Speedo

[wiglaf]

So... driving back to Cambridge from Sunningdale on Sunday, a 100mile trip, as I was nearing home I noticed the speedo didn't seem to be reading quite right - sometimes a little low, sometimes high, as if it were sticking.

On Monday morning I popped to the post office (5 minutes each way), and found that when I stopped, the speedo didn't drop to zero - it stayed at 5 or 10 mph.

Tonight, it really gave up the ghost - taking ages to pick up off zero, only dropping from higher numbers very slowly while waiting or when firmly tapped... generally very sluggish and "sticky"


Having read through old posts, I'm going with my gut instict of "something needs oiling there" as a first guess - but I'd like to know what everyone else thinks, as "the unit's dead/needs reconditioning/the cable needs replacing" all seem eminently possible too. So, opinions?

Also, having fumbled around the shiny chrome ring, how the hell do you remove the speedo? Neither Haynes, nor Porter's restoration book says anything about speedos whatsoever that I can find (am I that blind?)! And all I can find in the leyland Workshop Manual is about bushes at the gearbox end - in section FFF: not very helpful to the ingnorant ameteur like me!


As ever, all opinions, advice etc. very gratefully received!

I suppose this is a judgement from on high for not going to the local branch on Monday, as I had intended to for the first time in ages...

Many thanks

[bigginger]

New cable, I'd say. To remove it, you need to loosen the 2 cross head screws, one either side, which hold it to the dash. There are holes provided in the glove box inners, but I'd say you're best off taking the liners out. Just loosen them, if you remove them, it's odds on you'll lose them. Then push/pull the speedo forwards - it'll be held back by the cable, but it does go.
a

[wiglaf]

Thanks bigginger, I'll have a look at that after work tonight then, and see how it looks. I'll have a crack at oiling in the meantime, see if it's got any hope as a stop-gap, but with a new cable only costing £6.50 I'll order now and worst case oiliing turns out to be fine and I've acquired a perfectly affordable spare!

[alex_holden]

I wouldn't have thought a dodgy cable would cause the needle to stick above zero when the car was stopped.

[Orkney]

What makes them go back? is it like a clock spring or something ?
If it is surprised your not getting a new one every month for Fenchurch

[alex_holden]

Yes, I think there must be a return spring.

I'd be dubious about oiling it. I tried spraying WD40 into a rev counter that was sticking slightly and it threw the calibration way out. I recalibrated it, then a few days later the WD40 had evaporated away and it needed recalibrating yet again.

There are companies who can rebuild and recalibrate speedos. Someone will probably be along in a bit to recommend one...

[wiglaf]

Hmm. Yes, actually - having looked online at the mechanics of how the speedo functions it would seem unlikely to be the cable. I'd like to put it down to general stickiness that just needs a nudge of the right kind, but I should probably face facts and accept that reconditioning is now needed rather than doing it any more harm... better just spend the £50-100 now than get myself more costs and trouble as I go along.

There are a few pointers to refurbishment companies in old threads, does anyone have recent experience? I believe that ESM do them.

Anyway, I'm quite looking forwards to pulling it out and seeing the guts of my instrument panel soon.

[Orkney]

Will have to try and find a knackered one on fleabay for a quid just to take it to bits and see how it works.

WD40 is bad news for a lot of things, learned that as a a kid with bike chains given a choice but they dont sell it here 3 in 1 in a spray can is the mutts nutts - Good ole ballistol is best for a thin oil though and a thousand and one other things.

Remember ages ago someone worked for a tool/die/precision engineering place making some very special and sometimes very small fancy stuff, they used to swear by watch oil of all things, just looked on fleabay you can buy the stuff - not that youd want to pay £3.99 + £1.49 for 1 flippin ML of the stuff Crickey thats just shy of £18k a gallon

[alanworland]

Seems to me that the head (the bit with the pointer on) has gone sticky as it's lubricant has dried out. It may be possible to dismantle it for cleaning and re oiling - I would go for a light lube such as a touch of 3 in1.

