Handbrake Issue

Horizon81

I've noticed the following when applying the handbrake on steep hills (handbrake mechanism is the drum in disc type).

Apply footbake fully, pull up handbrake as far as it will go. Release footbrake, and the car rolls slightly as if the handbrake isn't on fully. As soon as the footbrake is released, a tiny bit of extra travel becomes available in the handbrake and this is sufficient to hold the car.

What I can't understand is how releasing the footbrake frees up a tiny bit of travel in the handbrake as there's no link between the two systems on a drum in disc set up.

So to clarify, when the foot brake is released the car rolls back so I have to pull the hand brake an extra couple of clicks even though when I put the hand brake on to start with it was fully up. Any ideas?

arcon5

Because you can excert more pressure with your foot using hydraulic principles than you can with your hand on a cable... which although move different parts in the drum, the effect is all the same in that the shoes are moved.

EdGasket

The two systems are linked because they both move the brake shoes.

facade

Wheelbearing gone?
Disc calliper seized?

Something might be allowing the drum to move when you release the footbrake and stop clamping the disc.

I've only ever had one car with this set-up, a Vectra-B
IIRR, that used to roll back on hills if I did as you say, and needed an extra tug to stop it.
I could solve it with a superhuman snatch at the brake lever (but then I couldn't get the thing off again without an injury) but I generally just pulled the handbrake on and stuck it in P and let the transmission take up the slack. (Vauxhalls had a habit of the handbrake flying off anyway)

I was told that it could be an adjustment/balance issue, but I could never see how.

I half wondered if it was the rust in the drum holding the shoes off*, and grinding down as it starts to roll back, so I started giving the handbrake a few tugs when going along slowly to try and clean it, but I can't remember if it worked.


*(the drum brake doesn't do anything, and is never normally applied when moving, so there is nothing to scrape rust off the drum.)

maninthestreet

Does the car rear drum brakes, or disc brakes?

reeac

There's been some mentions of drums and shoes but many or most rear brakes are now disc with calipers and pads and a common system for arranging a handbrake involves mechanically applying pressure to the same pad/disc system. As already stated the hydraulic system can apply more pressure than can the handbrake so when you release that hydraulic pressure the pads ease off a bit and you normally need to notch up the handbrake a bit.

Horizon81

Think there's only facade who understood what I'm saying.

The car has rear disc brakes. The disc centre is drum shaped and the handbrake mechanism is what's known as a 'drum in disc' system. So, footbrake operates the pads on the brake disc. Handbrake operates traditional handbrake shoes in a drum. The systems are obviously independent of each other. I know some cars have a rear disc and the handbrake works on the pads on the disc, but that's not the case here.

AdrianC

What car is it? On trailing-arm rear suspension, if you park nose-up a hill, the back end will "sit up" a bit, which feels like the car's rolling back.

The extra click or two might be due to a build-up of grot in the rarely-touched mechanism, causing the shoes to not move as freely as they should. You pull the handbrake on, one shoe moves out hard, but the second shoe takes a little while to move, as the pivot's getting seized. Clean, strip, copaslip.

TeamPlum

What car?

On my punto, the trick was to slacken the handbrake completely off, then head to the back wheels, where there was a grommit - pop it out, use a screwdriver to move the cable arm forward and back (sometimes it caught on the brake hub) and tighten everything back up.

Worked a treat.

facade

I don't think they auto adjusted on the Vectra, as they never wear in use, and the adjuster was through a grommet somewhere.
As Adrian says, they could be seizing up a bit through lack of use, a service & clean would probably be the first step.

I also remember when one of the cables seized on my Corsa. The lever pulled tight as usual, but the brake wouldn't hold on a slope, so check the cables are free,

gilbert_and_sullivan

I think most people haven't a clue what sort of brakes the OP is talking about.

Horizon i'd be inclined to whip those rear disc/drums off and have a poke nose whats going on, some..Volvo i'm looking at you..have a nasty habit of the parking brake shoe friction material parting company with the backing plate, it usually just sits there floating about doing its job when you apply the brake, but it can jam up the whole hub causing a large headache and a larger bill to sort it.
It might only need a good clean relube and adjusting up, but when dust gets in which it does you can get some horribly deep scores on the drum surface which new linings if needed wouldn't bed into in a month of Sundays, so new discs/shoes/pads might be order of the day.

I suspect loose shoe material is causing the effect you describe, when you apply the footbrake and steady the car again, the loose shoe friction material has a chance to get a better purchase...course that's only a theory and probably miles out.

Let us know what car it is we might have a couple of tips...Merc one you should know about in particular, another tip for Volvo if its one of those, Subarus tend to be simple and straightforward as you would expect.