I expect to get a bit of a beating about this - but I, and and my local MoT garage have spent ages trying to get it to work and hold my car on my sloping drive without chocking the wheels and leaving in gear. Any ideas?

 

I will say that I'm well used to mechanical things on cars, got 4  cars (one in back garden for spares), but this is what I've tried so far.

Checked the handbrake cable for free action - fine

Worked the pistons in /out many times - fine

Lubed the sliders many times - fine

Lubed the pad ears - they are free to move - fine

 

My next thought that it might be the mech at the back of the caliper which works a "cam/pushrod" to push on the back of the piston.

But perhaps not, as the hydraulic action seems very feeble as witnessed by disc wear. Is there an old fashioned pressure limiting valve to the rear? The rear pad wear is erratic and uneven.

On the other hand, my cr@p MG TF with Rover 800 rear calipers as standard, but with Ford Focus ST 170 rear discs sweep cleanly both sides, and have a very strong handbrake action - I've run out of ideas 

No pressure limiting valves these days, the anti-lock function is all done by the main ABS unit.

 

I looked up the last MOT brake test figures for my 1.4 TSi.  Weight 1530 Kg, distributed 58% front, 42% rear.  Footbrake (Service brake) total effort 920 Kgf.  Parking brake total effort 291 Kgf.  The latter represents an "Efficiency" of 19%.  I can't be sure if this is the maximum possible, or if the MOT tester just makes sure that the pass figure (16%) can be achieved.   A car managing 16% would just hold on a slope of 1 in 6.25

 

Many owners have reported premature corrosion of the rear discs.  I think there are two reasons for this.  Firstly, as you can see from the above, even in the static situation nearly 60% of the weight is on the front.  Once you are braking at close to 1 G, given the height of the centre of gravity there will be considerable weight transfer to the front, so there could then easily be a weight distribution of 75% front and 25% rear. The pad and piston sizes will be chosen to give braking in proportion to the weight on each axle, so the fronts do most of the work.  The second reason is that there may be a pressure threshold for operation of the rear brakes, so that under light pedal forces (the sort careful drivers mostly use) the rears may be doing hardly anything.  The answer may be to give the brakes a brief hard workout occasionally, to clean off the discs.

 

One technique which might help is to press very hard on the brake pedal whilst operating the handbrake, so that the handbrake mechanism is not being tasked with applying much effort but instead is efffectively acting as a non return device.

The corroded discs & manky pads will not be helping, the rear calipers on Octavias have lots of problems with the handbrake mechanism, not sure if its resolved on the Yeti. There are 2 checks that you can do, either/or:

 

Put on the handbrake & look to see the angle of the actuating arms on the caliper, they should be equal and not move very far, they should also both return to the positive stop when handbrake released, - dont run yourself over!!!

 

Lifting the rear of the centre console will allow you to check that the compensator is at 90° to the handbrake cables, if they are uneven dont be tempted to adjust the slack one, the problem will be with the self adjuster on that caliper.

 

My MOT handbrake effiiency was also shocking but the discs were in a right two & eight & I have since changed them, handbrake still struggles to do a handbrake turn on snow but holds on a hill.

Are you getting more than 2 or 3 clicks on the handbrake, if yes it may need the cable adjusting.

Thanks for the replies.

 

Yes, I do press hard on the footbrake when parking on my slope at home - it helps.

I was pretty sure there was no rear brake bias valve - just checking  I'm aware of the weight transfer - surprised it that it is that much as he doesn't test on the rollers.

Handbrake compensation arm is level, minimum clicks (normally don't let it click on - old habit)

 

But, on the movement of the lever on the caliper I have a suspicion. On my MG TF, I had problems with the rear calipers, and completely dismantled them to get at the needle roller bearing supporting the exterior operating arm. As this side of the caliper is open to the atmosphere, water was passing the seal and corroding the rollers. A good clean, drilled and tapped the rear of the caliper body for a grease nipple and treated the the roller bearing and the short pushrod to a good dollop of red rubber grease. Once a year I give a little squirt of grease and all has been well for the last 15 years.

 

I've not been brave enough to completely dismantle the rear calipers to see if the bearing and cam pushrod is crudded up - it's all I can think of.

Has anyone been there?

 

17 minutes ago, Yety said:

Handbrake compensation arm is level, minimum clicks (normally don't let it click on - old habit)

So that old habit means you don't do it once to check the adjustment, no point in any further interest is there.

14 hours ago, Austin 7 said:

One technique which might help is to press very hard on the brake pedal whilst operating the handbrake, so that the handbrake mechanism is not being tasked with applying much effort but instead is efffectively acting as a non return device.

 

This is the method recommended in the handbook, iirc?

9 hours ago, Urrell said:

So that old habit means you don't do it once to check the adjustment, no point in any further interest is there.

 

Sorry, I don't quiet understand 

 

I did say "Handbrake compensation arm is level, minimum clicks (normally don't let it click on - old habit)" 

 

Perhaps I wasn't clear enough to be thoroughly pedantic  proof- but I do check the number of clicks from time to time, but normally I don't.

 

Hope that is sufficient to satisfy your interest  

 

I was only seeking some information to an annoying problem. 

15 minutes ago, Yety said:

Perhaps I wasn't clear enough to be thoroughly pedantic  proof- but I do check the number of clicks from time to time, but normally I don't.

When I asked how many clicks you could have said instead of skirting around the problem if you really want help here.
What is a handbrake compensation arm?
 

2 hours ago, Urrell said:

When I asked how many clicks you could have said instead of skirting around the problem if you really want help here.
 

I'll make a point of counting the number of clicks next time I can drive the car - normally when I check it's 2 - 3 when pulled with extreme force. Does that mean you can help me now?

3 hours ago, Urrell said:

What is a handbrake compensation arm?
 

It's the part J.R. mentioned - the balance bar connecting the two cables with the handbrake lever - so perhaps you can't help