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Hydraulic Handbrake
kingr - 31/1/03 at 12:18 PM

Given that the hand brake arms on the rear brake calipers arms that I have got have seized, and fixing them looks to be a bit of a nightmare, and buying replacements is expensive, is it possible/SVA legal to use a hydraulic handbrake instead? I see they've got a hydraulic handbrake conversion in the latest rally design catalogue which would be pretty cool.

Kingr

[Edited on 31/1/03 by kingr]


johnston - 31/1/03 at 12:30 PM

No it wont even get you an mot You must have a secondary braking system which is totally independant

if you burst a pipe with a hydralic hanbraking system you lose your hand brake as well as foot pedal

thats why people are starting to have trouble with rally cars they've paid 80k for
silly buggers


JohnFol - 31/1/03 at 03:06 PM

Johnston, just to confirm, it's not the fact it's hydraulic, it's the fact it shares the same pipework / reservoir or pistons.

For example if I had a brake cylinder attached to my hand brake leaver, as long as it had independant reservoir, pipework and actuator (caliper / whatever) it would be allowed.

Is this right?


johnston - 31/1/03 at 03:18 PM

yeah sorry my mistake i was just thinkin if you were just runnin a conventional set up

i e drums or 1 caliper per wheel


BUT!!!! you could run hydraulic to bac and use citreon calipers on front for h/brake (bx i think)


Fifer - 31/1/03 at 03:39 PM

Thought it had to be a mechanical device ?
You can get duel system with hydraulic and cable combinations to do those lock ups at 80mph (for the 80K Rally Car, silly, lucky, buggers)


Liam - 31/1/03 at 07:35 PM

quote:
Originally posted by Fifer
Thought it had to be a mechanical device ?



If those are the official rules, then I suspect, like a lot of silly SVA/MOT rules it will be down to your tester's interpretation. I would argue a hydraulic system is a mechanical device - cos it's not an electrical device.

Liam


jollygreengiant - 31/1/03 at 07:38 PM

The trouble is that with the hand brake levers being seized the the pistons will stick and that will give you other problems. Go to your local factors and announce your self as a trader or mechanic, visiting, and ask for lots of trade discount (really haggle it) and I think that you will find that echange recon calipers aint that dear for piece of mind. As for Citreon calipers with hand brake on the front (BX, Xantia and likes of) you can't because you would need to run them on a seperate hydraulic system to the rear brakes, unless you used the rear as well from the same Citreon, because the seals in the calipers are not compatible with normal DOT4 type brake fluid, it makes them fall apart in very short order.

Enjoy.

[Edited on 31/1/03 by jollygreengiant]


stephen_gusterson - 31/1/03 at 08:52 PM

i am reasonably sure sva manual says it must be mechanical.

an xj-s has a single disk brake mounted inboard of the rear axle as a handbrake. but its cable operated....


atb

steve


philgregson - 31/1/03 at 09:48 PM

My understanding is that the primary handbrake my not be hydraulic to pass an MOT. A hydraulic handbrake must be suplimented by a cable handbrake.

People used to dangle non functional cables and allsorts under rally cars to try and fool examiners - it used to work in the old days but they tend to look harder these days.

People also knew examiners that would let them through with a hydraulic hand brake (and probably still do) but officially it must be a 'mechanical' not hydraulic linkage - the theory being that the system could develop a leak whilst it is parked and your car disapear down a hill.

Personally I would sooner my handbrake failed whilst I was elsewhere than my main braking system went whilst I was driving - twin circuit I guess.

Phil.


Rorty - 1/2/03 at 12:27 AM

What about laser cutting/machining a small disc, which could be bolted onto the diff input flange, then use a go kart cable operated caliper. Super light, and would meet MOT/SVA requirements.
Light weight hydraulic calipers could then be used at the wheels.


Viper - 1/2/03 at 07:56 PM

quote:
Originally posted by Rorty
What about laser cutting/machining a small disc, which could be bolted onto the diff input flange, then use a go kart cable operated caliper. Super light, and would meet MOT/SVA requirements.
Light weight hydraulic calipers could then be used at the wheels.



i believe landrovers used to use a handbrake on the propshaft...


johnston - 1/2/03 at 08:04 PM

quote:

the theory being that the system could develop a leak whilst it is parked and your car disapear down a hill.



i think the actuall technical term for the hand brake is an emergancy brake not a parking brake


stephen_gusterson - 1/2/03 at 10:24 PM

quote:
Originally posted by johnston

quote:

the theory being that the system could develop a leak whilst it is parked and your car disapear down a hill.



i think the actuall technical term for the hand brake is an emergancy brake not a parking brake



i think thats what the yanks call em - ever tried using one as an emergency device? better off stiking yer foot out the door - or using considerably as an anchor

atb

steve


jollygreengiant - 1/2/03 at 11:56 PM

quote:
Originally posted by Viper
i believe landrovers used to use a handbrake on the propshaft...



Yep & its called a transmision brake. Apply it at over 30mph in a land rover/range rover/discovery, and you could soon find yourself pole-vaulting over your prop-shaft.



Enjoy.


johnston - 3/2/03 at 11:41 AM

had a few lessons in a mk2 at the rally school i mechanic at at wkends it gets called a turning aid there
lots of fun especially in the snow this morn


Wadders - 4/2/03 at 06:52 PM

My understanding is that the primary handbrake my not be hydraulic to pass an MOT. A hydraulic handbrake must be suplimented by a cable handbrake.

How does the handbrake work on the latest 7 series beemers, they only have a switch on the dash, i guess they must be hydraulic, or does it somehow lock up the transmission. i'm keen to get to the bottom of this debate cos iv'e just spent ages fitting a pair of small independent hydraulic calipers to my car, thinking it would be ok for SVA/MOT.

Cheers

Al