M type brakes

[ashford]

Does anybody know how M type brakes differ from J2 brakes. I know they both have 8inch drums with shrunk on alloy fins and appear the same. However they are listed separately in the various MG catalogues suggesting thay are not interchangable. Ignoring the different cross shafts and cables - are there differences in the backplates, drums, cams etc.
I am asking this question as I have been offered a set of new J2 fully rebuilt brakes and Im wondering if they will be any good for a minor chassis.

[ian judd]

The J2 backplates are the same diameter as late Minor cable brakes, ie. slightly larger than M type. The drums are larger too having a bigger rim, and the same diameter as late Minor. The problem is that they are drilled for knock-off hubs so there are six large holes instead of three 3/8th holes and three chamfered ones. I have a couple of J drums but have never been able to work out a way to use them.

Regards
Ian

[ashford]

Thanks for your comments Ian. I have one j2 drum (which I had previoulsy presumed was m type) and I hadn't spotted the larger holes before; which means I can't use the six stud morris 8 hubs as intended. However I have found that the wolseley hornet saloon hubs (The main casting of which seems identical to morris items) have a larger diameter rim turned on the base of the wheel studs which located in the brake drums. This enabled wolseley hornets to use the same brake drums on the specials (which had knock ons) as the saloons (which had magna bolt ons). So thats one way you could use your J2 drums!

[dixiedog]

speaking of brakes, it seems there are two types of emergency brakes..one with a drum at the rear of the transmission, the other with some other set-up.
how was the later system hooked up, and what did it act upon?

[DF9053]

Your right there are two types of handbrake on the Minor and M type.

The first was a transmission brake and should only be applied when the car is stationary other wise unspeakable thinks happen to your back axle!

The other later type operated by pulling the brake cross shaft with the handbrake lever and thus giving a four wheel handbrake in the same way as the brake pedal worked.

You can modify the transmission handbrake lever to pull on the cross shaft easily, just get a short cable or chain made up and atach it at the point the rod attached to work the tranmission brake. Modifying the cross shaft is less easy although you could change it for a later one which has an upwards facing lever in line with the handbrake. The chain/cable linkage and its fixing to the cross shaft has to allow the cross shaft to move without putting the handbrake on as this can be a pain in use!

It is quite a worthwhile modification and on DF stopped it rolling away whilst you were not looking!

If you need more detail please let me know

cheers
Jeremy

[dixiedog]

Jeremy,
Thanks for the reply. I now see just how it works. Much better than the drum brake on the trans bit of work. Merry Christmas to all!