Is there something I don't know about my C3?

Ringmaster · 01-08-18, 10:10 PM

Folks,

Had a brake fluid change at my local Audi dealer today and they very kindly performed a vehicle health check on my C3 Avant. All was well, but apparently (and this is where I started having trouble understanding what I was hearing) the mechanism at the rear that compensates for forward motion when braking was dripping a bit of water,

but it was nothing to worry about.

Well, that was a relief as I hadn't realized my beloved Avant had anything related to the brakes, suspension or forward motion located at its rear, or anywhere else for that matter, that could leak water.

There are wiser heads than I on this forum so, I appeal to them. Am I missing a trick?

The car was already off the ramp, otherwise I'd would have asked to be shown the bit in question. There was no mention of it on the nice little video they later sent me. I suspect that they confused me with someone else. Are there modern Audis out there with gadgets as described above?

John. · 02-08-18, 04:46 AM

Forward motion is a good thing surely!.....Maybe ask them for a quote to rectify said fault?!

Load compensating valve sound like what they're describing, it would drip brake fluid surely, and that would be a worry?

Maybe water was running onto it and rather as dry it off they'd like to fit you a new one?!

Hanuman · 02-08-18, 08:45 AM

There is, as mentioned, a load relief valve (brake force regulator) on the rear axle. It is a simple piston valve that reduces the brake fluid pathway under braking. A spring coil connects between the axle and the chassis of the car, which pulls a simple lever, which closes the valve. This happens as the rear axle unloads during braking. The harder the braking, the greater the effect.

https://audi.7zap.com/en/rdw/audi+10...2/6/611-56000/
item 6
(i'll try and dump a pic in here later)

It's generally made by ATE. I've had 3 failed. One easily freed up, with penetrating oil. one needed some dismantling, and one refused to come apart.
The are prone to seizing up.

If it's dripping water from the lines, I would expect brake calliper issues, too!
If they fail open, it generally will not be noticed. They do sometimes fail part closed, or fully closed, leading to lots of head scratching as folks have difficulty understanding why one calliper won't bleed or operate correctly.

Ringmaster · 02-08-18, 12:37 PM

Thanks chaps...

It was the reference to water that threw me. The part in question is 31 years old, so I guess it will need monitoring. No sign of brake fluid on the floor yet. So far the brakes feel fine. Had both front calipers bind up the other day, but sprucing up their pistons sorted that.

As they said "It's nothing to worry about".

Getting old is no fun!

The one advantage I've noticed of taking a car as old as mine to a dealership is that they no longer carry 99% of the parts needed, so they are unwilling to repair faults they find.

02-08-18, 08:45 AM	#3
Hanuman Trickster Classic Audi Club Member Join Date: May 2009 Location: Heckling from the cheap seats, Phnom Penh, KoW Posts: 7,006	There is, as mentioned, a load relief valve (brake force regulator) on the rear axle. It is a simple piston valve that reduces the brake fluid pathway under braking. A spring coil connects between the axle and the chassis of the car, which pulls a simple lever, which closes the valve. This happens as the rear axle unloads during braking. The harder the braking, the greater the effect. https://audi.7zap.com/en/rdw/audi+10...2/6/611-56000/ item 6 (i'll try and dump a pic in here later) It's generally made by ATE. I've had 3 failed. One easily freed up, with penetrating oil. one needed some dismantling, and one refused to come apart. The are prone to seizing up. If it's dripping water from the lines, I would expect brake calliper issues, too! If they fail open, it generally will not be noticed. They do sometimes fail part closed, or fully closed, leading to lots of head scratching as folks have difficulty understanding why one calliper won't bleed or operate correctly. __________________ I wish they would keep the damned Chinese away now that I can go home, so that I can enjoy Fish amok and a draught Angkor Last edited by Hanuman; 02-08-18 at 08:49 AM.

02-08-18, 04:46 AM	#2
John. 4 ring whore! Classic Audi Club Member Join Date: Mar 2011 Location: Scottish Borders. Posts: 7,520	Forward motion is a good thing surely!.....Maybe ask them for a quote to rectify said fault?! Load compensating valve sound like what they're describing, it would drip brake fluid surely, and that would be a worry? Maybe water was running onto it and rather as dry it off they'd like to fit you a new one?!

02-08-18, 12:37 PM	#4
Ringmaster Senior Member Classic Audi Club Member Join Date: Apr 2008 Posts: 1,326	Thanks chaps... It was the reference to water that threw me. The part in question is 31 years old, so I guess it will need monitoring. No sign of brake fluid on the floor yet. So far the brakes feel fine. Had both front calipers bind up the other day, but sprucing up their pistons sorted that. As they said "It's nothing to worry about". Getting old is no fun! The one advantage I've noticed of taking a car as old as mine to a dealership is that they no longer carry 99% of the parts needed, so they are unwilling to repair faults they find.