Rear brakes - poor performance.

[kennatt]

be ok for making the tea when it had boiled

[BrianHawley]

The 1250kg refers to the max. allowable weight fully loaded. The 806kg (~3/4 ton) is the kerbside weight.
Both are mentioned on the German papers but as Nikol mentioned it is the total weight which determines the required brake rating.

Regards
Declan

Thank God for that.

Mine's under 800kg dry.

I didn't think 450kg could have fallen off as rust

[oliver90owner]

there is bound to be some free movement - I wonder why we do not use distilled water in the braking System?

You got it in one for the mechanical free play - free, and relatively frictionless if lubed properly. When that initial movement is taken up before the pedal even starts to have much effect (ie just 'backlash') is nothing like the progressive compression of the air (at the same pressure as the brake fluid, as they are both fluids) which is represented by the 'soft pedal'.

On the distilled water topic - one cannot guarantee air free distilled water. Even distilled water dissolves air once it cools down. Corrosion of ferrous metals will ensue, for sure. The age old chemistry experiment to demonstrate that iron nails do not rust in boiled distilled water always use a layer of oil over the water to avoid atmospheric oxygen dissolving in the water.

Mineral oil could be used with most modern day seals, but as there is always the risk of old rubber seals or components being used, this is not allowed, for obvious safety reasons.

The simple improvement is to use silicone brake fluid as that will not destroy old rubber seals and, further, does not absorb water vapour from the atmosphere (as alcohols can) and withstands much higher temperatures than cheaper alcohol based brake fluids.

One further safety advantage is that the silcone based fluids do not spontaneously combust when in contact with very hot surfaces. Normal alcohol brake fluids will easily cause a fire under those circumstances.

[Nickol]

Great post Oliver - of course that is why fish can breathe underwater because air/Oxygen is disolved in it. As an aside, the brake fluid in the car is fresh and new.

Update - rear Brakes leading edges bevelled. Replaced and adjusted as recommended. Handbrake also adjusted for equal resistance on both wheels.

Some notes in passing.
1. The workshop Manual Shows differing Pictures of the Installation of the solid spring and the other longish one with coils only at both Ends. Some pics have the solid spring near to the wheel cylinder, others not. I suppose it depends on which model? In any case the solid spring will not allow itself to be installed next to the cylinder as this is in the way - hence the other Long spring.
2. Similarly the holes in the shoes and which one, when the holes are doubled, to hold the springs is again shown differently. However, using that supplied by Mintex, there is only one possible Installation possible.
3. Adjustment. Turn the adjuster until it goes no further and then the wheels are locked. Loosen off one click. I found that some rubbing/resistance was still evident when turning the drum but I reason that if I can turn the drum by Hand without any other leverage, it is loose enough.
3. Road test
The stopping power seems a lot better both using foot pedal and Hand brake. I have new radial tubeless tyres all round (but fitted with innertubes as required by the TüV) and the roads were dry. Perhaps that is why I could not get any of the wheels to lock when braking hard at about 30kph. The car just stops in a short distance. This worries me a bit. Should it?

[Nickol]

To round off this thread.

Having reinstalled the shoes incororating the tips given, the Brakes were tested yesterday at the Workshop and satisfactory values obtained.