Vixen brake pipe
Vixen brake pipe
Author
Discussion

tomtrout

Original Poster:

595 posts

180 months

Friday 18th February 2011
quotequote all
My S2 was fitted originally fitted with a single line system with no servo. I really want the car to be as near to original spec as possible but just wanted some views on whether this is the sensible way to go. I'm not worried about having a servo as my leg muscles arn't that bad and I don't believe that the servo will make the car stop any quicker. I don't have any of the original pipes left to compare with but I don't think it was fitted with any balancing device just a 4 way union located on the chassis above the bell housing and a simple 3 way union at the rear end. I'm more worried about brake balance with this set up but should I be concerned for a road car? I know the dual circuit systems have some kind of pressure device to stop the rears from locking up under heavy braking.

I could route the pipes any way I want but would like to keep the the traditional route (whatever way that is?) Should the front to rear pipe be run down the top right hand chassis pipe? Does anyone have a sketch or photos of the prefered route for the pipes to run down to each leg? Also what clips are recommended. I have seen cable ties used but think they might look rubbish so was thinking about stainless jubilee style clips.

Sorry for the epistle but any advice really welcome.

heightswitch

6,322 posts

267 months

Friday 18th February 2011
quotequote all
sod the originality and fit a tilton pedal box.

the early s2 vixen can be retro fitted with a servo but I would still always switch to twin circuit brakes. its not a question of originality it is a question of stopping!!!

N.

tomtrout

Original Poster:

595 posts

180 months

Friday 18th February 2011
quotequote all

Well I definitely want to be able to stop but am I right in believing that dual circuit brakes won't help me to stop more efficiently but might save my life in the event of a catastrophic brake line failure? Realistically how likely is that in a car that is well maintained? I don't want to put anybody else’s life at risk so perhaps the dual system is the one to go for. I can feel more questions coming on regarding the pedal box!

Seabass

193 posts

216 months

Friday 18th February 2011
quotequote all
Tom,
What master cylinder is currently fitted? Is it a standard girling .70? You should be able to change to a later dual circuit master cylinder with some ingenuity. I'll get shot down in flames for this but TVR used the servo and cylinder from a TR6. This will then give you a split front / rear system (not a diagonal split as the M/C has two bores for front and rear brake bias). Some advocate the TR6 MC is a poor design and that a Cortina unit should be used.

There was no "proportioning valve" which alters braking force to the rear fitted to Vixens, don't let anyone tell you other wise. There was a Pressure Differential Warning Actuator inside which a shuttle slides when pressure is lost within one brake circuit and activates the brake warning light on the Vixen dash. In my opinion this is more trouble than it is worth as the seals fail and cause problems. I would not refit one but instead opt for a low fluid level warning cap to light the lamp.

Cheers
James

Slow M

2,834 posts

223 months

Saturday 19th February 2011
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Tom, I agree with everything here, just to add -the purpose of dual circuits is to separate in case of a failure. That way, you still have SOME braking.
B

heightswitch

6,322 posts

267 months

Saturday 19th February 2011
quotequote all
Switching to a Cortina master cylinder is OK in theory but this is an earlier S2 which has no servo and a different bulkhead with TVR's own pedal box and rear mounted cylinders as opposed to the TR6 affair!! Doubtless you could adapt something but my advice would be to switch to an ajdustable bias pedal box.

You are correct in that stopping isn't much different, Though repeated stopping power is vastly different!!!!! The single circuit system is a weak link in the chain and losing any connection or damaging any brake hose results in zero braking power.

It all depends upon how original you want to be. It all works and their will always be a purist argument against changing something on a car that takes it away from being original. I am not one of those purists.












N



Edited by heightswitch on Saturday 19th February 10:09

tomtrout

Original Poster:

595 posts

180 months

Sunday 20th February 2011
quotequote all
Thanks for the photos Neil. I think if I had 8 cylinders under the bonnet I would want some stopping power to match. With those early TVR peddle boxes were the peddles themselves nicked from the TR or were they also TVR OE?

thegamekeeper

2,282 posts

299 months

Sunday 20th February 2011
quotequote all
Not sure the number of cylnders is relevant. If you hit something at 70mph, the size of your engine no longer matters! Maybe you should have bought a van if you want to peddle boxes. My old wreck is only a 4 cylinder but is much quicker than Neils, it moves!!!! It has a single brake pipe system identical in theory to yours, been driving it a LOT for many years without any brake issues but I have used the correct materials and components and perform preventative maintenance. Lots of old cars had single pipe systems

Edited by thegamekeeper on Sunday 20th February 14:47

heightswitch

6,322 posts

267 months

Sunday 20th February 2011
quotequote all
thegamekeeper said:
Not sure the number of cylnders is relevant. If you hit something at 70mph, the size of your engine no longer matters! Maybe you should have bought a van if you want to peddle boxes. My old wreck is only a 4 cylinder but is much quicker than Neils, it moves!!!! It has a single brake pipe system identical in theory to yours, been driving it a LOT for many years without any brake issues but I have used the correct materials and components and perform preventative maintenance. Lots of old cars had single pipe systems

Edited by thegamekeeper on Sunday 20th February 14:47
Like I said. It all works, Just a question of what you want at the end. I was just pointing out the error in other info given regarding later cars which have the later TR6 pedal box. I think the first 75 S2's had the earlier S1 type TVR own Pedal Box assembly and bent bits of metal.

Mines getting a bit closer to working and I have rolled it on and off the trailer a few times this week Steve tongue out

Didn't you fit a servo to yours Steve?

N.

thegamekeeper

2,282 posts

299 months

Sunday 20th February 2011
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Yes mine,s got a servo and bent metal

tomtrout

Original Poster:

595 posts

180 months

Sunday 20th February 2011
quotequote all
So were the bent bits of metal, sometimes referred to as "pedals" in those early cars borrowed from another car?

thegamekeeper

2,282 posts

299 months

Sunday 20th February 2011
quotequote all
Nope, bespoke TVR

heightswitch

6,322 posts

267 months

Sunday 20th February 2011
quotequote all
Why? have you not got them in your car?

If you have all of the original fabbed pedal box which I think have TVR made Pedals (Steve may know different)then It can all be re-furbished to work well enough.

if you haven't then it may be prudent to upgrade to a different pedal box to achieve a better overall system.

Again it just depends how original you want to be..

At the end of the day the TR4 - 6 based braking system employed was designed by triumph engineers to stop a car much heavier than a Vixen. using good quality componants and upgraded modern materials will be more than enough if you are keeping your car standard or mildly warmed over.

I am also gluing together a nice Zetec engined S2 which is pretty standard apart from the later TR6 servo pedal box and Cortina master cylinder which essentially does away with a load of Brake failure warning light cack not required.
N

tomtrout

Original Poster:

595 posts

180 months

Sunday 20th February 2011
quotequote all
Yes I've got the original pedals but thanks for the advice on alternative options.