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MG TD TF 1500 - Talking about the front brake drums

TD 4139 came to me 48 years ago with the metal cap type cover over the axle nut on the front brake hub.

I know that a TD of this age should have the original grease seal with the axle nut outside of the seal. (picture 1)

I found two of the original seals and went to install them today. It will not work. After researching, I have found another interesting find.

The TD had at least 3 changes to the brake drum.

The original drum on early TD's was a two-part drum. It was replaced with a single piece drum around TD 4251.

But, they modified the drum again around TD 6035 to accommodate the press on steel grease cap. The drum was modified by extending the flange in the center of the drum. This allows the outer cap to go on without hitting the axle thread. Clausager lists the change to the cap, but the increase in the flange length is not mentioned. (Picture 2)

A kit was produced to change both the two part drum and the early one part drum to a cap type seal. (see page K 10 in the shop manual)

The old seal will not work on these later drums. If you put the old grease seal on the extended flange brake drum, the nut cannot get back to where it is pushing on the bearing. The nut also does not screw on enough to get to the split-pin hole.

In looking at the early cap, it is also clear that you would need to use shims to adjust the tension between the bearing and the grease cap/axle nut, as the cap sets against the flang of the drum.

Changing to the press-on grease cap allows the axle nut to push directly against the bearing with a single washer. This makes it easier to adjust the tension.

So, my car had the front brake drums changed sometime in its life to the later type. BTW, I could not find brake drums listed in the 1958 parts list.










Bruce Cunha

Here is a picture of the later brake drum with the early seal and nut. Clearly, it will not work.

Page K 10 showing the longer flange and the shorter flang single piece with the modified grease cap.




Bruce Cunha

No shim stock needed with the early set up Bruce. When assembled the cap will have a small clearance to the drum hub without any shims.
L E D LaVerne

I need to rethink that one Lavern. If there were any changes in the thickness of the bearing (IE a new bearing), there would be space between the grease plate (that the nut pushes against) and the bearing, Since the grease plate hits on the edge of the drum, it cannot move in farther. This would allow the hub to move.

In the improved system, the nut pushes against a washer which pushes against the bearing. So any adjustment would be by tightening or losening the axle nut.
Bruce Cunha

It would take quite an out of spec bearing to cause an issue. The gap between the hub and cap when assembled is roughly 1/8" inch.
L E D LaVerne

LaVerne is correct- quite a space between the early steel cover and the drum. "So any adjustment would be by tightening or losening the axle nut". The nut is tightened or torqued to the next split pin hole- early or late type. No adjusting at all, like you do with modern tapered roller bearings. George
George Butz III

On the early with the flat plate grease fitting, I cant see how the grease cap can adjust anything as it is pressing against the brake hub and cant move in any farther.

I can see what LaVern is saying. If the bearing is a standard thickness, the plate should touch, or be very close to the bearing with the nut tight against it.

The later is clearly set to press the nut against the washer on the bearing and gives the ability to set the pressure on the bearing.
Bruce Cunha

This thread was discussed between 07/12/2021 and 09/12/2021

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