TC rear axle oil leak onto brake shoes (yep, again ......)

[Nigel D]

Around a year ago I noticed oil leaking down the wire wheel spokes on rear left of my '49 TC, so I removed the brake drum to find brake linings covered in oil. I fitted Roger Furneaux's bearing nuts with lip seals which seemed to fix the problem, so I subsequently replaced the brake shoes.

A few weeks back doing routine maintenance I removed the brake drum & again found the brake shoes covered in oil - less than previous but still ruined / useless.

I'd read about need for a gap between hub and bearing housing (there wasn't one) so fitted an appropriate shim & tightened using new gasket & sealant in hope that would fix problem . Just pulled drum off & oil is still leaking onto the brake shoes. I suspect the lip seal nuts are doing their job, but oil seems to be leaking through the wheel bearing itself - I've tried to capture on pic attached.

I only have this problem on this side of the car, other side brake linings are perfectly dry.

I'm now considering replacing wheel bearings, possibly also including fitting new taper fit half shafts & hub. Before I go this expensive route anyone got any thoughts what else I could try? Thanks

[stephen stierman]

A couple of thoughts for you; is the splined hub tight on the axle? I mean really really tight and not moving even slightly? I assume you have replaced the seal at the bottom of the bearing holder? If the nut seal is working there essentially should be no gear oil in that wheel bearing, typically greased sealed bearings are used.

[Tom Lange, MGT Repair]

Also, did you install a Speedi-Sleeve over the splines where the half-shaft meets the hub? There's a good video of the entire process at From the Frame Up.com

Tom Lange
MGT Repair

[Steve Simmons]

Agreed, the surface the seal rides on must be perfectly smooth or the seal won't last. This is also a good time to install permanently sealed bearings. That should stop anything from coming through that way.

As a side note, you can save the oil-soaked shoes by heating them carefully with a torch to force the oil out. I do this, and then wipe with brake cleaner spray, then repeat as many times as necessary to get it all out. I'm also told that some people boil them in water.

[ian theobald]

My car leaks oil into inside of splined hub but does not seem to get inside brake area as some previous owner has applied silicone to where backing plate area is.
I was told by an old mechanic that a common simple fix for this was to insert a bath plug into hub under spinner.
I have not yet tried this .
My car has a TD diff married up to a TC welded at the area where nump rubbers are so have no idea if half shafts the same so have left as is.
Maybe the bath plug is the simple solution your after.

[stephen stierman]

These rear axles can be made not to leak lube onto brake linings even without the NUTSEAL arrangement although it can be helpful in many instances. The splined hub must be very tight on the axle. The seal in the bottom of the carrier must be good and sealant must be applied to the bearing carrier flange and the splined hub flange so oil does not leak out between them. The bearing in the carrier must be nipped up tight when the big nut is tightened down, pay attention to the clearance suggested between the two flanges. Also clean the grease from inside the splined hub where the axle goes through and hold it up to the light, you can see light shining through the gaps between the splines and the hub, no wonder they leak out onto the spokes. Lay a couple of good thick coats of silicone sealant into this area and allow to dry than assemble. All should be dry.

[Duncan M]

Sounds like you may have corrected for the poor gap, but damage to bronze scroll seal (oil slinger) has likely occurred. Slinger can be replaced. Scroll seals on the diff of this car (axle ends and pinion) can give drip free operation for tens of thousands of miles, if diff is not overfilled with oil.

The steel scroll seal of pinion typically gets wiped out if pinion bearings allowed to get worn out and the pinion shaft starts wobbling. Same sort of wear can happen to the bronze scroll seals if something is out of whack.

[stephen stierman]

Duncan,
My belief is that if you have the bearing area sealed up via a good lip seal at the bottom of the bearing carrier to the axle housing, the joint between the bearing carrier flange and the splined hub flange sealed, and than the axle splines sealed where they go through the splined hub (along with a very tight fit here) there really is no way oil can get into the brakes. I am not sure those bronze slingers really do all that much anyway....

[Duncan M]

Good point Stephen, the lip seal nut is also probably worn at lip seal. I know how the "modern" sealing is designed to work, but from Nigel's post it would appear the only mod is using just the (lip seal) Roger nut. When using the full "modern" sealing system the oil slingers can be removed.

