the bumper. These nuts are readily available from Coventry Fasteners at 172 Lavarack Avenue, Eagle Farm [ph 3868 3655] for the grand price of 37 cents each and the 20 mm long by 8mm diameter bolts cost about 20 cents each. The Coventry part number is for the caged nuts is 26 8MCAGEN and the bolts are 26 8X20MZPBN
I contacted Coventry Fasteners and was advised that their computer showed negative stock. I have run across this problem before with this company and asked that they check the actual stock bins, Surprise! Surprise! They had over 100 in stock! A quick 10 minute trip from my workplace at Brisbane airport secured 30 for our country member and I grabbed an extra 10 for myself as every time you touch a rear bumper you can expect to write off some of the caged nuts due to corrosion.
Club members unable to get to a Coventry Fasteners branch can phone  3868 3655 ask for sales, pay by credit card and arrange delivery by whatever method desired such as by post or courier etc.
For many years I drove on drum brakes particularly in MK7s and I did not have any major problems in pulling up. I am of the opinion that a well maintained set of drum brakes is nearly as good as disc brakes however they do have a problem with fade when hot and are darn near useless after being immersed in water while crossing a flooded causeway.
I was happily driving the metallic grey MK 1 which is equipped with drum brakes and knocking up a few Ks when I noticed an appreciable decay in braking effect and the pedal was getting closer to the floor. I almost ignored it as I am getting close to completion of the MK2 disc brake front end which is going to be fitted in the near future. However it is not in my nature to leave a vehicle in a "suspect" state and I also heard a couple of clacks from the front end while pulling up in the shed.
Getting my dearly beloved Honor to actuate the brake pedal while I roamed around outside revealed that there was obviously a fair bit of movement going on in the brake system in the front end. Jacking up the car, removing the front wheels and brake drums revealed brake shoes that were in very good order and brake drums that were smooth and shiny without any scoring. The previous owner had advised me that he had the brakes "done up" only a short time before I acquired the vehicle. When I was preparing it for a "roadworthy" (safety certificate) I had checked the brakes and the shoes and drums were in apparently first class order and they were also checked and passed by the person carrying out the safety certificate inspection.
On close inspection I noted that the automatic adjuster bar was at the limit of its travel. Hold on – what is going on here thought I!. I checked the lining thickness which was the correct ¼ inch and also noted that the trailing shoe on the right hand front brake did not show any sign of contact with the drum. In fact with the brake drums removed you could put your foot on the pedal and get brake pressure even though there was theoretically nothing to push against or to stop the slave cylinder pistons flying out of the slave cylinder.. It turned out that the brake slave cylinders were at the extremity of movement and locked up against the travel limit of the automatic adjuster bar.
The correct internal diameter of a MK 1 Brake drum is 11 1/8 inches. I checked the internal diameter of the drums on this car and found out that one was 11 5/16 inches and the other was very close to 11 3/8 inches. I.e. one was oversize by 3/16 inch and the other was nearly ¼ inch.
The person responsible for turning out these drums to such an amount and refitting them is guilty of criminal negligence. While I have been unable to find out any recommended limits by Jaguar, general automotive industry consensus is that on a drum of this size around 1/8 inch or about 125 thousandths of an inch (.125 inch) oversize would be the limit and after that the drum should be discarded. The problem is that a very hot thin drum under severe braking has the potential to separate the drum brake contact area from the brake drum face assembly leading to a total loss of brakes. What made matters worse is that they had not bothered to consider putting in thicker linings which are readily available by specific order.
I have all sort of good Jaguar things hidden away in the shed at the end of the stables which I have christened "Possum Palace" as a family of possums lives there as well. They have claimed their own paw paw tree which is regularly raided and I can't use the top shelf of the Dexion shelving as they use it for their daytime sleeping site. Anything stowed on the top shelf is promptly kicked off to the detriment of the car parked in the shed! Anyway back on to the brake problem. I found that I had four MK 1 drums which varied from .040 to ,080 inches. oversize and I selected the best two which got a quick hit from the angle grinder cup brush to clean up the light surface rust in the drum contact surface areas followed by a clean up with some 280 grit wet and dry paper.
