Brake Servo Or No Servo, That Is The Question

[Guest captn Pugwash]

Please can some one help me with the brakes on my part built exmo, do I use the sierra pedal box and servo or go with a pedal box with bias brakes and no servo, I have a sierra back axle with disc brakes fitted, also wheres best to run the brake and fuel lines with regard to sva preferances. Got to keep them happy.

 

Is there a book I can buy, borrow, or steal, with all the wants of the sva man. any advice appreciated.

[Guest mkeats02]

Dave

 

I have run my fuel and brake lines down the middle of my tunnel. Securing them every 20cms (8"). Think this is OK for the SVA, as far as I know the minimum is every 30cms (12").

 

 

Mike

[Guest Roger 2B]

A pedal box with adjustable bias won't pass SVA, I am told.

[Longboarder]

I believe you can have a bias adjustment fitted for SVA but the car must pass the brake test either with it adjusted to each opposite extreme or it must have been previously set and then made non adjustable so you can't go home and change it.

 

Nigel

[Mat-Moo]

Gonna bump this. When I had my Exmo it had 1.6 running gear all aroudn with a servo. WIth this setup I found it to easy to lock up the front wheels. Now for my latest build it's all 2 lt stuff (Bigger back breaks and vented fronts), I'm worried now that with a servo it will lock all to easily. SHould I run with or without the servo?

[Guest Ianz]

Mat

My 3a has 2 lt brakes ,vented front discs,standard drums,and servo

and works fine,ie the braking is very progressive,no lock ups,mind

you I've not driven the car in the wet yet!!!

 

Cheers Ian

[Guest chris]

I will second that.It took me a while to get the brake compensator set just right but

now the brakes are spot on.

regards chris

[Guest Charles B]

I have a 2B with drums on rear and have twin brake master cylinders (no servo) It passed the SVA fine with the bar locked up with two locknuts. The SVA man said it was fine as long as you couldn't adjust it while driving, ie with a knob on the dash.

I can lock all four wheels up if I push hard enough, the brakes feel very hard with practically no travel on the pedal unlike with a servo setup. I had to modify the sierra pedal assembly quite a bit. I think I would probably make a floor mounted unit if I was doing it again.

[Guest Alasdair]

I have a 2B which I bought ready-built. It has Sierra 2ltr brakes and a servo and they seem to work well.

 

However, a short while ago while driving home on wet roads someone stopped in front of me for no apparent reason and all I heard was a long drawn out whooshing sound of locked wheels, with no reduction in speed at all. Fortunately they changed their mind and got going again before I arrived!

 

I now drive more slowly in the wet.

[Guest Ianz]

Alasdair

 

Sorry to be a smart arse but..........

and all I heard was a long drawn out whooshing sound of locked wheels, with no reduction in speed at all.

 

You should have taken your foot off the brake,and braked again!!!!!!!!

called "cadence braking".

 

Thats how we did it in the good old days before ABS was commonly fitted.

 

Cheers Ian

[Guest Alasdair]

Yes I knew afterwards I should have done that but at the time my brain was screaming "Press Harder!"

[niduncan]

I have a Series III with standard 2.0l brakes, vented disks front and rear drums. I have run the car with and without the servo. Without the servo the pedal is is hard and it takes a lot of effort to stop the car, it was possible to lock the brakes but I really had to stand on the pedal. With the servo fitted driving is a lot more comfortable, the pedal is much softer but it is easier to lock the front wheels. The car is not fitted with the deceleration sensitive valve.

[Mat-Moo]

I guess you could improve brakes without the servo by changing the pivot point (or make brake rod connection point higher)

[Guest rizla]

this is a old argument,shall i have a servo or shall i not

in my opinion you dont need a servo,a kitcar is mutch lighter than the donor and the feel on brakes without a servo cannot be beaten

and you dont have to press the pedal as hard as you think

[Guest Stuart Ainslie]

I'll second Rizla's comments....

 

Having driven a Lotus Elise around Silverstone a few times, which does not have a servo, I found it a far nicer braking action. You do need to give the pedal a good shove though.....