2005 Clio Sport II - brake bleed fail-HELP

[aspire_helen]

I think I have cocked up and allowed the brake fluid reservoir to empty while bleeding the rear brakes after swapping the rear axle hard lines for flexible lines. (I blame the ridiculous location of the reservoir buried behind the cylinder head!).
After topping up the reservoir, the left rear brake bleeds OK with apparent normal brake pressure. However, on the right side there is no brake pressure. Applying the footbrake repeatedly on the bleed does push a little fluid (but no air) through the bleed valve, but at no significant pressure. I must have put a total of 300 to 400mil through the bleed valve to no effect. Of course, all unions are sealed, there are no apparent leaks nor kinks in the hoses. Can I recover this or will I need diagnostics?
Thanks
PS I will post the issues I had with Proline's flexible hoses in a few days.

[MattBLancs]

Can you try a vacuum bleeder? Suck through.
Or else a pressure bleeder (gunson's easibleed or similar)
Both can get the fluid moving at a rate of knots, so may help draw an air bubble through?

Can you try pushing / winding the piston all the way back in (so minimum volume in the caliper) ? Likely some disassembly to get to this point.


How is pedal pressure (with everything done up?) If reasonable but bit spongy pedal then perhaps gentle (quiet Sunday morning!) Drive to the nearest bit of gravel/mud/loose ground and see if can get ABS pump to do its thing and hopefully dissolve air in there?


I think the foolproof answer is probably diagnostics to open the ABS pump valves, but a few ideas to try.

Matt

[aspire_helen]

Matt
Thanks for the good ideas. I would like to say it makes a change from fixing my C5, but I am beginning to hate this Clio and its not even mine. Pedal pressure is good, because I think the rear left circuit is good. But when I open the bleed valve on the rear right all the pedal pressure disappears. I picture in my mind an open ABS solenoid valve on that circuit preventing pressure to be applied, but that's just in my head. I bought an Eezibleed and 5ltrs of Dot4 this morning, and will try that tomorrow. I will check the front brakes as well, although access is rubbish. This is a Clio Sport 182 with low suspension, and then fitted with even lower springs! If I can get a decent amount of braking, I will take it to a gravel farm track nearby and get the ABS to kick in a few times. Could that reset the ABS solenoids? I dont know. Do you know what diagnostics I would need bleed to the ABS? I have read of an RS Tuner with ABS module, and CAN chip. My next question is....who has one???

[Gibbo2286]

I did mine with a Snap-on diagnostic tool, there's a video here, it's a yank one but the principle is the same.

[MattBLancs]

Matt
Thanks for the good ideas. I would like to say it makes a change from fixing my C5, but I am beginning to hate this Clio and its not even mine. Pedal pressure is good, because I think the rear left circuit is good. But when I open the bleed valve on the rear right all the pedal pressure disappears. I picture in my mind an open ABS solenoid valve on that circuit preventing pressure to be applied, but that's just in my head. I bought an Eezibleed and 5ltrs of Dot4 this morning, and will try that tomorrow. I will check the front brakes as well, although access is rubbish. This is a Clio Sport 182 with low suspension, and then fitted with even lower springs! If I can get a decent amount of braking, I will take it to a gravel farm track nearby and get the ABS to kick in a few times. Could that reset the ABS solenoids? I dont know. Do you know what diagnostics I would need bleed to the ABS? I have read of an RS Tuner with ABS module, and CAN chip. My next question is....who has one???

Just a few thoughts, and sorry nothing Renault specific (never played with one of those!)

If there's two circuits, pedal pressure until right rear bleed nipple is loosened - does that not point to the air bubble being in the rear left circuit? (Basically pedal pressure you can feel is on the right, loosening that gives no pressure, instead you should feel pressure from the left circuit, but you get nothing)

My understanding of "air in the abs pump" is that it's just the wrong side of one of the valves, so can't be pushed through (without a fancy diagnostic machine able to open each valve in turn) - rather than something jammed.

So the gravel ABS pump action is my thought to get them valves opening and closing a bit in the hope of pushing the air bubble down the line (out the inaccessible area and somewhere you could then bleed out conventionally)
Not sure if it would work, but it's what I would likely try in your predicament!

Easibleed is good. Recommend a wheelbarrow wheel (or bike) as good source if air - note you are supposed to let it down to about 1 bar, takes ages depressurising and pumping back up a car tyre! Too much pressure not good for the reservoir I think. Have gone up to about 1.5 bar with mine. A faff to get it to seal sometimes (pipe connection to cap and rubber seal in cap to reservoir both play up. Just keep at it, not tighter and tighter, just back off, make sure seal is seating and try again.

