Morris Minor Owners Club

Hey everybody, I'm hoping I've found an open minded forum who might be able to help me out with a project I am working on. It's not strictly Morris related...

I have a 71 Triumph Bonneville T120R that runs a conical hub with a 8" TLS drum brake. The problem with the conical hub is that due to the way that the brake operates the cable run from the lever is a big loop and not very tidy. The earlier brakes are much more neat, but you have to buy a whole new fork assy to mount them. This got me to think if I could improve the brake performance by converting to a hydraulic drum, I could tidy up the run lines. There are a lot of rumours that the hub uses car brakes. A quick visit to the local parts place and a route through the parts catalogue has shown that the conical hub uses Morris Minor pads.

I have spent the afternoon trawling the Internet looking throught Morris sites and trying to find brake specifications and mastercylinder drawings. What I have found is that the Morris appears to have two different types of set up, side valve and the later type. And this is where I am stuck... So I have a few questions!

1) what's the main difference between the two different systems?
2) how do the lines attach to the side valve systems? Does anyone have any pictures?
3) Does anyone have any technical/dimensioned drawings of either of the systems?
4) does anyone have a scrap/rusted backing plate for a bit of beer money?
5) bit off piste, but are there and performance shoes available?

Lastly, thanks very much in advance.

Ian

Hi Ian

this is the set up that is most common on minors, from about 1953 onwards. These can be used with either 7 or 8inch brakes drums and shoes etc and has a separate hub assembly.

http://morrisminorspares.co.uk/shop/pro ... 0a1da3dfd1

the sidevalve cylinder is this one, it uses 7inch drums and has the hub built into the brake drum

http://morrisminorspares.co.uk/shop/pro ... 0a1da3dfd1

All the brake parts for the later set up will be easily obtained, the earlier set up will be a case of searching for the the drum hubs.

Heres a link to a post on brakes here and has great pics of the sidevalve set up from david53 on the second page

http://www.mmoc.org.uk/viewtopic.php?f= ... 2&start=15

I dont have any more technical data, hope this helps a bit.

David,

Thanks very much for that, the pictures are a big help. So if the later system can be used on both 7" and 8" shoes, does that mean that the two systems have the same distance across the wheel cylinder between the two mount points? I.e. between the moving face on the piston and the back face where the second pad sits?

The reason I ask, is that although the pads are definately the Morris 8" pads, the wheel cylinders for the 8" system don't lend themselves to the triumph hub. The anchor point for the brake plate on the fork looks like it would get in the way of the lines coming in.

The picture below shows a modified set up, albeit on a BSA, but it might give you an idea of what I'm trying to achieve.[frame][/frame]

Those aren't minor brake cylinders on the BSA unless they have been modified a lot.

Are there and performance shoes available?

EBC do Minor shoes, otherwise go for a named make like Mintex.

Minor front brakes use the same cylinders for both 7 and 8 inch backplates. For the weight of your machine - standard brake shoes (not pads - surely - or are you talking about a disc brake???) will be more than adequate.

Yes you're right, I mean shoes! First vehicle I've had with drums so I have to get used to using the right terms!! Although you are right that the brake should be adequate, my last bike was a 2011 Speed Triple, with twin 320mm Brembo radial callipers, so what ever I have on this will feel pretty dire compared to that!

I am thinking of using a couple of the cylinders shown below. Although this is listed as for a Morris Traveller, I think it is the same as the early Minors. This should allow me to have the fluid exit point through the 'cam hole' on my brake plate, and I will just need to sort lines and a bleed point on the bottom cylinder.[frame][/frame]

And a pic of the brake plate...[frame][/frame]

Those are early cylinders as you say.
There was also a change in the bore of the master cylinder, from memory from 1 inch to 7/8ths. Pretty academic in your situation as it's a big lump of cast iron that needs to be push rod operated.
As cars with discs tend to use servos I guess that bike master cylinders/levers are sized in a way to render a servo unnecessary.

You'll need to mark out and position the cylinders v accurately, and of course make sure they go on 'twin leading shoe' for best stopping efficiency.

I'll do some calcs to work out the master cylinder size I need. Should be able to benchmark some other bikes for piston vs. calliper sizes.

With regards to marking the plate up, I guess I'm pretty lucky as I work for an engineering company so the plan is to build the shoes on to the cylinders and get them on the ITP machine, and then produce a drawing for our CNC shop. Hopefully I should be able to get things pretty accurate.

I love projects like this, the ones that make you think. To make things work that shouldn't work.

Thanks all.

Is the picture of the cylinder a Minor one? I thought all Minor front wheel cylinders had two angled hose/pipe ports? Or are the Series MM different?

Yes the early cars had a different set up, where a banjo screws down the centre of the wheel cylinder.

One thing I think I've worked out is that although my brake is on the right, I think I need to order LH wheel cylinders, as the brake plate is stationary on the outside of the wheel, i.e. it will look the same as the Morris brake plate on the LH axle.

The second interesting part of this build is building the remote master cylinder. I'll be using inverted levers on the bike, so they will have to be cable operated through the middle of the handlebar, to a remote master cylinder hidden under the tank. Just need to size the master cylinder and then work out the details!