Compared to modern cars the MGB brakes can seem heavy and assistance in the form of a servo is a useful contribution to brake efficiency. Before contemplating fitting a servo you should ensure that the braking system is in first class condition.

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MGBs built after August 1973 are fitted with a servo as standard and earlier MGs can benefit from this modification. A kit is available from good parts suppliers, which consists of a Lockheed servo, additional brake pipe-work, vacuum hose, manifold adapter and additional brackets. This enables a remote servo to be fitted in the rear left corner of the engine bay. On some early cars the screen washer bottle should to be re-mounted in a convenient place close-by.

The first task is to mount the servo. The servo is fitted with the large vacuum chamber close to the wing, the narrow neck end should face inwards and upwards at an approximate 15° angle and the white plastic filter housing should face upwards and slightly forward. This is not an ideal position since there is a small internal passage extending up towards the white filter housing which is difficult to bleed.

The large bracket is bolted to the three studs on the large vacuum chamber and secured to the flat scuttle panel above the passenger's foot-well. On some cars there may be at least one captive nut that can be used from the scuttle blanking plate. The 'P' bracket is attached to the neck of the servo and bolted to the flat scuttle panel.

After the servo has been fitted the additional brake pipes can be put into place. It will be necessary to drain all the brake fluid from the braking system and once the fluid has been removed it should be discarded. This would be a good opportunity to change the fluid in the system. Beware; brake fluid acts like paint stripper if splashed on paintwork so take great care when using it. After the brake fluid has been drained from the system remove and discard the brake-pipe that connects the master cylinder to the three-way connector. Take the shortest of the two new brake pipes and connect it from the master cylinder to the inlet partway down the neck of the servo. The pipe should be routed from the master cylinder up along the top of the scuttle behind the two bonnet hinges and down to the servo. Then take the other brake pipe and connect it to the outlet at the end of the neck of the servo and connect it to the three-way adapter where the old pipe was removed. Again, the pipe should be routed along the top of the scuttle behind the bonnet hinges and down to the three-way following the path of the old pipe. Three brackets should secure the two brake pipes across the bulkhead. The pipe to the three-way adapter should be secured next to the pedal box. Once this has been done the brake system can be re-filled with fluid, bled in the normal way and checked for any leaks in the new joints.

The final step is to fit the vacuum pipe from intake manifold to servo. There is normally a blanking plug in the manifold, which should be removed and be replaced by the vacuum pipe adapter. If necessary the vacuum pipe can be trimmed to length before fitting. To complete the job road test the car to ensure the system is working perfectly.


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