Practically Classics Forum

It seems that three things are required; see http://www.speedycables.com/Calibration%20Guide.pdf. They are quite emphatic about not jacking the car up, so I have followed what they have said.

That turns a very simple operation into a needlessly complex one! You only need measure the distance the car moves if the TPM figure on the speedometer relates to a different drive pinion. Otherwise, think about it, the diameter of the wheel makes not a blind bit of difference when calculating how may rotations the hub has gone through.

It sounds well enough for task 3. I'll ask Speedy Cables (I think there is a connection of sorts with Smiths Instruments) to comment, as they are doing the job for me.

Attempting to bleed brakes again. More air coming out, still a rubbish feel to them. I'm thinking about vacuum bleeding them backwards, ie connecting a fluid supply to a bleed nipple on one calliper then sucking up from the master cylinder. 12 litres of fluid have gone through it now and it is getting expensive!

Martin Evans wrote:It sounds well enough for task 3. I'll ask Speedy Cables (I think there is a connection of sorts with Smiths Instruments) to comment, as they are doing the job for me.

Ah! I had assumed - erroneously it appears - that you were recalibrating the speedo yourself, now I get how they want the tyre size; it's because they don't know which pinion you have fitted as you would yourself, so they work out the long way how far the car moves from the size and the number of turns. It makes sense, but I still don't see why they couldn't simply supply a pinion to your specification in which case only the TPM figure from the head and the actual number of rotations of the hub would be needed. As it is, rolling both wheels is still the less accurate way as it means that wheel alignment enters the mix! When I've had speedo heads - for which I hadn't managed to find suitable hairsprings or worms among the pile in my tool chest - recalibrated (always by Richfield), they ask how many teeth the pinion has, the TPM number from the face and the number of turns at a hub per revolution of the cable.

Took the mog out for a stretch of wheels today, filled up with petrol and made it 7 miles before the water pump seized which snapped the fan belt. Fortunately I have a temp gauge fitted and the battery lasted long enough to do 10 miles back home in 6 goes without either flattening the battery or getting excessively hot.
Tomorrows job: fit new water pump. (or if I have the enthusiasm and it isn't piddling down pull the engine and FINALLY change the clutch)

Cleaning the engine bay over the last few days. Fixing odd silly things like a windscreen bottle that had no cap on it,but just some tape. Been like that for years. Now it has a cap.

Going to clean radiator fans, mud shields, battery boxes, ... You know jobs that are urgent, not even required, but have wanted to do for ages. Basically i decided that it wasn't going out for a month and then I could relax and take loads of bits off and not worry about finishing every job each evening.

Fixing the garage walls where my car is kept. Then painting the outside.

Today I have been drizzling or could that be beastings the selector arm of the automatic
gearbox with penetrating oil! The question is which goose has been cooked mine or it's?

Well the Disco now has a spanking new MOT (Yay!) which means a service, a bit of fettling on the advisories, then having a full size parts chaser to get bits for the series.