Re: F**king brake bleed nipples

Maybe nipples get tougher with age?

I do apologise, I'll travel back in time two or three years and buy the vehicle then, rather than last week :-)

A what? If you mean could I tell they were probably more likely to shear than loosen, yes I could, just couldn't see what else I could do about it, so applied pressure and prayed.

I used a proper fully enclosed hex spanner, what else was I supposed to do? :-(

I don't know why I care anyway, I'll just crack open the brake pipe unions and bleed them through there when I get round to it.

"Vim Fuego" wrote in news:mZa2h.36112$ snipped-for-privacy@newsfe4-win.ntli.net:

That's the normal way, at least on my French crap.

Why when pads are changed? I've changed a few sets of pads over the last 35 years, but never done that. Am I missing something?

John

On abs-equipped car it's good practice to open the bleed nipple while you push the piston back, to avoid reverse pressure in the ABS pump. In fact, it's often considered good practice anyway to avoid the possibility of reversing the master cylinder seals.

OK... I may be wrong here but I thought that when the brake pedal is completely released fluid can flow freely between brake lines and fluid reservoir and the master cylinder seals and pistons will form part of the conduit between the two, ergo when fluid is pushed back up from the brakes it just increases the level of fluid in the reservoir and as long as you've taken the reservoir filler cap off the only pressure on the seals would be due to the weight of fluid in the reservoir. Go on, what have I missed? :)

Peter.

Noted, thank you.

John

I'll admit I've had more difficulty bleeding brakes on some modern vehicles. My Nissan Almera manual says to release the brake pedal slowly when bleeding. I find that this helps with other vehicles the family owns too. I've speculated that there might be some increased restriction between reservior and master cylinder - perhaps to dampen pulses from optional ABS units?

John

Yes. I've yet to break off a bleed nipple despite having slackened many on all sorts of old cars. Perhaps I'm just lucky.

Tighten it first sometimes works.

I was referring to when you change the pads and have to push the pistons back in. When bleeding the brakes I use a pressure kit.

Peter.

No idea. It's just what I've read, and what I've done on my own car.

When you panic stop wonder what pressure is on the seals? And pushing fluid back through the system when changing pads puts any pressure on the seals in *exactly* the same way - think about it. The only difference is that with the master cylinder in the rest position a passageway is open to the reservoir.

How do you work that out? In it's relaxed state, the m/cylinder is designed to allow fluid to to return into the reservoir. Mike.

It also helps if a light smear of copperslip or similar is applied to the nipple thread, when they are replaced. Also making sure that caps are always replaced after bleeding, to prevent corrosion from the inside. Mike.

Vim Fuego ( snipped-for-privacy@fastmail.fm) gurgled happily, sounding much like they were saying :

No, last week'll be fine. Then you can get lots of penetrating oil soaking in to them.

Quite... Now, stop grooming your colleagues for fleas and don't sit on David Attenborough again, please.

Heat, penetrating oil left to soak in.

Chris Bolus ( snipped-for-privacy@RILEYELFb0lus.com) gurgled happily, sounding much like they were saying :

Easy. Modern cars are made of cheese.

I don't think so. More likely because you have mechanical sympathy. Something that's sadly lacking with many DIY car mechanics. Mike.

I appreciate that. The mechanism I speculated about to explain the desirability of releasing the pedal slowly may have ramifications for pushing a caliper piston back quickly.

Do these fit a wide variety of reservoirs? I presume that a good seal to the reservoir is necessary.

John