Hydraulic brake conversion backplate

[GK5268]

You could be correct, I did wonder if the bleed screw should ( logically) at the top so air would be expelled more effectively  but then The handbrake cables would also be above the back axle which seemed odd, but I suspect it could be correct for a hydraulic conversion and may explain my problems with the master cylinder if I am not bleeding effectively. When back home and under the Austin again I will investigate further. Hopefully someone on the forum with a Morris minor hydraulic. Conversion can give a definitive answer
Ian

The rear brake cylinders on my car are mounted so that the handbrake lever points downwards, i.e. the piston is pushed to the ground, this means that the inlet/outlet for the fluid is uppermost to ensure the complete bleeding of air. Mounted the other way up, air can be trapped. This is how they are fitted on Morris Minors, pointing downwards.

The orientation of the bleed nipple is independent of the wheel cylinder, but is best pointing upwards to allow air to rise to the highest point, as it is screwed into a banjo union it can be rotated to a convenient position. 

There is a similar problem at the front, as one cylinder piston has to be pointing upwards, so that the inlet/outlet is at the bottom - effectively trapping a small quantity of air. Bleeding all the air out can be helped if the backplate is removed from the stub axle (remove hub first) and laid on its side and thus allow air a route out.

My brake shoe have the beehive spring and also a nylon spacer fitted between the back plate and the shoe to keep the shoe square to the drum, otherwise it could tilt the other way...

[Terrytuned]

With aluminium back plates you need a spacer behind the brake shoe as it does not have does not have shoe rests which are on the steel back plates to keep to shoes
square with the drum. The rear brakes should be fitted with h/brake levers pointing down at the rear this in effect gives you a trailing brake setup but is OK as as it
reduces the the the rear brakes locking up before the front. Use a 3/4" Girling m/cyl as the original MM one weighs a lot as it is cast iron and is prone to rusting unless
you use Silicone brake fluid, and the Girling m/cyl is a much better option anyway.

[Dennis Nicholas]

After further research.
The Lockheed rears are one leading and one trailing shoe.
The design of (most) such set ups is that going forwards one shoe is leading and one is trailing.
Going backwards the previously leading shoe becomes trailing and the previously trailing becomes leading.
Researched sources say that therefore same amount of breaking is applied going forward or backward (important for hand brake to hold when car pointing uphill!)
Rear brakes need to be less effective than 2 leading fronts and 1 lead/1 trail achievs this.


Careful examination of inside of (MM) backplates will show them to be marked LH and RH (Just where welded on recessing bit meets backplate) This is so that on the Morris each backplate is fitted on the axle with the cylinder at the front of the axle and with leaver pointing down and piston opening downwards so MM handbrake mechanism fits.
This is irrelevant on A7. If mounted with cylinder in front of axle the leaver can't point downwards because suspension spring gets in way of pulling.  If mounted with leaver pointing up so cable can pull then leaver hits boot floor (on Nippy) (don't ask how I know).
With cylinder behind axle and leaver pointing down and piston moving down the bleed nipple can be positioned pointing upwards so no trapped air.  
I have a bracket held on the axle by 2 exhaust U bolts to take the end of the handbrake bowden cable outer (photos to follow). Bracket can be rotated to allow a strait pull on the leaver. 

Terry Griffins photo showing Girling shoe holding down pin/spring/washers:
They are from Ford Anglia 105E 1200cc - Pin 40mm, Spring 16.5mm high, 14.5mm dia. (The 997cc pin is 32mm)
See "Ford Anglia 105E shoe hold down pins" on ebay.  J&B Anglia 105E Parts have been helpful giving item measurements.
Pull up hand brake leaver fitted over tunnel by left elbow connected by adjustable rod to swinging compensator. From each end of compensator a bowden cable to cylinder leavers. Outer of each inboard end is fixed to vertical part of floor behind Nippy seats.  All hand brake parts - Alegro 1973-82. Prior to fitting swinging compensator each cable went to fixed rod through handbrake leaver and the hand-breaking was poor....now compensated and good.

Getting there slowly.

Dennis

[Dennis Nicholas]

More info.     Happy birthday to me 

Thats better. Shoes correct way round and another of my used shoe steady springs fitted now holding the shoe against the back plate with reasonable force.

   

Old spare pair of pliers modified with angle grinder to fit into shoe steady spring for fitting spring to backplate.

   

   

Shoe steady springs:-
 Left to right 1.  too squashed does not hold shoe in; 2. probably 0k; 3. new from MOSS but so difficult to fit due to hook end being too long; so 4. cut small piece off end of hook and was able to fit.  I also marked 2 positions on the backplate where the hook wire had to line up to enable hook to be pushed in and be turned through 90 deg.  Hook starts nearer axle centre so hooks outwards into backplate bracket.

   

The nice guys at ESM Morris Minors advised that their new springs were very difficult to fit - I suspect that was for same reason as the MOSS spring No.3 above with too long hook end. (that was why I got new from MOSS instead of ESM at a higher cost and higher postal......now wiser).
I noted that the MOSS Morris Minor parts catalogue shows the rear lower shoe the wrong way round (cylinder shown on left on backplate but shoe has cylinder notched end to the right!!.......if it was correct way round the double holes in the shoes would both be at the pivot end.......this could confuse and allow someone to put shoes on wrong with double holes at opposit ends.........that contributed to over streched and difficult to put on pivot end pull off spring and probably too much tension pulling shoe away from backplate.

With all new items the snail adjuster requires 11 clicks to get shoe to touch drum.  I made a 3mm spacer to fit between shoe and cylinder but it was too thick so will wait till shoes bed in and wear before fitting.  I have previously had the problem of running out of adjustment as shoes wear long before minimum lining thickness is reached.

I am now using the snail adjuster from the 8 inch Lockheed brakes.  It is slightly higher to start with at zero adjustment. The notch on the end of the shoe has to be enlarged slightly to take the larger diameter snail spindle.
Using a digital calliper fitted between bottom of MASK and top of cam adjuster I took the readings for each click of the adjuster:-
ADJUSTER  READING   increment   ADJUSTER  READING  increment       ADJUSTER  READING  increment
0                13.5mm    0                     8          14.60    = +0.17mm          14           17.30       = +0.60
1                13.7          = +0.2mm       9          14.82    = +0.22               15           17.91       = +0.61
2                13.92        = +0.22           10        15.15    = +0.33               16           18.58       = +0.67
3                14.08        = +0.16           11        15.65    = +0.50               17           19.21       = +0.63
4                14.18        = +0.10           12        16.16    = +0.51               18           19.99       = +0.63   MAX
5                14.28        = +0.10           13        16.70    = +0.54               Total adjustment = +6.49mm           
6                14.37        = +0.09           14        17.30    = +0.60
7                14.43        = +0.06           15        17.91    = +0.61

Since pivot end slides then total adjustment over whole shoe is halved = 3.29mm and since lining is around 5mm then a spacer may have to be inserted tu use lining down to thinest permissible.

Dennis

[Viteran]

Been busy with other jobs, grass hedges etc so Austin has been abandoned for a few days.
Went to local market today on what my wife refers to as the “ junk” day and got a copy of Morris minor autobook that has better diagrams than the Haynes.
Hopefully attached
Ian

                       

[Dennis Nicholas]

VITERAN  Thanks.....sure it will be of help.  The rear picture is offside and nicely shows the top shoe lining leading and trailing material length and position and that the double holes on the shoe are at the pivot end.  No mention of chamfering the ends of the linings!

As ever it is what these books miss out and assume you know that is the problem.

Dennis