Further to my posting, "My struggles with GV handbrake and MOT", this mod. will reduce handbrake travel from 12 clicks from a strong arm, to a max of 8 or 9 clicks. The application starts after 4 clicks. The mod. did not cause any brake-bind when fully off on my GV. The pictures are self-explanatory.

The mod. operates by improving the self-adjust feature of the handbrake assy. This self-adjust is performed by the square section spring end abutting a against the end-stop each time the handbrake lever is released. Thusly the self-adjust feature comes into play regularly unbeknown to the driver.

When a near suitable spring is fitted, the tension needs to be adjusted between making no difference, and causing brake-bind when handbrake lever is fully off. An old drum brake return spring from a small car could be a start as a mod-spring. Jack up a back wheel a little and use your foot to turn the wheel to check for brake-bind.

As a rough guide, a fair amount of force is needed to expand the spring, about the same as lifting a heavy suitcase. Obviously, a "cable-adjuster" as fitted in the pictures in my other posting is needed for one end of the mod-spring. You could of course fit some other kind of clamp, but then you wouldn't have the extra cable-adjust feature. Plain pliers and large long-nosed pliers are very useful to facilitate.

I don't yet know if any difference to braking force has been made, but at least an MOT tester wouldn't be immediately struck by a long handbrake travel. ATM I can apply my 18" wheel nut/lug nut telescopic wheelbrace to a wheel nut in the worst possible position with handbrake lever on by 9 clicks, and then stand on the wheelbrace end, wheel jacked of the ground of course. I do believe 18% brake-force is required from a handbrake by MOT testers, but don't quote me!

Cost? Peanuts really.
n.b. Due to the length of the cables various on this car, there is always going to be some 'stretch' to the cable in normal operation, even from a new cable.

Leedsman.

 

Nice one!

Regards
Richard

 

Noted for future use 8|
Thx

 

Section 3.10 Brake Efficiency Table (Vehicles with 4 or more wheels)

 

From Qinteq's link, the handbrake-pass efficiency could be 16% or 25% depending on whether one classes my GV's handbrake (06 reg.) as a single braking system or a dual braking system. This could be a moot point as only one cable runs first to the nearside, then another from that to the offside rear wheel assemblies. (I might have that the wrong way round) I would have thought that two parallel brake cables from a balancing compensator would be dual, and two cables IN SERIES would be a single braking system. Therefore all GVs like mine would require a 16% efficiency -- but not necessarily earlier GVs
Doesn't it all get so complicated?

Leedsman.

 

HiYa Leedsman, I never had your problem [I made a post on here sometime back] since I balanced everything from the handbrake lever all the way down the cables to the actuating cam in the 'top hat', and still even then and now I have 2 to 3 click handbrick which would not hold my car on a 1 in 4. Call me an old fashioned Yorkshireman but I do expect a handbrick to hold my car safe on a 1 in 3. The design of the inter-relation of (1) the top hat and (2) clutch spring ratchet assembly can never generate sufficient pressure between the (3) shoe and its surface area to hold a car of this weight on a 1 in 3 or 4.

 

Project Mu Brakes - Handbrake Shoe

This outfit (Aussie) claims to make special brake shoes partic. for 'difficult' handbrakes.

There is another aspect to this matter of handbrake stopping efficiency
If you think about it, an automatic car with the "park" facility may almost never have its handbrake used. And when it is used, the car is likely to be stationary anyway, therefore no wear to brake shoes.

Following the same logic, it follows that the drum-brake liners could never get "bedded-in" properly, only the hot-spots on the liners ever touching the drum. (Remember with this arrangement, the footbrake does not operate the drum brakes, only the handbrake lever can do that). So we could have a condition where only a low percentage of the liner ever gets used as friction on the steel drum.

I will therefore from now on bed-in the liners by using the handbrake for moderate normal stopping, finishing off with the footbrake. I shall use the natural "creep" of the torque converter versus the number of clicks stopping forward motion on level ground to assess/measure if any change is happening over time. I would guess this will take a month or two.

Leedsman.

 

Hi Leedsman

Looking at your pictures this looks a good idea


Pete..............

 

EPB's are a total arrass for VOSA but a better bet than the non-effective top~hat. In real world driving reality, particularly in the winter, my brother was driven mad with his Renault going down a sleight incline on ice the car would decide to slam the anchor's on - the very last thing in the world you would want. But the idea that all disk pads would be applied as a parking brake is a good one.

Fair comment on that, been there done that over a year ago but seemed to make little or no noticeable difference in my case. There's a good old world refresher on CMP and other associated engineering that reminds us that the engineering coefficient of friction for most brake lining/drum combinations is in the range 0.25 to 0.45.

 

FIELD TESTING OF HANDBRAKE SITUATION:--

Real testing on the road with plenty of handbrake action has revealed that the nearside (UK) shoes are coming on too soon and "dragging" when they shouldn't, i.e. handbrake off. Resulting in a warm nearside wheel when the offside was cool.

This proved to be the actuator (the little lever going into the shoe assy. via the brake back plate) not snapping back to its end stop when handbrake is off. However, this actuator could fairly easily be pushed back with a finger, so here's another minor mod, very easy to carry out. A lot less work than getting all the braking components dismantled, esp. the caliper bolts. (How on earth do the mechanics get that "hidden" one out? Some kind of special tool?) And then there is separating the disc from its mounting...I'm not going there.

If you look at the brake back plate, you will see the cable inner end att. to the actuator, and the cable outer end on its hefty clamp-bracket. Between these two there is a coil spring around the cable inner, obviously intended to push the actuator back to its end-stop.
My mod. is to find a spacer/distance piece abount an inch long which will fit into the cable end clamp (a bit less than half-inch dia.) from the bits-boxes one keeps. With a hacksaw make a longitudinal cut in the spacer so it will go over the cable inner.
Pull back the spring manually (strong fingers needed here) and slip the little spacer you've made over the cable inner and push it into the end of the outer cable at the clamp, thusly imposing more "push" on that return spring when the handbrake lever is released. By good fortune, there happens to be a socket there which will hold the little mod. in position against the cable end clamp despite road bumps etc.
This took me only half and hour all told. And no money. Suits me sir.

One other tip for this handbrake:--

The end-stop for the auto-adjust square-section spring at the base of the hand brake lever can be CAREFULLY adjusted so that the spring's clutching action is only just released as the handbrake lever is moved to fully "off" or down. This will result in a most immediate clutch-bite action when you next move the handbrake lever up, so no wasted "clicks". There will of course be a few actuating "clicks". This is the nature of the beast.

Leedsman.