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Joined: Sep 14 2016
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The big red beast is showing definite "Yank Tank" wallowy ride characteristics. Seems more at rear suspension related than front. I'm pretty sure that it used to be much taunter, by big 4x4 standards anyway, but its hard to evaluate the handling of your own car as one tends to adapt. Doesn't help that the roads round here are terrible for lorry humps and similar vehicle upsetting features running more or less in the direction of travel.

Normally I'd go straight to shock absorbers but new Boge labelled "OEM" units with the correct Land Rover part numbers went on about 15,000 miles ago. Unfortunately I missed putting them in service record spreadsheet so don't know exactly when. When it stops raining I'll verify that there are no leaks but they certainly looked dry on Friday.

Rear Panhard rod got new factory bushes around the same time as the shock absorbers were changed. All the front end bushes, steering assembly bearings et al have been done over the last year except for the front Panhard rod bushes which, according to the MoT man, are in fine fettle but will be done soon anyway as I have new ones. The rear ones were certainly well past their best so the front ones must be showing their age.

I've heard that dying height sensors can give wallow issues. If so what breed to go for. Britcar show genuine Land Rover factory ones at near enough £64 and £67, cheaper than Dunlop or Britpart. Island show Dunlop about £5 cheaper with OEM quality similar prices to what Britcar wants for the factory version. At Britcar prices I'm inclined to go genuine. Obviously if it is likely to be height sensors I'll change the lot. At that age if one is past its best the rest can't be that far behind. if nothing else the arms on the rear ones are looking distinctly manky.

Anything else I should be considering remembering that all the EAS stuff has been done relatively recently. Airbags, compressor rebuild, valve block re-build and so on.

Thanks

Clive.

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Joined: Dec 30 2015
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The Britpart rear sensor I ordered last year turned up in the dreaded blue bag but was marked with Dunlop logos. The theory is that Britpart order enough in one go for Dunlop to be interested in a producing a batch.

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Joined: Mar 22 2016
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You say you changed all bushes, does that include the radius arms ?

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Joined: Sep 14 2016
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Radius arm bushes. Yup thats where I started the front end re-furbishment process.

With 20-20 hindsight all the suspension refurb work I've done, except for the EAS, has been chasing this not quite right, wallowy ride feeling. Each fix made things a bit better for a while before the issue came back. So obviously I've not hit the real cause of the problem yet. What ever it is deterioration clearly continues. So far as I can see the height sensors are about all that's left. Over the last year or two it has been occasionally intermittent about sorting itself out on start up and on the low speed / high speed up and down business.

Height sensors were on the set the clock back list anyway so no worries about changing them.

Clive

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Joined: Apr 23 2019
Posts: 190

It sounds a bit weird for something essentially mechanical, like the suspension, to be inconsistent (whether bad or good). Why would the height sensors make it wallowy? Although, did you check your ride heights recently ( have they crept up, due to black spots) you may be able to take them down a couple of cm

How about tires and pressures ? Perhaps wallowy (because the panhard rod translates up/ down movement to left/ right) means you want firmer shocks ie to reduce movement in both planes? Did you take another P38 er for a spin recently to cross check? Wd be a shame to chase this only to discover "that they're all like that". I'd describe mine as more floaty than wallowy, but there's a bit of wallow in there, for sure

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Joined: Sep 14 2016
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Having been through everything else the EAS is about all thats left.

Now if I read certain internet references correctly the EAS is working all the time to keep the car stable when running. Obviously there is smoothing and delay but into the system so it doesn't try to be a true active ride system reacting to every twitch and bump. But it is monitoring the sensors all the time and, should things get sufficiently out of kilter, it will alter the air spring pressures to suit. Sensible, simple, system but it does rely on the sensors working linearly and tracking each other correctly. If you have sensor track damage and nonlinearities floating around the poor suspension ECU is likely to get its knickers in a twist and react wrongly. I know from work experience that fairly slow reacting systems with quite heavy damping but plenty of actuator power can do really strange things if the tracking side is off.

Anyway I've bitten the bullet. Four new Dunlop branded sensors from Island are due about 2 pm today. A metre of 30 mm delrin arrives tomorrow or Saturday to do the setting spacers and by this time next week we should be up and running with new sensors. From other occasional issues I'm pretty sure that at least one is getting up to its sell by date anyway.

Clive

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Joined: Apr 23 2019
Posts: 190

Re Delrin, a bit off topic - and I guess I'm late to the party, but if Delrin is such a pig to cut then why not use wood for the calibration blocks?

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Joined: Jan 16 2016
Posts: 234

I made up a set of blocks using nylon 66. It is very easy to turn and plenty strong enough.
I have also turned a set in hardwood. I think an old piece of mahogany, full of wood worm anyway.

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Joined: Apr 23 2019
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Tnx Dav, if my soft wood ones don't work I'll do the nylon 66, and it won't break the bank - thanks for the suggestion

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Joined: Dec 30 2015
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Go the other way and get a chop saw like wot I did. Delrin? like BUTTER! :)

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Joined: Sep 14 2016
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Delrin is lovely stuff to machine. Sharp tool and reasonable speed with a decent cut does the deed. My fave plastic.

Don't care much for nylon. Tendency to birds nest when turning and its easy to overheat it at the tool tip getting melted bits. Especially when milling. Unfilled grades tend to move around with humidity changes too. Which is a bummer if you make some nicely fitted bearing bushes with material which hasn't been properly dried first!

