340 Speedo problem

Hi all, I have a 1987 340 GLE that I have had for several years now and over the last few years I have noticed the speedo needle "waggles" a lot of the time, moving a lot at slow speeds but seems to calm down and give more consistent readings at higher speeds. My late fathers 240 GL speedo also developed the same behavior. As recommended I have tried searching but strangely no-one seems to have posted on this problem before, as I have a feeling this is quite a common problem on the older volvos. Any advice greatly appreciated.

It is an early sign of the inner cable wearing or fraying , or the cable is routed incorrectly with a sharp bend . The car is warning you that it will fail in the future so i'd try and get a cable for it .. I know the cable for the earlier 300 ( Smiths) up to 1984 is no longer available , but i got a new one made at Speedy cables in South wales they always give a great service .... The later cable ( VDO ) may be still available though ..

hi there the shakey speedo is caused by bad earth. check the earth strap which connects the bonnet to the bar which runs across the top of the headlights. has your choke or heater temperature control become stiff recently? usually the poor earth causes circuits to earth via the choke cable and the heater selector. the little bit of extra heat inside the metal of these cables makes them stick to the inside of the cable sheath. its a one way process Im afraid. these two items being stiff gives hint that a car had a bad earth at some point check the one by the bonnet, once there is a good earth here, the speedo should settle down. I believe on the earlier cars there was an earth connection you could get to on the cable but not the later ones. good luck!! my wifes 440 TD (mechanical speedo ((480s have electric)) also has a wobble. need to look into that in 740s and more rarely in 340s, if the speedo goes to say 60mph as you pull away but then drops down and works above 20mph, it is the speedo head unit ie the dial itself which is at fault S

yes if the main battery earth is dodgy the starter moror will earth up the acccellerator cable and make it stick , the inner ckoke cable is isolated though since the plastic outer cable was introduced around 1985 so that never got warm ! Actualy the Brown earth cable fitted to the speedo cable near the bulkhead was for radio interference reasons as was the earth cable on the bonnet hinges , you will notice the speedo cable goes right past the HT Leads and it was bringing ignition interference into the car near the radio until they decided to earth it ... i was soldering an earth wire to the outer smiths cable a few years before volvo came up with this cure :-)

Well I never did...you hear about something new every day :) cheers James

hi my tip re the choke cable came to me from a retired engineer I used to learn mechanics with, in fact he started teaching me when I was 16. He loves Dafs and 340s so re the choke that applied for the older ones (mk1 and mk2) which nicely fits with your comments about 1985 as Iv enver seen a later one do this nice seeing it all come together! :)

Thanks to everyone who replied. I'll print this thread out, take a tour under the bonnet and let you know what I find... Again, thanks everyone. :notworthy: