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LEGACY VENDOR
1995-2002 Range Rover P38A
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4,159 Posts
Discussion Starter #1 (Edited)
Ok, back again with some questions.. this time about the ABS system/feel of the braking.

I've had a search and read a load of posts about braking issues - and a lot of them write about a "click" feeling as the pedal depresses, which I don't have. And none of them seem to have posts of conclusive fixes/what actually resolved the problem.

So.. my situation...

Bought the vehicle, brakes felt a bit spongy. ABS pump ran for 30-45 seconds on power up, and I'd get 1-2 - maybe 3 light presses on brake pedal before it ran again... Dead accumulator - had that one before.

Bought a new accumulator, replaced it, and braking felt a *bit* better - but still not how I remember my previous P38's.

Brake pedal still occasionally felt spongy, and needed a lot more force to get the RR to stop than it should. Brake fluid looked black, and I didn't fancy messing about trying to bleed the bloody thing, so got the Indy to replace fluid and bleed. (cost £134 for 2L of fluid and 2 hours labour).

They said there was a fairly big airlock in it, and it took awhile to bleed it. Great! I thought - there's a reason for it!

Got the RR back, and it felt a bit better. But it's back to how it was, if not a bit worse. I am also now very much doubting the actual competence of my Indy with p38's for a variety of reasons mentioned in my other threads, and I'm not 100% sure that they bled the system properly. Now, after the car has been sitting for awhile, the brake fluid is up above the max mark and showing through the bottom of the screen. I remember checking it when I first picked it up and it was at the max level.

What it does... sometimes if I go to press the brakes - especially after a while since the last brake application, but sometimes even on multiple consecutive applications - the pedal feels very soft and spongy, and takes a lot of travel to get the vehicle to stop. I have found that if I know I'm going to be braking and very lightly put my foot on the brake, after a few seconds I get a nice solid pedal, and good feeling braking. I don't get any 'clicks' in the pedal travel, just sometimes a lot of travel.

My ABS pump runs for the normal 30-45 seconds on startup, and still after ever couple of pedal presses. I've also noticed that if it's left sitting there, without pressing the pedal, the pump comes on after awhile for a few seconds again.

When I took the hubs off to do the front diff, I took brake discs off, and set calipers aside. There's no sign of any brake fluid leaks around any of the components, and all the guide pins feel free in their movement. The brake discs and pads look very well worn - and were very rusty. The front discs had a good couple of millimetres of lip on them (a lot of it cracked off on disassembly as it was solid rust!)

So.. my current plans:

New brake pads and discs all around (the back ones looked pretty worn too - so I figured it was worth doing it all now and then I know where I stand) I've gone for grooved/slotted discs and EBC ultimax pads, so hopefully that will eliminate any disc/pad causes.

I've also bought a 1L container of brake fluid, and a bleeder kit (one of the ones with a collection bottle and a one-way valve). I plan to de-pressurize system, remove accumulator, top up with fresh fluid, and re-fit. This should then mean that there's no chance of an airlock from the accumulator side of things, and the accumulator should charge fully/properly.

Next, I plan of tackling the (somewhat) dreaded task of bleeding the brakes again, but not taking it to the Indy... I looked at the bleed screws on the booster/modulator unit and the 2 rear ones look like a pain to get to under the foam on the firewall - and as a result, think that the indy probably didn't do that part... or at least not properly.. My trust was lost a bit when they were telling me that they had the airlock to get rid of, and if it comes back then it could be a case of a leak somewhere, and a replacement of the master cylinder... they then went onto (I presume microcat or equivalent) to look for the part number for the master cylinder, after I asked how much a replacement was.. I presumed they meant ABS pump - and I know the list price is about £1K.. however they were a touch perplexed when they couldn't find on the system a master cylinder part number for my vehicle.. and then saw the modulator and pump part numbers.

If they were under the impression up until then that it had a standard master cylinder etc, then that made me wonder about the quality of the bleed they'd done - because if it had been done per RAVE manual, then they would have found that out pretty quick!

