Line Lock / JPE Screen

[Nick M]

 

Line Lock - Arnie, I noticed your line lock is located just under the scuttle on top of the transmission tunnel. I'm toying with the idea of fitting one to my car and was curious to know how you'd plumbed it in.

 

Is it done in such a way that it locks off the rear circuit so that you can close the line lock and press the brake pedal and the rear brakes don't work and hence the rear wheels are able to spin ? Or have you done it so you press the brake and lock the front circuit "closed" so the front brakes remain on when you release the pedal ? Suggestions welcome.

 

JPE Screen - is it effectively a flat piece of perspex (polycarbonate ?) that is simply set at the correct angle to deflect the air flow, or is there some vertical curvature in it to help direct the air upwards (more like the R500 carbon version) ? I've tried looking at numerous pictures and none of them are particularly clear.

 

Thanks

 

 

Nick

[Mike C]

Hi Nick,

 

I too have this fitted and to answer your question....

 

The line lock is plumbed into the front brakes and it's fittment is straightforward. They operate by depressing the brake pedal and pulling the line lock lever so that it effectively holds the fluid pressure into the brake line. When you release the brake pedal, the rear brakes are de actuated but the fronts stay locked.

 

You can purchase from Demon tweaks.

 

JPE Screens, these are moulded "roughly" to the shape of the scuttle and have some deflective curvature. Buy one from Redline Components!

 

regards

 

Mike C

K9 JPE

[EFA]

To add further, you need to plumb from the T-piece at the side of the pedal box, to the t- piece on the front chassis vertical leg (to which the damper bolts) in flexible hose. Run these lengths back down the tunnel and plumb them to the DT line lock valve. Dave Kimberley at DT will supply you the correct mish mash of metric and imperial fittings (he's good at that...)

 

The line lock valve itself can be secured to the top front trans tunnel cover (assuming you do not have a girly upholstered tunnel top, with a piece of ally folded around the line lock valve and rivetted to the small tunnel top cover panel.

 

It works well and you suffer no brake problems due to the long lengths of flex hose. However, be aware of the following:

 

A cable handbrake is spring tensioned so as your brakes cool, tension is maintained in the cable keeping the handbrake on tightly. On a hydraulic system there is no tension, and as the brakes cool, braking effort is reduced. I discovered this to the cost of a carbon nosecone about 5 years ago.... If the brakes are coolish when the line is locked (such as on the ferry to Le Mans after queuing) full braking is retained over a long period.

 

MOT. As a 7 has split circuits front rear there is a clause for vintage cars in the testers handbook which defines the "two independant forms of braking" as having to operate on exclusive axles as opposed to exclusive systems. Anyway the Sierra calipers use the same pads for handbrake and normal stoppers so that makes a mockery of the regs anyway. Bottom line is, you can pass the MOT.

 

Third problem is that with the ability to lock your front wheels you get a tendancy to try to drop the clutch at high RPM. This results in lots of smoke and more agressive tyre wear. Fun though.....

 

Oh and the "you need a line lock on the front to do doughnuts" is a complete nonsense. An LSD is what you need there....

 

Arnie Webb

So fat the chassis snapped....wink.gif

 

See Fat Arnies 2 piece Seven here

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