Hydraulic handbrake

[sgroves]

Has anyone fitted a hydraulic hand brake, I'm planning to build a superlight from a new kit and can change/weld/adjust from scratch.

 

Steve G

[EFA]

You will fail SVA on this unless you have a completely discreet setup.

 

You will pass MOT with a hydraulic handbrake "in line" with either of the brake circuits as the Seven is unusual in that the dual circuits are split front rear.

 

I have passed 5 MOTS with a hydraulic line lock for a handbrake.

 

The matter was referred to the DOT testing office on one occasision and it was given the OK as the ciurcuits are split as they are. This is because of some quirky regulation inclusion for vintage cars.

 

I shall be attempting to fit the hydraulic handbrake in the DT catalogue (p241 - item 19) on Counts car soon as a development of what we already have.

 

 

 

 

Fat Arn

Visit the K2 RUM siteid=red>

See the Lotus Seven Club 4 Counties Area Website hereid=green>

 

[elie boone]

sgroves, fitting an hydraulic hand brake is simple, just mount a single brake pump in front of the hand brake inside the tunnel but leave the original hand brake cables in place ( disconect )also i would close the opening under the propshaft so that the brake pump is not vissible any more.

To mount the single brake pump, just interrupt the hose witch goes to the rear wheels and mount this where the reservoir should be, the outlet from the pump then goes to the rear wheels.

One note : when you brake with your foot you will have very little mouvement on your hand brake lever.

[Chelspeed]

I've got one. Lever on the passenger side of the tunnel, mounted vertically. Master cylinder inside the tunnel behind the lever. It's better than a line lock as you can use it to handbrake turn (put the brake on rather than just hold it on once you use the footbrake).

 

Definetly not MOT legal as it's hydraulic and MOT says you need two braking systems one of which must be mechanical. Also it's fly-off with no button or ratchet so in that case even less legal than a line lock.

[EFA]

Graham said:

 

MOT says you need two braking systems one of which must be mechanical

 

Not the case on cars with a front/rear split as I said.

 

Fat Arn

Visit the K2 RUM siteid=red>

See the Lotus Seven Club 4 Counties Area Website hereid=green>

 

[Chelspeed]

This contradicts what I have been told and read in the MOT manual but I can't be bothered to argue about it.

 

I suspect DOT testing office felt the same....

 

From personal experience a master cylinder is not designed to maintain pressure for more than minutes at a time and will not do so. If you park and rely on a conventional hydraulic handbrake (ie one using a conventional master cylinder rather than a line lock) then the car will not be there when you get back. It'll be at the bottom of the hill in someone's front garden. This is presumably why the MOT people don't like it.

 

My view is that leaving it in gear, a mechanical lock, is much more reliable than relying on hydraulics to hold pressure when they're only designed to be used in a transient basis. Perhaps I'll try that stance at the next MOT.

 

I remember a rally car (fitted with a hydraulic handbrake) that had a hole thro the tunnel and a screwdriver in the footwell, to park the car the screwdriver was pushed thro the hole and thro the propshaft UJ, it wasn't going anywhere after that!! Not sure what the MOT people made of that, it was cetainly mechanical.

[Graham Perry]

The rally car trick would be very easy to do on a seven

[sgroves]

Graham,

I used to have a rally car, with a hydraulic handbrake. It also had a cable arrangement to keep the M.O.T.happy - it passed an MOT at least 3 time like this. But I don't know what you mean by "Rally car trick"?

 

Steve

 

Steve G