I've also just bought a Nanocom Evo, so I can interrogate the ABS system and look at various voltages, and sensors.. I think I can test parts of the circuit piece by piece too, so that may/may not shed any light... From memory, when I had it last on testbook, the ABS system didn't show up any faults, and I don't get any sign of faults on the dash. The traction control light takes awhile to extinguish on startup - I don't know if that's a clue. I'm also not sure how long it is supposed to stay on for. Will look in RAVE and see if it has anything listed there.

So, that's my situation, and current plan of action over the next couple of weeks... What do the trained eyes of people from the forum think? am I missing anything obvious? I don't want to go out and buy a replacement ABS pump or modulator unit if I don't have to!

Thoughts, experiences, etc are all welcome... and I will endeavour to keep the thread updated if/when I get it sorted!

Cheers,
Marty
 

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1995-2002 Range Rover P38A
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Hi Marty

I am sorry about your troubles. From your story the following things:

The level of brake fluid: The pump build up pressure in the accumulator by compressing the rubber bellow filled with Nitrogen. This compressing stores oil in the accumulator and the level of your fluid in the reservoir will go down. If you use your brakes this fluid is pressed out by the nitrogen filled bag and the pressure of the system goes down until the pressure switch detects this and starts the pump again. This pressure switch has 3 switches inside for start pump at low pressure, stop pump at high pressure and alarm when pressure goes down too low.

When your level is higher or lower this could indicate that the pressure in your accumulator is different form when you checked it before and not necessary that air entered the system.

Have you checked your reservoir filters? To do this you have to remove your reservoir, make it empty and shine with a torch light under the reservoir. You will see clearly if your filters are dirty. This could cause your pump struggling to get enough fluid to keep the pressure in your system healthy and could also cause ingress of air through suction line connections leading to air lock.

Does your ABS light flicker at times when you press the brake indicating low pressure?

Regards

Jos
 

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LEGACY VENDOR
1995-2002 Range Rover P38A
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4,159 Posts
Discussion Starter #3
Hi Jos,

I was kinda hoping you'd post... you seem to be the person in the know around here when it comes to the ABS system!

I understand how the acccumulator works, and indeed, think that maybe the Indy when they topped the brake fluid up after bleeding, did it whilst the system was pressurised. I checked it just after getting home, so it would have still been pressurised. The time I noticed it was a lot higher was first thing in the morning before starting it up, so could indeed account for the extra fluid.

The top screen filter looks nice and clean, no sign of anything in there at the moment. How hard is it to drain and remove the reservoir?
I am always a bit wary about messing around with the braking systems, as they're kinda critical! But having said that - it can't get much worse I suppose...

Even though the brake fluid is only a about a month old, I still need to replace it all completely, don't I? All the warnings say never to re-use brake fluid, and use only fresh stuff from a sealed container etc.. guess that was a waste of £134! And I'd better order some more too, as 1L won't be enough!

Regarding ABS light... no, it doesn't come on at all (solid or even flicker) on brake application - whether light or heavy.

So, I think I need to add to the shopping list...
Couple of syringes to suck out fluid, and put new fluid into accumulator etc.
More brake fluid
Brake cleaner to clean the reservoir and all the other braking components
Container to put all the old brake fluid in.

Anything else I'm likely to need, special tools, seals, o-rings, washers etc?

I'd ideally like to have all the bits ready before I start!

Cheers,
Marty
 
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Hi Marty - you may well be right about your Indy not carrying out the bleeding process correctly... such as they don't de-pressurise the system properly first .... and another 'classic' is when the system (accumulator) is later fully pressured up they then top-up the fluid in the reservoir.... !
[In theory the pressure should remain within the accumulator... but over time/night it does not do this of course....]
 

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LEGACY VENDOR
1995-2002 Range Rover P38A
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4,159 Posts
Discussion Starter #5
I just don't know how much I can trust them with doing...

I think it's probably best if I just start from scratch with the accumulator, clean the reservoir, and re-bleed the whole thing as per RAVE. At least then I'll know it's been done properly and if any problems come back, then I know that there's something else going on!

