Speedo question

[skippy]

Just fitted a new speedo cable to the Satellite. Before I fitted the cable ( without one on there) the speedo was stuck at 10mph, with new cable fitted the speedo works great with no jumping but now when stationary its not going below 40mph.
I can live with deducting 10mph of my current speed to determine how fast I'm going but 40mph plus is going a bit while driving.

Any suggestions how to cure this or could it be a faulty speedo?

[Dave999]

speedo drive worn or full of muck.

or the pointer has moved on the shaft, the speedo is genuinely at 0 MPH but the pointer has twisted 40MPH round so sits at rest in the wrong place.

in which cas the calibration is all to cock any way a change of 10mph road speed will be shown as way more 40 -65 or something like that


I think in there is a cylinder with a magnet ig ring, running round the base of the pointer shaft (potentially with reversed pole magnets. i.e drives the point via magnetic force as it turns.

it drives it against a hair like spring. usually just above or just below the gauge face, its clamped to the pointer shaft and an anchor the start point i.e how much that spring is coiled is sometimes adjustable
trouble is adjusting this alters the calibration.

lifting the pointer over the 0 MPH stop mark usually allows the spring to uncoil to an at-rest place somewhere backwards round to 60 mph. if it wants to go further carefully count how many revolutions, mark where it stops if it does this. you need to be accurate so you can put the pointer back on in that position, then wind it back to zero mph and ease it over the stop pin...

what i'm getting at is

you can't really do much without taking it apart....

if you try to oil or clean the whole assembly the oil wd 40 etc finds its way up onto the face or gums up the spring and ruins it.

your current problem could be cable oil in the last 40-50 years has migrated upwards through the magnetic collars onto the spring and is causing the coils to bind

the hair spring is much like the tiny springs in watches.....

i'd be inclined to lug it out and send it to one of the reconditioners who at least will have the big magnifying glass and tools to do it right.

cheap option

take it out
take off glass front
gently wind the pointer back and forth to see if it frees up
then find its rest place backwards beyond 0 MPH as mentioned above

take off pointer
take off the face

gently blast off the drive mechanism with WD40 then alcohol to take the wd40 off be gentle when you clean the spring

put it back together when totally dry remember to put the pointer on at its position at rest wind it forward the right amount and lift it over the stop at zero

the last time i did this i think one or 2 speedos were sacrificed to the god of clog handed enthusiasm. i have resisted the temptation to ever do it again. VW bug speedos were easy to find had the same internals for 30 years and didn't cost much at the time...Mopar speedos i guess will be harder to find, much more expensive and potentially be made of cheap rubbish plastic.

Dave

[Dave999]

if its a strip speedo

i'd guess a similar set up

but it would be a guess


Dave

[skippy]

Thanks Dave, The speedo needle moves freely but it now sits at 40mph while at rest. Cant even blame the new cable as was sitting at 10 mph with out cable attached. Tried spinning cable in reverse and it goes back to 0 mph, soon as let go of cable it goes back to 10 mph ish.

[Dave999]

MMM

i think you have a perfectly functioning speedo with the pointer in the wrong place

take it off
put it back on 20 mph before 0
lift it over the stop

and see how you go


check it with the sat nav or app on phone

if it reads too fast repeat action with it set at - 30 and so on till its telling you you are doing 70 mph when the sat nav says 68

job done

Dave

[Stu Twin]

Hi Dean, it must be a Satellite thing.
Ours has developed a similar issue since it was sat for a couple of years. Now it's back on the road the speedo's stuck on 25. Moves freely when you get going except it always shows +25 too fast.
I've read it's magnetically coupled to the cable, ie not mechanically driven or the needle would spin all the way round!
The magnetic coupling gums up as Dave says and would need removal. That's why ours is still like that!

I stopped to look at a stand at the NEC of a firm who rebuilds speedos. The chap confirmed it's a magnet type thing and likely just needs cleaning.
He gave me his card (as they do).
If it's of any use their details are:
Mike Flannery,
Flannery Speedometer Repair,
Tel 01594 861095
Mob 07910 287721
Gloucestershire.
http://www.magnetic-speedometer-repair.com/
(other speedo repair companies are available)

Good luck, Stu.

[Dave999]

sounds like a useful chap

skill of a surgeon and the engineering practice of a jeweler needed

which is why i'm less inclined to open another up i have neither. but i am good at snapping off bits that are vital to future operation of the unit

dave