Rear brake adjusters, rods and servo tips
R-R Silver Dawn, Silver Wraith. Bentley MKVI, R type.
N.W.Geeson I.Eng. M.I.R.T.E M.S.O.E

The following applies to all rear brakes on all year models.

Applies to front brakes also on cars made before approximately June 1950 that is cars with wedge front brakes. For identification these cars also have only one steering idler.

The correct brake operation depends upon the rear brake assemblies being set up correctly. If any stretch / distortion occurs in the rear brakes the pedal travel will increase alarmingly and the servo will not be as effective as it should.

Note it is possible to obtain shoe centralisation with a trammel when the adjuster is NOT centralised. This is because the equal wear shoe linkage has been adjusted to obtain shoe centralisation. In this case it is possible for the shoe action to pivot around the equal wear linkage, hence the reason for assuring centralisation of the adjuster FIRST, so that the shoes pivot off the adjuster. In the former case the brakes often sprag onto the drum and drag, this is not felt by the driver! It is important to establish that the rear adjusters are centralised BEFORE the equal wear linkage is fitted.

It is important when rebuilding the brakes to do so initially, by assembling them WITHOUT the equal brake shoe wear linkage. Loosen off the adjuster to back plate screws and lock up the brakes to the drum with the adjuster, this will centralise the adjuster. Then lock up the adjuster mounting screws. Turn back the adjuster until the brakes are exactly as you would normally have them on the road. Then BACK OFF the adjuster COUNTING the clicks (say 10 clicks) until you can remove the drum. Remove the drum, take UP the adjuster to the normal position (our 10 clicks). Now assemble the equal shoe wear linkage and set the adjustment with your trammel. Ensure the shoe linkage has the fulcrum lever (see saw) at the TOP and the shoe return spring, nearest the actuator, hooked to the TRAILING shoe. If you do not follow this action the rear shoes will pivot wrongly.

When adjusting the chassis rods it is necessary to adjust the rod running rearwards to the equaliser tighter than the manuals suggest, so that the actuator pull rods are quite tight but the brakes release cleanly. Make sure the brake actuators are fitted with the later fitted return springs. Do not adjust the rod to the equaliser with the rear axle hanging, rather have supports under the axle. If the rear springs have just been re-arched, set the equaliser rod, then back off some (count turns back) then run the car for a few miles in the laden condition to settle the springs. Readjust the actuator rod after the springs have settled. Reason, the actuator rod does not pivot from the spring eye centre!!

When finally adjusting the servo, do not follow the manual. Instead, lock up the left rear brake, jack up and support the car, lie under the car with feet touching the right rear wheel, rotate the wheel with your toes whilst adjusting the servo to obtain the exact point that the servo grips, then back off two nut flats. This replicates the exact servo action on the road and you can see the action as it happens.