Overhauled the rear brakes.

[steve_earwig]

Rear rotors rotting away is endemic on many cars, not just the 406.

Put the brakes you know can handle a V6 on the 4-cylinders and diesels

So they're underpowered on the V6 or overpowered on a 1.8? Can't have it both ways

[GingerMagic]

They are under-powered on my car - took it to a weighbridge and it weighs 1665 Kgs with only half a tank of fuel.....
It doesn't like slowing down very much, I've had many 'brown trouser ' moments.

[steve_earwig]

Time for an overhaul?

[GingerMagic]

No, I quite like my trousers....

[markw]

I've only had the car for four months

Sorry mate, didn't know that! I retract the earlier statement!

[KozmoNaut]

Rear rotors rotting away is endemic on many cars, not just the 406.

Put the brakes you know can handle a V6 on the 4-cylinders and diesels

So they're underpowered on the V6 or overpowered on a 1.8? Can't have it both ways

406s all weigh the same within 50-100kg or so, depending on engine and whether it's a saloon or estate, so they're equally adequate in power on all trims.

Engine power and top speed are largely irrelevant, it's the total weight of the car that matters. Doesn't matter if your engine is a 1.8 or a 3.0, you're still trying to stop the same ~1400kg car.

Remember: "You can never have brakes that are too powerful, as long as they're set up to let you modulate braking force correctly". Overpowered brakes don't exist, only overboosted brakes. The only issue you can possible have with "too big" brakes is that it takes more time to put some heat into them, especially if your car is really light. It absolutely isn't an issue on any road-legal car, though.

[steve_earwig]

Ah, I get it, it's not like the brakes are fighting the engine all the time... I still think rear brakes are overpowered on a lot of cars because many need rear disks due to rust, more than need rear disks because they're worn out or anything. The estates have a load valve on the rear axle to limit the pressure applied when the car is unladen. I doubt if anything is there on saloons or coupés...

[KozmoNaut]

Rear discs are definitely underused on most cars equipped with them, simply because most people brake too gently outside of emergency situations. If you brake hard, even just once a week, they're fine. You don't have to stomp the pedal, just brake harder and later than normal.

The real problem comes with drum-in-disc handbrakes, as a lot of people here have discovered. The handbrake shoes and drums simply doesn't see any heat or wear, like they would on a car with rear drum brakes, so everything eventually seizes up and corrodes. The only way to combat this is to drag the handbrake for 5-10 seconds once every month or so, or right before parking on wet days. This puts heat into the brakes, freshens the braking surfaces and gets rid of moisture inside the drum.

For a normal, everyday road-going car that will never see track time or anything harder than normal "spirited driving", rear drum brakes are best, from a longevity and reliability standpoint. Rear discs look better, though ;-)

[Doggy]

The estates have a load valve on the rear axle to limit the pressure applied when the car is unladen. I doubt if anything is there on saloons or coupés...

Now you come to mention it, on the original Dogmobile's first MOT, it couldn't generate enough braking force on either back wheel, until jasper's mate stood on the tow hitch. Oddly, it never had the problem again. Perhap's I had unconsciously adopted KozmoNaut's 'preventive maintenance' technique?

[D4B]

Hi Dirtydirtydiesel,

Great work on your rear brakes, I too have today uncovered rear discs pads and handbrake shoes which are very similar to how yours were........

I am in the process of fitting new rear discs, pads and handbrake shoes, but on reassembly have found that the lower slider (the big one with the 16mm bolt head) is totally
seized solid, and no amount of levering and plumbers wrench seems to be having any effect. I was trying to avoid removing the caliper from the brake pipe as I don't have
anyone here to help with bleeding them

Am I kidding myself or is there another trick to freeing these off?

Cheers - fairly urgent - Steve

[steve_earwig]

You need an http://www.ebay.co.uk/itm/Gunson-G4062- ... 53e6c97205

I had one seize on my D8, I couldn't budge it on the car but once I'd bitten the bullet and taken it off it was a piece of cake.

[D4B]

Hi Steve,

Ah yes, I HAVE got one of those, although I bought it in about 1990 !!

It has never had the right cap for any of my previous cars ~ but then I usually own quite rare / classic / import models...

I imagine there wont be the correct brake master cylinder cap to suit the 406, I will go and check & report back

cheers Steve

[steve_earwig]

Mine had one that fitted, although if yours is that old perhaps the main problem will be all the rubber's perished

[D4B]

Amazing, it has a cap that fits....... I might finally get to use it, and the cap rubbers look as good as new too

Looks like the calipers will be coming off this weekend....

[dirtydirtydiesel]

Sorry D4b,
that I didn't reply last night, I was out . Anyhow you will need to remove the calipers to overhaul properly ,best tip I can give is to make sure that you clean up a round the brake pipe fitting very well & make sure you use plenty of penatrating fluid.
Overnight if pos, then you need to use a brake pipe spanner so as not to round off the fitting & gently work it back & forth aplying plenty of penatrating fluid as you go.
Take your time & you should be all right.
I personaly use a vacuum bleader, but you can also use a one way bleading pipe, you pop it on the blead nipple & open it pump the pedal & the valve in the pipe let's the fluid out but not the air back in. Simples .
I too have a gunson easy bleader But be carefull I have found cars ie: my old Audi on which this would not work ( brake fluid just went every where )