I would appreciate photos of the "cover" which the remote brake booster is mounted. This cover protrudes into the well well and is adjacent the crossbeam where the suspension arms attach. I am modifying mine in order to fit a twin circuit 420 (and series 3 e type) brake booster as part of a brake upgrade. I need to determine if there is sufficient clearance. Thanks.

 

I was going to say that does not look like an OE booster.

 

Glyn, Have you fitted AC to your car? I noticed the AC hose and crimps in the photos above, I'd be interested in details of what you did for an evaporator and interior air ducting if you can share.

 

No ~ I've not fitted A/C to my car. This is credit Lin ~ Valvechatter. I always credit if I know from my archive, but forgot to above..

 

BTW> ~ You are aware that the 420 does not really have dual circuit brakes. It's only dual circuit from the booster. It remains single circuit from the master cylinder to the booster which somewhat defeats the object as the master cylinder is usually first to fail.

 

I am aware the master cylinder has one circuit white the servo two circuits with a single fluid reservoir.

 

I am interested in seeing a photograph of the clearance between the brake servo "cover" and the front crossmember sispension. Thanks.

 

This was something that concerned me too Glyn. I resolved by using a more modern X308 master/servo unit. Not sure where I'm going to put the wiper motor yet though!

 

I don't recall how it works, but doesn't the 420 have a fallback for loss of fluid in the circuit between the master cylinder and the brake booster. There's some sort of air valves on the end of the master cylinder that are operated when the master piston goes to the end of its travel. These cause the booster to apply pressure in the lines to the brakes. I'm uncertain as to how sensitive this system is. If it locks the brakes solid it might be almost as dangerous as no brakes.

 

That's neat, The 420 is not a good system with it's single Master cylinder & Double booster arrangement. Not a decent system. I wonder who dreampt that up.

 

It's almost identical to the Series 1 4.2 E Type braking system, so they probably transplanted it.

 

Underdash wiper kits used to be available for these cars. I wonder if they are still available. This car had one fitted. I now regret not taking a pic of the underdash mehanism although it would have been difficult. ~ I used this car as a reference of an SA built car for many items ~ now sold unfortunatally.

 

The front pivot of the top wishbone is the closest part of the suspension to the cover over the servo.

Apologies for the dirt, rust and cobwebs.

 

I appreciate your photographs. It appears I will not have clearance issues with my modifications to date but leaves little room to extend rearward. I agree with the earlier appraisal of the 420 / e type brake system I am using. Added complexity without true dual circuit safety. I had a 1970 Rover 3500S (NADA) which had a similar system. I lost the brakes in that car. I will consider returning to the single circuit booster with the simpler master cylinder. Both have the same lack of dual circuit and offer similar failure risks. I wonder why I get into these projects. Thanks to all who replied.

 

Remember that most E Types have 2 single master cylinders that operate in tandem rather than a dual master cylinder.

 

The 3.8's do, the 4.2 is a single master.

 

Interesting ~ Thanks for that. We live & learn. The only Jag I know down to every screw is the S Type Manual OD. The rest is from prolific reading and helping friends on their specific model.

 

... and the series 3 V12 E, at least the DHC, also had the 420 system, I think. That should keep it in production, but also inflate the price.