My Speedo Angle Drive was leaking because it was sitting for 8 years after my retirement!
Upon inspection of the o-ring inside the fitting, there are several things you need to prevent leakage:
Check the o-ring for wear or cuts.
The o-ring must be installed correctly: the brass collar inside the knurled cap must be exposed by pushing the drive thru the knurled cap. Once the groove at the circumference of the brass collar is exposed, place the o-ring in the groove.
The seal is made by compressing the o-ring like a pancake!
Be sure to push the brass collar against transmission side and hold in place. Slide the knurled cap towards the transmission end of the drive and screw it down. May need pliers to screw down tightly!
Do not allow the drive to move or it will displace the o-ring!
Interesting…I wasn’t aware there should be an O ring in there, mine has never had one and I don’t remember a groove as you describe. Maybe there are different types of angle drive ? I use a fibre or nylon flat washer between the brass face and the adaptor piece.
Going from memory here, but I think the O-ring is on the adapter that is toe-clamped to the tailshaft housing. I recall a fiber washer on the brass face. I used a bit of sealant on the washer too.
I cut an O ring groove in the aluminum part from the transmission where the angle drive attaches, replacing the fiber washer. It has helped with the leaks, but now they have moved up to where the cable attaches. Sigh…
My MT75 uses an angle drive that is held in with a circlip. The circlip can be seated OK when the transmission is out of the car. However, when in place it is very difficult to even attach the speedometer cable fitting to the angle drive output without disturbing the circlip.
I thought adding an ~8? long cable extension to the angle drive output would solve the issue nicely. I could then easily access the connection of the two cables from below the car without disturbing the angle drive. Got the idea for a cable extension from seeing similar looking short extensions for the chopper motorcycle crowd when they relocate the instruments. Not the same Smiths thread though.
Having difficulty sourcing a male x female extension though. Not even sure if something exists. Speedy Cable didn?t reply after several enquiries, which I eventually took as a no. Relatively local and very knowledgeable Smiths cable guy says he could not supply the male thread similar to the angle drive output, which he says are 3/4" dia by 26 tpi whit. So the cable extension would be m x f between angle drive output and the existing cable.
I am not sure if this will help but I was having connecting my cable to the angle drive when the angle drive was already attached to the tranny. I ended up first attaching the angle drive to the cable then simply attaching the agle drive to the transmission.
In case of interest to anyone who has not already taken one apart, below is a shot of the assembly.
The steel ferrule is about .235 inches dia. O/D, .125 I/D, cable piece about 2.2 long though hard to measure when sheared…
I just warmed up the angle drive to pop out the welsh plug, the steel ferrule took a lot more heat to disassemble from the cable piece.
.
Jack
I think I ended up doing something similar Jay, but it was very difficult to ensure the circlip was seating correctly. Are you speaking about a circlip setup? I am assuming the stock transmission used a threaded coupling to the transmission, but can?t honestly remember.
The dimensions of the fiber washer that seals the speedo angle drive to the transmission gear drive?
Did this seal the leakage? I had to tighten up the knurled nob with pliers to make it tight enough, I thought it was strange… i guess the washer would take up the slack and seal better!
My hypothesis was wrong about the o-ring sealing the speedo drive…too much thinking!
Checked out RDent’s Parts Manual for diagram of *washer. rdent.com/manuals/index.html * Parts Manual>Transmission>Casing>Item 40>Part #E316-ME-1>Gasket
Thanks to all that dispelled my theory of sealing the Speedo Angle Drive.
Fitting a washer inside the knurled nut will certainly help with sealing the assembly but won’t guarantee it will be leak free. After numerous attempts I eventually found that my angle drive itself was leaking from the large plug in the end which is just staked into the housing … took it apart and applied sealer round the plug and that seems to have finally fixed it.
The speedo gear has a spiral groove around the stem designed to “wind” the oil back into the gearbox as it rotates, unfortunately it also provides an escape route for the oil when stationary. Our cars are generally stationary for longer periods these days which could be why we seem to have more of a problem with leakage. Well that’s my theory anyway
I don’t have dimensions for the washer I’m afraid, I just made one to fit when I had it all apart. The parts list does not show this washer as it was not an original fitment as far as I know.
No. That gasket (washer) #40 goes between the Speedo gear housing and the adaptor piece.
As said before, as far as I know, there was never any form of seal between the adaptor and the angle drive itself and certainly it does not appear in the parts list. I have added a washer in there during my various attempts to stop the leaks.
Errr, slightly off topic, but my speedo cable has (I think) snapped. I have a Plus 2 with the Lotus five speed box. So I am wondering how I get to that angled drive without taking the engine, gearbox or both out.
Has anyone cut a hole in the top of the transmission tunnel to get to it? I would glass it back in afterwards, or if a circular hole put a big rubber bung, grommet over the hole, just in case I have to do it again. This method does feel wrong!
Any other method gratefully recieved.
Kind regards
Jeff 72+2 5 speed.
On the 5 speed the right angle drive is on the upper rear/right of the tail housing behind the gearstick and roughly above the gearbox mount. I’d expect direct access to be shield by the chassis (fold metal chassis anyway) so cutting a hole in the body won’t give you access.
I think you might just about be able to get it from the u joint access hole reaching forwards (and upwards). Failing that I’d see if i could lower the gearbox enough to be able to get a hand to it via the gearstick hole. You’ll need to remove the center console, gearstick (don’t forget to put it in gear first), may be loosen/remove engine mounts and disconnect the gearbox mount plate to the chassis.