AHC system - 'A stitch in time'

[nathanrobo]

Guys

Decided to overhaul my suspension before the spheres got too flat and ruptured. So I opened the bleed valves on the four spheres and the main accumulator. The spheres where a little stiff (well they have been on the car for 10 years), but using a 37mm thin jawed adjustable they came off. I then took a trip to Pleiades to get them re-gassed.

And the good news is! Martin confirmed that from visual inspection that should be okay to recharge as he could see the diaphragm (which means that they haven't gone completely flat)

The lesson? Maintain your AHC with a fluid flush every couple of years and don't wait until the suspension goes stiff to have the spheres recharged. You'll be quids in and the LC will feel as it should.

I'll post tomorrow when I get the spheres back, maybe some pics too!

 

[uHu]

Well done.
Can't bear the thought of having the cruiser off the road for several days...

What's the going rate at Pleiades?

Pics would be nice.

PS
Could you ask him if he would ship to Norway, if I send him a set?

 

[Dark Dude]

Me too!

JC

The Dark Dude

 

[nathanrobo]

Uhu

I certain that Martin has sent spheres all over the world. He was showing me a picture of a Maserati yesterday, I think it was in the states in a museum. Anyway it's the only one of this particular model left in the world and they recently sent him it's set of spheres.

I know in Australia he used to do a lot of work on Citroen spheres in the '90's

Will check pricing and get the photos up later.

Anyone know the best way of posting pics? Is it a link to photobucket or something similar?

btw. he typically does them same or next day, so it's that plus postage time. Although I reckon that it would be a good thing if between interested forum members, we could get him a spare set so that he could work on an exchange basis. I'd be happy to chip in even though mine are done. I might give Julian V a call to see if he's any that he has taken off.

 

[uHu]

I use Flickr.com - particularly easy if you have a Yahoo account.

 

[Jon Wildsmith]

I'm pretty sure Julian will have some spares Nathan and I have to visit him soon to reclaim some AHC shocks for Frank If one of my sets are still available I would gladly send them to Martin so he can do an exchange service and mine were only about 6 months old when I abandoned them I think he takes more off than he's likely to have put on but I could be wrong (don't tell my wife that )

 

[Pleiades]

Hi All.

Just a quick introduction, as after speaking with Nathan today, I decided to register here.

I dont actually have a Land Cruiser, I would like one but a scruffy pick up truck suits my needs more and to own a nice vehicle like the Land Cruiser would be a shame.

At Pleiades, we have been overhauling spheres for mainly Citroens since the early 1980's. We do spheres for all Citroen models, Maserati, Rolls Royce, Case tractors, JCB and just about anything that needs it.

Recently we have been dragged into the world of the Toyota AHC system, it is not too different from the Citroen C5 hydraulic system, working with an electric pump, spheres and electric height control.

All spheres have a life span. All spheres lose pressure over the years, this is not due to any faults, it is due to a proccess called "molecular diffusion" (google Grahams law if you are bored).

With the spheres the diffusion is the gas molecules migrating through the diaphragm inside the sphere, this takes a long time especialy as Toyota made the sphere with the multi layer diaphragms, these diaphragms are made up using 2 sheets of rubber with a sheet of thin plastic in between (a bit like a windscreen glass and plasic make up)

If you treat the sphere as a service item and change it before it goes completly flat, the sphere can be re-charged and serve another life, if you leave the sphere untill completly flat, you will damage the diaphragm inside, making the sphere scrap metal.

We can re-condition the original Toyota spheres if they are still in good enough condition or if the spheres are scrap, then we have developed a pattern sphere, using a stock sphere and an adaptor neck to fit the Toyota system, this has worked well and we have now fitted several sets of our spheres to Land Cruisers, the results have been good and so far all owners have reported that the ride is back to normall.

I will sort out some pictures so that you can see for yourselfs, when I work it all out. ( I fix cars, computors are still a bit of a mystery to me)

Regards.
Martin.

 

[nathanrobo]

Jon,

Thanks for that! And Martin... Welcome!

I'd intended to write up the job with photos as soon as I'd finished but work kind of got in the way :-(

Anyway I'll get to it a little later. In the meantime Jon / others... I'd appreciate your view on any damage likely to be done by my MOT station testing my brakes on the two wheel roller system. I'll start a new thread for it though.

