RRC brakes

[MikeAK]

Hi all, as the title suggests I'm having trouble bleeding the ABS system on my RRC.

Some history of what I've done. Replaced front callipers and all the front rigid and fexi pipes. During this I screwed blanking plugs into the 4 ports on the solenoid block to prevent all the fluid runing out. Unfortunately while attacking the inner wing with the angle grinder to replace some rot I nicked one of the rear brake lines without realising and all the fluid ran out overnignt anyway D'oh!

So with all the front pipes re-fiited and the rear one replaced refilled the reservoir and followed the bleeding procedure in RAVE to the letter 4 times and cannot get a firm peddle, it will travel all the way to the stop if pushed hard. The last 2 times were with easibleed fitted as well.

Its now had best part of 5 litres of fluid through it with no air bubbles coming out since the first attempt. Rear of the vehicle is raised above the front as suggested in RAVE.

Brakes were working perfectly before changing the corroded pipes.

Ideas anyone?

Thanks

Mike

[MikeAK]

Had another go at this today. Went through the entire RAVE bleeding procedure another 3 times and still can't get a firm peddle.

Seen some threads on here suggested it may get better if driven slowly and brakes applied a few times, so tried this but made no difference. When appying brakes the peddle is very soft gets a little firmer about halfway down. Vehicle does stop but very slowly.

I'm beginning to think the valve block may be faulty, although I don't know why since it was working perfectly before changing the pipes.

Any suggestions much appreciated. I don't know what else to try, and its getting expensive in brake fluid!

Thanks

Mike

[sheltie50]

I have to confess that I know little about this system but, I reckon you must have air getting in if it were an older model it could well be the master cylinder seals, could be worth checking all joints again keeping an open mind towards a plumbing error.

Sounds like a head-ach, good luck.

[scube]

If your RRC has traction control which the later one’s had.

Plugging textbook in or other PC interface will allow the traction control and abs to self bleed.

Never done it myself but that’s that the book says.

Other than that have a look at this for bleeding ABS

Hope this helps

abs_brake_bleed_rrc.pdf

[MikeAK]

Thanks Scube,

Mine does have TC

The info in the PDF is different to whats in RAVE, I will give it a try next time I get to it.

You mention "Plugging textbook in or other PC interface". I don't have access to textbook but what is other PC interface? Is there some other interface and software available, like EAS Unlocker for the air suspension?

Incase I have made an error re-fitting the pipes does anyone have info (or could maybe look at the layout on their vehicle) on which port (all have numbers) goes where. Microcat and RAVE are a bit sketchy on this.

Thanks

Mike

[bishbosh]

Go for a drive (quiet road obviously!) and gave the brakes a work out. IIRC this is how Bowie69 sorted his out.

I just used to use an easibleed. Worked every time for me.

[Bowie69]

Yup, worked on more than one occasion, within quarter of a mile it was perfect.... This was after 4 hours of continuous bleeding to get it right the first time, with an Eazibleed, second time it was 30 mins to bleed, quick drive and the pedal firmed up very quickly.

I think it is related to the front brakes, as when I have worked on the rears I've never had a problem, normally just 5 mins with an Eazibleed and it was sorted.

[scube]

Yes there are a bunch of them about. Bearmach sell a number of different versions.. Some where a donor card is required so you can leave your arm or and leg at the door as you leave and some not so expensive.

http://www.rangerovers.net/repairdetails/scanners.html

http://www.bearmach.com/products.html

[MikeAK]

Hi again,

I tried taking it for a drive down local farm track at weekend and give the brakes plenty of use, even had the TC light on the slippy bits. Must have gone about 3/4 mile, absolutly no improvment in brakes at all.

Spotted a supposedly working ABS master cylinder on fleabay and got it for £4.99 + £8.00 postage, so if Scubes alternative bleeding sequence doesn't work I'll fit that when it arrives and see what happens.

If someone could check which pipe goes to which port in case I've been a muppet with the plumbing that would be great.

Thanks again

Mike

[SteveRK]

Have you checked that one or more pistons are not being sucked back in when releasing the pedal creating a gap between the piston and pad thereby creating the impression of air in the system - unlikely culprit but worth checking.

