Hi, On our Corrado 2L 16V, I had to replace a corroded brake pipe that sits on the rear axle driver side (the one that goes along the axle between the two flexible hoses). While I was replacing this pipe, I had a proper brake hose clamp firmly on the first flexible hose. Despite doing this, I went back outside to find that the bugger had still dumped lots of fluid onto the floor. The brake reservoir tank had run empty, probably below minimum. When I came to bleed the brakes, we were initially able to get some fluid out of the caliper, but then it stopped. Even with the nipple fully open, nothing would come out and the pedal remains rigid. I most definitely do have the rear brake regulator held open. I have even disconnected the brake pipe from the regulator to see if any fluid comes out of there, to rule out a problem with the regulator or blockage in the pipe that goes from the regulator to the caliper via my new pipe. Even with the pipe disconnected at the regulator, I still can't push any fluid out. If we apply pressure and undo the nipple on the caliper on the passenger side (opposite to the side I fitted the new pipe to) fluid will freely rush out. I believe that the ABS system on this car is the Teves 04 or something. When the ignition is turned on and car started, the ABS light goes on for a few seconds and then turns off just like it should. Is it possible that the ABS unit has completely shut off the supply to that pipe? We ensured that the pedal was not pushed too far (I know it should not be pushed to the floor) and once the problem is rectified I shall use an Easy Bleed which I now have. Desperate for help here as this is an apparently simple job gone bad. Car needed for tomorrow. Thanks Trev
usually you have to prime the abs pump while pressure bleeding if it has run dry using vag com. what method are you using for bleeding? forget about the other side, you want to try the opposite front brake if no fluid this will indicate you need to prime the abs pump - if its ok it will indicate that your abs module is blocking fluid off the the rear wheel in question. my money is on priming the abs
Many thanks. So far I am still struggling to find specific service information on the Teves MKIV system that's used in the RHD Corrado. The Bentley manual doesn't seem to be much use. The method we started to use for bleeding was the simple two-person method (i.e. my wife pressing the brake pedal). I now realise that this was not a good idea as it can damage the seals, but fortunately the pedal was not allowed to go to the floor. In future I will use the pressure bleed system. I'm going to get hold of VAGCOM.
Hmmm.... I'm wondering if the flexi is the issue here - maybe the clamp damaged it and it's collapsed internally? - this is why i'd never use a brake clamp, just use blanking plugs instead. How does the pedal feel now? ie do the brakes work? The Bentley is US based so completely different system, On UK RHD ABS Corrado's you should always pressure bleed and the ignition does NOT need to be on either and I would expect fluid to still flow even if it had run dry... If it does run dry apparently there is a procedure using VAGCOM and about 50 pedal presses to re-bleed the system but I have never had to do this... I think your problem is more fundamental...
i once had a problem with an ibiza where i was pressure bleeding with no joy untill i pumped the pedal at the same time. trev said he has pulled the 3/16 rigid pipe from the load proportioning valve - surely this would isolate any issues with the hose?
I did wonder if the flexible hose could have collapsed, and that's the reason why I decided to disconnect the rigid pipe from the rear pressure regulator to see if fluid would flow out at this point. This would have confirmed that I probably had a blockage in a flexible hose. But sadly, I got no flow from the inlet to the rear pressure valve either, meaning the blockage must be at the front end of the car. Yes the information regarding the Teves MKIV is very conflicting. There's the LHD version that uses a completely integrated module (which my G60 Syncro has) and the RHD version with separate servo. What's difficult is that all of the documentation I can find is pretty much US-based stuff regarding the LHD system. I have found several documents that state that on the MKIV you bleed the front axle by just simply applying the pressure bleeder and opening the nipples. But to do the rear axle, you need to: (1) Do 20 pedal presses with ignition on to get pressure out. (2) Ensure rear valve is open. (3) Turn on the ignition WHILE pressing the brake pedal and continue to hold. (4) open rear caliper nipples. The thing is, I don't know if that above rear axle bleed procedure applies to the RHD system or not. I am also not 100% certain whether VAGCOM will work on the RHD MKIV system. I have also read in a number of places that the Teves MKIV does not have a software bleed mode; only the Teves 20 does. EDIT: Also, if there were any faults (e.g. solenoid), wouldn't the light remain illuminated? I could go and try the procedure of holding in the pedal and turning on the ignition in the morning. But what bugs me is the fact that the nearside rear caliper was able to bleed very fast and easily, and the brake pedal suddenly wanted to colapse as soon as I opened the nipple on that side. So that leads me to believe that I should be able to bleed the rear axle without that procedure, and there's something more fundamental as you say.
teeves 20 i am thinking of - soz trev, hmmm, id try pressure bleeding with a few 1/2 pumps along the way - or wait for someone that knows!!!
Hello, yeah deffo don't need the ignition on or pedal depressed - I've done my G60 Corrado many times with Eezibleed. I would give it another try with the pressure bleeder at 20 PSI and then try and get it to a VAG dealer if no luck.
Many thanks for confirming that. Cheers to both for the advice; it has been most helpful. I do have a complete set of spare ABS parts from the wife's previous Corrado which was exactly the same model. There are four outputs on the regulating unit, one for each wheel. If it turns out that one output appears to be blocked then I may resort to swapping in the spare regulating unit. My understanding of the regulating unit is that it has: (1) four outputs for the wheels; (2) two flexible hose connections directly from the reservoir tank, that feed fluid to the pump for the very high pressure system; (2) two rigid pipes from the master cylinder, with one feeding the inlet valves (fluid supply) and the other connected to the outlet valves (fluid return, for when ABS wants to empty out a caliper). So, if one output from the regulating unit is blocked, then I come to the conclusion that the blockage must be within the regulating unit, because the single fluid supply is split across all four wheels within that unit - if that makes sense. How damage could have occurred from letting the reservoir tank dry out is a mystery. The colour of the fluid is horrible and I wonder if letting that one brake channel run dry has allowed crud to float down into the valve.
I just came across this old thread of mine from a year back. Thought I'd just add that in the end, I had to replace the ABS valve block. This cured the problem. Fortunately I had a spare good ABS valve block from the wife's previous identical Corrado 16V that was shunted. To this day I don't know why the original valve block permanently stopped suppling fluid to the one wheel following the loss and subsequent refill of fluid, but the horrible colour of the brake fluid and the fact that I allowed a lot of fluid to flow down from the reservoir suggests that a bit of crap found its way into the valve for the wheel / corner in question and blocked it. I still have the original block and I might open it up someday to look.