Is the case of the pressure slowly diminishing a case of a leaking check valve or internal seal somewhere? are these replaceable, or are they a whole new ABS pump job?

Cheers,
Marty
 

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LEGACY VENDOR
1995-2002 Range Rover MkIII / L322
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765 Posts
The fluid level should be at the max mark on the reservoir when the system is fully pressurised. ie. after the pump has run and turned off. If left standing for any length of time the fluid will bleed back to the reservoir which will increase the level by an half an inch or so. (I am away from home at the moment or I would go and measure this increase and give an accurate number). This is totally normal as the only thing that holds the pressure is the mechanics of the pump itself. There is no valve on this part of the circuit. The older and more worn the pump the quicker it will bleed back.

If the fluid level increases more than this it could indicate air in the modulator unit. The accumulator is basically a big air bubble in the system which is contained within the ball and used for reserve pressure. I know you are aware of that but if we have a significant amount of air trapped in the modulator it will also behave in much the same way as the accumulator. So when the system is pressurising, both the air bubble and the accumulator shrink in size till the pump switches off. If the reservoir is then filled to the max level, when the bubble and accumulator push the fluid back to the reservoir the level will rise much more and even overflow. (I am not too familiar with the internals of the modulator so am not sure of how much or where the air can get trapped).

The air bubble can get there for a number of reasons one of which may be cavitation within the pump due to a partially blocked reservoir filter as Jos mentioned. Even if it looks clean it is extremely fine and is easily blocked so if your fluid was black its almost guarenteed to be restricted. Removing it and cleaning is very simple. I tried many different chemicals over the years and finally found one which cleans the reservoir and filter 100%. Here in South Africa it is called "Clean Green". I dont know if it is an international brand or not but it is just a very strong detergent that I buy from my local Autozone. Its even available in supermarkets here for household cleaning. I totally submerge the reservoir in the stuff and leave it for 24 hours and then rinse with water including reverse flushing it through the outlet, being carefull not to use too much pressure or the filter may rupture. And leave it near a heat souce to dry completely - very important.

Phew. Fingers getting tired now. Will carry on in a new post.
 

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LEGACY VENDOR
1995-2002 Range Rover P38A
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4,159 Posts
Discussion Starter #7
Ghur: Thank you very much for that insight... I'm going to have a look up on Clean Green, and see if there's something like that in the UK.

I will do some more searching on removal of the reservoir... do you have to remove the whole modulator block, or will the reservoir separate whilst still in the vehicle?

Also, I'm going to double check in RAVE, but how much brake fluid does it generally take to refill/bleed the system if I empty the reservoir?

Is it worth me removing the ABS pump too and looking at the internals of it for wear and tear?

I am fairly mechanically inclined, but as mentioned before - a bit hesitant working on such a fundamental part of the vehicle!

Thanks again,

Marty
 

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LEGACY VENDOR
1995-2002 Range Rover MkIII / L322
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765 Posts
Removing the reservoir is simple. One allen head bolt holds it on. It actually holds a small right angled piece which slips into a slot on the bottom of the reservoir and the bolt goes into the modulator. Difficult to explain but should be obvious when you have a look. Its on the right hand side of the modulator closest to the the coolant tank on RHD cars. There is only one bolt there so cant be missed. The right angled piece also holds a clip that the accelerator cable routes through. You may need to bend the brake pipes that exit the modulator slightly when manouvering the reservoir out.

The bulkhead foam tends to shed bits so use a plastic bin liner or something similar and place it over the reservoir and tuck it in behind to prevent anything going into the modulator. Also the gap betwen the modulator and the reservoir collects debris so clean that first with compressed air or water.

Two litres should do it but I always have a bit more just in case. Nothing like running out when you are nearly finished.

There is not much that you can see with the pump dismantled except for the pump parts and I dont know of any way of measuring clearances so would not worry. It seems to be working ok going by your description so best left alone. Dirt is a killer so the less you have to dismantle the safer you will be.

There are a couple more things that I will point out and will do so in an hour or so. Joining my buddies for a beer or two. Priorities.........
 

