SIII Speedometer Problem

This site contains affiliate links for which LandyZone may be compensated if you make a purchase.
GingerPuss

GingerPuss

Active Member
Posts
232
Location
Southport
Hi Folks,

My 'new' (1976) 88' SIII Petrol has only ONE mechanical defect :p

Driving back from Manchester I seemed to be overtaking lots of cars.. but my speedometer showed 45 MPH !!

I decided to use my SATNAV as a means to check the speedometer. I get the following:

Speedo = 26MPH (SatNav = 30 MPH)
Speedo = 45MPH (SatNav = 58 MPH)
Speedo = 55MPH (SatNav = 65 MPH)

Obviously my speedometer is under-reading (I assume the digital speedometer function of my GPS system is accurate). Given that I do not want a speed camera to flash me unwittingly breaking the speed limit (I don't want to have to use a GPS full time!)... can anyone please suggest what the problem might be and how I might start fixing it.

Wheels/tyres are stock (?) 205 R 16 (Michelin)

Many thanks
Mark
 
All I know is the tyres are Michelin 205 R16 (that is all I can make out on the sidewalls). I don't know what the wheels are - they just look like standard pressed steel land rover wheels (painted 'Limestone').

I have been busy fitting a fuel filler hasp and padlock today anyway... some fuel thieves have been noted in the vicinity!!
 
Well... today I fitted a brand new Britpart speedo cable... took off the steering wheel so I could withdraw the instrument panel properly.. pushed the speedo cable in until it 'clicked' into place... threaded the cable to the gearbox end carefully and pushed it into the speedo housing and tightened up the 3 screws that hold the cable end in place. Final checks to make sure the cable was properly routed and not kinked or crushed anywhere... then took it out for a test drive.....

... the bast### doesn't evenb register any speed at all... like the cable isn't even turning!!!!

The new cable looked the same as the old one... but how come I don't even get the needle moving on the clock???

I just treated it to a set of new 235/70/R16 tyres as well!!!
 
GingerPuss said:
Hi Folks,

My 'new' (1976) 88' SIII Petrol has only ONE mechanical defect :p

Driving back from Manchester I seemed to be overtaking lots of cars.. but my speedometer showed 45 MPH !!

I decided to use my SATNAV as a means to check the speedometer. I get the following:

Speedo = 26MPH (SatNav = 30 MPH)
Speedo = 45MPH (SatNav = 58 MPH)
Speedo = 55MPH (SatNav = 65 MPH)

Obviously my speedometer is under-reading (I assume the digital speedometer function of my GPS system is accurate). Given that I do not want a speed camera to flash me unwittingly breaking the speed limit (I don't want to have to use a GPS full time!)... can anyone please suggest what the problem might be and how I might start fixing it.

Wheels/tyres are stock (?) 205 R 16 (Michelin)

Many thanks
Mark
Click to expand...
Tis a long time since my SIII 109 rotted away but I always had the same problem. From what I recall (and it's a long time ago) the drive for the speedo is not gear driven, just pinched onto the final drive shaft by pressure of the nut on the back. I was told that you can cure it by overtightening the nut on the back of the shaft. I never bothered, so don't know if it works, or if it's a load of ****!:D
 
I believe a loose speedo drive is more likely to give a fluctuating reading (v common on LRs) rather than a consistently low reading. Tight-knit the nuts in the middle of the Hand Brake drum (take off the prop shaft first, will sometimes cure a fluctuating speedo.
 
Davec said:
I believe a loose speedo drive is more likely to give a fluctuating reading (v common on LRs) rather than a consistently low reading. Tight-knit the nuts in the middle of the Hand Brake drum (take off the prop shaft first, will sometimes cure a fluctuating speedo.
Click to expand...
That sounds familiar. I think mine did tend to fluctuate. Speed cams had not been invented then, so i never cared much!
 
The other option is that the diffs have been changed for a different ratio. I had exactly this problem with a Bedford CA, into which someone had stuck an early model axle. Someone may have wanted some extra speed and put in alternative ratio diffs - I understand there were options available. It may be possible to put in a different ratio transfer box too, which would have same effect, but I don't know if that's an option.
 
The speed drive is after the transfer box, so that wouldn't affect it, Diffs is a thought though.
 
Well... my parcel arrived yesterday... new pinion gear and speedo housing, gasket and seals etc. I will try and fit it all today.... but since there isn't much else to replace at the gearbox end of the speedo cable if it doesn't work then my old satnav will be a permanent fixture for speedo duty!!
 
GingerPuss said:
Well... my parcel arrived yesterday... new pinion gear and speedo housing, gasket and seals etc. I will try and fit it all today.... but since there isn't much else to replace at the gearbox end of the speedo cable if it doesn't work then my old satnav will be a permanent fixture for speedo duty!!
Click to expand...


Replaced the speedo pinion gear/housing/oil seals/screws and gasket...put the new cable in and set off..... still no fu##ing movement in the clock needle...although it works when I attach the end to electric drill.

Sod it.... will have to use the satnav !! :mad:
 
Try pulling the speedo cable off the clock, then drive the vehicle. If the flexible shaft in the cable is not turning then there must be a problem with either speedo drive mechanism or the connection between that and the speedo cable. Is the end of the speedo cable to the gearbox correctly shaped compared to the old one. With the cable removed from the clock but connected to the gearbox, can you turn the flexible shaft with your fingers (you should not be able to). Disconnect the cable from the gearbox. You should be able to turn the flexible shaft now.
 
You must log in or register to reply here.

Similar threads

EmilH
Series 3 Think i found the problem.....
Replies
1
Views
389
biketeacherdave
biketeacherdave
kurgan
D1 V8 auto jap import Speedo reading wrong.
Replies
1
Views
1K
discool
discool
T
Hello from the Scottish Highland.
Replies
4
Views
296
brianp38dse
brianp38dse
Flat 6
Poor running when warmed up
2
Replies
32
Views
2K
Turboman
Turboman
dag019
speedo drive
Replies
5
Views
709
dag019
dag019
Back
Top