Speedometer

Mopaul · Post by **Mopaul** » Sat Jun 10, 17 10:41 am

Hi guys, just looking for a few pointers.. Bought a car and the speedo is stuck on 110, is there a specific reason for this or could it be any number of causes?

MilesnMiles · Post by **MilesnMiles** » Sat Jun 10, 17 11:07 am

It went too fast! I've not seen this before, usually they go erratic and very noisy. I took my speedo out and cleaned where the cable goes in, lightly greased it then refitted it. Worked fine after that for a few years.

Dave81 · Post by **Dave81** » Mon Jun 12, 17 1:59 pm

Yep....Graphite Grease in the sheath that the speedo cable runs in. Gives you a constant speedo rather than a bouncy one.

As said remove, clean, grease and install!!

Post by **MattH** » Mon Jun 12, 17 8:05 pm

I just fitted a new cable and gave the tiniest amount of WD 40 in the back of the speedo, a really small amount!
The old cable had a melted outer near the exhaust so had got rusty at that point.
Now works beautifully, and reads steady and spot on compared with a sat nav, also doesnt now sound like two cats fighting in a biscuit tin.

Checked it over 600 miles this weekend with no issues.

Dave999 · Post by **Dave999** » Tue Jun 13, 17 10:01 am

the spinny bit in the back of the speedo has magnets in it . It needs to be suspended away from the bit connected to the needle which is a drum type thing moderated by a spring

the needle rides on a separate section that has a torsion spring with a specific spring constant. you alter calibration by moving the spring stop factions of a mm.

if the spinny bit wears its housing it starts to rub the drum section that the needle is on and it causes a jumpy speedo

too much grease clogs it up and the gap between the two gets filled and just winds the needle right round

WD40 or the smallest amount of graphite cures most

too much Wd40 and it will come out the middle of the speedo and make a greasy mark on the dial

if the needle is stuck you may find that its torsion spring has come unlatched or has snapped

or it has been wound round so far it is jammed.

it can get wound round due to the two separate parts, magnet and the needle drive drum colliding or being gummed together with grease.

often easier to make 1 good speedo out of 2 and in most cases the internals are similar year on year

best internals in best housing with your dial glass and bezel.

easy to ruin any gauge its watch menders work :~)

check out the speedo and gauge refurbishers in the back of practical classics think the main one is VDO specific but there isn't a whole lot of difference inside, they could probably remount a spring for you, they are often glued in place with a blob of shellac/resin.

dave

Mopaul · Post by **Mopaul** » Wed Jun 14, 17 9:39 am

Many thanks for the info guys, I'll whip it out and give it a good seeing to

Mopaul · Post by **Mopaul** » Wed Jun 21, 17 1:32 pm

So, had a look under the dash and the cable wasn't connected to the speedo.
The plastic clip thing was half missing, managed to just Bananarama! back onto the the speedo, the result being that mileage gauge now works but the seedo needle now only works in reverse and bounces all over.