Resetting the brake shoes and wheel cylinder pistons to the inboard limits of the automatic adjusters and fitting these "new" drums resulted in only a small movement outward in the automatic adjuster bar and the brake pedal returned to a maximum height. The differences in a road test were quite dramatic as I was able to lock up the front wheels on bitumen in a panic stop from 60ks/hr.
My advice to anyone overhauling early model drum brakes [which ceased in Jaguar production in 1959] is to speak to a brake specialist and ensure the drums are properly measured and reasonably legal and that appropriate thickness lining are used to re-line the brake shoes to account for any oversize drums. By the way the correct composition linings for a MK 1 drum brake system are quite soft and the experts at Action Brakes in Nudgee Road, Hendra suggest a maximum life of only 20,000 miles in normal use.
A club member got in touch with me and raised the subject of fitting an electric fan onto a MK2. Some people think they are rather exotic devices however the majority of modern cars use them and particularly anything fitted with an east – west engine except the original Mini is almost guaranteed to be equipped with one. In addition have a look under the bonnet of your modern Commodore, Falcon and Magna and you will find an electric fan doing all of the cooling work.
It appears that one stumbling block for many people is the problem of fitting a sensor to turn the fan on when the engine is starting to overheat. There are several ways of handling this. One is to fit a sensor which plugs directly into the upper radiator hose. I consider this as rather crude and am more inclined to get a new thermostat outlet pipe and have a modern sensor fitted by machining an appropriate hole in the metal.
You might also investigate fitting a genuine Jaguar thermostatic fan switch as fitted to the E types and Series 1, 2&3 XJ among others. These were originally fitted in the cross flow radiator tank. Another access point is the original thermostat switch hole for the starting carbie which is generally redundant as most MK1/2 owners have modified their cars to use a dash mounted switch for the starting carbie function. You would have to do a bit of fettling to make a plate to carry a thermostatic switch
Another method is to fit a manual switch somewhere around the instrument panel. Anyone used to old Jaguars in hot weather will be monitoring the water temperature and it would be a simple thing to turn the fan on when it is starting to get hot. This is done in many competition saloon and sports cars which have had the mechanical fan blades removed. I am told that the only time the fan gets turned on is after the race and when returning slowly to the pits. Note that this switch needs to control a heavy current relay which will do the actual switching. Many modern electric radiator fans could be pulling upwards of about 50 amps while running and you would need an almighty big switch to handle that sort of load.
An electric radiator fan will consume about twice the output of the old Lucas generator. It may be worthwhile to consider fitting a modern alternator to carry the load particularly if you intend to drive the car frequently in traffic. The old Lucas generator has the further disadvantage of being “off line” while idling in traffic while the modern alternator will be on line and supplying power even when idling. I have alternators on two of my historic registered cars [a Mk1 and Mk2] and they are a boon in getting the battery charged quickly and giving better lights in traffic at night
Some of you may have noticed my wanted ad in last month’s issue of the JDCQ magazine. I was chasing a 12 blade MK 2 radiator fan and a club member has responded with a couple of fans available. The story behind that ad is that the early MK1 2.4 cars only had a simple 4 blade fan which is adequate for normal use on the open road and general use but it is absolutely hopeless when caught in heavy city type traffic.
I attended Geoff and Gerry Underhill’s Australia day BBQ at Tingalpa on Sunday 23 January and it was a typical Queensland summer day with the temperature around the 30 degree C mark. I was travelling from Pine Rivers on the Gateway Arterial and sitting on the 100k speed limit with the water temperature gauge steady on 75 degrees. However I got caught in a surprising amount of traffic and a number of red lights around the Capalaba area and by the time I reached the Underhill estate the temperature was around the 100 mark.
Expecting the worst I let the car cool down and borrowed a bucket for water off Geoff [queries he - not another breakdown?] however it had not lost any coolant. The return trip home was uneventful with the temperature gauge sitting as before on 75 degrees.
I have had this problem before in my first MK1 2.4 in 1986 and the fix of putting a late model radiator fan on the car solved most of the traffic overheating woes. I expect it will make a major difference in this case.