Clive

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Joined: Sep 14 2016
Posts: 402

Four new height sensors fitted on Saturday in friend Mikes "barn" workshop. Nice level floor and lift with headroom to get car right up to make life easy. One of the new rear ones ones was way different calibration compared to the others. Actually had to swop sides as its was right not the lower limit when fitted to the drivers side. See what its like after week or so but looks like I'll have to get that one changed under warranty.

After all the fiddling around I think the original "iffy sensor, or two" issue might actually have been poor connections not align sensors. But nice new ones now.

Car seems a touch more stable but its still very wallowy and doesn't seem to be running quite true. Clearly the problem is still evolving. On further reflection the issue seems more roll related than damper travel as I managed to find some straight across the road bumps and hollows to play on and it seems much better behaved when both sides hit at the same time. Single side bumps, hollows et al feel awful and roll is certainly excessive. But its had new factory anti-roll bar bushes and links fairly recently so that ought to be OK. Front Panhard rod bushes are still good but I shall be sourcing used panhard rod to fit new bushes in for a change-over.

Frankly I'm out of ideas.

Clive

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Joined: Apr 23 2019
Posts: 190

what wheel/tyre/ pressure combo are you running? might you be better off with firmer shocks ie a shock transferred to both shocks at the same time is according to your preference, but a shock to one side produces a yaw

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Joined: Sep 14 2016
Posts: 402

Running General Grabber HTS tyres at their recommended 35 psi all round. Which worked fine when first fitted perhaps 15,000 - 20,000 miles ago. Still have reasonable tread but there will probably be new Vredesteins going on next year.

On reflection this wallowy & roll issue has been hanging around in the background pretty much all the time I've had the car. Its what has shown up whenever other suspension / steering things have got to the worn / end of life stage. I'd just put it down to being thats what P38s do when bits underneath get too worn. Everything I've changed has either been well worn or clearly getting old so its not as if anything wasn't pretty much due. Even if I'd gone the just do the knackerd bit route I reckon everything would have, of necessity, been done within the next 10,000 miles anyway.

Clive

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Clive603 wrote:

Running General Grabber HTS tyres at their recommended 35 psi all round.

Recommeded by who? Pressures should be 28 psi in the front and 38 psi in the rear, although I tend to run a couple of psi higher all round, particularly when doing a long distance towing job.

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Joined: Dec 30 2015
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Clive,have you checked your viscous coupling? I was chasing what sounds to be identical symptoms. Essentially the car was fine on the straight and flat but became unpredictable on bends, especially on odd cambers or bumps. It was more likely to wallow when loading the front downhill/braking.
I replaced Panhard rod, TREs, Radius arm bushes, one height sensor (the others were fine) etc etc but no change.

Now, having changed the viscous, she's much better. Still a bit of a fat barge but at least she's now honest and predictable. I claim no credit for the diagnosis, Marty worked it out when we were doing the radius arm bushes.

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Gilbertd wrote:

Clive603 wrote:

Running General Grabber HTS tyres at their recommended 35 psi all round.

Recommeded by who? Pressures should be 28 psi in the front and 38 psi in the rear, although I tend to run a couple of psi higher all round, particularly when doing a long distance towing job.

35 psi was off the General Grabber list for HTS tyres. Some of the other Grabbers were closer to the standard. Queried that with the type shop at the time. They said try it on both and see. Certainly seemed happier at the General Grabber settings than book. Wear pattern is good and its been generally well behaved until very recently unless there was something needing fixing.

Morat
Thanks for the heads up on the viscous coupling. Certainly sounds a possibility. Time to read up in RAVE. Hopefully if it is the coupling I have plenty of warning before "bang" as gotta drive off to Southend airport in a few minutes to collect brother off the Aberdeen flight. Usual hour (ish) wait on the M25 to get to the Dartford Crossing coming up.

Raised the front at the weekend for another look. With only one wheel up the lifted one turned smoothly by hand with noticeable stiffness. So I guess the VC at least somewhat functional and not locked up.

Clive

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Joined: Dec 30 2015
Posts: 1571

Fair enough, sounds like it's OK but it's cheap to check!
The VC itself isn't likely to go bang, for me it was the UJs on the front driveshaft. If they're not "cheeping" then I'm sure you'll be OK.
Good luck!

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Joined: Sep 14 2016
Posts: 402

Darned if I can find anything fundamentally wrong so, working on the premise that if it looks like a duck, quacks like a duck and waddles like a duck it is a duck I guess my set of OEM Boge shocks have clapped out in 15,000 road miles. Not good. Especially as they came with Land Rover part numbers.

So what to change them for. Paying the Green Oval tax for factory replacements come out at around £500 a set delivered! OEM Boge like I had before is around £110 a set once front & rear pairs have been tracked down. In retrospect far too close to Britpart prices for confidence in quality. OEM or not I'm beginning to think these are just plain old basic oil units so two tons of P38 is overworking them more than a bit.

Monroe and Woodhead gas shocks claim to be OEM too and are around £200 to £250 a set.

Paddock have Bilstein B6 Yellow monotube gas shocks at around £300 a set which is pretty attractive as being about half list. But its not completely clear if these are road or off road shocks as the same part number appears in both sections. Checking on the Bilstien site the true off road versions carry different numbers so those probably are road optimised.

My steering damper is clearly getting old and must be changed soon and Paddock also have the Bilstein steering damper for £70 odd delivered, which is about the same as Genuine, I'm tempted to add a splash of yellow underneath. OK so called OEM Armstrong steering dampers are about half the price but, right now, I'm not that confident that the OEM tag really means proper quality.

What does the team think.

Clive

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Joined: Dec 30 2015
Posts: 1571

I think you can't go wrong with Bilstein as far as quality goes. It's probably worth phoning up to ask about damping rates vs stock to see what they're set up for.