A homage to coffee filters - and David Rutherford

[Debelix]

Well, firstly Happy New Year to all of you folks out there, members of the BX pain sharing group

About the filters - my personal opinion is that adding another filter is quite... useless. For my system it just didn't change anything - and I'm talking bot positive and negative side - just... nothing!

I guess in a well-maintenanced hydraulic system (hopefully like mine, heh ) adding another filter is just pointless. During the use of the extra filter (about 4-5000 miles) I didn't notice any change in the behaviour of the car - after removing the filter again - nothing changed. The filter itself was quite dirty but not as dirty as one might expect to be - the color of the filtering element was just dark brown and that's about it... Too bad I didn't take a picture of it, but when I was removing it I wasn't at home, but at some garage.

Anyway, that's my contribution to the experiment with additional filters

[MULLEY]

Happy new year debelix. I wasnt anticipating that the cars suspension would improve, i was interested in whether the filter actually caught the crap in the lhm, that perhaps the main lhm tank filters wouldnt pick up as it was too fine for them.

So it sounds like it did its job, perhaps using some hydraurincage cleaning fluid might have an even bigger affect on the filter capturing all the crud in the hydraulic pipes.

Have you decided to keep the filter on?

I'll have a go at adding a filter sometime soon, & report back with any findings etc....

[Debelix]

Hi again

I decided to remove the filter, because I don't think that the small dust & mud captured by it is so important for the system. After all, changing the LHM every 2 years or 60k km is quite often, so the system don't mind the small dirt in the hydraulic fluid - my 20 years old BX is a testament for (or is it right to say "to"?) this

[kevlights]

i think that is a really good idea,cannt do any harm that i can think of and might do some good,will save me from having to empty the tank and clean the filters and the deflector disc '{" by the way what is the purpose of that plastic disc the sits in the bottom of the tank"}IM off to the parts shop to get another filter ,yippie a chance to fiddle with the BX

[MULLEY]

It would be useful if you could keep this thread updated on how you've found fitting a filter to the lhm & what was lurking in the lhm which you thought was clean.

[cauchoiskev]

Well I have had mine in for a couple of thousand miles and I make the same observation as Debelix i.e. it makes no difference to the performance - if everything is working O.K to begin with anyway.

However, my conclusion is the opposite, i.e. it is indeed useful, and I'm going to stick with it. I can see it starting to get dirty now, even though the LHM was newish and had been coffee filtered only a few months ago. When I take it off I will take photos.

[MULLEY]

Would be interesting to see the piccies of jus what it managed to capture. Again i dont think performance would come into it, as its just fluid with some bits in it. I'm waiting for someone to do a hydraflush & report back what they found in the filter....now that might be an eye opener.

[cauchoiskev]

Well, after a couple of thousand km, here is what the filter looked like inside :



As far as I'm concerned it's better if that silt is not circulating around in the system.

[MULLEY]

Quite dirty, is that what was in the hydraflush?

[cauchoiskev]

Not Hydraflush, Mulley, just ordinary - and quite recent and "clean" (coffee filtered) - LHM.

[MULLEY]

Hmmm, when is green not green

I'm hopefully going to get around to doing this shortly. Do you know what size the filter lugs/ends are on yours? or did you have to modify the pipework at all to get it to fit ok?

[DLM]

My personal preference if choosing to fit an in-line filter would be to do it after the standard tank + filter-block clean-out + complete LHM replacement - even though I do admit that "in theory" little of what ends up in the tank should recirculate.

by the way what is the purpose of that plastic disc the sits in the bottom of the tank

My guess at the function of the disc, in response to Kevlight's question, is this:

(i) To Allow "fall-out" of very fine particles at the bottom of the tank, and to keep those small particles there there without disturbance. There's nearly always a sediment underneath it when you change LHM).

(ii) Possibly to inhibit swirl in the tank, for pretty much the same reasons : if the bottom of the tank weren't blanked off with the false bottom that the disc provides, then some unpredictable eddies could occur under conditions of rapid LHM return because of the actual shape of the bottom of the tank where it's been shaped to fit into its locating space.

What's the tank shape like in a Xantia or similar that doesn't have the bell-shaped lhm tank, and does it have the disc (or an equivalent)? That might provide clues (or clues to the bean-counter's art in cost-cutting by reducing numbers of components).

[MULLEY]

I was going to fit a filter like the guys have tried on here, but time & uncertainty put me off.

Can anyone let me know which way the lhm flows in/out of the pipes where the extra filters have been fitted, i didnt want to fit it the wrong way round.

Does anyone know what size the filter endings have to be in order to snuggly fit the pre-existing pipes & is it worthwhile getting a filter that can be cleaned rather than the throw away type?

[DLM]

Can anyone let me know which way the lhm flows in/out of the pipes where the extra filters have been fitted, i didnt want to fit it the wrong way round.

These have been fitted onto the return piping and therefore there's only one possible direction of flow - to the tank!

is it worthwhile getting a filter that can be cleaned rather than the throw away type?

There are already cleanable fine-mesh filters in the input/output block in the tank, filtering both ways (for larger particles). The theory is that the rest will drop as sediment to the bottom of the tank, hopefully on or under the plastic disc. It's that kind of contamination you're aiming to filter some of - think of it as like an air filter or oil filter, both of which are normally throwaway (with the exception of foam air filters fitted to earlier BXs).

My personal take is that this kind of filtering would be of most use in conjunction with a hydraflush cycle: it'd give an indication of the progress of that procedure if checked/changed regularly during it, and tell you when it's time to revert to lhm.

[MULLEY]

Cheers for the flow info dlm.

Another question, so the 2 guy's have fitted their filters to pipe number 4, after the bulbousy T part, theres another pipe exiting it which then goes round the tank & into the wing, what does that one do?

To make it a bit easier to fit, i was going to fit the filter before the T part further away from the lhm tank, but that would mean the above pipe if it does anything wouldnt get filtered?

Any advice?

I just wanna get it on now because i'm really curious how much crud the hydraflush is picking up.

Erm, i forgot to put the plastic disc back into the lhm tank I only realised after i'd put everything back togther & bled the air out & gotten the car to rise up. I guess theres no harm in the short term in not being there?