Disclaimer : Any technical tips are produced in good faith. Brown and Gammons Ltd. always recommend that vehicle maintenance and diagnostics are only carried out by suitably experienced people using appropriate tools in a safe manner within a workshop environment. Brown and Gammons Ltd. cannot be held responsible for the correctness of, or misinterpretation of the technical tips. Any images shown are for illustrative purposes only and may not be representative of products or vehicles described.
The Technical Tips page is sorted in to Car Type. Please select from the list below to see Technical Tips for your car type.
MGA
MGA – Seat belt fitting query
I have just purchased a beautiful 1957 MGA in Orient red. My problem is because of its age it does not have seat belts fitted and my partner, in particular feels insecure without them. My questions are, a) can you fit seat belts to an A, b) if so are seat belts readily available to suit the car and where can they be obtained. c) Do you need a fitting kit and if so is this available or does it have to be purpose made. I look forward to your reply
Answer:
Seat belts can be fitted fairly simply if one goes just for a lap belt. Its relatively easy to weld mounting plates into the propeller tunnel and the outer chassis rail to take the mounting bolts. [Later MGAs came with them already welded in] Period harness are available from Quickbelt in North London. However to fit a lap and diagonal is possible using a fitting of a similar nature on the upper part of the rear wing. This however does cause considerable interference with the hood frame and the harness would probably prevent the lowering of the hood with any ease. A full race harness is much the same although I have seen the shoulder element mounted down near the rear bulkhead. This however will be next to useless in a accident as it will allow the body to move forwards without significant restraint which rather defeats its purpose. For proper mounting any harness should not be expected to work at any more than a 15 degree angle. This really calls for a shoulder harness to be mounted on the rear decking in a similar manner to the late sixties MGB. The harness was removable to lower the hood and was in truth rather a pain. If one went this route the rear decking would need reinforcement.
Personally with a open car I prefer a lap belt only. At least with that you have some chance of rolling sideways into the cockpit if the car rolls, otherwise its your head and torso which will be holding the car up!
MGA - 1960 1600 Mk.1 Leaking Radiator Cap/High Running Temperature
I have a problem with my 1960 MGA 1600 Mk. 1. Following a cylinder-head gasket failure I took the opportunity to overhaul the engine and fit a lead-free cylinder-head, a new radiator and a Revotech electric fan.
During a careful running-in period the engine has constantly run hot, up to 212 degrees and higher under load or in traffic, where previously it had been approximately 190.
I have fitted a new summer thermostat, a 7psi radiator-cap in an attempt to both improve fluid flow and retain cooling fluid but even on a constant speed drive on a dual carriageway the temperature remains high, and on slowing the electric fan runs but the temperature remains high.
Upon stopping, fluid leaks from the radiator cap (ruling out a faulty temperature gauge) and the mixture appears fine and there are no signs of any static fluid leaks. Please can you help?
Answer:
Firstly if the radiator has been topped I would expect fluid to be discharged upon stopping, due to the heat soak forcing the temperature up and expanding the coolant. The loss of coolant in itself does not confirm that the temp gauge is accurate at 212 degrees. An external temp reading would at least help confirm or deny that the coolant is boiling and verify the gauge accuracy.
The second point is to confirm is whether the cap and circuit are actually holding 7psi since the results would suggest that they are not now! It may be that the cap is either faulty or poorly seated [or the wrong length, some MGA radiators have the deep radiator cap seat!] It may also be worth checking whether the new thermostat is actually opening?
Thirdly, it's fairly easy to get an air lock in the heater since it's the highest point. One way to remove the air is to slacken off the top heater hose and ensure that coolant is able to flow around. Some repairers elevate the front [and radiator] of the car so that the flow is assisted.
An additional point to check is that the electric fan fitted is actually flowing air through the radiator, it's certainly not unknown for them to require the wiring reversed so that the fan goes the right way round [and the "A" could well be positive earth with a dynamo].
