Drive Gear for Speedo cable

W

winston

New Member
I would like to know if there is any detailed drawing regarding the speedo drive gear available,as on the original part the shaft had twisted and broke.I have this machined 3 times as per the original , but after a few kms it breaks again.How is it installed in the gearbox housing and is there anything that can cause it to either get stuck, or come loose insuch a way that it breaks.I am told that the original gear which is made from plastic,are prone to failure,however having had replacements machined to spec,this still breaks.The first tme the plastic gears were still good, as mentioned above, but the shaft had twisted and broke.
Please help!!!
My car is a 74 rover p6 3500 Auto.

Secondly is it possible for the rubber hoses on th fuel line to create a suction.I still have the surge problem mentioned months ago,if the tank is half full or less.If it is full then i get petrol fumes in the cabin.I originally thought that there may be a leak in the tank after watching a similare scenario on the telly with a triumph,The tank however remains dry. Any thoughts?
 
Hello Winston,

Have you checked your speedo for possible problems? If the gears within are binding then that will place untold strain on the right angle drives, and the weakest link will fail,...as you are experiencing.

Ron.
 
Going for the speedo drive first, Winston. I presume you are talking about the gears inside an auto box? You could well find that the true problem is outside the box in the angle drive at the box end, the cable, the angle drive at the speedo end, or the speedo head. All of these are prone to seizure, starting by getting stiff and "lumpy". I'd guess that at the lumpy stage it is possible for a defect to take out the gears in the box, although the usual victim is one of the other components, especially the gearbox end angle drive. All are reasonable readily available new, so it's just a question of working through them all until you are confident you have found the stiff component. But bear in mind there could be several at once!

For the surge problem, I would start by taking each breather pipe in turn off the tank and blowing through, preferably with an airline. Then make sure the pump is up to scratch (if mechanical fit an overhaul kit). Then fit overhaul kits to the carb float chambers. That ought to eliminate problems in the tank and also the possibility of aerated fuel reaching the float chambers and the vapour spilling to atmosphere. If that still doesn't cure things you are looking for an air leak into the fuel between the tank and pump. This could be a pinhole in a pipe, or perhaps at the reserve tap (fit a new O ring).

Hope that helps. Other suggestions welcome!

Chris
 
Thanks for the tips will forward them on as my car is going back to the garage that did the fittingof the speedo (twice Before).The speedo cable, once disconnected turns quite freely , even by hand,however i will have them look at both.(as they should've done).

In terms of the float chambers, these have been overhauled previously, so i don't think this is where my delema is. Another part of the symptom is that the car will drive okay for the first 10 kms, and then only does the "trouble" arise.

I will however check all breather pipies as suggested,as this has crossed my mind as well.
 
I've never experienced a failure of the speedo driven gear, (the one inside the box) and the most common failure is the lower angle drive, often caused as said earlier by siezed speedo heads & cables, or upper angle drives.

I have good used lower angle drives, driven gears, and driven gear housings. I even have the drive gears.
 
Harvey,
any chance that i could urchase one.lease send detailes to the following e-mail ( as i am unfortunately in south Africa) I do not know what the ostage charge would be.My e-mail is winston.shoesmith@sasol.com.I I am also looking for the indicator unit on the steering (as mine acked u yesterday ) this would be the indicator arm that fits on the steering column.
 
Thanks
Harvey
I will forward accordingly.I have been tellling them that i think there is something else causing the speedo to keep failing, but it seems that the mech knows better than me , so everytime it fails i send back to him at his cost.I think they have now realised the i am right ,and will be giving them all these suggestions to go through step by step.Inthis way hopefully it will solve the problem, and save us both money.You don't perhaps have any indicator units,as mine had packed up last week.this would be the part for the indicator arm.I have contacted rimmer bros,bu to no avail.
 
Sorry, any column switches I might have I would keep as spares for mine, but it is possible to clean the contacts in them and that can get them working again.

If you need the speedo bits let me know.
 
winston said:
I have been tellling them that i think there is something else causing the speedo to keep failing,
Click to expand...

Just to clarify, if you look at the link that was in my earlier posting, what's the number of the part that keeps failing?
 
Thanks Harvey

The garage owner has fetched my vehicle this morning,so i have asked him to check and see if he can repair the indicator .They will let me know once the car is finished,as there are other things that i have asked them to check as well.

Will let you know,once i get her back again.
 
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