Matt

[aspire_helen]

Well, that was a disaster! Eezibleed, my a**e, scuse my french. It took longer to get the tubes to seal than use the damn thing. What a cheap design. Anyway, I used it to bleed the rear right (where there had been no brake pressure) and the rear left (there there had). I was disappointed at how slow it was, much slower than brake pumping - which I did as well as per the instructions. No air came out, but I did get brake pressure on both callipers. Although they were binding somewhat afterwards, whereas before they were free to rotate. The pedal felt a bit spongy but it did not go to the floor. I didnt touch the front brakes which have been undisturbed.
So, put it all back together, started the engine, and......no brakes at all, the pedal went to the floor with little foot pressure. Grrrr. So I cant even drive it anywhere. Does that point to anything more serious than "just" air in the system/ABS?

[MattBLancs]

Seems I underplayed the "faff to get it to seal sometimes" but, but yes agree, can see there's not a penny wasted in its construction. It is cheap though or at least was when I bought one.

Very odd results you've had.

Binding somewhat is good, means pistons have moved a bit which is a step towards functionality.

I'm not sure what to suggest other than more bleeding to be honest, try the fronts too. Perhaps the air bubble is on the move.



Am trying to think what could be wrong at present and indeed what could now give you no brakes at all. Master cylinder is about only thing I can think of to give nothing at all. But no clue that would fail like that.

Puzzling.

[aspire_helen]

Ive been through the normal manual bleed sequence twice now. Significant air came out of the front left calliper the first time around, but all was Ok on the second bleed sequence. The brake pedal is rock solid, so I suspect the master cylinder and basic brake system is OK.....until I turn on the engine, and then the pedal looses most if not all resistance. I think I need an ABS bleed.

[MattBLancs]

Interesting!

Wondering about failure modes for the servo? Can't think of a way you'd get "too much assistance"
(hole in diaphragm is less assistance but wonder if something else going on there to give too much??)

Can you plug the servo's vacuum feed and if pedal then stays firm once started, then perhaps risk a gentle drive, see if continues then perhaps would confirm is servo issue rather than something going on with the ABS pump when the engine is switched on?

Thinking aloud really, quite a perplexing issue!

[aspire_helen]

I will see if blocking the vacuum has an effect. I read on another Renault forum of exactly the same symptoms after some brake component changes. Advice suggested that, if the servo was OK, it was possibly a sticking ABS valve or air in the ABS. In his case, he had some braking, albeit at the end of the pedal travel. He solved it by driving on a wet grassy field to activate the ABS repeatedly, and then basic bled the brakes. He did this 4 times, improving each time, until his brakes were back to normal. There are Youtube videos of similar....ie driving and causing the ABS to function repeatedly to "clear" the ABS, whether air or a stuck valve. I understand a diagnostic ABS bleed also activates the valve solenoids, so maybe that is my best option if I cant drive it.

[MattBLancs]

Hi,

Yes, that's the same strategy I tried to describe with gravel/mud/loose ground above, get the ABS pump activating and hopefully move the air somewhere you can bleed it normally.

Interested to hear how it goes / if drivable with servo blanked off as that should steer us one way or another

[aspire_helen]

Aha. Having just manoeuvred on the drive, I too find the car has some pedal braking, but only towards the end of the pedal travel. I may have to leave it for a week or 2, but I will update.

[aspire_helen]

RESULT. Borrowed an RS Tuner (with ABS module). It had 3 historic ABS faults, one each for 3 of the wheel sensor resistance. Having fully bled the primary brake circuit, I ran the ABS bleed function wheel by wheel. 3 callipers ran clear, but the front left discharged a lot of aerated fluid. Then I ran the sequence a second time - all callipers ran clear. Only used about one litre of fluid. I noted that the process had cleared the wheel sensor faults automatically. Started engine and brake pedal back to normal. Test drive OK, good brakes and no ABS warning light.
One comment though - the RSTuner provides no guidance or procedure whatsoever. So, I followed the CLIP procedure after activating the function for each wheel ie open bleed valve, start the RSTuner function, depress the brake pedal half way and hold, on completion of the function (approx 30 secs)- close bleed valve and release pedal. Worked a treat.

[MattBLancs]

Success at last! Excellent news