It's noted the engine has been 'rebuilt' - if this has included new bores these will take some mileage to bed in and in the interim will produce more heat [always use running-in oil for the first 250 miles or so to help the rings on this long stroke engine bed in].
Has the cam been changed? What is the mixture like? If it's now weak the engine will run hot!
Has the compression been raised? What ignition advance is the engine running at? If it's retarded it will run hot!
Does the ignition advance on a reasonable gradient from tick over? What is the max advance at about 4000rpm vac off? I would suggest with a road cam that 26 degrees would be approximately right but it depends on many variables.
Some basic steps and then perhaps a rolling road check for mixture and ignition throughout the range and the problem should become clear. Good luck!
MGA - 1600 MK.1 Push rod extention/Leaking slave cylinder piston
I am just completing a restoration of a 1600 Mk. 1 MGA. I had an MGB clutch and flywheel installed and now find that, on bleeding the slave cylinder, there is insufficient travel on the pivot rod and arm to activate the clutch. In fact the slave cylinder piston is leaking where it has pushed too far forward.
I am considering extending the push rod to alleviate the problem.
Have you ever heard of this conversion or had a customer with the same problem?
Any help would be appreciated.
Answer:
It is nothing to do with the slave cylinder. The MGB runs a "diaphragm" clutch which is much shallower in depth than the coil spring unit the MGA uses as standard. This will mean that the clutch operating fork will be operating too far forward, having the effect that the clutch release bearing will be out of line with the clutch centre. That can only be solved by fitting a MGB clutch operating fork and front cover rather than the MGA one. To do this you have to remove the engine!
The problem of the slave cylinder is caused by the first in that the operating rod is having to extend too far because the clutch fork is at the wrong angle. Lengthening the rod will only disguise the real problem.
MGA - Twin Cam Windtone Horn Wiring Advice
I have an MGA Twin Cam fitted with twin Windtone horns. I want to fit a relay in the circuit as the horns demand a lot of current from the battery, even though they are used only briefly. The earth return from the horns is not via the chassis to which they are mounted, but there is a separate wire from one of the internal contacts to the horn push switch, which when operated closes the circuit.
I'm not sure how to wire the relay. The one I bought is marked with the usual Bosch numbers 30, 85, 86 and 87 and 87a. I'm tempted to wire it in as follows, but I'm not sure and would appreciate your help. (I think the fact that the car is wired positive earth is irrelevant).
30 to Horns+ (Diverting existing brown/green wire from horns+ to Fuse A2)
86 new wire to fuse A2
85 to push switch (Try to find the brown/black wire in the loom connecting Horn - to push switch, and connect into it)
87 and 87a - not used
What do I do with the black/brown wire from the Horns - now cut off in the loom near the bulkhead?
Answer:
While this query is a little complicated for a technical advice page, we shall help regardless in case there are other MGA owners in a similar situation!
The correct method of wiring the horn is as below:
Wire 30 to horns
Terminal 87 - connect brown/green which originally went to the horns
Terminal 86 - new wire from fuse A2
Terminal 85 - to push switch on dash [brown/black]
Where the original brown/black wire on the horns was connected, a new earth wire must be made
MGB
MGB GT – Overdrive problem
I have recently purchased a lovely MGB GT which came with overdrive fitted. Just recently when switching on the overdrive it either takes a while before it engages or does not engage at all. I would not call myself a mechanic but is there anything I can do or should I entrust the repair to a specialist garage. I do most of the simple routine servicing of the car myself and once the override is repaired is there any routine servicing that should be carried out on the unit that I could do as the manual seems vague about this.
