Brake lights, Fuel gauge, throttle........

[jaglover842]

Recently had car back from garage and gradually addressing various on-going issues.

On the way back home after a 40 mile round trip, a passer by shouted 'brake lights jammed on'. He was correct. Tonight I inspected the switch and connections. Connections cleaned and now brake lights work normally. I can't guarantee there isn't a fault with the sensor switch, so I have ordered a new one. Plenty of WD40 on the thread over the next few nights to help loosen it.

Fuel gauge was reading below an eighth full. I put 20 litres in the other day. The fuel gauge needle did not move! I suspect that after such a long hibernation period, the fuel sender has got corroded/dirty and won't move to correct level. I will remove it soon and have a look at it. Hopefully there isn't rust in the tank. Carbs have been cleaned, engine runs well and fuel filter looks good.

Throttle issue:
Car starts normally from cold or hot and gradually settles to about 750rpm. I then touch accelerator pedal to about 2000 rpm, leave for 10 seconds and let go. Engine moves back to about 1500rpm. Repeat and same thing happens - 1300rpm that time. I then momentarily raise the revs then lift off. Engine revs then drop back to 750rpm. Repeat and same thing happens. Stop engine, restart and engine idles happily at 750rpm.
Is this behaviour normal? Does the brief revs rise cause a 'reset to normal' on the idle?

Various oil leaks underneath:
Put car on garage ramp and took photos.

[piman]

Hello Jaglover842,

it is unlikely to be a connection fault, unless there is the unlikely situation where both wires are shorting together at the switch? It is possible that the switch is faulty but another cause can be a delay in the pressure reducing when the brake pedal is released? A quick check is to have the car on a level surface, apply the brake then see if the car is hard to push?

There are a few better products than WD40 for assisting in freeing components, Plus Gas being the most well known. WD40 is a moisture remover and can be used as a lubricant but it is not so good as a penetrating fluid. However the brake light switch is usually very tight as it has a taper thread,and the danger is that the adapter will turn, and unlesss you have a secure grip on it there is the danger of twisting and so kinking the brake lines which thenl need their replacement.

If you do change the switch have the new one to hand, and as the old is removed, fluid will seep out, so promptly fitting the new will save on brake fluid loss and bleed the system at the same time, hopefully.

Removing the fuel gauge sender should quickly tell you what is wrong.

The throttle shouldn't work like that so a check around the linkages for tight spots is called for and that all springs are fitted. A few spots of light oil doesn't come amiss on the linkage.

Alec

[PPV]

Totally agree with Alec. In addition the revs rising could be sticking pistons due to the lay up causing gum to coat them. A quick clean or even before that a quick lft and drop test would check it.
Regarding the oil leaks then it looks a bit like mine and the only leak I have is from the rear crankshaft oil seal!
Regards,

[jaglover842]

Thanks for the advice.

I tried the car on a flat surface last night. Brakes come on and off fine - repeatedly. No delay in lights when releasing brake pedal. Maybe switch just gets stuck on after a semi long drive with normal braking.

Unfair to compare brakes to a modern car, but I have to apply a lot of pressure before brakes stop the vehicle when driving (still learning!) Switch contacts cleaned but did not appear to be touching.
Good advice about kinking the brake pipes when undoing switch - will exercise caution.

The fuel sender on the E-Type was a bit seized when I refurbed the fuel tank last year - so yes, suspect similar problem (Rusty Fuel Issues Part 1).

The carbs have recently been serviced by the garage, so the pistons should not be sticking or sluggish. I will lubricate all linkages and let you know the outcome.

Thanks.

[piman]

Hello Jaglover842

Is your garage familiar with S.U. carburettors?

One check you can do is to lift the piston on each carburettor and release, it should drop smoothly and stop with a distinct click. Unfortunately the connection to the air cleaner needs removing and is a little awkward to do due to restricted room at the nuts that fasten it to the carburettors. Alternatively, remove the damper pistons and start the engine. If you operate the throttle you will see the pistons rise in response to opening the throttle and fall on closing. They should rise and fall in unison. If one is sticking it should be obvious. A small rod or something like a pencil could be inserted in the pistons and give a better view. Push hard down on both before starting the engine should give you the datum.
A sticking linkage could give misleading results to this test so make sure the throttle linkage is fully closed by manually shutting it. This can also tell whether it is linkage or pistons.

Alec

[jaglover842]

Brake sensor switch:
Replaced with a new one today. Same thread size but takes a much smaller spanner size (22mm? compared to 26mm). Not much brake fluid came out during the change over (I was quick).
I guessed at the torque setting. Reconnected wires and tested brake lights. All seems fine, but proof will be on a long drive as before to see if there is any long term effect.

Ignition Barrel Lock:
Replaced with new one today. Whole switch mechanism now feels less loose and more mechanical.

Throttle:
After spraying lubricant on all throttle linkages the other day, the problem seems to have gone away. Engine now returns to normal revs under all conditions (was only done while not moving in garage though).

Fuel Sender:
Not investigated yet.

Heater:
Fan seems to decide for itself when and whether to come on (slow or fast speed). With water temp gauge solid at 60 deg C and car not moving, no hot air came out of vents. Hot/Cold lever arm in cabin moves to half way position nicely from Cold, but when moved to max Hot, it springs back to halfway. I have lubricated all controls I can see. Will try again tomorrow. Possible though that whole heater matrix is clogged up. I noticed that the input and output water pipes to the heater were not getting hot. External air intake vent shut.

