Handbrake advisory following MOT

Post Mon Oct 15, 2012 8:53 pm

In 2011 I had an advisory that the 'DBT Park Brake Efficiancy was 20%' and only just met the required standard so I cleaned the rear drums and fitted new shoes and adjusters.

Just had the car MOTed again one year later (by the same tester) and have the same advisory.

The hand brake works perfectly and engages after a few clicks.

Does anyone know why the tester keeps picking it up?

Post Mon Oct 15, 2012 8:56 pm

Cos E30 handbrakes are sh1t !

The drum braked ones are OK but on the cars with disks I've not had a good one yet - they need to be properly and perfectly adjusted with properly lubricated adjusters and cables that move freely - and even then they aint much cop.

Post Mon Oct 15, 2012 9:01 pm

OK, so I just live with it. Seems fine to me.

Post Mon Oct 15, 2012 9:06 pm

The shoes need time to bed in - if they're new you need to drive a bit with them slightly on and then readjust to give them bite - and the shoes need to be adjusted so they start to bite the instant you start to lift the lever - as well as no slack in the cables.

Post Mon Oct 15, 2012 10:11 pm

20% is 4% more than required.

Not sure what is meant by DBT?

Post Tue Oct 16, 2012 9:22 am

The main problem found with E30 handbrakes (on disc braked rear axles) is that someone has 'adjusted' the brakes at the nuts at the lever instead of the adjuster inside the hub. The result of this is that just the ends of the shoes are in contact with the drum, with the resulting loss of braking effort you may expect. If the handbrake is used for any length of time like this, the surface of the shoes end up with two different radii, and are impossible to set up.
The other problem is that you don't read your handbooks and omit to 'service' the handbrake every three months as described on page 61: "Apply the handbrake lightly at about 25 MPH until definite resistance is felt, then pull the lever up to the next notch and drive the car about another 400 metres."
I'll also mention here again that last year I rebuilt an E30 handbrake with Z3 parts (simply because that was all I had around at the time) and was rewarded with the most effective handbrake I've ever seen. The Z3 parts are slightly different than E30 parts, but fit perfectly. I've no idea if the results were due to the Z3 parts or just coincidence, and make no claims that this is an upgrade.

Post Tue Oct 16, 2012 9:33 am

I have all standard parts from the 325 on the rear of mine and it throws itself out of the brake rollers with 80% efficiency,

Just adjusted the handbrake until the shoes were providing enough resistance to stop the wheel from turning and then just back it off slightly

Post Tue Oct 16, 2012 8:20 pm

Brianmoooore wrote: The other problem is that you don't read your handbooks and omit to 'service' the handbrake every three months as described on page 61: "Apply the handbrake lightly at about 25 MPH until definite resistance is felt, then pull the lever up to the next notch and drive the car about another 400 metres."

Thanks Brian. I will give that a try.