Tach cable O-ring sizes

[esmeby]

My tach cable at the dizzy is one of the many places my car is leaking oil. Does anyone know what size or number o-ring(s) it uses co I can run down to the hardware store to get a new one?

Thanks for any input.

[jeffvh]

I recently replaced my tach cable. My orginal cable had a flat non-metallic washer for the seal. I couln't remove it to move it to the new cable so I searched for a suitable replacecment. I used a new oil drain plug washer that matched the diameter of the end of the tach cable seal. The gasket is non metallic and meant for oil seal duty..
After looking at my old tach cable and the impression in it's gasket, O dont know if an O ring would work,,,

[itsa68]

Its probably not an o-ring leaking.

Take off the cable and look inside the sleeve assy for the tachometer pinion drive. There is an oil seal (not an o-ring) inside there that everyone overlooks.

I believe the part# is 32709-14600 for both the 1600 and 2000.
It not shown in the part book figure 22 diagram but its is in the parts list (item 105).

I have one in front of me and it measures .635 o/dia , .375 i/dia, .155" thick.
When installed you must face the inside diameters seal lip towards the distributor so the oil pressure forces the lip against the pinion shaft for a positive seal.

This oil seal is also used for the speedometer pinion drive at the transmission.

Hope this helps.
Ray B.

[esmeby]

That does help, thanks.
One question I am not clear on, does the seal stay inside the dist housing when you pull the cable out?

I found a rubber seal inside the cable end itself that looks a bit shot. It is more of a boot, or funnel shaped seal. I don't think it is the item you are talking about.

.

[jeffvh]

As I posted earlier, I replaced my tach cable I must not have the right oil seal components because Oil is coming through the cable and out of the tach and over an hour of driving I get a few drips on my leg. had a similar problem once when the oil guage fitting was loose, but this time it's coming from the back of the tach.

My old cable is shot, but I do see a funnel shaped gasket at the "dizzy" end that may be what keeps the oil where it belongs.

[Guest]

The seal I'm talking about stays inside the pinion sleeve assy on the distrib. (I replaced my seal while my dist was out because it was easier to remove pinion assy and splindle)
Its stays there even if you remove the cable because it is internal. Remove the dist pinion sleeve assy and you will see it press fitted in place.
It looks like a small version of the front timing case crankshaft oil seal.
The metal line connected to your dist base provides oil pressure to the distrib.
This seal is the primary seal that prevents dist oil pressure from getting past the tach drive pinion shaft (which drives the cable) so it cant get into the tach cable side.
The plastic and rubber cone seals you are describing are more like secondary seals which prevent none pressurized cable lube from leaking from the cable.

Hope this helps
Ray B

[70MTroadster]

amen.....

my 1600 tach cable was leaking profusely....replaced the pinion seal and no more worries whatsoever.

Not too tuff to do either.

scott

[itsa68]

You might want to get a few spares as they are not expensive and you should replace the one (same size) that is on the speedometer cable pinion at the transmission if cable is leaking.
It is not oil pressurized so it doesnt leak as much.

Good luck
Ray B.

[Minh]

I was reading the back of PB Blaster can...

It says that it is great for restoring O-rings.

Hmm go figure...

[S Allen]

itsa68,

Hey, this has come up before and this is some really good info. Is there any way to verify the PN's short of ordering a couple. Do you mind if I put it up on the main website as an FAQ? Thanks.

Steve

[itsa68]

In front of me I have a nos transmission repair kit which lists the speedometer pinion oil seal as 32709-14600.
The oil seal inside the box is exact same one as measured for the tachometer pinion and has same manf name and number.

Nismo has them listed for $2.

The 7/8" diameter o-ring which fits over the threads of the pinion assy ,which screws into the casting, is 32710-14600. This joint never seems to leak ,so I wouldnt bother getting a spare one.


You could probably also get an over the counter alternate oil seal from your local bearing supply house by supplying them with the inside diameter of the pinion sleeve,outside diameter of pinion shaft and the thickness of old oil seal. (also bring your old one with you).

Good Luck
Ray B.

[esmeby]

My new seals came in about two weeks ago, but in between home, child and work projects, I have very little time to work on the car right now. I may get a few minutes here and there, so can anyone tell me what is involved with replacing the seal?

I know this has to be an extremely simple job, but if I go into it with an idea of what I need to do, that will make it much easier.

Do I unscrew the pinion housing? Will any parts spring or fall out of there? Just remove cable and reach in with a dental pick to remove the old one?

Thanks

[itsa68]

No loose parts should fall out.

Unscrew the pinion housing nut and the pinion should stay in the distributor base with its shaft sticking out.
On the pinion housing nut you removed, notice that there is an "o-ring" on the threads. This o-ring rarely leaks.
Look inside the counterbored hole on the cable side of the pinion housing nut and you will see the small black oil seal at the very bottom.
The flat side of the oil seal is facing towards you at the cable attachment end of the housing nut (the grooved side faces towards pinion shaft) .

Remove oil seal using dentists pick (or seal hook),using caution as not to scratch inside the housing nut bore. (The seal is pressed in pretty tight to the bore, so it might take some tongue to get it out.)
If you get some minor scratching on the inside you can give it a quick light hone with some 400-600 emery paper and wash of any grit residue.

Put some motor oil/wheel bearing grease on new oil seal and install with grooved side facing towards bottom of the pinion housing nut counterbore.
Use a piece of hardwood dowel (with a squared off end and is same size as the outside diameter of the seal) and push the oil seal into the bottom of the housing nut counterbore until "seal seats square against the bottom of the hole".

Put some oil/grease on the housing nut o-ring and pinion shaft and re-install pinion housing nut to distibutor base.
Re-attach tach cable...and you done and no more leaks.

The speedo cable oil seal at the transmission end (under the 90 degree speedometer adapter) is done in same manner, but if I recall correctly, the pinion shaft wants to drop out when the pinion sleeve is removed.

Ray B.

[esmeby]

Perfect!
Took me 1/2 hour total including battery removal, getting the camera, customizing a tool to remove the old seal etc.... Cheapie dental picks aren't up to the task to pull the seal. It was fairly stubborn but it came out.
One other note, a 11mm deep socket works great to press the new seal in. Just use the 3/8" side against the seal and you are all set.

Thanks for all the help.

[itsa68]

Nice to to hear that it eveything went fairly smooth.
Now you can enjoy a oil free engine compartment.
It always seems that the oil from the tach cable makes its way down to the trans bellhousing and drips onto the ground making one think the rear main or pan gasket is leaking.
The tip about the socket install tool is a good one.
I tried to avoid mentioning the use of metal because of a possible jam or scratching the bore.

Happy motoring!
Ray B.