[alex_holden]

Remember ages ago someone worked for a tool/die/precision engineering place making some very special and sometimes very small fancy stuff, they used to swear by watch oil of all things, just looked on fleabay you can buy the stuff - not that youd want to pay £3.99 + £1.49 for 1 flippin ML of the stuff Crickey thats just shy of £18k a gallon

That could be worth a try. You would only need a tiny dab of the stuff on the bearings. I just looked at eBay myself and the first one that came up was 15ml for £2.49+£1.75. Bargain! Think I'll buy a bottle myself.

[Orkney]

yeah but the expensive stuff is genuine swiss watch oil and not cut with wd40 Rodney
Sureley something that fine you'd be appling in a dust free environment - how thats done is another question? end of needle as a dropper ? show the watch the bottle?
You'll know when i'm rich - out with scabby's 10w30 and in with watch oil

[MoggyTech]

The way to clean speedo mechanicals is to remove the speedo and suspend it face up over a bath of methylated spirit or IPA. The fumes will disolve any cruddy old lube. Works for old mechanical watches as well. Ensure area is well ventilated and no naked flames. Leave it overnight for best reults. No need to relube afterwards.

[wiglaf]

Thanks for the various advice - the beautiful instrument is now sitting beside me as I type: with the glove boxes out, it was a dream to remove even by torchlight (and yes, I've got a record of which wires/lights go where in the back!)

If I decided I should add some more lube - I'll probably give it a go without and see how that works first - where would I add it? There don't seem to be many (or even any) obvious ways into the mechanism that would be suitable...

While I'm happy with the idea of using meths as a solvent, are there any other cleaning methods people here have used? I assume that there'd be issues in getting access to the interior/front anyway, the chrome ring seems pretty immovable... it depends on what those two big screws in the back do. I hesitate to touch them as one lines up exactly with the mileometer, so unless I'm told otherwise I worry they might be to do with calibration. If they're definitely not, and give access, I'd be interested to see the inside.

That said, if cleaning with meths, and possibly lubing, didn't get the job done I'll probably send it away to be refurbished rather than risk damaging it with my ineptness by doing anything to the insides of it.

Probably ought to sleep now, or I'll be too tired to remember to pick up meths tomorrow...

Cheers all

[IslipMinor]

Wiglaf,

The 'two big screws' allow the speedo head to be released from the case. Before you undo these, you will need to remove the chrome bezel and glass, then the two big screws. The bezel is removed by 'unbending' the bits of the bezel that have been bent over to retain it. Be very careful as the needle is exposed once the bezel and glass have been removed.

At this point you have done nothing to affect the calibration, but do not be tempted to remove the needle unless you have marked the aluminium drum with the needle on zero mph. I would leave it alone unless you really need to remove it.

I would not attempt to clean the speedo mechanism at all - job for the experts in my view. Lubricating the needle spindle should do the job; if not then it will need refurbishing.

The needle turns in two plain bearings, and you could try to lubricate them with a drop (not spray, it's only the bearings that need lubricating!) of 3-in-1 oil on each - not WD40. One is under the aluminium drum and cannot be got at without dismantling the front part of the speedo. The other is up under the face, and if you can't get at it, turn the speedo 'face down' and put a drop of oil on the needle spindle as close to the face as possible, and allow it to run down into the bearing.

If the needle is not returning to zero, it is more likely to be the one you can get at. If the one under the drum gets sticky, the needle can get dragged around the face to wrong side of the zero stop by rotating cable!

Gently move the needle to 30/40 mph and release it a few times. Check that it returns to zero cleanly, with no sticking or hesitation. Reassemble, keep fingers crossed and try it out!

Two places to try for refurbishment - have used both and they did a good job:

JDO Instruments - 01535 672125

Speedy Cables - 01639 732213

Good luck.

[wiglaf]

Final update to say thankyou for all your kind help with this - after cleaning, and a spot of light oil, the speedo is working again. Slightly sluggish, but during the test drive it improved over time, so hopefully it'll continue to get better: the important thing is that it functions for the meantime before I send it for servicing in a month or so, when it will be infinitely more convenient.

Once again, thanks for the tips.