Hydraulic Handbrake

[Guest NantLladron]

Hi

 

is a hydraulic handbrake ok with regards MOT ? i think they just check efficacy

 

......i am changing rear brakes from drum to disc so was thinking of putting hi-spec calipers on rear without mechanical handbrake part then just fitting a inline hyd handbrake?

 

Mark

[Guest russell555]

In a word..... No

 

There needs to be a mechanical brake as well as the hydraulic system...

[sj-bradley]

Not entirely correct.

 

The IVA manual states that it has to be an independant means of braking "all wheels on at least one axle" and held in the "on" position by mechanical means. (This doesn't mean a cable but the ratchet) and cable is not mentioned as required.

 

So a separate hydraulic circuit from the main service brakes should also comply.

 

Section 9a

 

(revision 24/5/2010)

 

Simon.

[Guest russell555]

That would mean an extra caliper wouldn't it?, as it's not a separate circuit if it uses the same piston on the brake?

 

You can get calipers that also accept a mechanical handbrake cable though.... Might be a solution?

[sj-bradley]

I suppose it would mean an extra TWO calipers as it has to operate all wheels on at least one axle.

 

Or for drums, it could mean a different piston on the other end of the shoes.

 

(I'm not sure if you can get a cylinder just to operate the mechanical part of the handbrake caliper).

 

Simon.

[nicko]

I remember reading about a company that produced a mechanical handbrake to fit Ford calipers. I think it might have been Marlin, deffo a kit car company. If I find the info, I'll post on here.

HTH

Nick

[Guest MarkB]

Hi

 

is a hydraulic handbrake ok with regards MOT ? i think they just check efficacy

 

......i am changing rear brakes from drum to disc so was thinking of putting hi-spec calipers on rear without mechanical handbrake part then just fitting a inline hyd handbrake?

 

Mark

 

Hydraulic parking brakes as a sole means of operation are not acceptable on vehicles first used on or after 1 January 1968. However, they may be used to assist the application or release of a mechanical brake.

[Longboarder]

Or as Russell said, 'In a word, No.'

Think about it. You pull up after a hard drive with the brake very hot. Apply the handbrake. Walk away, they cool. A cable contracts as it cools although hardly a problem in reality but this could only apply the brake more firmly. Fluid also contracts as it cools. Definite problem in reality as this reduces pressure in the system and your car runs off down the hill. That's why it is a fail at IVA and under construction and use I believe.

 

Nigel

[nicko]

Hi, just done a search for the handbrake I mentioned earlier. I was Marlin, but it's been taken off the market.

See here...

http://www.marlinsportscars.co.uk/news/115/

Might be worth contacting them for further details

 

HTH

Nick

[sj-bradley]

Or as Russell said, 'In a word, No.'

Think about it. You pull up after a hard drive with the brake very hot. Apply the handbrake. Walk away, they cool. A cable contracts as it cools although hardly a problem in reality but this could only apply the brake more firmly. Fluid also contracts as it cools. Definite problem in reality as this reduces pressure in the system and your car runs off down the hill. That's why it is a fail at IVA and under construction and use I believe.

 

Nigel

 

I take your point about this. Strange that the IVA manual doesn't make this more clear. I can understand now why different testers / stations can pass an item that others would fail. It really should be clarified much better than it currently is.

 

Simon.

[Guest russell555]

its been a problem in motorsports for a while now..... cars being pulled up on mot for this very reason...