Conversion to manual suspension from AHC

[mudassar1972]

I recently changed to standard shocks / coil springs due to continuous problems with the auto height control in 1998 land cruiser HDJ100 (4.2 Diesel), the change involved replacement of all 4 shocks with standard hydraulic shocks, and the coil springs to hard and stiffer coil springs. The coil springs were changed because the original coil springs didn't take the vehicle weight and it would drop to lowest height on standard shocks. After harder and stiffer coil springs were installed from a non AHC LC the vehicle came to a reasonable height close to the N position but the ride quality has gone done and has become harder. My current experience on slightly bumpy roads is hard and noisy but on motorways its quite OK. I also suspect my vehicle height to be lesser than other similar vehicles after this change, Any suggestions how to improve this situation ?

thanks
MM

 

[Julian Voelcker]

Depends on the springs and shocks fitted. Did you swap out the torsion bars as well? You should do.

You can get the Toyota springs and shocks intended for the non AHC models, but they are very pricey.

A cheaper option is to go for one of the standard lift kits, but most are aimed at +50mm which you may not want for day to day driving.

Best combination so far we have done is replacement front torsion bars (upgraded ones), replace rear springs with +10mm of lift and then the key is Bilstein shocks all round.

 

[mudassar1972]

Thanks for your reply, i have not changed the torsion bars so far and will plan for it. One question in my mind which is not clear because of my lesser 4x4 experience is that whether the front height and the rear height of the vehicle should be same ? is there any standard height which should be done on 100 series ? does raising the height of vehicle provide a smoother ride or otherwise ? as i see the front end of my vehicle is lower than the rear end, is it also contributing to the bad ride experience ?.
thanks

 

[uHu]

You should definitely change the torsion bars before driving another mile. The ahc bars are not designed to carry the whole weight. With the lower arms (A-arms) hitting the bumb stops, they might develop cracks.

Also, fitting 2nd hand rear springs is not a good idea, unless they are nearly new.

A heavy vehicle like the cruiser requires good quality shocks. The ride quality will improve with better shocks.

As for measuring the height, there is a good procedure in the FSM.

 

[mudassar1972]

thanks, my current LC configuration is as follows

right side fender to hub center = 45mm
left side fender to hub center = 45mm
right side rear fender to hub center = 47mm
left side rear fender to hub center = 49mm

Tyres = Yokohama Geo-lander H/T-S
RIM = 275/70/16
Air pressure = 33PSI on Tyres
All 4 non AHC toyota genuine hydraulic shocks
NON AHC Coil springs
is it OK or do you see any change required

thanks
MM

 

[Zeusv8]

Hi, I am about to do this conversion as well and was wondering if you removed every bit of the system or just the socks and springs? How did you drain all the ahc fluid?cheers.
Should these measurements be CM and not MM??

 

[mudassar1972]

I only changed the shocks and springs and did sway bar refresh, didn't change the AHC torsion bars so right now i am planning to swap them also to improve the ride quality over bumpy roads. The dealership mechanic did the fluid flush so i am not really sure of the method used.

thx

 

[Julian Voelcker]

Zeusv8,

Depends on how far you want to go - I prefer to remove everything including the ECUs, etc but it does take time.

We have a suction system for bleeding brakes that we use for sucking all the fluid out of the reservoir first and then run it on the actuators and pressure reservoir.

For measuring suspension height, best to measure from bottom of the rim, up through the centre of the wheel to the wheel arch.

 

[nathanrobo]

What did you do with the AHC components removed?

Sorry for being a vulture, but if you don't ask...

 

[Dark Dude]

What did you do with the AHC components removed?

Sorry for being a vulture, but if you don't ask...

Julian runs a business NOT a charity! Don't blame the player, blame the game.

John

 

[nathanrobo]

Hi John

Wasn't asking for a freebie... there's some value in having spare parts that you might need!

 

[Dark Dude]

Yeah, I know what you mean, I've got my eye out for a few AHC bits and pieces too........Like they say, one mans lost is another mans gain.

John

 

[mudassar1972]

I didn't remove ahc components except shocks and springs

 

[Zeusv8]

I removed most of it. Binned the shocks and springs, kept the sensors,Ecu and pump,spheres are still on until I find a slim 37 mm spanner to remove them or a suitable bit if steel to fab my own one! I still have the torsion bars as I'm not sure what to do with them,would they ever be needed by anyone??

 

[uHu]

I removed most of it. Binned the shocks and springs, kept the sensors,Ecu and pump,spheres are still on until I find a slim 37 mm spanner to remove them or a suitable bit if steel to fab my own one! I still have the torsion bars as I'm not sure what to do with them,would they ever be needed by anyone??

Binned the shocks??? Why? (They don't wear out like normal shocks)
For spanner (36 mm btw), the cheapest is to get a cheap normal spanner and grind it down to required thickness. The globes are normally not hard to get off.

 

[Zeusv8]

They were binned because I drilled a 12mm hole into them,inserted threaded rod to stop them twisting while I undid the seized top nuts. I figured they were F.all use to me and as you said"they don't wear out like normal shocks", so why clutter up my shed with them on the off chance someone might need one!! Thanks for the spanner tip b.t.w.

 

[nathanrobo]

Shame you're not closer, I have a 36mm - the only time I've used it was to get my spheres regassed!