Waving speedo

[Deleted]

???Hi, I am new to this, have just acquired our first P5B Coupe. It needs some work but, as a starter for ten, what's the likely cause of the problem, please?

[Phil Nottingham]

Could be sticky inner cable - its shoud be revoved, cleaned with petrol and very, very light greased. It may also be routed badly - its hould have gentle curves.

Its more often though the magnet in the speedo head which require the glass and face removing and then careful cleaing first.

Try the first two options first

Good luck and welcoem to forum.

Tell us more about uou and you car

[Deleted]

Thanks for that Phil, will let you know how I get on. My apologies for the somewhat tardy reply.
About us; see 'Wet'n Blow Dry' in Oct. 2006, issue of 'takefive'. The Escort has moved over (after 26.5 years) for our 1971 P5B Coupe, in Arden Green. Am talking to as many people as possible about all sorts of things and, 'bits and, pieces are coming in from a variety of sources.
We are booked into a Tour of Italy in a couple of months time and if it is not ready, we will have to take the 'day car' !
Will open up a couple of other 'boxes' to deal with other probs.
Keep smiling !

[Deleted]

Hi Phil, the inside of the speedo head looked very clean so, gave it some air and, a bit of a wipe and put it all back to-gether. Will re-fit into the car and, if prob persists, will have a go at the cable.

Thanks again, John A.

[stantondavies]

You can test the speedo using an electric drill to drive it. My speedo is rock steady when tested but waves frantically when fitted to the car. I do have a new speedo cable which I'll fit when I can make the time.

[Deleted]

Good suggestion Peter, did think of it but was wary of trying !
Anyway, have now re-fitted the original, so will see what happens !
By the way, if anyone has not had a go at taking the 'speedo' out, it is made an awful lot easier if you first release the chrome locking nut on the under fascia end of the trip return knob ! Saves time, patience and, skinned knuckles !!!
John A.

[dorsetflyer]

My, you learnt that little trick fast. It's surprising how easy it makes things once that has been disconnected.

[Deleted]

Hmmmm, thanks for that,John, I understand that necessity is the mother of invention, at times! Friends 'in the know' are also useful !!
Kind Regards, John A.

[Welsh Warlock]

Could be the speedo head needs a drop of oil. Worth doing else it may seize and break the 90 deg drive into the gearbox.

I wrote an article wbout this for Take Five in the August/Sep issue 2000. Drop me a mail at [e-mail] and I'll send it to you.

[stantondavies]

Feb 17, 2007 18:11:33 GMT stantondavies said:

You can test the speedo using an electric drill to drive it. My speedo is rock steady when tested but waves frantically when fitted to the car. I do have a new speedo cable which I'll fit when I can make the time.

At last I've fitted the new speedo cable! The job finally reached the top of the priority list. A friend helped me and we used a four-post lift. Having released the instrument pod (not forgetting the trip adjuster) I disconnected the cable from the speedo head. I then attached a piece of string using a slip knot and my friend withdrew the old cable from underneath the car. He the attached the string to the new cable which had been lightly greased, and I pulled it back up to the speedo head.

Quite straightforward apart from sorting out the wiper switch which came out of the pod and the oil warning light. It is difficult not to disturb something.

And what a revelation it is, a rock steady needle - I'm fascinated by the novelty of knowing how fast I'm travelling at. Or do I?
Up till now I judged my speed by instinct, but I wondered how accurate the speedo might be. Obviously it is calibrated for crossply tyres with a typical rolling circumference of 2124mm but a 185/85 x 15 radial's circumference is typically 2055mm, a difference of 3.25%.
This translates into a "true" speed of 29mph against 30mph and 67.7mph against 70mph on the speedo. I reckon that's close enough and i sha'nt bother with recalibration. There's a 1% difference in rolling circumference between a new and worn out tyre anyway. The differences are too small to bother about in my view.