My car will have a vertical panel at the end of the footwell where the pedals will mount. I wish to use a twin circuit master cylinder (sierra or similar) and a hydraulic clutch. Any suggestions as to which donor will supply my needs?
John

I always used Crapi/Escort master cyliders on my cars, with only the last one using a floor mounted setup using twin Girling cylinders.

Make sure you get any proportioning valves fitted to the donor, and always overhaul it at the very least, if not buy a new cylinder.

As for the clutch, it depends on what engine/gearbox combo you are using. There's no point converting a cable clutch to hydraulic. If you are hydraulic, then you can use a Girling individual type cylinder for the master, and a slave from your donor (again, new is best), don't forget that you need a big bore size for the clutch.

Thanks for the advice, Dave, but it has to be hydraulic clutch, so what I really need is a pedal setup from a car that already has hydraulic clutch so that the pedal will suit the pushrod
John

A lot of kits of old used a marina/Ital pedal box because they could be taken out of doner complete with master cylinders on.
Ive seen a few cobras with V8 Rover and manual box using this config if that helps

I would be happy to use the marina pedal box if it was just for one car, but I am hoping to make more than that, and so am trying to avoid any donor cars that have been out of poduction for a long time, similar situation to the allegro steering column specified in the 'book'. Thanks for all the replies so far

Hi all -

Problems with using servo-mounted mcyls in non-servo application.

1: Servo output rod provides backstop position for mcyl, and therefore determines cut-off (mcyl travel to commence pressure generation).
2: Servo output rod is factory-adjusted to ±0.15mm.
3: Using mcyl in non-servo application, actuating rod (from brake pedal) must be clear of mcyl primary piston (unless you can replicate the ±0.15mm setting).

This last measure ensures that the mcyl returns past cut-off, to allow rapid pressure release.

Westfields of similar spec to Locosts use Ø17.8 tandem mcyl. Suitable item is from early Fiesta (p/n 74066198).

Re: proportioning valves - use later Fiesta type (screws into mcyl outlet port). Don't use Sierra G-valve (requires very carefully angled installation).

Dick Axtell

Was that last posting for me? I should have said that I want to use servo brakes, my plans allow room for conventional servo.
John

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Was that last posting for me? I should have said that I want to use servo brakes, my plans allow room for conventional servo.
John

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How heavy will it be? good question. A fair bit more than the average Locost I fear. Firstly, it's been a long time since I was only 75kg. Secondly,I will be using Jaguar front and rear suspension (quite chunky, though I don't have any figures yet, and the Jaguar AJ6 3.6 24v engine, all alloy but I wouldn't want to drop one on my foot.The chassis will be longer, wider and incorporate some larger sections. All in all, I reckon to be nearer to the average Cobra replica in weight than to the average Locost, and AFAIK all Cobra replicas use a servo (Ford Sierra is popular, but clutch is cable). Naturally I'm hoping for good news in the weight department but I think it would make sense for me to plan on a servo. If it turned out that I don't need one then I would be tempted to get a dual master cylinder set up.
Thanks everybody for all the info so far
John

Hey John -

Your variation on the Locost theme certainly won't weigh in at the 700kg level!. Do you intend using the Jag rear suspension saddle complete? Presumably that will mean the use of rear disc brakes. All these factors suggest that a booster will be required.

If you check out the sportier, later Fiestas (or those with ABS), they will be fitted with booster/mcyl assemblies. I specified the sportier/ABS models because they use Ø23.8mm mcyl (which is the black-painted, steel tube type). A similar booster was fitted to Sierras, but with cast iron Ø22.2mm mcyl.

Regards
Dick

Has anyone used the brake bias bar set up from Locost? If so how does it work?

I havn't seen one to copy yet but have the pedal box, from a Reliant (not the Scimitar the other one but don't let on!). It looks the same as Locosts so it will be adaptable once I know the principal of it's mechanics.

I can see from pictures that it uses a threaded bar between the two M/Cs push rods to adjust the amount of force applied to each M/C. But this is at right angles to both push rods and not as I would have expected, in line with the foot pedal pivot and M/C push rod.

A photo or web page link with a photo of one would be great.