Morris Minor Owners Club

Hi,
My speedo and odo don't work. Could someone walk me through a step by step plan to determine the cause(s) of why they don't work? I did check that the speedo cable was inserted into the transmission but have done nothing else. Thanks in advance

G'day Steve,

This is for the centre dash speedo, I don't know about the earlier ones. Do this stuff at your own risk. Speedos are delicate, you can stuff them if you're not careful. What I detail here is from speedos I have pulled apart and played with. I've limited it to fairly obvious stuff where the fault is fixable.

Disclaimers aside, first things first, if it has been a long/unknown time since the speedo last worked, remove the cable from the rear of the speedo itself by undoing the knurled screw on bit and DO NOT try to turn the speedo itself. The odo drive gear is a little plastic gear wheel on a spindle which can sieze in it's housing. Turning the drive causes the brass worm drive to strip the plastic wheel. This is especially inportant for vehicles which have been standing for a long time. I have three speedos like this:



Lubricate and check that the spindle is free first before you try to turn the speedo itself.

Having said that, your problem is probably the speedo cable. Once you unscrew the cable at the speedo end you can check and see if it turns when the wheels are turning, or simply remove the inner and check visually.

If a visual check shows that the cable is ok, check that the speedo drive on the gearbox is working by having some one watch it while you turn the engine (by hand, with the rear on stands and the car in gear),

You can decide to go further and dismantle the speedo itself. It is a very simple, but very delicate device, don't do it if you're not confident with this sort of thing.

To remove the speedo itself, there are two clamp screws (at 9 and 3 o'clock) which can be accessed through the glove boxes. There should be a hole which corresponds to the rough location of the screw. You only need to loosen these, to remove the speedo from the dash, by pulling it towards you. You can see them in this photo:

http://i22.photobucket.com/albums/b322/ ... doback.jpg

You then gently remove the outer ring (with the split in it), and twist the chrome ring, lining up notches with bent in bits, one at at time, to remove it.

Undoing the two slotted screws on the centre rear of the unit (near where the cable screws on) will release the mechanism from the back cover. Noe you will be able to see the state of the plastic wheel and lubricate it if necessary. The face of the speedo is in two parts and these will separate when you undo these screws. Be very gentle and hold the assembly together, ensuring that when you re-assemble the speedo needle is on the correct side of the stop pin.

To summarise:

1. Don't try to turn an unknown speedo
2. Check the cable itself first
3. Check the gearbox drive
4. Lubricate the Odo drive spindle


That's the limit of my knowledge on the subject. I hope it's helpful.

steve without being disrespectful in any way,if you need to ask how to check out the speedo,I would say that you will certainly mess up the workings if you dismantle it,as shaun says it is very delicate.Unscrew the connection at the rear of the speedo and with the car in top gear push it and see if the inner cable is turning. If not then the cable has either broken and needs replacing or not engaging in the gear box drive,or (Unlikely)a problem within the gear box itself.If its turning try to get a replacement speedo. Then you can practice taking the old one to bits ,if you fix it you have a spare. Good luck with it

Thank you for your inputs. I appreciate your help. If I purchase a speedo from Britain is it easy to switch a KMPH face with an MPH face?

Thanks Again

Steve

Steve-B wrote:If I purchase a speedo from Britain is it easy to switch a KMPH face with an MPH face?

I'm a bit confused. It's still MPH in Britain (we're not 100% metric yet), which is what I assume you'd want in the US as well. I'd imagine that a Minor speedo in KPH would be fairly rare outside continental Europe and Aus/NZ.

Yes - I thought only Canada had KPH speed limits ?? Our Minor speedos are mainly MPH, although some of the later ones also show KPH numbers in smaller figures. No - it's not easy to swap dials without wrecking the unit - so don't plan on doing that!

Hi Steve, I have just had a spare speedo recalibrated for different diff and larger tyres. The old one works perfectly ( for standard running gear) it has 39,000 miles on it. Could sell you it if you are interested.

The only difficult part about changing the face is removing the needle. Once that's off, there's only a couple of screws. To pull the needle you should have some kind of tool to get underneath the needle near the stem and pull. The plastic breaks fairly easily.

I worked on a car that had a odo drive gear with missing teeth. But all may spares had a different pitch/tooth count. I did find an aluminum one that I modified to work.

But - then you have to get the needle back on in the correct location - or the speedo will be wildly inaccuarte!

I've never been game to remove a needle, for that very reason. Unless you had some way of marking the spindle to ensure exact replacement...

I did it once - ruined the speedo!

When I picked up my re-calibrated speedo last night, the bloke who did it imparted a few words of wisdom.
1. Do NOT oil the cable (it cuases friction)
2. If needle jumps around. Remove inner cable and very carefully inspect it. With a magnifying glass if possible. There may be bits of frayed cable sticking out and catching on outer cable.
3. While doing this inspection. Check for any shiney bits. This is where outer is kinked, slightly.
4. When putting inner back. just pull it through an oily rag (to prevent rust)
5. When screwing cable to speedo. Make sure inner doesn't stick out more than 1/2" otherwise it will bottom on inside of speedo and the 1mm pitch thread will cause damage. Apparently you can get a few hundredweight of pressure with the secureing nut.

One last point, apparently there are 2 sizes of inner cable 3mm and 2.5mm. The latter more commonly used on Fords. Type 9 box possibly??