Aurelian master cylinders

[Tony Stephens]

Is the 6th series B20. Master cylinder different from that on the 4th series? Perhaps a different size? Are they interchangeable?
My 4th series car has a 6th front axle and brakes - no regrets as they are trouble- (and judder-) free, but the pedal pressure is a bit high from my now jaded modern car corrupted viewpoint, and I would like to change this if possible. I won't fit a servo as that is one step too far from originality.
Advice from experts?

[DavidLaver]

While I can't comment on hydraulics a couple of thoughts: How fresh is the friction material?  Is the drum surface 100pct? 

Tim improved my braking performance no end simply cleaning up the drums (might have been John Savage). 

I remember the peddle as "like pushing a brick wall" whatever, it was just the car stopped quicker for it. It was very much a "more pressure gives quicker stopping" rather than "more movement".  I can also remember having the reverse worry where every time I got in "the modern" I'd be really concerned at what felt like lost motion and sponge in the brakes, a couple of times it had me properly worried.

David

[chriswgawne]

Tony,
I think you will know all of this but........
Aurelia brakes have only 2 flexible hoses in the system on the front wheels and so if they are in good order and the brake linings  are bedded in then the pedal will feel very firm when braking.
The efficiency of the braking will be affected by the brake shoe material, the surface of the brake drums, the adjustment of the brakes (particularly 5th and myth series with twin leading shoes which need setting up properly when new shoes are fitted) and of course the diameter of the master cylinder.
I am away at the moment and so I don't have my data to hand but I have seen non standard steel 1" master cylinders fitted to several UK  B20s over the years (original diameter aluminium master cylinders are available in Italy these days).
If you don't have a supply of 'old' asbestos type linings then I always use a particular lining material recommended by a Healey racer. I will dig this out when I return if you wish. And the thickness of the new linings needs to take account of the actual I/d of your front drums in particular.
Hope this helps.
Chris

[DavidLaver]

Just to link it all up for the future Chris's supplier here but not the material spec:

http://www.lancia.myzen.co.uk/forum/index.php?topic=7267.0

[fay66]

A number of years ago John Brain of Bob Brain Developments fitted a Aurelia B20 with a new master cylinder from a LDV Van, that fitted and worked ok.

Brian
8227

[Tony Stephens]

Hi everyone: thanks, keep going, all of this is very helpful
!

[Kevin MacBride]

My car has discs on the front, I also have a spare axle (praise the Lord, 'cos I'm going to need it) with 6th series drums and twin leading shoes. I used braided steel hoses on the front, and when I renewed the metal piping I used a slightly smaller diameter for the front. I hate 'spongy' brakes so I took great care to have everything adjusted properly. Initially I could lock the rears quite easily, which after a while actually was quite useful, as I was able to force the car to drift. Was very good for hillclimbs and hairpin bends. However on the track, it was a bit much, and I was pulled up a few times. I since fitted a bias valve.
The other thing I noticed was that after heavy braking, the fronts tended to bind. I found that by releasing a bit of pressure, and leaving the plunger 'down' this cured the problem.
The master cylinder was a new unit I bought from Cavalitto some years ago.
At the moment however....brakes are the least of my concerns.

[chriswgawne]

Just looking through my bits and pieces and trying to 'close the loop' (and confusing myself into the bargain):
According to Paul Mayo's excellent Aurelia Manual, B20 Master Cylinders were originally aluminium as follows@
4th Series 23mm I/d
5th Series 23mm I/d
6th Series 26mm I/d

On our cars, we mostly have steel 1" I/d UK master Cylinders fitted which need an adaptor to connect and which were originally Lansing Bagnall fork truck spares and latterly I believe may have come from China my supplier let slip!! Seal kits are available for these and braking is fine.The 'new' aluminium 'Aurelia' m/cylinder I bought at Padova Mostra Scambio  a couple of years ago is labelled 27mm I/d. I now wonder if it is a reworked old one.

The brake shoe material I specify from IBC is 3921F and I specify the thickness according to how worn the drums are. 5th and 6th Series B20 twin leading shoe brakes take a little while to set up correctly and they have to bed in....but when settled down they are as good if not better than any drum brakes I have ever used.
PS I ALWAYS specify that the linings should be glued AND riveted.

Hope this helps.

Chris

[chriswgawne]

I should also have said in my previous post that there used to be a VW 7/8* diam master cylinder which could be fitted to Aurelia with slight adaptation.
Chris

[Parisien]

A number of years ago John Brain of Bob Brain Developments fitted a Aurelia B20 with a new master cylinder from a LDV Van, that fitted and worked ok.

Brian
8227

In reference to the use of a non original master break cylinder above, I'd just noted a reference to the same in a 1994 VL edition by John savage stating " that a new master cylinder from a certain type of milk tanker fits!"

Can anyone shed any light on this or comment as to suitability or efficiency?

P

[chriswgawne]

Back when John wrote that, replacement brake master cylinders were in v short supply or unavailable so all sorts of alternatives were used. No need now as one can easily get new cylinders to the original pattern from a number of Italian suppliers.
Chris
.