brake adjustment for SVA

[davey.knowles]

Hi,
SVA people want me to adjust my brakes on my 94 3.0 Surf,.
The SVA mans comment was;
'The braking ratio of the axles is not,for all values of total brake force less than the friction force ration 9taking account of the weight transfer) between axles with the vehicle in running order. Rear brakes lock before fronts. The brake efficiency with the servo fully depleted and at a pedal pressure of 50kg is less than 30% cgvw'.

Now he might as well have written this in Dutch for all it means to me, but heres the sting. The SVA guy then says, Mr friend can sort this out for you, here's his number. I call 'friend' who says he can sort it but it takes 3-4 hours of labour.

I've asked a couple of other surf owners I know and one has suggested that he solved his SVA brake problem just by fitting hard brake pads (apparently Japs use soft) and adjusting a valve on the back axle.

Can anyone shed any light on this, give me any info etc..
appreciate any help

Thanks
Dave

[gemini]

Hi,
SVA people want me to adjust my brakes on my 94 3.0 Surf,.
The SVA mans comment was;
'The braking ratio of the axles is not,for all values of total brake force less than the friction force ration 9taking account of the weight transfer) between axles with the vehicle in running order. Rear brakes lock before fronts. The brake efficiency with the servo fully depleted and at a pedal pressure of 50kg is less than 30% cgvw'.

Now he might as well have written this in Dutch for all it means to me, but heres the sting. The SVA guy then says, Mr friend can sort this out for you, here's his number. I call 'friend' who says he can sort it but it takes 3-4 hours of labour.

I've asked a couple of other surf owners I know and one has suggested that he solved his SVA brake problem just by fitting hard brake pads (apparently Japs use soft) and adjusting a valve on the back axle.

Can anyone shed any light on this, give me any info etc..
appreciate any help

Thanks
Dave

say to him you tw*t, i know that The longitudinal brake distribution for the service braking shall, for all values of total braking force,vehicle speed and adjustment settings (if any), be greater than the ratio of the vertical forces transmitted to the road through the front and rear wheels respectively when the vehicle is in running order and being braked on a level surface.

The brake efficiency with the servo fully depleted and at a pedal pressure of 50kg is less than 30% cgvw'.
[this should be not less than 50%] sometimes you get this when new pads have been fitted and not bedded in

[rich]

There is a load compensation valve on the rear that operates on the position of the rear axle reference to the chassis. The theory is that the more weight you put in the back the more braking is biased to the rear to compensate. I am not sure if this is adjustable???

Had the same problem when I got mine but then that was because some fool had lowered it - the springs were half the size that they should have been.

Has your Surf got a saggy arse?? It is quite common for the shocks/springs to be worn with age and drop the back-end. This would have the same effect on the compensation valve.

Rich.

[da SLUG man]

There is a load compensation valve on the rear that operates on the position of the rear axle reference to the chassis. The theory is that the more weight you put in the back the more braking is biased to the rear to compensate. I am not sure if this is adjustable???

Had the same problem when I got mine but then that was because some fool had lowered it - the springs were half the size that they should have been.

Has your Surf got a saggy arse?? It is quite common for the shocks/springs to be worn with age and drop the back-end. This would have the same effect on the compensation valve.

Rich.

he's right!... happened on an escort turbo van project... lowered suspension made the rear lock up, had to adjust the bias valve.... good fun though!