While doing all the right things on the MK2 front end I stripped it out completely and had the major components sandblasted. I was contemplating what sort of paint finish I would apply when an acquaintance of mine suggested a paint I had not heard of before. It is Ronstin’s Rapid Dry Industrial Black Enamel. He said he had been using it for years for chassis and sub frame painting and it stood up very well to the abuse and knocks that come with the under vehicle territory.
I purchased some at our local automotive paint outlet in Brendale and was pleasantly surprised at the price that was a tad over $13 per litre. It did require some thinning to spray but covered very well with a really deep black gloss. The quick drying part lived up to its name, as I was able to handle parts within half an hour of painting. As an experiment I really loaded up some areas with paint, which would have produced runs in a standard enamel, but it did not display any propensity to run.
The grey MK1 2.4 speedo was bouncing a little up to 30 miles per hour but beyond that it really got bad with swings of large variations which meant that at 40 MPH it would flick up to 60 MPH and back again. It looked like a crook speedo cable but as it had a brand new cable I suspected the instrument.
I removed the speedo and on the work bench connected up a drill set to run in reverse with a bit of old speedo cable in the chuck of the drill. I found that the problem was in the instrument as with the drill full on I got 45 MPH with bouncing up to 70 MPH.. I attempted to remove the speedo case and to repair it but was unsuccessful as the trip odometer connection was jammed.
Luckily I have accumulated a number of spare MK1 speedos and I had one which matched the diff ratio for a 2.4. I checked it on the bench and it worked OK but I noticed some serious lag in the indications as it took 5 seconds to catch up to correct speed and a similar time to come back to zero after the drill was stopped. I removed the case and delicately applied with the smallest artists brush a dab of WD 40 on both jewels [pivots] of the speedo needle. That fixed the problem and the replacement speedo was installed and is working as Jaguar advertised.
Sometimes it is the simplest things that get you going (or stopped). One of my MK1s was doing odd things in that the generator and regulator seemed to be all over the place and sometimes not charging. One quiet afternoon I grabbed the digital multimeter and tools and attacked it.
The generator proved quite capable of putting out more than adequate volts and amps. This is a very simple test. Simply attach a piece of wire between the D [dynamo] and F [field] terminals on the generator and start the car. Don't over rev the engine, as 1500 to 2000 RPM should be adequate. Measure the voltage being generated at the generator D terminal. This will be typically in excess of 14 volts and possibly up to 16 or more volts. This is because you have bypassed the regulator. If the ammeter in the car shows a large output that also proves that the cutout is working. It pulls in when the generator volts are typically above 12 to 13.
All this was OK and I now suspected the regulator. I cleaned the regulator points but there was no change and I decided to replace it with a spare that I had. While undoing the terminals on the regulator I found that the screw for the wire running to the generator field was quite loose. Tightening this up was the answer and the generator now performed as Lucas and Jaguar advertised. Moral – look for the simple things first
Whilst I had the MK 1 radiator out I was having a serious look around for rust and any other problems prior to painting the general area surrounding the radiator. I had a close look at the steel brake line that feeds the left front wheel brakes from the hydraulic distribution block just after the power booster. Overall it looked pretty good however there was one spot where there was some rust for about 10-mm. When I touched this the line started leaking hydraulic fluid. This spot is actually hidden from normal view as a U shaped bracket below the radiator supports the brake line in this area.
I went to make a new line but found that parts of the flaring tool were missing and suspect they were in eldest sons toolbox as he was the last to use it. I was also very busy with work and decided to outsource the manufacture of a new line to Stopmasters in Brendale. They made a new line complete with new fittings for the grand sum of $18 and at that price I have decided that I shall no longer persist in these sort of minor repairs with all the running around to get line, fittings and a working flaring tool all together at the same time.
I also enquired about the possibility of using copper line rather than steel but they informed me that Queensland Transport has ruled copper line as illegal because of problems of work hardening and cracking around the end fittings. That is a little strange as all of the Pommy restoration magazines seem to recommend copper brake line as a solution to their never ending corrosion problems.
