MkIV Golf R32 Brake Bleed Issues

[Banshee]

Hi Guys

A non Nissan related one from me as I'm helping my neighbour out with his R32 as he's got spongy brake issues at the moment.

He's replaced the front calipers with 4 Pot Porsche ones, we've done a gravity bleed on all of the calipers in the correct order and getting high pressure fluid each time.

We haven't use and eezibleed or pressure bleeder yet as we don't have one and trying to utilise what kit we already own before having to buy anything else which leads me to my next question.

I have a VagCom compatible lead and wanted to know if I will get the functionality I need from VagCom Lite to cycle the ABS pump and bleed in this fashion? Or will I need a full version of VagCom?

Any help would be greatly appreciated as this one is doing our head in, I haven't told him yet but I'm starting to suspect a fault with his master cylinder :nenau

 

[macabethiel]

Spongy Brakes my experience & methods

I had an issue years ago with brake bleeding that was due to a rear wheel cylinder letting air into the system. I had moved the brake servo from the engine compartment to under the offside wing on a BMC Cooper S circa the 1970's.

Am I right in thinking that it has disc brakes all round if it has then unlikely to be the problem I had back then. In my experience I would go back to basics.

1) Were the brakes okay before the Porsche Calipers were fitted? If they were then I would rule out the master cylinder. Other areas are is a load sensor if fitted - probably not if it has ABS anyway.

2) Obviously use new brake fluid only - I am a big fan of Brembo DoT 5.1 specification brake fluid as it is not daft money (it's not silicone based as is DoT5)but is manufactured synthetically so has high boiling point. A lot of manufacturers sell DoT 5.1 including Comma & Halfords etc.

3) When pumping through I use the old method of 6 fairly quick pumps followed by a couple slow pump whilst closing the bleed nipple. I always use a pipe on the bleed nipple that has a simple slit valve. Start at the furthest point on the brake system i.e. one of the rear brakes moving towards the closest. You should get a fair pedal using this method on the first round of bleeding.

If the pedal is fair then I find it often improves overnight or after the first few miles if use. I then repeat a final time - I generally use 1 litre of fluid by the full second bleed.

4) An Easy Bleed Kit is useful but I can't use this on our Merc as it has a vent inside the reservoir so it will not pump up as the pressure is relieved by the vent!

5) Lastly a lot of ABS brake systems seem to have brakes that cause the pedal to go down whilst applying continuous heavy pressure - when driving normally this is not apparent. Some Mercs models especially exhibit this trait - I assume it is built into the ABS design. Lastly the fly by wire brakes on some E class & SL models can only be bled via a computer with all four bleed nipples simultaneously being bled - understandable when you realise there is no mechanical link between the brake pedal & the calipers.

 

[Banshee]

Just wish it was as easy as a bleed on a Terrano, 5 mins and you're off :thumbs

 

[Wallace]

Were the brakes ok before swapping the calipers? I use a vacuum bleeder with a good dollop of red brake grease around the bleed nipple threads to stop air getting in as opposed to the pressure bleeders. The auto top up bottle works well too. :thumbs

 

[solarman216]

If bleeding on my own I use a long length of clear plastic tube good tight fit on the nipple, and hang it over a set of steps at least 2 ft above the master cyl, any air is immediately visible, and on releasing the pedal there is no chance of air entering as the nipple threads are under pressure from the 2 ft head, nip back under, tighten nipple, pinch hose and remove, on to next wheel, Rick

 

[macabethiel]

Great Idea

Were the brakes ok before swapping the calipers? I use a vacuum bleeder with a good dollop of red brake grease around the bleed nipple threads to stop air getting in as opposed to the pressure bleeders. The auto top up bottle works well too. :thumbs

Never heard of these vacuum based devices sounds like a good tool !

Looked online do you need a compressor to provide the vacuum power?

 

[Wallace]

Never heard of these vacuum based devices sounds like a good tool !

Looked online do you need a compressor to provide the vacuum power?

Yes, mine is a bit guzzly of air on a 3hp 14cfm compressor but you can get a hand operated pump version, I have not used one though. if you are servicing cars for people the vacuum bleeder can be a profitable little tool for fluid changes. :thumbs:augie

 

[elty001]

Have you tried reverse bleeding from the caliper.
Have to do my mates 110 this way.
I use one of the pump type oil cans and a length of clear hose onto the bleed nipple.
Remove master cylinder cap,prime up the pipe from the can to remove any air.
Connect onto bleed nipple,crack it off and pump away.
Air naturally travels upwards and the bubbles will be pushed up In to the master cylinder.
It's an idea to remove some fluid from the master cylinder before starting so it doesn't spill out:thumb2

 

[solarman216]

On Terrano's I usually do similar, except I pump the brake peddle till the cylinders are out to blocks I put in the calipers then push the pistons back in, as you say all air is pushed back to the MS, it works just the same for the rears, Rick