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LEGACY VENDOR
1995-2002 Range Rover P38A
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4,159 Posts
Discussion Starter #9
Thanks again Ghur! Beer is definitely a high priority!

I've ordered a couple of seals from LR direct - about £9 - but RAVE recommends replacing them, so figure it's worth it if I'm going to the effort of cleaning it all.

Interesting to look though... Microcat lists the modulator/reservoir unit as a single part number, and that the seals aren't applicable to my Vin no. However, looking in the generic P38 section without putting VIN in, it came up with part number for the 2 reservoir seals... I wonder why that is....

Will leave pump intact, but will re-do the accumulator fitting after first filling it with brake fluid, so there's no air in it.

I haven't been able to find anything like "Clean Green" in the UK - are there any other recommendations for cleaning products?

Cheers,
Marty
 

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LEGACY VENDOR
1995-2002 Range Rover MkIII / L322
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765 Posts
www.wynns.co.za

You can see the stuff on this web site but there does not seem to be a data sheet for it so cant help with UK products. There has to be a multi purpose cleaner similar. It must be non corrosive though.

Regarding the seals- the modulators are different due to the 2 vs 4 wheel traction control but are essentially the same and the reservoirs are identical as are the seals so you are safe there. As to why they dont list the reservoir separately - who knows - its a "Landrover thing".

Getting back to some pointers. When re-fitting the reservoir, lighty smear the two outlets on the bottom with grease to ease pressing them back into the grommets. Brake fluid is not slippery enough and you will go mad trying otherwise. The bleed process seems a bit daunting but its actually quite simple if you follow RAVE exactly. No shortcuts! The bleeder you have may help a little but its definitely a two person job as some of the steps are impossible without a helper. It can easily be done in under an hour once you get the hang of it.

One bit of caution though. I have had three cases of the pressure reducing valve (ANR3323) leaking shortly after the bleed. Within a day or so. I guess thats due to the gunk in the system being flushed away and exposing leaks. Very easy to change so if you are going all the way consider replacing it beforehand or it will need a re-bleed should you need to change it at a later date. Thats like a 10% failure rate of the valve on the bleeds I have done. I personally would rather wait for it to start leaking and then do the job as the bleed process does not scare me and its quite pricey. I must say though that the ones that did start leaking had been on very heavily contaminated brake systems.

On the right hand drive model the three bleed nipples on the modulator are fairly easy to access. I use a long flexible clear hose with a short length of rigid pipe - about 12 inches - and finally a one inch piece of flexible again. The rigid piece makes it easier to control the end considering the awkward position of the nipples and you can bend it to a shape that helps fitting the short piece to the nipple. Armed with one of those extra long "long nose pliers", I go in from behind the coolant tank and fit the bleed pipe to the nipples when called for in RAVE. It does help to remove the tank which is very easy to do. Then compress the bulkhead foam with one hand and use the pliers to do the rear one. The rear nipple can be seen easily when you squash the foam. Loosen and then lightly re-tighten the nipples before starting. They can be very tight. (I love talking about nipples).

Any leakage can be washed off with water and I have noticed that the paint work in the engine bay seems to be very resilient so there is no mad rush to clean any spills.
 

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LEGACY VENDOR
1995-2002 Range Rover MkIII / L322
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765 Posts
Marty. Reading back over your posts the filter Jos and I are talking about is not the filler screen filter but the filter at the base of the reservoir just above the outlet to the pump. Its inside the reservoir and can only be seen when you remove the filler screen which is easy to get out. Looking down at the neck of the reservoir there are three small cut outs round the neck of the screen filter. Get three small electrician type screw drivers or something similar and push them down thru the cut outs I guess an inch or so. This releases the small tangs that prevent it coming out and then leaving the screw drivers in place gently grab the rim of the filter with pliers and pull it out. You may damage it very slightly if you are not careful but its no big deal as it is not a perfect seal anyway.
 

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LEGACY VENDOR
1995-2002 Range Rover P38A
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4,159 Posts
Discussion Starter #12
That information is going to be invaluable, thank you!
I knew that there were the 2 filters in the reservoir, but the info you have given is now giving me the confidence to pull it apart!