How the original axle end slinger sealing system can gradually wear out is never discussed any more in forums like this. Also never discussed is how the "modern" system will wear out eventually and cause the same problem.

[Steve Simmons]

All valid points, although the modern rubber seal can be replaced far more easily than a worn reverse scroll.

[Duncan M]

True, but when the original setup has everything adjusted and properly maintained in the rear end, those scrolls are not a wear item.

[Steve Simmons]

True again! Although one more counterpoint would be that even a perfectly set up scroll will weep a tiny amount, and possibly a larger amount if parked sideways on an incline. And preventing wear would require making sure the bearings never get worn to the point of allowing contact. But now we're picking at straws.

[stephen stierman]

If everything is sealed up properly as I described in my first post and the splined hub is TIGHT on the axle shaft there can be no leaks onto the brake linings. Whether the slinger does any good or not there is always going to be gear oil in the area around the bearing that is sealed up as I describe but it just cannot escape onto the brakes. The nutseal is a good idea as it just keeps gear oil from entering this space, but if everything is sealed properly it is not needed as the oil it prevents from getting into the bearing space stays there..

You know if you look at the differentials of other Brit cars of the fifties and sixties and beyond with straight axles, they are made up the same way as the TC and they use no reverse scrolls to keep oil in. The big difference is the axle and the drive flange are one piece with often times a bolt on splined hub for wire wheels. There is no splined axle pressed into a splined hub that can get sloppy and cause all manner of leaks back there. None of them need any sort of nutseal arrangement to keep oil out of the bearing carrier.

[Duncan M]

FTFU has a good tech tip that gives guidance on the "pinch" to look for on the rear bearing to hold it in place. Must be done on either old or new style oil seals. #16-18. https://fromtheframeup.com/uploads/TT_C ... ersion.pdf

[Steve Simmons]

If you're talking about later cars as in TD, TF, MGA etc, there is a rubber oil seal on the carrier after the bearing, unlike the TC. But yeah in theory if you set everything up correctly on a TC then it's possible to stop the leaks.

[Duncan M]

Stephen, you are right of course. I run the original sealing setup and no leaks. I have even run a lighter gear oil for a while to help flush things out, and just cannot get it to leak. I suspect the Hylomar has helped keep things contained. You are right that everything gets sealed up in the arrangement. The axle end oil scrolls were to keep the oil from contaminating the grease on the original (open) ball bearings. That is why there was an oil fitting to refresh grease there. Even with the sealed wheel bearings I use, I still like the idea of gear oil being more or less kept away.

[stephen stierman]

Steve, the TC DOES have an oil seal under the bearing at the bottom of the carrier just like all the rest of these cars, it seals against the outer machined surface of the axle housing.

[Steve Simmons]

The TC has a seal behind the axle bearing, outside of the bearing. It's dual-purpose, meant to keep road grime out of the bearing, and to hold back at least some of the oil which gets past the reverse scroll and through the bearing grease.

The TD/TF axle, and MGB Salisbury axle, have an oil lip seal at the outer end of the axle, which rides on a machined collar on the half shaft. There is no reverse scroll to keep oil away from the bearing, so oil is free to flow all the way past the bearing where it is held back by the rubber seal. This is sort of what the sealed nut mod on the TC replicates. There is no seal that rides against the axle housing on these cars like on the TC.

The MGA uses a more similar arrangement to the TC than does the TD, TF and aforementioned B, but incorporates a rubber O-Ring between carrier and hub and an oil seal meant solely to hold back oil, which is free to flow through the bearing. The paper gasket then becomes merely a spacer. No sealer is necessary.

[stephen stierman]

It appears that the Brits used several different sealing arrangements in an attempt to keep oil out of the rear brakes. Big and little Healeys used a set up almost exactly like the TC with a one piece axle and flange that mounted either a wire or disc wheel hub arrangement. Doing away with that splined hub pressed onto an axle was a step in the right direction.

[Steve Simmons]

Agreed! The guys who race early MGBs (with banjo axle almost identical to MGA) sometimes cut the axle ends off and in their place weld the ends of the Salisbury type axles for their stronger axle retention technology. Then they install an appropriate axle to match the splines of the spider gears. The later axle setup is structurally superior and far less likely to leak.