Brake sizes

[Astronomer]

What is the actual measurement which determines whether I have 7 inch or 8 inch brakes? According to the year of manufacture I ought to have 8" brakes but the snail cams appear to be for 7" brakes. I am very confused.

[philthehill]

Measure the inside diameter of the brake drum.

[geoberni]

You have previously asked about Cam adjusters and the differences were explained.
However you never acknowledged that topic after asking the question.
viewtopic.php?p=688374#p688374

The Cams themselves are the same size; it's the diameter of the cam lugs that are different.
Only the front Drum is 8", the rear remained 7".
Therefore there are 2 different cams on the front and rear brakes.

It might well be that your car is fitted with the wrong, thinner shaft 7" cam on the 8" brakes.
Past owners may well have screwed them up mixing front and rear cams, if all brakes were off at the same time or any other mistake.

My car was 7" all around when built, but about 25 years ago received an upgrade of donor 8" on the front.
I serviced the brakes the first time when I got him 5 years ago, and on close inspection found not all the cams were correct. My guess is the person doing the work 20 year previously hadn't paid attention, because I was short two 8" Cams and the error wasn't even both on the same wheel!

The age of our cars, there has been ample opportunity for past owners/mechanics to get things wrong....

[Astronomer]

Sorry I didn't respond earlier. I got distracted whilst on the website and forget to return to the topic
]

[geoberni]

Sorry I didn't respond earlier. I got distracted whilst on the website and forget to return to the topic
]

Thanks for the acknowledgement/apology, but we still don't know if you now understand the subject...
Do you understand how easy it is to fit the incorrect Adjuster Assy if the person doing the work doesn't realise the difference between the 2 sizes?
Have you got it all sorted?

[Astronomer]

Finally got round to getting the brake drum measured and it's 7" on the rear. So the 8" cam won't do and I'll need to get the right one.Should have checked before ordering! Thanks

[geoberni]

Finally got round to getting the brake drum measured and it's 7" on the rear. So the 8" cam won't do and I'll need to get the right one.Should have checked before ordering! Thanks

It's not surprising you've found the rear are 7".....Considering the number of times you've been told in response to your questions, that the rear brakes were always 7", and only the front were increased to 8" with the increase in engine size...

The only way they wouldn't be 7" is if they had been changed to something completely different, such as Wolseley 1500 brakes, which are 8".