I'll definitely get a second person to help me with the bleeding process. I just think that the non return valve is going to help with stopping air getting back in at the end of every pedal press.

I haven't seen any leakages from anywhere, but will check around the valve before I take it all to bits, just to be sure!

Seals are ordered, I now just need to get a couple of syringes, and some more brake fluid, and a decent cleaner. Is brake cleaner worth using? I remember reading that someone used hot soapy water to clean the reservoir out?

I have carb cleaner and electrical contact cleaner, white spirit (turpentine) and probably methylated spirit about at the moment. I'd be a bit worried about turps and meths eating the plastic though, so will steer away from them!

Cheers,
Marty
 

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LEGACY VENDOR
1995-2002 Range Rover MkIII / L322
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765 Posts
Brake cleaner is more for cleaning the crud that has bulit up from brake dust and oil etc. around brake parts like the calipers but the high pressure ones are useful for cleaning all sorts. One of my most used "tools" but they eat paint.

I am sure a very strong solution of washing up liquid and water should do the trick. But it does need a good long soaking. And a good shaking. There are three chambers in the reservoir connected by small openings but only the front one beneath the filler is accessible so if you dont manage to get the others totally clean you can get into the front one with a small brush to do the final cleaning. A bent toothbrush works well. When rinsing the reservoir after the soak I would suggest attaching a hose pipe to the outlet to the pump and at a low pressure just leave it to run for a while. Maybe 5 minutes. Anything still lodged in the filter should then come out.

Turps and meths should not hurt the plastic but it does nothing towards cleaning the gunge from the reservoir. The float for the Low Fluid Warning system makes a racket when you shake the reservoir around but does no harm.

I forgot to say that to remove the reservoir once the bolt is out you may need to lever it up with a large screw driver or pry bar to pop it out of the grommet / seals. Does not take too much force.

This is all coming out of my head as I am a long way from home so I hope I have not missed some crucial bit of info. Please dont sue me if I have.`)
 

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LEGACY VENDOR
1995-2002 Range Rover P38A
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Discussion Starter #14
Haha, no suing I promise! Don't think that's allowed in the UK anyway!

I figured I'd need a screwdriver or something to separate the two bits, so will make sure there's one to hand. I just hope it's not beyond repair/cleaning. New reservoir is about £100+ tax....

Will sink it in some nice hot soapy water for an afternoon, give it a scrub out, and a good thorough rinsing.

Will snap some.pictures as I go, and will put them up, as there's a distinct lack of pictures...

Will let you know how I get on... And if I get stuck!
Cheers again,
Marty
 

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1995-2002 Range Rover P38A
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Hi Marty

Since my post you have gotten a lot of extra info and I have little to add.

The following link shows the brake reservoir filter:

http://rangeroverworld.blogspot.com/search?updated-max=2010-02-17T13:39:00-08:00&max-results=10

For cleaning I use liquid detergent mixed with water and compressed air to blow back from the outlet connection. Filling half with water detergent mixture and shake it pour out the liquid and repeat, repeat etc till you get clean screen. As already mentioned it can be seen when using a torch light under the reservoir.

Regards

Jos
 

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LEGACY VENDOR
1995-2002 Range Rover MkIII / L322
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765 Posts
I had forgotten about that link Jos. Some very good photos showing the insides of the components.

I got it wrong. There are six chambers in the reservoir - not three.
 

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LEGACY VENDOR
1995-2002 Range Rover P38A
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4,159 Posts
Discussion Starter #17
Cheers guys!

I had found that link in some of my searching. Was a very interesting read!

They recommended replacing the reservoir if it was fully crudded up, so will bear that in mind too... I'll definitely attempt a deep clean first!

Probably going to be Thursday before I get the chance to start doing all this, so will see how it goes!

Cheers,
Marty
 

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LEGACY VENDOR
1995-2002 Range Rover P38A
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4,159 Posts
Discussion Starter #18
Ok, so bit of an update...

