OT; Service intervals

[Mr Pounder Esquire]

One clutch master cylinder on a Hillman Hunter.

[bert]

In article , Mr Pounder Esquire writes

You probably haven't ever had to brake hard enough long enough to cause any problems.

[Adrian]

Well, yes, you can do that. Then you can be surprised when the hygrometer tells you it IS due for replacement, and you find that the bleed nipples are all seized. Still, on something where minimising service costs in the short term is a higher priority for the manufacturer than long term maintenance, it's not a great surprise that they'd recommend such penny- pinching.

No, the usual DOT 3/4/5.1 is still just as hygroscopic as it ever was.

[Adrian]

Because it's ethylene-glycol based.

Hydraulic Citroens used LHM - bright green - which is mineral based and non-hygroscopic. But it isn't compatible with the seals used in DOT-based systems.

Not really.

DOT4 has a higher boiling point, dry, than DOT3 - which means it has a higher boiling point for the same amount of moisture, too - so the risk of boiling the fluid is lower. Still there, but lower. DOT5 was silicone based, but is a bastard to bleed. DOT5.1 is glycol again, higher boiling point still, but still only about the same as LHM, and still hygroscopic.

'course, a higher boiling point doesn't mean moist fluid'll rot the inside of the cylinders any slower.

Which is exactly why I've now got to replace the clutch hydraulics on the Landy, despite having changed the fluid when I got it last year. Wet fluid, rusted bores, leaky seals. All very predictable.

[Mr Pounder Esquire]

I would say that 19 years of owning taxis and never changing the fluid confirms my view that changing the fluid is a load of bollocks. I'd say that 44 years of driving and never changing the fluid confirms my view that changing the fluid is a load of bollocks. I will say again that I have never had brake failure.

[kshy]

Me neither, and I used the last one for more than 40 years quite literally.

and guess what? I

I had one, in that car I used for 40 years, a Golf. But that was because I didn?t do anything about the known windscreen leak that would produce a wet floor after heavy rain. Eventually that rusted thru the floor and the brake line that runs down the inside corner of the floor. That's why it was replaced by the Getz because I couldn?t be arsed to replace the floor and the brake line.

[Scott M]

Just because the brakes didn't fail didn't mean that nothing's going on. Have you, in 44 years, never compared the colour of fresh brake fluid (light straw) to old fluid (varying shades of dark brown)? Bearing in mind it's a non circulatory system and not being contaminated, what do you think causes this?

You could easily use any liquid that takes your fancy as brake fluid; they're all equally good at basic hydraulic operation. You might not want to live in a hilly area or do much towing, but otherwise they'll be fine.

[kshy]

I didn?t replace any in the Golf that I used for 40 years without any brake fluid change.

[Dave Liquorice]

That is the key, "normal" driving doesn't really give modern braking systems a hard time. The problem is when the absorbed water gets down to the cylinders and they get seriously hot and the water boils forming compressible gas pockets releasing the pressure between pad and disc.

Hands up those that have had the brakes on a modern car fade? I have Ford Monedo, ventilated discs on the front. But that was after a very "spirted" 1,100' descent in about 5 miles from Hartside Top to Melmerby. A very nice road to "drive", with sharp 2nd gear bends, straights, sweeping bends and sections where you can see what is (or isn't) coming as you approach a bend.

It's bit unnerving approaching a 2nd gear bend at 60 mph, hit the brakes, and something, followed rapidly by nothing, happens. Pressing the pedal harder makes things worse. Once in that state it wouldn't take much braking to fade them out again. The brakes didn't reliably come back until I'd driven a mile or so without using them.

[kshy]

It doesn?t tell you to use a hygrometer, it's just talking about checking the level.

and you find that the bleed nipples

They weren't in the Golf that had never had the brake fluid changed for 40 years. I tried to bleed the brakes when the brakes had clearly failed and discovered that the problem was a failed metal brake line when I could see the brake fluid coming out onto the concrete driveway because I had not bothered to fix the known windscreen leak which eventually rusted the floor and the brake line.

Still, on something where minimising service costs in the

The don?t do that with that engine and transmission oil, so that line can't fly.

Presumably they have enough of a clue to use brake cylinders that handle brake fluid with some water in it fine and have decent seals too.

[newshound]

You have *never* had a cylinder seized owing to corrosion? I find that hard to believe.

[kshy]

I don't drive any car in a way that produces that result.

I have

[kshy]

Not in any of the cars I have ever owned.

I find that

I have had brake failure in a 1960s landrover, but that was a work vehicle so I didn?t find out what the problem was because I didn?t fix it myself.

[Mr Pounder Esquire]

The brakes did not fail .............................. ffs! Did you actually read my postings? The ones where I mentioned that my taxis of 19 years were doing the best part of 1000 miles per week? The bit where in 44 years of diving I have never changed the fluid? The bit where in 44 years of driving I have never had brake failure?

[Mr Pounder Esquire]

I do not tell lies.

>

[Mike Barnes]

BTDTGTTS - on the Cat & Fiddle pass in Cheshire, Golf GTI Mk. 1.

Not exactly "modern", though.

[Capitol]

I've never had a cylinder corrode to any extent requiring replacement. However worn seal replacement has been a common problem after a decade or two.

[damduck-egg]

Was that used by BMC/British Leyland in the hydrolastic suspension as well? I recall seeing the surprised look on someone in a breakers yard* when they cut a pipe or something and ended up looking like the incredible Hulk, in truth only his colour had changed and unfortunately it did nothing to enable him to talk.

• Breakers yard was probably too posh a description by todays standards, Muddy field full of rusty and broken vehicles dripping fluids and other substances into the ground and near a watercourse. Even though in a town it is undeveloped as the soil will have to be removed. The owner did have one interesting vehicle he kept in a tin shed but would never let on how he got hold of a 1950's ZIL

G.Harman

[Tim Lamb]

Also used on David Brown/Case tractors circa 1980. Strong handbook warnings about not using other brake fluids.

[Fredxxx]

I've replaced 1/2 dozen or more in my time, but none in the past 15 or so years. Hence my question about brake fluid, perhaps seals and other materials have improved as well?