If its down to air my bet would be a bubble somewhere in the rear brake pipe section - try opening up the rear bleed screws and really stamp on the pedal then bring it up 2/3 then stamp down again to try and dislodge the bubble.

There is some kind of compensator on these models for the rear brakes and on mine it would require ignition on and lots of pressure to get fluid to pass through to the rear calliper bleed nipples - might be worth unscrewing this a few turns on the reservoir side first to see if any air is trapped on that side of the compensator.

[MikeAK]

Hi again,

This goes from bad to worse! Tried all the bleeding suggestions and could not get a peddle at all. So swapped the master cylinder/valve block. Bit of trouble getting the fluid to flow on the lower bleed nipples at start of bleeding procedure probably due to the valve block being completely empty but was fine was it got going. Then round the car in 15 mins all bled with firm peddle.

Whohoo I thought time for a test drive.

Car wont move unles give plenty of revs (automatic) so back up on stands again seems the brakes are partially on all the time. Brakes stay on even if peddle pumped 50 or so times to depressurise the accumulator. If the bleed nipples are then opened fluid is ejected and the pads free off. As soon as the ignition is switched on and the accumulator pressurises the brakes re-apply without touching the brake peddle. Only got chance to check the front brakes before the rain started so not sure what the back brakes are doing. Another faulty master cylinder/valve block?

What are the legalities of de-ABSing, Im getting pretty pi55ed of with this now!

Thanks

Mike

[teslo]

Hello,

friend of mine have similar problem with blocked brakes. He was changing bodywork and after refitting servo( was disconnected for couple of weeks) and connecting electrics it is not working properly. Diagnostic doesn't show any error code. All seems to be connected correctly. After switching ignition on and system is pressurized all wheels are blocked.

[SteveRK]

If the replacement master cylinder was a used part make sure the tiny bypass bleed hole (in line with the main feed hole) in the reservoir is not blocked as this can cause locking brakes. If its new then i can only guess that a valve inside the ABS unit is blocked, certainly sounds like a real frustrating situation thats going from bad to worse.

[MikeAK]

Steve,

That sounds like it needs investigating. But Im not sure what the "tiny bypass bleed hole" is or where it is. Can you describe where it is exactly please. To be clear this is the Wabco combined master cylinder/valveblock with the separate hydraulic pump and accumalator.

Thanks

Mike

[SteveRK]

The bleed hole is very small and is positioned in the reservoir in line with the piston. It is positioned to be behind the seals and main entry hole to the piston. I had a motorcycle once where this hole got blocked and caused the brake to bind on. I'm guessing its function is to allow the psiton to return back fully in the cylinder

[MikeAK]

Had another look at this after having to leave it for a while due to work commitments.

Swapped the master cylinder back for the original, and bled it again couldn't get a firm peddle as before. Took it for a drive and no improvement if anything getting worse the more its used.

So decided its time for a different approach, got a syringe and suked up some fluid from the master cylinder reservoir. The fluid was full of "micro" bubbles. So left it overnight. Next day checked fluid again bubbles had floated out overnight.

So started bleeding again according to Rave procedure hydrostatic circuit first bled OK checked fluid, no "micro" bubbles.

Bled accumulator, a few "micro" bubbles appear in reservoir.

Bled rest of power circuit as per Rave. Seemed to be getting better as beld at first then the more its bled the worse it gets. Checked fluid ain reservoir again, full of "Micro" bubbles.

So starting to think the pump is pulling air in somewhere. Don't have a spare pump to hand so looked for where else air might get in and thought of the flexi pipe from reservoir to pump or its connections. Pulled it off to inspect it, jubillee clips were tight st both ends, pushed back the cotton outer braid and the pipe seemed slimy although not actually wet.

Replaced it with some new pipe, topped up with freah fluid. Re-bled brakes again as per rave. 20 mins later good peddle and perfect brakes!

Can only assume the flexi pipe had become porous allowing air in but not fluid out.

Don't understand why I never saw the "micro" bubbles at the calipers but the bubbles must have been getting in the master cylinder and upsetting it!

Mike