Caliper bleed valves

[dan_b]

I thought I might buy some bleed valves just in case I bust any when I do my brake upgrade in a few weeks time.

My question - are all bleed valves the same?

Are bleed valves for the Porsche 968 calipers the same as for the S2 rear calipers?

Are there "better" ones aftermarket?

Thanks!

[Stick Insect]

Bleed Nipples or Bleed olive have many different styles. there are several differences.

thread type/size
nipple length ( ooh err)
sealing type o ring seal or conical end.

Most bleed nipples are steel which has been chrome plated or Zinc Passivated.

Do not use stainless steel nipples in an aluminium caliper. It would seem like a good idea but the two compounds are a long way apart in the metal periodic table. The nearer together the less problem. have you seen aluminium which has been next to steel and has been exposed to moisture. It goes all white and crumbly. This is called electrolosis ( That's not the removal of leg hair)

Steel studs and bolts which are screwed into aluminium castings in aircraft have to be Cadmium plated to avoid corrosion problems. Maybe Porsche nipples are cad plated?

I feel the best bleed nipples are Phospher bronze or Kunifer. they do not corrode, they do not cause problems with aluminium.

If the bleed nipple is stuck be careful, try to tighten the nipple slightly before you undo it ( Gently, Don't force it)

When refitting make sure that you use brake grease which is red and does not affect seals, brake fluid etc. It is red and comes in small sachets, but it is not easy to find. and then refit the rubber caps.

I do not know if the 968 and the S2 bleed nipples are the same I'm afraid.

David

[dan_b]

Thanks for the comments - I think a trip to German and Swedish (dodgy sounding name really that isn't it!) is in order, see what they've got on their systems.

The ol bi-metal corrosion thing, always entertaining. Takes me back to A-level physics...

Brake grease - do you mean the copper grease stuff?

[Stick Insect]

No the Coppaslip stuff should not be used on brake items. This stuff is made by Lockheed/ Girling and Lucas and comes in a small sachet which is about the size of a sugar sachet in a cafe.

It is red and very sticky. It does not affect brake seals and fluids. It is not easy to get. I have found mine at shows in the past.

Girling SP 1280 is a number I have found on the Internet.

Some people say that there is some white silicone grease for this purpose. I don't want silicone in my brakes ever again after boiling the brakes in the Peak District downhill. This was just going down a hill slowly, no boy racer stuff.

Brake Grease is not easy to get hold of but it is the right thing!!

[Mikes2]

Dan,

You can buy RS2 caliper bleed valves from Audi. I have a spare one if you need it.

Cheers,
Mike

[91_S2]

Just to further muddy the waters in your decision making, I think there are nipples called E-Z-bleed or some such. The have a tiny one way valve built into them so that they don't suck air when you are bleeding the calipers. You open them slightly and go off and pump the brake pedal. People use them on the other side of the pond. Some swear by them. I've never tried them personally.

[Stick Insect]

I've tried e-z bleeds twice in the last 24 years, they rust and the internal springs stick. You still need to use a pipe obviously.

From and older style car accesory shop a brake bleeding aid. It was basically a length or red rubber pipe 4 or 5 mm internal diameter. There is a pin in the end (blocking the pipe). The side has a split in it which allows the brake fluid to squirt out but not allow air back in. £1.50 it comes vacuum packed on a bit of white card. Hi tech!

I then got an empty 2 litre soft drink bottle, drilled the cap and put the pipe through it. I attach the pipe to the nipple slacken the nipple and then I can either use the Gunson Eezi bleed or just pump the pedal.

Brake bleeding is a one man job.

This is far better than using an old jam jar half full of brake fluid to watch the bubbles. You then kick it as you are walking past, the fluid goes on the bodywork and driveway and the jar breaks.

The right kit is not expensive and is readily available.

[dan_b]

I bought the "Eezybleed" system bleeding kit - this uses constant pressure from (say) the spare tyre and pushes clean fluid straight through from the master cylinder.

I did read about those "speedbleed" valves, but as you say they seem to have the potential to jam/sieze up.

I'm just paranoid that if I don't have a couple of spare caliper bleed valves, I'm bound to nadger one, but of course if I buy some spares, it'll all go smoothly. Sod's Law nearly always seems to apply...

[Stick Insect]

What are you doing about brake pipes?

I have a Coupe quattro 20V ( s2 shape non turbo)
I am converting to 5 stud hubs so that I can fit 16" avus wheels and Porsce brakes.

If i can get a set of 996 calipers I will get some brackets to suit.

David

Ps My sister live on Petersham Road Ham near the common.

[dan_b]

Brake pipes - the car already has metal hoses installed, and the calipers have very kindly been supplied with their caliper-end hoses attached. Am going to plug, and hopefully, play...


Ham - nice place, not too far from the 'Mond!

[Stick Insect]

I'm hoping to use all Audi/porsche parts so that there aren't any Insurance company liability problems.
Propbably won't manage it though.

Erm what the 'Mond' ?

[dan_b]

Sorry - Richmond. Stupid local colloquialism.

Insurance companies can be quite ok with mods, or they can be a nightmare. It's a bit of a lottery.

[Stick Insect]

Should have realised, I'm with Direct line.

Good luck with the brake conversion.

David

[91_S2]

Originally posted by dan_b
I bought the "Eezybleed" system bleeding kit - this uses constant pressure from (say) the spare tyre and pushes clean fluid straight through from the master cylinder.

I did read about those "speedbleed" valves, but as you say they seem to have the potential to jam/sieze up.

Speedbleed was what I meant. My memory is being destroyed by cheap booze. A note to myself: Only drink expensive booze.

E-Z-bleeds are as you describe. I chased all around London trying to find a Halfords. I never really liked the E-Z. The pressure has to be just right.

But that is another topic.

[Stick Insect]

There are 2 different product

Eezi bleed by Gunson which is a plastic Brake fluid resovoir with pipes and uses a spare tyre for power. they are great as long as you watch the pressure and don't have an air leak.
I like them

e-z bleed brake nipples have a spring loaded plunger in them. These rust very easily and are weak.
I don't like them.

Mind you I wouldn't like to be working on my Audi in the street in Sweden. You would need a garage.

David