For the true, original 61 OBL builders - you missed one

A few days ago there was an ad in classifieds for brake calipers (and went to scrap). The big ones were for early E front discs, but made with a screw-on plate for easy rubber install, and also with a brass piston. Bet you"ll search a while to find another pair.


If you are referring to this advert:

The only difference between the early 3.8 front brakes and those fitted post December 1961 were the design/material of the pistons and pads. The calipers #7715 remained the same for all 3.8’s.

If you are referring to this advert then they are indeed very rare and desirable:

Up until cars 850253/860022/875963/885142 (December1961) the front and rear brake cylinders were made of Malleable Iron.

On all subsequent cars the brake cylinders were Cast Iron. ‘C’ was added to the casting to denote the later cast iron cylinders.

Malleable Iron starts out as Cast Iron but is heat treated (annealed) which gives it properties similar to mild steel. After annealing the item was plunged into oil for rust protection and giving the item a matt black finish. It is easy to machine and is shock resistant. Jaguar probably moved to Cast Iron on cost grounds saving money on the annealing process but used a plating process for rust protection. The Mk2 saloons changed to Cast Iron in June 1961.

The early cylinders also had a separate piston and backing plate so the parts are not interchangeable with the later cylinders.

Finding malleable pistons is very very difficult as most were replaced during service as the dedicated pads became unavailable. As the front are visible the purists must have the ones without the ‘C’. You can get away without the C marked rears as they are hidden away. OBL owners would have paid $$$$ for those! Such is the price of lack of research and patience (the advert was only live for 5 days).



@jagman66E maybe still on the heap? In the bucket?

Nope, gone Sorry

Not a problem, just means anyone who has any have doubled their value! $2,000 going forward - those were the first set of Malleable iron rear pistons I have ever seen. Don’t suppose you have photos of the piston faces?


I had a few more. Tried selling them here, ebay and other fb groups with zero interest. I’d love $2000.00. But will settle for $50 plus shipping

I think if you had photographed the other face of the piston housings showing the cast Dunlop numbers, without the magic ‘C’, you would have been deluged with offers. Everyone with an early car and wanting originality are looking for these unicorn parts but they don’t really care about the internals - just want to show the Dunlop design.

They were fitted to all Mk2’s up to mid 1961 and then to the E-Type until December that year in case you come across any more.

On the other hand, there was only one complete front caliper.
And now only half one still available.
As these are unicorns, maybe interested people would have looked for a complete set of two front calipers at least…

Actually the fronts are easier to find than the rears. I have see a few of the former but never seen or held rears. Can’t even find a good photo!

I have some Rover rears, which on the early P6s, where the same brake as on the E type: before I toss them in the recycle pile, I will take a picture of them and see if they are of any use to anybody.

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Good Idea Paul. Easy to spot if they are the unicorns - they will not have the ‘C’ (for cast iron) on them.

The rear 1 3/4" cylinders 8514 (VBO.5375) were Malleable Iron with multi part piston:

The later rear Cast Iron cylinders 8778 (VBO.5506) had the ‘C’ mark:
Image 008

If you have any Angus Moss would be most interested as he is restoring LHD OTS #47 to the highest level of originality. He eventually found the front pistons but the rears elude him.




Thank you!

I will ‘check stock’ today.

Interestingly 850251 has 3 cast and 1 malleable callipers on the front and I haven’t pulled the rear apart yet ……apparently the offical change was at 850254…… did the callipers on hand include the new cast ones a couple of days earlier …… ? Possible I guess

What I do have is a set of 2 1/4 malleable callipers ! Came off a Mk X I think ….i had thoughts of swapping them over …but not so much now …I’ll hold onto them …… I’ve also got some 17/8 rears as well ….I’ve just been collecting stuff for years!:grinning: