Thread: Brake Master Cylinder Help

Originally Posted by jedwards

Gentlemen,
Once again, I apologise for so many questions. So much for me to learn.
Firstly, I'm restoring a 1953 S1 80". My original Brake Master Cylinder is a corroded under the PushRod boot, around where the spring clip sits to retain the push pod and retaining washer. As a result, I am a bit uncomfortable about how secure the push rod will be over time, as the spring clip can be made to let go by manually moving the push rod in a circular motion.

When I first got the old girl, a few years back, one of the first things I ordered was a nice new Series 1 Master cylinder. ERROR!!
I had not realised just how many S1 master cylinders there were. The new one that I purchased seems to be for the S1 54-58 years (I believe). The new and the old seem identical internally, other than for the diameter of the rear threaded outlet port that accept the Banjo bolt that splits the brake between the front and the rear. The original cylinder accepts the Banjo (#216909) but the 54-58 cylinder has a smaller outlet, and I don't seem to be able to find a Banjo to fit. I am unsure of the size and thread count.
Later Master Cylinder.jpeg So I seem to have 2 options. Find an outlet port setup as shown in the image, that will fit the later Master cylinder 54-48 (#241687)
OR
Find a used but serviceable Master Cylinder cast iron body for a 48-53 model (#235006) and legit all the nice new internals into that.

Any advice would be hugely appreciated,
regards
Jeff

geoff send your old one to me and will see what i an do jim

Jeff, the picture you posted shows (I think) a master cylinder with 2 bolts to attach it to a bracket on the chassis. Compare this with your old master cylinder. Does it have 2 or 3 bolts? From memory my '53 has a 3-bolt flange arrangement. Also from memory, there's a washer behind the circlip though which the pushrod passes. If the circlip is loose in its groove, is there sufficient sound metal to have that groove machined out a little to accept a larger circlip?
Trusting this helps.
Cheers Rob S

I'm sure the Series I master cylinders were all 3-bolt.
There are conversions that use a 2-bolt and an adaptor flange or you drill an additional hole in the outrigger.

I had thought about machining off the 2-bolt flange, cutting a thread and making a 3-bolt flange for it to thread into.
Seems that this has been done and available on Ebay https://www.ebay.co.uk/p/7045098432



I managed to source a 3-bolt master cylinder from India. Good reproduction but the ports for the brake lines were threaded right through which is incorrect. I had to buy adaptors to allow the brake lines to fit, cost nearly as much as the master cylinder !!
My original was re-sealed and still OK so the Indian one is a spare.

This doesn't help with the problem of the port size.
I know little about the earlier Series I's but from memory the brake pipes were larger diameter.
You might find approaching an old established brake company they might be able to help with an adaptor. I remember Four Wheel Drives used to keep adaptors so you could fit later wheel cylinders to early Series I's but they didn't list anything for the Master Cylinder.

Might be worth contacting Dingocroft.
Brake Master Cylinder and Conversion Kit

The adapter you need is shown but I couldn't find it listed. The above link is for a 2-bolt master cylinder 'conversion' but means you need to drill another hole in the outrigger.


Colin

Originally Posted by gromit

I'm sure the Series I master cylinders were all 3-bolt.
There are conversions that use a 2-bolt and an adaptor flange or you drill an additional hole in the outrigger.

I had thought about machining off the 2-bolt flange, cutting a thread and making a 3-bolt flange for it to thread into.
Seems that this has been done and available on Ebay https://www.ebay.co.uk/p/7045098432



I managed to source a 3-bolt master cylinder from India. Good reproduction but the ports for the brake lines were threaded right through which is incorrect. I had to buy adaptors to allow the brake lines to fit, cost nearly as much as the master cylinder !!
My original was re-sealed and still OK so the Indian one is a spare.

This doesn't help with the problem of the port size.
I know little about the earlier Series I's but from memory the brake pipes were larger diameter.
You might find approaching an old established brake company they might be able to help with an adaptor. I remember Four Wheel Drives used to keep adaptors so you could fit later wheel cylinders to early Series I's but they didn't list anything for the Master Cylinder.

Might be worth contacting Dingocroft.
Brake Master Cylinder and Conversion Kit

The adapter you need is shown but I couldn't find it listed. The above link is for a 2-bolt master cylinder 'conversion' but means you need to drill another hole in the outrigger.


Colin

Hi Colin.
At least 86" used a 2 bolt MC. Usually one has to make an adaptor to use a later 3 bolt MC, as the 2 bolt MCs are rare and expensive.
Chris

Originally Posted by cjc_td5

Hi Colin.
At least 86" used a 2 bolt MC. Usually one has to make an adaptor to use a later 3 bolt MC, as the 2 bolt MCs are rare and expensive.
Chris

Chris,

My 86" has a 3-bolt.
As far as I knew the 2-bolt didn't come in until Series II.


Colin

Series 1 M/c
Pic 2: 2x80" 48-53
Pic 1: Left 86 88 107 with 10" brakes
.........Right 107 109 with 11" brakes
.W.

Originally Posted by gromit

Chris,

My 86" has a 3-bolt.
As far as I knew the 2-bolt didn't come in until Series II.


Colin

Sorry mate, I had it the wrong way around... Yes I had to make an adapter to run a later 2 bolt MC to replace my original 3 bolt MC when it failed. My apologies.
Chris

Gentlemen,
Many that for your help.

I have discovered that the Series 1 80", part Number 235006 is actually a Girling Master cylinder, part number 64067534. Unfortunately, I cannot find any other vehicle that ever used the same one cylinder. The Series 1 80" uses 1/4" brake lines, so that is probably where the problems start.

New replacements for the S1 80" cylinder are horribly expensive (around $400 plus postage from the UK).
However this cylinder itself does not appear to be very special. Its a standard 3/4" bore, Master cylinder, so its possible that others, more common, might work just as well.
Has anyone found a good alternative?

regards
Jeff