Sticking Handbrake: How Does The Handbrake Work?

January 25, 2010

Our Aygo is 3 1/2 years old, 32k miles. Lovely thing... ex warranty though. We've had it since it was 6 months old.

Last couple of months the left rear handbrake has taken to sticking on after it's been parked overnight. It's not because it's been washed or driven in the wet - this is a new characteristic!

I decided to have a look yesterday but ran into all sorts of problems!

Firstly the rear wheel took an hour to get off (we've got steel wheels so they had rusted on to the drums). The chap who was helping me services big machines (the ones that make toilet rolls!) so he knows a thing or two about seized components.

We concluded that Toyota don't take the rear wheels off for a normal service (it's had 1st, 2nd and 3rd year at a main dealer). They must just do an inspection.... You may wish to make sure you can get the wheel off if you have a puncture.

Because of the trouble on the near side wheel we decided to take the offside off too and that took even longer!

With some WD40 (carefull not to let it get into the drum and contaminate the shoes) and a large screwdriver being hammered down between the wheel and the drum, we finally got them free. (be careful not to hit the wheel arch with the hammer...)

We're now stuck because the retaining screw holding the drum on is also seized. We decided we'd spent enough time already and that we'd arm ourselves with the tools to drill it out and rethread it if necessary before going any further.

SO TO MY MAIN QUESTION.

Is there anywhere on here / do any of you know howthe handbrake works on an Aygo? What's the mechanism inside the drum? How would we get the drum off once the retaining screw is removed?

ALso the handbrake 'cable' is a thin rubber tube which doesnt seem 'stiff' enough to have a cable in it. But it can't be air pressure or hydraulic can it? Wouldnt that be more expensive (and thus unlikely on an Aygo!)?

Also the cable goes into the centre of the drum and you'd have thought that wouldnt generate enough leverage to apply the shoes.

Can I get hold of the service manual somehow? I think Toyota's website charges.....

Any thoughts or comments would be appreciated.

Dave

January 25, 2010

Hers a simple way to loosen sticking wheels be they steel or alloy. Firstly spray the centre dub with releasing fluid. In my experience WD40 is next to useless. In fact it was never invented to be a releasing fluid in the first place but a primarliy as a dewatering agent. Brands such as Plus-gas, etc are much more effective. To break the corosion between the wheel and hub keep the car on the ground - loosen the whell nuts or bolts by about one turn. Drive the car a short distance forward brake sharply - do the same thing in reverse - this usually helps break the corrosive bond although you may have to do it a number of times. This tactic has got me out of many a scrape especially at the road side.

The retaining screw can be more difficult though and using a manual impact driver may assist. Some drums have two threaded holes through which you screw in a couple of bolts which act as a puller.:)

January 30, 2010

Just wondering if anyone could help?

January 30, 2010

OK, Here goes......

If you start on this site......

HERE

Click on "EBPONA" then "AYGO"

"Power Train / Chassis" Click the second (grey) tab.

Click on "Rear backing plate"

This shows an exploded diagram of the rear brake.

It's a very conventional setup.

Hydraulic cylinder presses out both shoes at the top.

Handbrake levers out one shoe which then presses the other out.

With what appears to be a screw type manual adjuster.

(probably accessable from the rear of the backing plate). You can see the usual large rubber bungs.

I should imagine that at service time, the drum will not be removed.

Shoes will be inspected by removing an inspection cover then the

adjuster will be poked round with a screwdriver to give the correct clearence.

Sounds a bit crude but it's simpler than designing automatic adjusters.

Course, it may be an automatic adjuster but all the parts are not shown.

Hope this helps a bit.

Ian.

January 30, 2010

We concluded that Toyota don't take the rear wheels off for a normal service (it's had 1st, 2nd and 3rd year at a main dealer). They must just do an inspection.... You may wish to make sure you can get the wheel off if you have a puncture.

Actually they should, the service include measuring of the pads ets that require getting the wheels of. On my first service they did that and the service was excellent all around. One should remember local resellers are usually local businesses and you may get a good or bad service...

Good luck gettin the handbrake working!

January 31, 2010

The rear brakes are auto-adjusting.

The slot is probably to cure the stuck on drum problem where over time the shoes grind a groove in the drum which forms a lip stopping the drum just pulling off.

You should be able to insert a screwdriver into the slot and manually wind the self-adjusters back, retracting the shoes sufficiently to get the drum off. Chances are though one side will be left hand thread and the other right hand, so which way you wind them is important. In addition, all the dust and crud that forms inside the drum can settle on the screw thread making them hard to wind back enough. (I know, I've destroyed a few in the past!)

Used to have the problem all the time many years ago.

Regarding the stuck wheels, I used to find a shot-filled plastic hammer striking the wheel at opposite edges all around the circumferance shifted most of them. But of course the best course of action is to take the wheels off before they're stuck on and copperslip the mating surfaces. I've already done that to my new little Red.