sunbeamtiger.co.uk

Hi everybody,
I have searched and read through the forums but can't find anything describing the issue I have with my brakes, which I think is the servo but I would like some learned input form the wise forum members to confirm.
The problem is that as I press on the brake pedal it starts gently and then suddenly grabs like a switch has been thrown.
I have replaced the seized front calipers and pads, ensured the rears are working fine and the shoes are good, hand brake works, master cylinder seems to be fine and I have flushed and bled the whole system but still have the issue.
The servo looks ok from outside. (I know some run without the servo but my Tiger is stock but was rarely driven over the last 10 years before I got it and I'd like to keep it stock as long as I can.)
So the long winded question is:
What do I look for and can I fix it myself? If not, does it need a rebuild or exchange or should I bite the bullet and start on the wallet wilting upgrade road that will inevitably end with a 427 psycho tiger/cobra/boss hybrid, tyre destroying monster.
Advice please?

Hi Maxtwee,
what make of servo is fitted to your car ?,if it's original it will be a Girling manufactured unit and this may be the cause of the problem.
The servo may be coming in to slowly,due to the diaphragm sticking in the vacuum chamber.
The servo piston has a primitive sea lof leather in the early units and they can dry out and cause sticking.
Far better to replace with a more reliable unit of Lockheed manufacture,they employ a rubber diaphragm in the vac tank.
Regards David

I'm pretty sure it's the original unit. Does anyone make a rebuild kit for them with rubber instead of leather?

I rebuilt mine, original factory unit, and I used a type of special grease used for guns and shotguns. Copious amounts applied to the inner drum and leather seal and it works perfectly now. Before the brakes would 'grab' and stay locked on. Girling actually recommended the grease type, I have it somewhere if you need to know exactly the type. Cleaning the inner drum to a clean polished finish helped also.

Original Girling unit with decent pads (though am using Brembo pots) is up to the job - anyway, worked at the Nurburgring

at the ring your car wasnt going fast enough to need brakes .we spent most of the time with the bonnet up on it.
i would fit a modern lockheed unless your a purist or paid up tiger police member .shouldnt take any chances with brakes

garyv8tiger wrote:your car wasnt going fast enough to need brakes

I know it's deceiving, because I am taking the correct racing lane and being so smooth you rarely see me braking. Though I suppose you get tired of seeing my rear brake lights

most of the time i see the rear of that car the boot is open and there are tools all over the rd .its had more breakdowns than the rac

Coming to the rescue of other folk, mate!!

if mine breaks it usually needs a flatbed

redbaron wrote:Far better to replace with a more reliable unit of Lockheed manufacture

Great tip David, I know a few members who have also installed the servo under the dashboard area away from the engine bay - really, just to get away from the heat and also for a 'cleaner' look.

servo under dash .may aswell put your drivers seat under the bonnet too

The sunbeam spares website advertises a rebuild kit, what comes with this? does it include a replacement leather seal and the special grease? There is also a servo filter listed, what is that? Is it standard or just a useful addition?

If people are putting servos in the cockpit and seats in the engine bay, has anyone found a use for the steering wheel? I originally assumed it was for changing direction but seems to be more of an ornamental piece so i was thinking of keeping it in the boot to get a better view of the instruments.

Hi Maxtwee,
the rebuild kit typicaly contains the rubber seals for the hydraulic cyl on the servo,a couple of gaskets for the cyl to tank and one for the air valve chamber cover,a gasket for the tank end cover,a grommet for the vac tank pipe and the Sorbo foam seal that fits under the leather seal,it will not have a new leather seal as that is part of the vac piston and it is trapped between to pieces of steel to make the piston.
You will also need the special grease to lubricate the seal in the tank to make it slide easily,this can be a tiresome exercise in itself.
Also the hydraulic cyl may be beyond use due to scoring where the piston is and it must be carefully centered upon reasembly.
Best bet buy a new Lockhead unit,unless originality is your desire.
Regards David