 

[nathanrobo]

Step by step with photos,
1. Set car to lowest
2. use brake bleeding hose/valve to bleed sphere valves (well that's what I call them) and accumulator (that's the large cylinder with bleed nipple). Car will drop further (be careful that you are not under the car when this happens)
3. Carefully using a brake spanner (10mm - I think) take thinnest pipe off and out of the way to avoid it being damaged
4. When fluid completely drained use a tool to grip sphere and rotate anti-clockwise or use a thin jawed 37mm spanner to brake seal. Note spheres are fitted like an oil filter - hand tight using an o'ring or rubber seal - but they do get a little tight over time
5. After you remove sphere inspect the orifice that the oil goes through, if you can see the diaphragm (silver) then they can definitely be re-gassed. If you can't the oil pressure against them diaphragm may have ruptured on the internal part of the fitting used to gas the sphere in manufacture
6. Send or take sphere to Martin at Pleiades if serviceable, if not get him to make up a pattern sphere (specify front or rear or both as pressures are different).
7. refit sphere using a small amount of AHC fluid it's O'ring seal and tighten by hand as tight as you can
8. close all bleed nipples
9. Open the AHC fluid reservoir and refill
10. Start car on tick over (with all doors, boot etc closed), when the suspension pressures up the car will move slightly upwards. Open car and set suspension to normal.
11. Check that there are no leaks - It won't if every thing is nipped up. Check reservoir again.

original sphere use 37mm hex thin jaw spanner

Sphere valve with sphere out

Accumulator - bleed this too

Sphere valve bleed nipple

Front sphere slightly smaller than rear

O'ring seal

Pattern sphere with toyo collar set to LC pressures

That's it folks!... let me know what you think

{Admin - fixed your pics for you! Remember to use the

 

[Pleiades]

Some photo's of the spheres.

Our pattern spheres in place.

The pattern sphere next to a Toyota Sphere.

I hope that this is of some interest, They may well need to be re-sized as I do not know how to do this!!

Regards
Martin.

 

[Dark Dude]

Nathan/Martin

Thanks for the headz up and pictures. Very informative but say if (like me) you're not very good with a hammer and spanner. What do you do then if you want your AHC system checked over, Pleiades style?

Unlike Jon, my surname isn't Wildsmith.

The Other John

The Dark Dude

 

[nathanrobo]

Dark dude, where r u based?

 

[Dark Dude]

Tottenham, London. Follow the burned out buildings and the looted shops and you'll find me.

The Other John

The Dark Dude

 

[nathanrobo]

For anyone in travelling distance of Martin (Sawtry near Peterborough), he'll fit sphere's and possibly whilst you wait.

I'm trying to get a AHC pump, sensors and maybe even shocks, preferably from a member that's changed their AHC system out for a Ironman system. Hopefully I can interest Martin in playing around with them to see if they can be rebuilt.

Any cheaper alternative to Mr. Toyo has to be good!

 

[HDJ100]

Dear all,

I have a 1999 HDJ100 VXE fitted with AHC system.
My spheres needs to be removed inspected and re inflated by Martin at Pleiades.
I have removed all AHC fluid using the 4 bleed valves, and the piston bleed valves.
during the operation the truck was in neutral position.

I ask your help cause I may have done a bad mistake.

To facilitate the AHC fluid removal I have restarted during 5 seconds the engine and went from Low to Neutral. It did not work since there was not enough fluid left in the system. The AHC OFF signals started to flash.

I have not manage to remove the spheres I have decided to send the truck to a small toyota specialised garage.

I have refilled the AHC system, bleed valves locked. the AHC OFF signal keeps flashing, all AHC fuses are ok.

Fluid seems to be stuck in the tank without getting down the spheres. It is like the system does not get under pressure or like the pump is defused.

Does anyone has ever faced this? how can relaunch the system please?

thanks in advance

 

[nathanrobo]

Hi

I've not had this issue, but is it worth bleeding all the spheres one by one, using a tube and traditional bleed valve (as used to bleed brakes)?

The correct way to empty / replace fluid when removing spheres is to drain the from the valve at each sphere (any pressure supporting the car's height will have gone so the car may drop), then when no further fluid can be removed this way, remove the spheres. When you replace the spheres you refill the tank and keep bleeding from the valves until the fluid runs clear.

 

[Jon Wildsmith]

I vaguely remember there's a procedure you have to go through to prime the AHC pump if you've emptied all the fluid out. Either the FSM or google might expand on my vagueness.

 

[Dark Dude]

Well it looks like I'll be off to see Martin at Pleiades, sooner rather than later because by all accounts (and Julian) my spheres are shot to hell. Alas I must reiterate, anything is better than getting totally ripped off by Mr T.

John

 

[Dark Dude]

I've just come off the Pleiades website and I can't find any prices per corner anywhere?????

John

 

[andyw]

A set on ebay http://www.ebay.co.uk/itm/Toyota-Landcr ... 20c21db278