The Princess & Sheerline Handbrake (right hand drive vehicles)
How many times have you heard car owners say something like, ‘The handbrake was never any good on this
model’? To a certain extent, what the owner was saying is correct. Yes the handbrake does not work
correctly if adjusted incorrectly. The method of successfully adjusting the handbrake is a most essential part
of vehicle maintenance.
My DM4 Princess had, what I call, an ornamental handbrake lever under the dash. Ornamental because you
could pull it out to its full extent with no affect on the rear brakes. I inspected the brake linings for ware and
found them to be quite good. After adjusting the front and rear brakes and handbrake, using the sparse
instructions in the Workshop Manual, it still did not work. The foot brake worked well. It was obvious by the
amount of movement of the pistol grip at the dash, that my efforts had not reached the back brakes.
First problem discovered: The cable between the pistol grip and the lever in the engine compartment, had
been adjusted to its fullest (ie cable shortened). Mistake. Although there is allowance for adjusting this cable,
it should not be used to adjust the handbrake. Why? Because adjusting that cable here, by shortening,
reduces the travel of the Pistol grip inside the car. Secondly, if you look at the lever that the cable is attached
to, it consists of a very long portion above the pivot point and a very short portion below the pivot. It is built
that way so that maximum mechanical advantage can be achieved. This is achieved by translating a long
movement of the pistol grip with low effort from the driver, into a short movement below the pivot (and at the
rear brakes) with considerably increased force.
- Disconnect the cable from the lever in the engine compartment, by removing the split pin and clevis pin
(click here to see Fig 1 for illustration of Upper handbrake lever);
- Release the locknut on the cable adjuster and unscrew until the threaded portion is no longer visible
inside the ‘U’ bracket. Stop when the ‘U’ bracket is aligned to receive the top of the lever.
- Tighten the locknut.
- Reconnect the cable
I noticed the clevis pin was a worn about 1-mm. So I replaced it. At this point I might add, the action of
replacing all the clevis pins in the handbrake train, resulted in a recovery of 10-mm of lost travel over the
entire handbrake system due to wear. Clevis pins and split pins are cheap so I recommend replacement of
both. (click here to see Fig 3 bottom pivot of break lever and here to see Fig 5 forward brake rod pivot)
Second problem discovered: The ‘Balance Lever’ (click here to see Fig 2 it lives on the differential housing
and is where the rear cable and rods meet) was not in a position that would result in effective travel of the
brake train. The bottom lever on the ‘Balance Lever’ is attached to the rear handbrake cable. That lever
should be as far to the rear of the vehicle as possible, so that when the handbrake is applied, maximum
travel can be applied to the rods attached to the brake levers (behind the rear backing plates).
- Disconnect the rods attached to brake lever behind the rear backing plates and disconnect the rear
cable. (click here to see Fig 4)
- Adjust the rear brake shoes until the drum cannot be turned by hand then release one notch at a time
until the drum turns freely.
- Adjust the short rod (driver’s side) until the holes in the ‘U’ bracket align with that of the handbrake
lever then insert the clevis pin. While doing this you must maintain the following:
- The lower lever on the ‘Balance Lever’ (the one connected to the rear cable) must be in the rear
most position (click here to Fig 2); and
- The shaft on the ‘Balance Lever’ must remain vertical
- The handbrake lever is pulled away from the backing plate until free-play is taken up (click here
to see Fig 4)
- Then on the other side of the car (passenger side), adjust the ‘U’ bracket until the holes in the ‘U’
bracket align with that of the handbrake lever then insert the clevis pin. While doing this you must
maintain the following:
- Lightly push the rod away from the brake drum until slack is taken up;
- The handbrake lever is pulled away from the backing plate until free-play is taken up.
- Now reconnect the cable, with the handbrake still released, check the slack in the rear handbrake
cable. There should be only the slightest bit of slack visible when the cable is moved up and down by
hand (about ¾ inch). If more, then the slack can be removed by adjusting the ‘U’ bracket on the rod
forward of the cable (click here to see Fig 6). Reconnect and try the handbrake. There should be
about 4 or 5 clicks from the handbrake pistol grip.
Conclusion: The Handbrake will operate satisfactorily when:
1. The rear brakes shoes are adjusted correctly ; and
2. The handbrake train has maximum front to rear travel; and
3. Worn clevis pins have been replaced (optional depends upon ware); and
4. The rear cable is adjusted to remove excess free play.
This procedure should work on Sheerline and other Princess models.