Club member and friend Ben Stafford had just returned from Papua New Guinea and dropped in for a beer. I told him of this brake line problem and he said that he had had precisely the same problem in the same line in his 420. i.e. under the radiator. It appears that this "sleeper" corrosion problem may exist in MK1&2, S type and 420 cars, which share fairly similar engineering in their front ends. I'd suggest that next time you have the radiator out of one of these cars a close inspection of the brake line would be in order. It is relatively easy to replace the line with the grille and radiator removed.
As a result of the problems I had with the spark on the MK 1 3.4 auto while headed for the display day which I never got to [see Oct 03 Nuts and Bolts] I had a serious think about the ignition system in this car. It is very simple and on a par with the FJ Holden employing a coil, points, condenser and distributor. In fact alongside the modern day electronic systems it is downright crude. I pondered is there a better way?
There are modern electronic ignition system which can be fitted to run without points and deliver a massive spark however I detected some reluctance from a couple of commercial distributors of these devices when I wanted firm guarantees that they would fit a MK1 distributor. In fact they asked what was a MK1!
Using my vast background of Datsun 120Y experience I decided that the simple way was to retain the system, as it was however I would introduce a ballast resistor and coil. As I had lots of 120 Y used components in the parts bin including ballast resistors and coils I thought that a simple no cost experiment would be worthwhile. The results were quite spectacular. This car, which was always finicky on the start roared into life immediately. From dead cold it would catch on the first revolution of the crankshaft. Encouraged by this I purchased a new coil, ballast resistor and relay and the car has not looked back. In fact tonight I had to move it around in the shed and it still stated immediately although it is at least one month since the last time it ran.
How it all works is quite simple. When you are cranking over an engine on a 12-volt system the actual battery voltage drops to about 8 volts. This means your 12-volt coil will not work very efficiently when starting but is OK when running. If you substituted an 8-volt coil it would be good when starting but would burn out with continuous running. However a resistor designed to get rid of 4 volts when continuously running will protect the 8-volt coil. That is the ballast resistor. The relay is used at start up to short out the ballast resistor. The coil of the relay is connected to the starter motor voltage supply and activates when the starter is turning. The points in the relay are connected to either side of the ballast resistor and when they come together the relay shorts out the ballast resistor and full battery voltage is available at the 8-volt coil.
As we get more sophisticated I will try to introduce circuits and diagrams but at the moment I am stuck with a pretty basic computer and you will just have to bear with me on the description. While the foregoing information is not rocket science it appears to be a worthwhile modification to older Jaguars and is relatively inexpensive. Anyone who is really stuck can phone me and I will see what I can do to mail them a circuit diagram.
The grey MK1 project progress hit a brick wall and stopped as I tried to get the windscreen wipers operational. I should have woken up that there was something pretty wrong when I saw the flexible drive cable from the wiper motor to the wiper arm gearboxes disconnected and I also had noted that an attempt at a roadworthy a couple of years ago resulted in a failure because of inoperative wipers and body rust. [The rust is all gone now.]
Removing the Lucas DR3 wiper motor revealed a lack of brushes and some pretty amateur soldering of new flying leads into the motor itself. By luck I had another wiper motor that had a seized armature bearing and I was able to use the field windings and brushes to get a basically serviceable motor running on the bench. But the wiring colour code seemed to be wrong and I could not for the life of me make out the switching system to get the two-speed operation. There are 6 wires running into the motor with the colours of red, green, blue, brown, white and yellow
I resorted to the internet to attempt to sort out the colour codes however there was nothing about internal wiring of DR3 wiper motors but the mention of the name " Lucas" certainly brought a number of jokes about the "Prince of Darkness".
Finally I pulled the top off the wiper motor in one of my other MK1s and established the correct colour codes. Whoever had installed the new leads had certainly got it wrong as only two colours of the 6 wires were correctly terminated I then connected the motor to the car system and all hell broke loose as the supply fuse got blown. What now? A crawl under the instrument panel revealed that in the past some one had installed a wire to run 12 volts from the fan switch to the wiper switch. That is not how it should be done and when the wipers were turned on the 12 volts was being taken straight to earth.
Obviously the system needed to be restored to original specifications and the wiper system is now working. I will do a diagram of this wiring in the future as the leads on these motors are now typically 40 years old the colour on the original wiring has completely faded out and anyone wanting to overhaul one is going to have difficulty without "the knowledge"