Answer:
Generally overdrive faults are either electrical or serious! But the first thing to check is the oil level in the gearbox since this also serves the overdrive. Lack of oil could cause the symptoms detailed however it could and perhaps is more likely to be electrical. On the MGB gearbox fitted with the overdrive there is a switch on the left hand side of the remote which acts as a cut out so that the overdrive can only be operated in third or fourth gear. The action of selecting either of these gears with the gear lever to the right of the quadrant pushes the switch into contact and allows electric current to flow through to the solenoid thereby activating the overdrive. The mechanism is slightly crude and the continual action when ever third or fourth is selected of the switch being pushed in wears the operating faces. The switch is screwed into position on a taper thread with spacer washers under the head. The first thing is to verify that this is the fault. With the ignition on select fourth and then with the overdrive selected verify whether you have current on the lead to the solenoid. If not using your assistant [fair or otherwise] pull the gearlever towards the driver [on a right hand drive car] Its most probable that the current will then flow. It is possible to remove and adjust the packings with the gearbox in situ by dropping the gearbox crossmember and pushing the box across to one side. Access is then possible to the switch. Its certainly easier with the car on a ramp but it is possible from underneath at ground level.
As for maintenance the normal oil change of the gearbox should include a filter change. This is under the flat plate on the underside of the overdrive. You will need a new gasket which includes the filter
Its worth noting that on the later V8 cars the overdrive facility on third was deleted and the gear linkage modified. It is possible that if the gearbox has been changed one of these modified units may have been fitted hence my suggestion above to check in fourth gear!
MGB - 1965 MGB Roadster wire wheel noise issue
I own a 1965 MGB Roadster with wire wheels. Recently when accelerating or taking a left corner I hear quite a loud noise from the rear nearside - it’s a clicking/knock noise. Would you have any suggestions what would cause this please?
Answer:
A common fault with wire wheels is that the owners fail to "knock up" the wheel spinners tight enough to hold the wire wheel firmly against the two cones, one at the back of the wire wheel hub and the one on the outside of the hub . One regular problem is that the outer cone of the knock on does not get greased and it locks up on the cone before its tight. The first course has to be to jack up the car and see if there is any play either laterally or in rotation. If there is the wheel should be removed the splines cleaned and checked for sharpness. If they are sharp its almost certain that the wheel has been run loose and sadly both the wheel and the splined hub will be candidates for replacement.
Another possible cause is that the splined hub is loose on the halfshaft where it is a press fit. If this is the problem again these two items are due for replacement. A further problem is that the inner hub is located on the end of the axle by the wheel bearing which is secured by a eight sided nut. This has to be torqued up to 140 pounds feet and the bearing has to be a press fit on the eye of the axle, if its not no tightening of the nut will solve the problem. The bearing should of course be in good condition The axle has to be removed and welded and machined to size. The other area that should be checked is the rear spring location on both front and rear pick ups and where it locates onto the axle. The shock absorber location should also be inspected and bolts check tightened.
MGB - 1800 fuel leak / carburettor disassembly
I managed to get some secondhand SUs for my standard form 1800 B roadster from someone doing a V8 conversion.
Taking carburettors apart in anyway fills me with apprehension. The hose seems to be surrounded by, and held in place at the dashpot end by, a metal spring.
Could the age of the spring and its resultant loss of compressive force be the cause of the leak, or is there meant to be something else holding the hose on where it joins a lower point on the side of the dashpot?
As soon as the electric fuel pump starts up, it pours fuel out.
Any help is much appreciated.
Answer:
The question is not very clear, however from the description we suspect that what the owner is referring to is the feed from the bottom of the HS 4 float chamber to the jet. These consist of a flexible neoprene tube secured by a gland nut and 'O' ring into the base of the float chamber. The "spring" the owner refers to is merely a protection for the neoprene tube and is nothing to do with the attachment of the tube. Although these parts the jet and tube, are available separately [and its worth noting that they are handed with differences between the front carburettor and the rear one] they also come as part of a kit of parts, all of which you will need in an overhaul of a pair of carburettors. There also has to be a warning that the overhaul should be undertaken by somebody with adequate knowledge. Petrol is hazardous and an error could result in a serious fire and possibly injury. Various books including the MGB Workshop Manual detail the construction and overhaul of the carburettors and it would be wise to obtain and read a copy particularly without previous experience of overhaul techniques.