[PPV]

Regarding the heater then the water temp at 60 deg is very very low. Do you have a thermostat in? As the heater is low efficiency then the water needs to be up to temp. Is the water supply to the heater hotter than 60 deg?
Regards,

[piman]

Hello Jaglover,

a couple of things to check on your heater. If you disconnect the cable at the water valve, can it then be physically moved from open to shut? It may be that the valve is partially blocked?
There may be an airlock in the heater, it may be a blocked or partially blocked matrix, but it could just be that there is no water flow, which also will be influenced by the condition of your water valve. Normal practice is to set the valve fully open when refilling the coolant system and run the engine so as to push coolant through the heater. As with many problems you may have more than one fault.

Alec

[jaglover842]

Thanks for advice about heater and temperature etc. I will investigate when I have time.

Regarding the fuel gauge issue, I removed the sender unit from the petrol tank yesterday. The float arm is completely seized, probably due to 16 years of having just below a quarter tank of fuel in and not moving.

I was interested in the mechanism of the sender - see last photo. The Service Manual says apply a suitable gasket sealing compound when fitting the new one. On a particular web site, the sender unit seems to come with a thick rubber gasket. Do I need the compound?

Hopefully going for a drive around Eastnor Deer Park today.

[Doherto]

Jaglover842, i have just picked upn your thread and notice that you have exactly the same problem i had with my tank sender. It will never read more than a quarter full even if you free it up. In your picture the copper strip on the inside of the mechanism cover, which the slider arm comnnects to is broken part way along. Therefore when the slider passes over the broken section connection is lost. I replaced mine with new but then purchased a circuit board strip from Maplins, which i beleve is now closed, and made an effective repair. I have photos which i will attach and i also have some spare circuit board, somewhere, which you are welcome to if it helps you.

[jaglover842]

Thanks Doherto.
Your post was very interesting. I will have a closer look at the strip and action a similar repair as you have done. However, the main problem was that the float arm mechanism is completely jammed. So when I buy a new unit from the supplier, it will (should) include the complete assembly.

BUT I NOW HAVE A MORE MAJOR PROBLEM - THE ENGINE IS DEAD.

Background:
I drove it to and from Cheltenham a month ago (40 mile round trip) with no issues.
Three weeks ago I got it out of the garage for a mile trip down the road. It was quite sluggish to turn over on starting.
I parked at my friend's house and turned the engine off.
An hour later, on pressing the starter button, the starter sounded like it was not engaging and free ran. The next try hardly turned the engine over at all. The next try just about started the engine. I know I have a strong battery.
We got 2 miles down the road and I pulled into another friend's driveway. His driveway had a small kerb to go over and his drive was a bit lumpy and uneven.
While slowing down in neutral the engine suddenly died. There were no symptoms or strange noises before any of this.

On trying to start it again, I just got a clunk from the starter, then nothing.
Tried rocking the car back and forward, putting a new battery on, banging the starter motor lightly - no change.

Got a tow home and day was ruined.

The garage that did the original recommissioning work came out. They rocked it back and forwards (in gear) a slightly more amount than I had done. On pressing the starter, the engine just about turned then came to a sudden halt with a mechanical clunk. This was repeated several times. The headlights dimmed each time the lock occurred indicating current drainage.

Garage suggested hydraulic lock up, possibly due to head gasket going and water getting into cylinder bore and being compressed. I took out spark plugs (all dry) and inspected cylinders (all dry). With a blanket over the six cylinders I tried the starter again - no joy - same result.

I fear something catastrophic has happened to the engine. I will use and endoscope to look inside the spark plug holes to look for any clues. I can't help feeling there is something connected with the starter motor performance issue. The garage have said they need the car back to do a proper assessment.

Any ideas or has anyone had similar problems? Did something in the engine just come loose when I went over that kerb and is locking up a cylinder?

Thanks

[davidr]

Could the engine earth strap be loose?

[piman]

Hello Jaglover,

two things, put a spanner on the crankshaft pulley bolt and see if you can tturn the engine over a turn or two, plugs out will help slightly. If that is OK I would then remove the strater motor and check it, especially the drive gear and shaft for straightness? If that seems fine have a look at the ring gear and flywheel Especially if it is an automatic.

Alec

[jaglover842]

Been busy recently, apologies.
I went to the British Motor Museum yesterday. I wanted to see the cut away of the XK engine in the Collections Centre. This was to help me understand what might be the problem with the seized engine.

Today I found the problem.....
Cylinder 2 (air intake side) has a dropped valve stem. I can clearly see this (just) with the endoscope I bought connected to my laptop, poked through the spark plug hole. The engine is currently in the jammed position with the piston being jammed by the the dropped valve in the bore.
There appear to be a few fragments of metal on the piston also.

Relief that I have found the problem, but concerned now about the cause and potential repair.

The carbs were serviced at the garage a few months ago. Is it possible they left a nut inside the carbs and this found its way between the valve seat and seal, causing the piston to hit the valve?
The garage did tell me about noisy tappets but they said fixing this could wait until a later stage.

So the head will have to come off and I will look at where I go from there.

Really annoying since it now won't be going oh Shelsley Walsh in June.

[davidr]

Anything that gets you closer to the cause is progress! At least you now know the next step - take the head off.