Brake fuild in front trunk - questions on R&R

[Highlander]

Couldn't decide whether to post this here or in the suspension/brakes/wheels sub forum. Since this is actually a braking system issue, decided to post here...

Sitting at a light the other day with my foot on the brake, all of a sudden my foot slowly went to the floor! Bummer, I thought. Time for a new master cylinder. Babied the car home (was pretty close anyway) and safely parked in the driveway. Ordered a nice new master cylinder and when it arrived, went out to pull off the old one.

Pulled all the carpeting and trim and in doing so, noticed brake fluid in the bottom of the ABS/PSM proportioning block (the big aluminium cube with all the brake lines attached). There was also fluid under the carpet in the front trunk. I cleaned up the mess and after a thorough inspection, could not determine the source of the brake fluid. Once I got my son to help by pushing gently on the brake pedal, I saw the fluid was coming from the side of the ABS/PSM proportioning block that is adjacent to the fender.

Question 1 - Anyone experience this, or know what it might be?

I started to dissasemble everything so I can pull it off to get a look at where the fluid is coming from (since it's impossible to see with it mounted in the car). Unfortunately, I got stuck attempting to remove the black tubes from the brake booster.

Question 2 - how are those black tubes removed? I don't want to pull too hard, but then again, I can't see any latch mechanism.

I'll post pictures when I get the ABS/PSM proportioning block off.

TIA,

Graeme

[RFM]

There is a leak in the ABS block itself, that happens sometimes, fortunately not much. I have no knowledge of repair possibilities, this is probably a new block. Check BOSCH for factory rebuild parts, if they exist. I have trouble with the second question, i can't see any connection between the brake booster(vacuum) and the ABS block(hydraulic), not literally and not technically.

[Highlander]

Looked at it again. It's the black tubes attached to the master cylinder, not the brake booster.

On looking further though, I should be able to remove the ABS block without removing the master cylinder. Do you agree?

Thanks,

Graeme

[Highlander]

Just found out this is a $3600 part - no reman available!!!!

Anyone have suggestions for a wrecking yard that specializes in Porsche parts? This should be a pretty common piece from cars that got hit from behind.

[JFP in PA]

The ABS/PSM control system is a very expensive unit. If you get a used one, be careful, they are sensitive to dirt, moisture and corrosion, so know whom you are buying it from. You will also need access to a PST II/PIWIS or Durametric system to swap it out as it requires a special bleeding sequence and activation.

Are you sure it isn't a cracked line? They are a lot cheaper.............

[Highlander]

The ABS/PSM control system is a very expensive unit. If you get a used one, be careful, they are sensitive to dirt, moisture and corrosion, so know whom you are buying it from. You will also need access to a PST II/PIWIS or Durametric system to swap it out as it requires a special bleeding sequence and activation.

Does the duramteric pro support ABS/PSM activation now? Their website FAQ states it only works on 964's. I have been toying with purchasing the Pro (already own the enthusiast version) and this feature will convince me to upgrade.

Are you sure it isn't a cracked line? They are a lot cheaper.............

I hope it's a cracked line or leaky connection, but the fluid is coming from the side that has no lines atached - it's the side adjacent to the fender so I won't know 'till I get it off completely.

Thanks,

Graeme

[JFP in PA]

Both versions are capable of activating the pump for the bleeding/flushing on a 986.

[logray]

Reputable used parts places:

dcauto.com

oklahomaforeign.com

[Highlander]

Both versions are capable of activating the pump for the bleeding/flushing on a 986.

Thanks! I guess I just need to update the cable so I can run Version 6 of the software.

[logray]

It's a good buy, Durametric will take your old cable and give you a new one at a discounted price. Well worth it.

[Highlander]

Finally got some free time to finishing getting this expensive hunk of aluminium and electronics out of the car.

There are a few plastic caps on the piece and as RFM suggested, fluid was leaking from one. Of course, the one that was leaking was the one thats beside the fender, and the only one not visible until you remove the block itself...

You can see how wet the cap is here (it goes on the brass nipple in the middle):

I decided to bite the bullet and order a new one from board sponsor Sunset Porsche. Their price was less than 2/3's the retail price - still a pretty spendy part! It's going to take 2-3 weeks to get one from Germany :(

I also ordered the Version 6 compatible Durametric cable so that I can effectively bleed the system once it's all back together.

Thanks to all for their suggestions and support :thumbup:

[Urs4_2008]

The black tubes I would suppose is the clutch connection, since the clutch uses the same reservoir. Tiptronic, of course, doesn't have this, and the reservoir is only plugged.

[Highlander]

The black tube you see is another electrical connection. Only 2 pins.

All of the hydraulic lines use flare fittings.