how do suspension bushes affect ride quality?

[maxgreenwood]

what difference to ride quality do the condition of front wishbone suspension bushes have? Mine have been identified 6 months ago by a specialist citroen garage here as needing replacing and looking at them they're split and flaky.
the reason i'm asking is i've been trying to locate the source of my choppy ride over small undualtions. Spheres are good and 1 yr old all round. ran hydraflush for 2.5k and changed back to LHM. Bled brakes properly etc. The HC linkages probably need lubricating properly which i hope to get round to this week, but the ride height seems ok and the thing goes up and down without a problem. Did the internal LHM lube through the return pipes and greased the outside of the struts under the gaitors. Struts v smooth. The main source of my puzzlement is the fact the car rides like a dream after releasing pressure whether by undoing bolt and doing back up or left in low over night - but only for about 5-10 mins, seemingly til the car warms up. I have a new reservoir to pump hose on there so no air getting in i don't think.
My uncle (ex-citroen mechanic) thought the HCs might be sludged up after the hydraflush dislodged stuff but i don't want to recon / change these unless i'm more certain they could be the problem.
Pump is also v quiet after released all Hydraulic pressure and rebooted, compared to normal running. Tick time is quite rapid but this shouldn't affect ride? Might reseat non return valve ball bearing.

The ride is gradually improving through all my tinkering, but still not as smooth as before i changed the old (very dirty and water-consistency) LHM to hydraflush, so i wonder if its something to do with that, although i'm aware many component related things may be changing over time. done about 4000 miles since old LHM was in.

I sometimes wonder whether i'm expecting too much from the ride of the bx, but the ride i get when starting up is so smooth compared to after 5-10mins, i'm wondering. The power steering is also much lighter immediately after the car has been started up for about 5-10 minutes, then gets a little heavier.

[Aerodynamica]

The power steering is also much lighter immediately after the car has been started up for about 5-10 minutes, then gets a little heavier.

mine does that too. I thought it was because the engine and pump were running faster on the autochoke but maybe not.

I wonder if the worn bushings cause excess flex and this throws the struts slightly out of true so they don't slide straight? ( bit of a long shot there!)

[maxgreenwood]

yeah i wondered about the struts moving around. Been out in it today after fitting a coolant hose and bleeding - takes so long!
I have definately got a sticky front height corrector as i think it was ratcheting lower after braking etc and a move up to high and normal again brought back an ok ride...
And i should say now before i cause too much head scratching on the forum, i'll tackle that one soon and report back and i also have to check out the struts (again). Sometimes they're really smooth, sometimes they stick for no apparent reason... could be moving around due to suspension bushes? - Perhaps this is why when the car has been in low overnight the alignment of the wishbones and struts is reset??

[DavidRutherford]

what difference to ride quality do the condition of front wishbone suspension bushes have?

Almost none. My BX had completely (and I do mean COMPLETELY) dead wishbone bushes, and the only problem is that it knocked quite badly. Changing the bushes made it all go quiet again, but didn't affect the ride.

I think the issue you are having is related to the temperature of the LHM. Stone cold LHM will be more viscous than when it heats up, so the pump will have a higher flow rate (and greater power requirement) and everything will be a little more damped.

[Aerodynamica]

I have definately got a sticky front height corrector as i think it was ratcheting lower after braking etc and a move up to high and normal again brought back an ok ride...

was it running a bit low on the front end?

This won't be caused by braking as the BX, like the CX and GSA has anti dive geometry - the front will not go down under braking!

I'd wager the front height corrector linkage has free play at the bushing in the subframe.

[maxgreenwood]

Well after suspecting all sorts of problems i think its just down to the front HC and those good old struts! - they are most definately seizing up. I lubed them externally and sucked up LHM into them about 400 miles ago before a long trip and all seemed smooth at the start of that, they must have lost their glide already? I'll try cleaning under the gaitors again and get some silicone grease.

A couple of seasoned BXers on here advised me i didn't have to look too much further than struts and height correctors and i've been imagining all sorts of problems. Experience counts obviously.

And thanks Aerodynamica - i'll check the brass bush of the linkage. I saw your pics and post on here about it.

Checking the front after driving, the struts are very sticky, quite alot of force needed on the front bumper to push through the 'stick'

I think the front height corrector is definately sticky. When moving from normal to intermediate height, it takes alot of pumping and an age for it to rise and then it jumps up. A few citerobics relieves but only for a short while.

Recon struts? New struts? What about the collar round the shaft under the gaitor - doesn't that have e teflon coating or something which degrades - is that the cause of all the sticking?

I'll get them relubed and the HC greased and report back.

[maxgreenwood]

was it running a bit low on the front end?

not 100% sure but i reckon its getting stuck below normal riding height cos the HC is so sticky.

I'm a bit nervous about taking the linkage off to do work and setting up the correct height and everything afterwards. I'll be forever tinkering with it! Worried i guess that old or partially sludged height correctors wont be as accurate as reconned/new but i guess thats mostly down to the brass bush thing and eliminating play in the linkage?[/quote]

[Way2go]

I think the front height corrector is definately sticky. When moving from normal to intermediate height, it takes alot of pumping and an age for it to rise and then it jumps up.

That sounds more like the struts binding or air bubbles in the lhm than the height corrector. If you hear the pumping then the height corrector has already enabled the hydraulic circuit.

[maxgreenwood]

what are possible places for air to get into LHM apart from reservoir to pump feed hose? I replaced this already. There doesn't seem to be any frothing in the reservoir although i have discovered very tiny bubbles in there before. I suspected air as being the problem but ran it past my ex-citroen mechanic uncle and Martin at Pleiades and they doubt this could be the problem. Concurrent with possible air though would be the fact it rides great after being left in low overnight or after all pressure released and bolt done back up. Tick time was 26 secs with old LHM and new acc sphere, this or more when new hydraflush put in, then down to 10 secs when ride niggles began appearing. Boot test on acc shpere works immediately after engine switched off but not after a minute or so. Returns from struts just drip but i must check this again to be sure.

the struts are definately binding in some way.

[Way2go]

the struts are definately binding in some way.

Have you checked under the gaiter with the suspension on high to see that the moving shaft is bright & clean? Try wiping it with 3in1 and applying more 3in1 to the strut bush too.

[maxgreenwood]

the struts are pretty clean and smooth but there are a couple of dark rings on them i guess from where the bush sits at normal height that don't seems to come off wiping with wd40 - is it a case of lots of elbow grease. Would that be making the bush stick?

[Way2go]

That could be it. Are these rings worn into 'steps' so that they can 'lodge' top and bottom of the bush?

[maxgreenwood]

i'll have to check that - would that be the actual metal being worn and having depressions/roughness? is that what i'm looking for?

in which case i need to replace them do i?

i have a free bx 17tgd coming my way in Jan with about 70000 miles on it, wouldn't pass the NCT now but been maintained in its life, that might be able to donate some suitable struts.

[Jaba]

If lubing the struts externally makes no difference then the problem is internal.
There is an internal piston that the seals operate on that develops wear ridges and gives the stiff jerky suspension. The cure is new internal seals for a few pounds each and polishing out the ridges with some fine abrasive polishing paste.

This is a very difficult thing to DIY as the strut is near to impossible to dismantle.

Fit the donor car struts, I would.

There is a theory that swapping the struts from one side to the other may give a new lease of life. They tend to wear internally on one side only as they are not actually vertical and therefore wear unevenly.
A corollary of this theory is to loosen the strut top mounting nut and move the shiny outer piston round 180 deg to try and achieve the above result.