Donations towards server fund so far this month.

 
£0.00 / £100.00 per month
Page:
Home > General Chat > Which rear wheel Cylinders?

garethlloyd

User Avatar

279 Posts
Member #: 616
Senior Member

Birmingham

Hi,

Can anyone offer any advice on this please?

I've got a Mk1 (1966) with tin top master cylinder, single line brakes with regulator valve on the rear. Cooper S discs + calipers front with drums to the rear.

It's just failed the MOT on lack of brake effort at the rear. I've replaced the wheel cylinders (+shoes and drums) as they were seized. I wasn't sure what to go for and there we no refs on the them. In the end I've fitted 0.500" following some advice I found on here.

Failed again today on the same thing. To be honest I think they need bleeding again as the pedal is still not very firm but just wanted to make sure 0.500" wheel cylinders (GWC1126) are the right choice.

Any thoughts?

Thanks in advance.


Tom Fenton
Site Admin

User Avatar

15155 Posts
Member #: 337
Fearless Tom Fenton, Avon Park 2007 & 2008 class D winner

&

TM legend.

Rotherham South Yorkshire

Its a long time since I've done anything with rear brake wheel cylinders, but the 1/2" rear cylinders I thought were for use without the rear mounted limiter valve?

Edited by Tom Fenton on 8th Jun, 2018.


On 29th Nov, 2016 madmk1 said:


On 28th Nov, 2016 Rob Gavin said:
I refuse to pay for anything else


Like fuel 😂😂


Tom Fenton
Site Admin

User Avatar

15155 Posts
Member #: 337
Fearless Tom Fenton, Avon Park 2007 & 2008 class D winner

&

TM legend.

Rotherham South Yorkshire

Have a look at this chart

http://www.minispares.com/catalogues/class...rt.aspx?1~9~105

I reckon a 0.625" rear cylinder is a better choice.


On 29th Nov, 2016 madmk1 said:


On 28th Nov, 2016 Rob Gavin said:
I refuse to pay for anything else


Like fuel 😂😂


Sprocket

User Avatar

11021 Posts
Member #: 965
Post Whore

Preston On The Brook

yed Deffo not much on the rear with the 1/2” cylinders and the limiting valve. Which valve is it though as the cooper S had a different valve rating as well.

Mine only passed the test as there’s so much brake on the front it made up for the lack of rear.

What brake force were you getting on the rear. Mine barely made 12kg per wheel

On 26th Oct, 2004 TurboDave16v said:
Is it A-Series only? I think it should be...
So when some joey comes on here about how his 16v turbo vauxhall is great compared to ours, he can be given the 'bird'...


On 26th Oct, 2004 Tom Fenton said:
Yep I agree with TD........


Tom Fenton
Site Admin

User Avatar

15155 Posts
Member #: 337
Fearless Tom Fenton, Avon Park 2007 & 2008 class D winner

&

TM legend.

Rotherham South Yorkshire

Maybe the simplest route is to remove the rear limiter valve and fit a T piece and then see how they are? Be a shame to have to remove brand new 1/2" cylinders to fit something else.


On 29th Nov, 2016 madmk1 said:


On 28th Nov, 2016 Rob Gavin said:
I refuse to pay for anything else


Like fuel 😂😂


garethlloyd

User Avatar

279 Posts
Member #: 616
Senior Member

Birmingham

Thanks for the input so far.
I'm sure the limiter valve is a normal one rather than an s one.

He didn't give me any figures only that it's worse now that before I changed them!

Might order a new limiter valve and some 0.675 unless anyone has any better ideas.


Sprocket

User Avatar

11021 Posts
Member #: 965
Post Whore

Preston On The Brook

What were on the car to begin with? If they were bigger than the 1/2” ones then that’s why it’s “worse”.

Most minis were fitted with the 3/4”. The chart Tom links to is all you need to refer to to find out what should have been in there.

Edited by Sprocket on 8th Jun, 2018.

On 26th Oct, 2004 TurboDave16v said:
Is it A-Series only? I think it should be...
So when some joey comes on here about how his 16v turbo vauxhall is great compared to ours, he can be given the 'bird'...


On 26th Oct, 2004 Tom Fenton said:
Yep I agree with TD........


Sprocket

User Avatar

11021 Posts
Member #: 965
Post Whore

Preston On The Brook

On a side note. If the parking brake passes, but the service brake fails on the rears, it’s to do with the wheel cylinder size and limiting valve.

On 26th Oct, 2004 TurboDave16v said:
Is it A-Series only? I think it should be...
So when some joey comes on here about how his 16v turbo vauxhall is great compared to ours, he can be given the 'bird'...


On 26th Oct, 2004 Tom Fenton said:
Yep I agree with TD........


garethlloyd

User Avatar

279 Posts
Member #: 616
Senior Member

Birmingham

Thanks for the help guys


Elfturbo

User Avatar

44 Posts
Member #: 2576
Member

South Staffordshire

Before you spend any money did the MOT tester know what he was doing?

The MOT system won't have the expected brake efficiency for a 1960s mini, so he will need to do a calculation on the basis of axle weight.

Because there is not much weight on the rear axle, required brake efficiency is quite low, otherwise you would lock up rear wheels under hard braking.

HOSS


Elfturbo

User Avatar

44 Posts
Member #: 2576
Member

South Staffordshire

I use Dave Payne at Seisdon Post Office Garage for my MOTs. He has a couple of classic minis so knows what he is doing with them. If you are in bham, not a million miles away. He did the brake efficiency calculation when he tested my Elf.

HOSS


Elfturbo

User Avatar

44 Posts
Member #: 2576
Member

South Staffordshire

With the single circuit limiter the harder you press the brakes the less effort goes to rear brakes, to avoid lock up under hard braking, Dave was able to demonstrate this on the MOT brake tester, again a lot of testers don't understand how old car brake systems work, they are used to modern cars with ABS etc.

Maybe why 40+ year old cars no longer require MOT.

HOSS

Home > General Chat > Which rear wheel Cylinders?
Users viewing this thread: none. (+ 1 Guests)  
To post messages you must be logged in!
Username: Password:
Page: