Hi all.
I have Lockheed hydraulic brakes fitted on my Nippy. I feel sure they are the standard kit that used 195? to 196? Morris Minor bits with the back plate modified to move it more inboard to line up shoes in drum.

THE PROBLEM I have to have 2.5mm packing spacers under the ends of the shoes to get the shoes to touch the drums and even then I run out of adjustment with the snails before the linings are worn down to minimum.
The packing spacers are fitted:- on the rear- one either side of the fixed pivot block and one on the bottom of the cylinder. Thus putting the shoes 5mm further apart at the pivot end and 2.5mm further apart at the cylinder end.
The middle of the shoes wear while the ends show little wear. (poorly made shoes with incorrect curve for the 7" drums??)
I have attached a page of notes/measurements I have taken. (NO I have not as I can't see how to attach said .jpg file!)
I can think of only 3 things that would cause the problem:
1. The pivot block being too short between shoe ends...........mine are 36.7mm between bearing faces.
2. The cylinder being too short.......mine are 55.12mm between shoe bearing surface at bottom of slot and the flat surface of the piston cover. The snail adjuster (larger than front brake ones) has a distance of 10.45mm between the top of the round pin in the adjuster, where the shoe cut out sits, and the base of the mask that the adjuster sits in (so cylinder plus adjuster in lowest position give length of 65.57mm)
3. The shoes are not long enough. Placing them with heal and toe on a flat surface the height at the centre to the top of the lining (3mm thick) is - 2.42 non slotted shoe and 2.46mm slotted shoe.

To get some of the measurements on the attached page I clamped the old shoes, with 3mm lining in middle and near 5mm at ends into a new cast drum (bought from trader at Beaulieu).
Would someone who has a good working set up which will take full zero to maximum adjustment of the shoes (as on a MM) please take some measurements as above for a comparison.
What makes of shoes and cylinders have been found to be good quality and who supplies them? (part numbers please)

Some thoughts.
The drums are 7 inch.
The heal of the shoe is not circular but elliptical so as the other end of the shoe is pushed up by the cylinder the shoe at the fixed pivot end rolls on an ever increasing radius so that end effectively is pushed upwards as well.
The adjuster snails for the back brakes are slightly larger than the ones on the front brakes (because there are 2 on the fronts but only one on the rears).

Location: NW Devon

Dennis' sketch...

I've just done a quick check of a spare set of new brake shoes with 4.5mm of lining clamped in a used Seven drum, see photo C/O Rhuaridh, and this gives a gap between the shoe ends of:
cylinder end 70 mm measured to bottom of snail cam adjuster slot
pivot end 39 mm.
Placing the shoe ends on a flat surface I measure 2.5" to the top of the lining.
My shoes are stock items from the Morris Minor centre and unfortunately there is no part number on the boxes. It may pay you to visit your local Morris Minor centre and compare your shoes with theirs.
You make no mention of the front brakes, do they have the same problem? If not compare the shoes from the front with those from the rear, the only difference is one of the rears doesn't have a snail cam slot.

Dave's photo...

Re a supplier of genuine Lockheed wheel cylinders and Lockheed equivalent (Delphi) shoes for the 7" brakes on the 1948 to 1953 Morris Series MM Minor (918cc side valve engine) / 1952 to 1956 Morris Series II Minor (803cc OHV) / 1956 to 1962 Morris Minor 1000 (948cc OHV)

The 1948 to 1962 rear wheel cylinders were 7/8" bore, the 1962 to 1971 were 3/4" bore. I believe these later 3/4" bore cylinders can be used as a replacement for the pre 1962 7/8" bore so long as both LH & RH cylinders are replaced at the same time - check with Bull Motif to make sure that information is correct.

Bull Motif Spares offer the following:

http://www.morrisminorspares.net/shop_item.php?ID=4209

http://www.morrisminorspares.net/shop_item.php?ID=1531

http://www.morrisminorspares.net/contact.htm

Bull Motif also supply non original i.e. pattern cylinders and shoes which are cheaper than the above parts.

Do check with their technical sales staff to make sure these parts do indeed match the ones on your Nippy.

Photo below is the set up on a Morris Series MM Minor rear backplate (not sure if one of the shoe springs isn't wrong though)



Jeff.

Location: Almost but not quite, the far North East of England

There should be a short spring in the middle of each brake shoe to hold the shoe back against the back plate. They have not been fitted, therefore I suspect that the person fitting the spring on the back of the shoes has done so to keep them flat.

2 different size snails available. Small ones (x2) for the front Morris brakes and a large one for the back, IIRC. I may have this 'backwards'.
Might this be the issue?

Location: Cardiff

David and Ruarid thank you.
I have not started on the front yet but just had a look and they do have a 2.6mm spacer between each shoe and the base of each cylinder and at the moment with old drums and part worn shoes - about 4.2mm lining in middle - the adjusters are at 5 clicks to get shoes against drum and just able to turn.

David or anyone do you have a back plate that you can measure the pivot block width to compare with my 36.7mm?
I seem to remember seeing someone somewhere had 39mm (can't remember where I saw that).
David adding up your gaps, that is 39 + 70 =109mm whilst mine is 111.2 mm (without taking spacers into account).

Just as an aside I have just realised that one cylinder is 7/8" (that is pre 1952 cylinder?) and the other is 3/4" which was the 1953 to 71 size BUT the length of both cylinders is the same at 55.12mm (Some sellers say that the later 3/4" can be used as a direct replacement)
(I hate the way the sellers of spares give vague descriptions and do not actually give the dimensions of what they are selling but sometimes just what car they are for). I just cant believe that there are Morrises running around out there also needing the spacers?

Location: NW Devon

Jeff thanks for picture and info.

Would you measure your pivot block to compare with mine.
My back plates are the modified Morris Minor to fit Austin Girling axles. They have the two little brackets welded on to take the "beehive" springs that hold the shoes against the back plates.

There are different length shoe pull off springs advertised for each of the two different springs on the back
mine are 4" between hooked bits (where they would rest on the shoe) for the spring with two short coils and 3" for the single coils.

Dennis

Location: NW Devon

Location: NW Devon

The pivot block is 37 mm Dennis measured in situ, I wasn't into dismantling the hub to get the shoes off

Location: NW Devon