MGB - 1974 petrol - conversion MGB stalling/hot engine
My petrol-converted 1974 MGB keeps stalling at junctions, traffic lights and other obstacles that require decreasing speed.
The car is able to travel four to five miles before this happens, takes five minutes to restart and repeats the cycle.When it happens, the engine and everything in the engine bay is red hot and untouchable.
I have replaced the coil, alternator and just about everything there is. The engine has been flushed out along with the cooling system and a new thermostat has been fitted.
Can you please help?
Answer:
Without sight of the car to try and answer these questions with anything that's definitive is almost impossible as most will understand, however as I think I have written before in general there are only three things that will stop an engine that has started and run already.
1] A lack of fuel - so the first thing to check is whether there is any fuel at the carbs (You may check by either pulling off a fuel pipe or removing a float chamber lid and checking for adequate fuel flow). You are looking for 8 gallons an hour, this can be measured by how long a pint or litre takes to flow through.
2] Lack of spark, so remove the plugs quickly and by reconnecting one whir the engine over and check for a spark. Lack of a spark could be the condenser [a regular culprit] the rotor arm [another, better quality rotor arms are now available] or possibly the main coil to cap lead [although this is more likely to fail under damp conditions].
3] A large hole in the side...this one is fairly obvious!!
What has not been stated apart from the fact that its very hot [which could indicate a very weak mixture, i.e. a poor fuel flow] is why its running hot and this needs to be investigated. It may be that the new thermostat has jammed. But heat in itself is unlikely to cause it to stop unless it vaporises the fuel in the carbs, which makes the heat shield worth checking!
The most important and useful action to take is to check the engine basics immediately after it stops.
MGF & MG TF
MG TF - over winter battery issue
I hope one of your specialists can help with a problem on my 2004 MG TF 135. As you probably know, this model has the Pektron unit with the two button oval Key Fobs.
At the end of September last year, I disconnected the Battery over night to top up the charge. On reconnection, the C/L, E/W and interior Lights do not work, the Alarm LED on the Dash isn't working, and the Engine Immobiliser cuts in a few seconds after the Engine has started. After leaving the car (with the Battery still connected) for two hours or so, the problem had gone and everything was working as it should.
As the MG was going to be sorn'ed through the Winter in a Garage, the Battery was removed from the car shortly afterwards and stored inside the house. When the snow finally disappeared just after Christmas, the Battery was fully charged before being refitted. I now have exactly the same problem as four months ago. I have tried pressing the buttons on the Key Fobs several times to no avail, and I'm at a loss as to what to try next to make the car "wake up". I don't think it can be a blown fuse or relay, as otherwise how could the problem have "cured itself" four months ago.
Answer:
Without getting too technical this sounds very much like a SCU fault, however there may be some hope if the owner has the emergency key access code [EKA] which may enable the blips to be reinitialised. Sadly if this does not work the car will need to be connected to a diagnostic machine, the ubiquitous T4. Its possible that the disconnection and reconnection of the battery may well have caused a "electrical spike" which has caused the SCU problem. Disconnecting the battery is not necessary for charging purposes if you use one of the CTek battery conditioners. They help keep the battery at a charged level and are ideal where the alarm circuit has a constant drain on the battery even when the vehicle is switched off and parked. Our display cars in the showroom are nearly always connected to a conditioner.
Midget
Midget- 1978 rubber bumper removal
Could you please outline the best way to remove the rubber bumper from the front of my '78 Midget?
I won’t be putting the replacement chrome ones back on, just going 'bumperless' at the front! I guess the large box section mounts which protrude through the grille will need to be removed somehow as well? Please could you give me some advice!
