I have a 47 P2 Chassis on which I'm building a special. I would like to convert from the original cable brakes to hydraulic. Has anyone done this, can i use Rover/Land Rover cylinders or are there other alternatives.
Any help appreciated.
Thanks
Simon
Brake Conversion
Re: Brake Conversion
I got my first P2 in 1968, and the seller warned me that its mechanical brakes are no good and should be replaced asap with hydraulic brakes. However, in Israel doing that without a written permission of the manufacturer is illegal. Therefore I had written Rover (which was still an independent company) and asked for their permission. Here is what Mr. T. Wall of the Technical Service Department wrote me, for the Rover Company Limited on 24th November, 1969:
In fact, There were good reasons for that.
First, the Girling mechanical brakes are good brakes, as long as they are properly maintained and adjusted. This is what V. H. Watson writes in his book “Rover Cars” (pp. 146 -147):
“General Description
The effort from the brake pedal is conveyed to the shoes by a simple system of rods in tension, torsional members are virtually eliminated. It would be appreciated by modern standards that this system when first applied in 1934 constituted an enormous improvement over all other systems then in use employing torsional stresses.
The rods operate the shoes through an expanding device consisting of a hardened-steel cone to which is attached a pull rod, running between a pair of steel rollers located in an insert in the shoe ends. The cones, rollers and shoe inserts are enclosed in a substantial housing which serves to keep out dirt and retain lubricant.
As the housing is attached to the outer face of the brake anchor plate in a manner that allows it to "float", centralisation of each pair of shoes with the drum is assured. Compensation between front and rear wheels is obtained by a swinging link at the base of the brake pedal, and by a free mounting of the transverse operating levers. It is interesting to note that although this type of brake may be regarded as commonplace today, when introduced in 1934, an Autocar test recorded the first known instance of a theoretical 100 per cent braking efficiency, i.e., 30 ft. from 30 m.p.h.—a previously unrecorded figure.”
Second, since these cars are equipped with free wheel, the drums may become very hot under extreme situations. The mechanical expanders would never boil and will continue to be operational even if they are very hot, unlike hydraulic expanders that may fail.
Rover has published Service Bulletin A465 (that “renders obsolete Bulletin 465, which should be removed from your file and destroyed”) which explains in detail how to properly maintain these brakes. Following these instructions the brakes are good, and year after year I enjoy watching the MOT people eyes when they see the brake meter results.
Having said that, I should mention that my other P2 had been converted to hydraulic brakes some time in the fifties. For the same legal considerations we have decided not to re-convert it back to mechanical. You can see pictures of the conversion, before and after the restoration here: http://wp.me/pXLKy-if
So far I do not feel any real advantage of the hydraulic system over the mechanical one.
In fact, There were good reasons for that.
First, the Girling mechanical brakes are good brakes, as long as they are properly maintained and adjusted. This is what V. H. Watson writes in his book “Rover Cars” (pp. 146 -147):
“General Description
The effort from the brake pedal is conveyed to the shoes by a simple system of rods in tension, torsional members are virtually eliminated. It would be appreciated by modern standards that this system when first applied in 1934 constituted an enormous improvement over all other systems then in use employing torsional stresses.
The rods operate the shoes through an expanding device consisting of a hardened-steel cone to which is attached a pull rod, running between a pair of steel rollers located in an insert in the shoe ends. The cones, rollers and shoe inserts are enclosed in a substantial housing which serves to keep out dirt and retain lubricant.
As the housing is attached to the outer face of the brake anchor plate in a manner that allows it to "float", centralisation of each pair of shoes with the drum is assured. Compensation between front and rear wheels is obtained by a swinging link at the base of the brake pedal, and by a free mounting of the transverse operating levers. It is interesting to note that although this type of brake may be regarded as commonplace today, when introduced in 1934, an Autocar test recorded the first known instance of a theoretical 100 per cent braking efficiency, i.e., 30 ft. from 30 m.p.h.—a previously unrecorded figure.”
Second, since these cars are equipped with free wheel, the drums may become very hot under extreme situations. The mechanical expanders would never boil and will continue to be operational even if they are very hot, unlike hydraulic expanders that may fail.
Rover has published Service Bulletin A465 (that “renders obsolete Bulletin 465, which should be removed from your file and destroyed”) which explains in detail how to properly maintain these brakes. Following these instructions the brakes are good, and year after year I enjoy watching the MOT people eyes when they see the brake meter results.
Having said that, I should mention that my other P2 had been converted to hydraulic brakes some time in the fifties. For the same legal considerations we have decided not to re-convert it back to mechanical. You can see pictures of the conversion, before and after the restoration here: http://wp.me/pXLKy-if
So far I do not feel any real advantage of the hydraulic system over the mechanical one.
Re: Brake Conversion
Thank you for the advice and a great link.
Thanks
Simon
Thanks
Simon
Re: Brake Conversion
I had a 47 16hp (with the same mechanical brakes)for a few years early in my motoring time. At some stage the brakes needed attention , and I found that once the operating mechanism in the drum was cleaned and lubricated, and all the clevises and pins were adjusted properly (replaced where necessary), and slack removed, they were very effective indeed. Depending on the type of lining material fitted, you may find that regular deglazing is needed. In my case I removed some glazed surfaces , I think with a wire brush, or a rasp, and the improvement was quite marked.
jp Oz
jp Oz