Thread: RTC3510 v's RTC3511

If I was to take a punt I would say you need RTC3510. Both my 109s have a sals rear diff and are 1976 and early 1980. The change over date as I understand it refers to the standardisation to metric. I think the inner and outer bearings post the change over date in 1980 were the same size. If they are not then your diff is pre the change over date in 1980.

Thanks 109. RTC3510 seemed to fit neatly. I test fit it over the spindle first (with a bit of lube) and it tapped in nicely into the hub. All fit up well. Could I ask what you mean when you refer to the bearing post? Is that where the inner and outer bearings inner race meet the spindle?

Both of my sals diffs use the RTC3510. I would measure for your but my hubs are back together finally.... I did however buy the wrong part! I had purchased the RTC3511 because it's a double lip seal, but alas it doesn't fit!

Option 2 would be to look on the side of the old seal - has numbers on it. These are measurements; just take them to the local bearing mob and get double lip seals in that size. Alternatively take the old seal to them.

I ended up giving my RTC3511 seals (a full set) to a friend with a county, then purchased a set of RTC3510. Hope this helps you.

Good luck!

Okay - post equals after..... The beauty of the English language! Hard to tell without knocking them out. I think the spindle was the same diameter down its length. Is it the outer race that changes? Don't think I'll worry about pulling apart again unless the seal don't stop the leak. Searching for drawings now.

if the seal doesn't fix it, check your stub axle collars, they tend to wear... easy enough to change if you have a little shop press.

Originally Posted by snafubar

Thanks 109. seemed to fit neatly. I test fit it over the spindle first (with a bit of lube) and it tapped in nicely into the hub. All fit up well. Could I ask what you mean when you refer to the bearing post? Is that where the inner and outer bearings inner race meet the spindle?

Sorry my bad, I meant to say "inner and outer bearings" I have edited it now


What I meant was after the 1980 change date both bearings are the same size. If the inner and the outer bearings are different sizes then RTC3510 is the correct one.


seems like you are onto it anyway


I had had a few bevvies when I posted lol

If you are chasing leaks around an axle it might be worth swapping the breathers. I did this whilst waiting for the seals to be delivered and..... Presto leak stopped.

Breathers! Yeh. Didn't consider them. This weekend, fuel hose and a couple of barb fittings. I'll stuff the ends with a bit of rag for now. Anyone have any neat ideas where to mount the ends (f & r) once I sourced some breather filters?

Re the difference in seals - I heard it may be when the metric system started cutting in.....(confirm 109 comment) And that the collar the seal runs on was no longer removable and the step was machined as part of the spindle. Anyone noticed on a late model sals if the hub seal running surface is part of the spindle?