Answer:
It's not difficult to remove the bumper since its only held on by nuts and bolts, however the mounts would then have to be removed, the normal way is with a small grinder [use goggles against sparks] and to finish off the aperture as neatly as possible. A number of cars have since then had the GAN 5 grille AHA 9925 fitted which makes a very neat job albeit at some cost since the grille is now close to £200. The alternative is to obtain some stainless mesh and cut to shape,although this will call for some metal working skills to obtain a decent looking finish. On balance the better job is obtained by using the original grille
Midget- 1970 Engine cut-out
I have a 1970 Midget which wouldn’t start a while ago, so I took it along to my local garage. I was told that the problem was the auto advance springs in the distributor. So I ordered a set of springs and had them fitted, and the problem was solved. I drove away happy.
However another problem has developed in that after driving for about 8-10 miles the engine cuts out. I turn the key and the engine just turns over but won’t fire. If I leave the car for about five minutes the car will start again allowing me to travel another ten miles before cutting out on me again.
Do you have any theories as to what the problem may be?
Answer:
It's difficult to understand why the distributor advance springs being either worn or broken could bring about the lack of a start. All the springs do is to control the bob weights which as the rotational speed of the weights increase expand in order to advance the firing point relative to TDC. Therefore it must be suspected that the true fault lay elsewhere. Now recently there has been a lot of problem with ignition components, sadly regardless of the "manufacturer" since a lot are just made by one supplier and others then label them as their own. In particular, condensers and rotor arms the latter having a rivet holding the brass contact plate in position whereas the originals were moulded in. This has led to a considerable numbers of failures and frankly it's worth substituting these two items to see whether they are the culprits. However as I seem written in another of these queries there are only three things which cause a running engine to stop.
1] Lack of fuel
2] Lack of spark
3] Some mechanical derangement such as a great hole in the side.
So next time it stops immediately switch off the ignition and ascertain whether there is any fuel in the carburettor. If there is it's unlikely to be the fuel but do a fuel flow check to verify. Then check the ignition side i.e. remove a plug and see if you have a spark, but do take care that you don't have an explosion from the fuel you have just checked!
MG TC
MG TC- Cooling problem
I am the owner of an MG-TC 1948 and have fitted the X-Pag engine with a Shorrock Supercharger. The engine and car are running very well and have run for several thousand km.until now. But I had and have always a small problem: When I run the engine over 4700-5200 rpm the temperature raises up to 100 degrees and over. I have just fitted a bigger radiator but nothing has changed. I read in the ABC of Shorrock Supercharging written by Jonathan Peck that replacing the thermostat for a racing blanking kit part nr AJJ4012 and the 74c thermostat part nr GTS 102, the engine runs much cooler. Is this the correct solution?
Answer:
We stock the AJJ 4012. There isn't any insurmountable reason why you could not use it along with a thermostat but it may call for a little machining. The design of the thermostat housing has been modified over the years. If your housing has the facility of being able to remove the thermostat you should be able to fit the blanking sleeve. The current thermostat housing and thermostat cannot be dismantled and in that case the task of fitting the sleeve is more difficult.The purpose of the sleeve is to reduce the flow of hot coolant down the bypass. The bypass is required so that there can be some flow of coolant before the thermostat opens.The new thermostat housing has the casting modified so that the flow is slowed by a smaller orifice.Could I suggest that another likely cause of poor cooling is that the radiator is unable to accept all the air at speed. The slats need to be as near into streamline shape as is possible. Thus the area of the slat presented to the oncoming air is at the smallest it can be. They are easily bent round with pliers carefully masked with tape to prevent damage Unfortunately modern fuels are not good for old engines which do tend to run hotter as a result.
Disclaimer : Any technical tips are produced in good faith. Brown and Gammons Ltd. always recommend that vehicle maintenance and diagnostics are only carried out by suitably experienced people using appropriate tools in a safe manner within a workshop environment. Brown and Gammons Ltd. cannot be held responsible for the correctness of, or misinterpretation of the technical tips. Any images shown are for illustrative purposes only and may not be representative of the products or vehicles described