This is taking me longer than anticipated - partly due to me deciding to paint the brake calipers whilst it was all in bits... I figured if it's getting nice new brake pads and discs, then it seemed silly not to spend a bit of time tidying up the 11 year old, rusty calipers and hanging brackets. Though, I'm nearly at the re-assembly stage, and was going to clean/re-grease the guide pins... then found that some muppet in the past has used the wrong bolts on a couple of the rear guide pins - causing the threads inside the pin to be damaged... grrrrrrrrrr I hate paying for other people's incompetence!!

So... New front and rear guide pins are ordered, and some new bolts for the rear (the front bolts are all correct... I checked after that!) But being as it's a bank holiday this weekend, they won't get here until Wednesday/Thursday :(

So... ABS reservoir... I suctioned out as much brake fluid as I could from the top of the reservoir, and have got it off, and it's in for a clean. the filter at the bottom of the main chamber did look a bit sludgy and clogged...

It's had a bath in washing up liquid and hot water, followed by some other household cleaning products - and it has only got marginally better. I can actually see through the filter now though! I'm just a bit worried about the fact that looking at the bottom of the tank, I can still see a bit of dark residue on the inside of the tank, in most of the chambers. I haven't been able to get rid of it, and it has not been soaking overnight again in another bath of washing up liquid and water. I've scrubbed the inside of the main chamber as best I can with a toothbrush, but obviously the other chambers are inaccessible.

So I guess my question is... will it be ok? or should I replace? or... does anyone have any other magical tips for cleaning/dissolving the residue/sludge?

I can fill it up with water, put the hose on, and if I suck water through the hose (as a pump would) then the fluid flows freely, so I think the fine screen filter is ok..

cheers for everyone's help so far! I'm going to go and take the last wheel off now I have some more jack stands, and do my other axle oil seal, and start cleaning up the last caliper and dust shield for painting..

Cheers,

Marty
 

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LEGACY VENDOR
1995-2002 Range Rover MkIII / L322
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765 Posts
http://www.wynns.co.nz/resources/msds/64820-MSDS-Wynns-CleenGreen-AUS54520.pdf

I found the above Data Sheet for Cleen Green so maybe you can decypher the long words and find something similar. It certainly sounds quite nasty when you read its Hazard Identification but I am still alive so it cant be that bad.

The way I check to see if the fluid flows ok is to fill the reservoir with brake fluid and see if it runs out without any help from suction. It should flow freely but it will reach a level and stop. The filter is very fine so it will reach a point that there is not enough weight of fluid to push it through the screen. I have never tested a new reservoir so dont know how normal that is. The pump is high pressure but low volume so it does not suck the fluid from the reservoir at a high rate so I am sure yours will be ok. Just wont look as pretty if there is any residue left in the in-accessible chambers.
 

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LEGACY VENDOR
1995-2002 Range Rover P38A
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4,159 Posts
Discussion Starter #20
Hi Ghur!

Thanks for that - am doing a bit of a search now on the ingredients and will see if any of them match up to a cleaner over here... interesting that they say in there that it shouldn't be put down drains... and that release into a sewer may be possible depending on local laws, and that used wash water may have to be collected for treatment. LOL I wonder who follows that?? I haven't seen many places with installed waste water treatment, unless they are major industrial areas/factories etc.. For a home user, people are just going to put it down the drain, surely? my random off topic musings!

I haven't tried it with brake fluid yet, as it's now outside drying in the sun for the afternoon, but with water I can fill the reservoir, and have it run out smoothly (not a massive gush of fluid, but a steady stream) until the level is a little way above the screen (probably 5-10mm - I didn't measure it though), so I guess it will be fine for the moment! It looks a bit better than it did... and hey, it it doesn't work properly, then when I have to do it again, at least I'll know the process!

There is some residue left in the inaccessible chambers, but it's sitting right at the bottom by the looks, and if it hasn't come out with my efforts of washing, shaking, backfilling, more shaking etc - then I doubt it will suddenly shake loose in the system.

Will update again when it's re-installed in the vehicle and filled. Am still planning on removing accumulator and filling it with fluid this time before fitting, just to be sure!

Cheers again,
Marty
 
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