Is this shock absorber compatible with AHC ?

[jonarnar]

Hi,
I'm based in Iceland and am looking for affordable springs and shock absorbers for my 2001 4.7 V8 with AHC.

I've found these on spareto.com, which are listed as compatible with the Landcruiser 100 and Lexus 470. They use oil pressure, but the other shocks on the site use gas pressure. I'm just not sure whether the shocks are compatible with AHC.

Can anyone here take a look and shed a light?

JHE268T - Shock Absorber

Same goes for the rear springs, which I think should work.
RF6052 - Coil Spring

I've been looking into either replacing the AHC components or rip it out. The rear springs are rusty and I get 7.4 Mpg for pressure. I've cranked the torsion bars and am within range on the front.

The shocks and springs from spareto cost the same as just the shipping cost for a conversion kit from roughtrax4x4.com.

Thanks,
Jon Arnar

 

[PADDO]

Those shocks aren't suitable for AHC applications as they don't have a nipple tube to connect to the receiver cap in the flexible line as per the image of a real AHC shock actuator. And those coils at 505mm and 16mm wire diameter are significantly heavier than the spare set of AHC coils I just checked at 460mm and 12.2mm wire diameter (5.5 total turns and approx. 90lbs/inch rate)

 

[jonarnar]

Thanks PADDO. I didn't see the nipple tube either, but wasn't sure whether that was a stock photo. The shocks are listed as compatible for the LX470, which I think came only with the AHC. The coils are not listed as compatible with the LX470 though.

I'll keep looking then

--jon arnar

 

[PADDO]

Yes all 470s came with AHC standard. The fine print under the shock image said something like "actual product" so I think the vendor is a little loose with their fitment guide
Are your existing shock actuators completely done? as in totally rusted out or chronically leaking? If not then most damping issues relate back to high neutral pressures and/or exhausted damper accumulator globes - not "shocks" as such.

 

[jonarnar]

The shocks are rusty but functional, no leakage. I've adjusted the neutral pressure to within spec up front, using techstream and cranking the torsion bars. Had to raise the driver side a bit, adjusted the height to a number from one of your previous posts. Think it was 51.7 cm.

The neutral pressure at the back is 7.4 and the spec is 5.6-6.7 and I can't lower it without changing the springs. I've done an AHC fluid drain as well.

I get around 8 graduations in the AHC height test, the consensus here seems to be that 11 is the minimum.

The ride feels stiff, and when I drive over a speedbump doing 30 km/h or more, the backend is very harsh especially when I've gone over the speedbump, much harsher than the frontend. I swerve around potholes rather than going over them.

My front left height sensor failed a couple of months back, which I replaced with a used one. I did not adjust the height sensor and am not sure if I should?

Honestly, I love the truck and it's just the suspension that is bothering me. I've been looking at doing a non-AHC conversion OR finding replacement globes + rear springs. I've probably read all discussions here and on the internet about AHC problems and conversion stories about now. Not that it has helped that much though, still not sure what to do

 

[PADDO]

Sounds like new coils (please consider adding spacers too while you're down there) are in your future. You'll want to ensure your neutral pressures are read in context with factory neutral heights of 500mm front and 520mm rear, which is pretty close to factory stock height. If your rear is higher you'll read higher pressures, compounded by tired and set coils. Once you get that rear pressure down around 6 MPa then redo your L to H grad check and I bet you pick up a grad or two (and a much better ride).

 

[jonarnar]

Good point, I have not measure the rear height so I'm not sure how that is affecting the pressure. New coils are around 350 pounds from the local dealer (actually the only one in Iceland). I'm due for a tyre change as well, so hopefully those two changes will add up to a more comfortable ride!

Thanks PADDO..

 

[PADDO]

Have you investigated the cost and availability of Kings Springs KTRS-79s? They are made in Australia and are uprated, by about 25%, AHC specific coils. They fall between the normally too heavy 100 series coils and the often too soft AHC coils. Dialing in rear neutral pressures with a stock height/weight vehicle and the 79s will take a bit of trial and error but is easily doable - add an inch in height and throw some weight in the back and call it good. Might be a less expensive option to OE coils?

 

[jonarnar]

No, have not.. somehow assumed that they were only for AHC conversions. Found them on ebay for half the price of the OEM coils locally, straight from Australia. They look good, I think I'll go with them. Not sure about the yellow colour hehe.

How do I dial in the rear pressure though? Since the coil stiffness controls the pressure, do you mean that I can control the pressure by adding spacers?

thanks, jon arnar

 

[PADDO]

Those higher rated KTRS 79 coils will lower your rear pressure about 2.5-3.0 MPa more than OE coils - all else being equal - so what you'd do is install them and expect your pressures to be a bit lower than ideal. This is when you'd actually want to sensor lift the rear to raise pressures, and you'd also sensor raise the front too (for handling rake) and adjust torsion bars. For the rear the pressure/height ratio is about 0.6MPa per inch (OE AHC coils) while the coils are in their normal linear range and pressure/weight ratio is about 210lbs/1.0MPa. For example if you fitted the 79s at your present height/weight and read a rear pressure of say 5.0MPa you could get that up to 5.6MPa by sensor lifting approximately one inch or adding 100lbs or any combination. You may well find that you prefer the damping quality when the neutral pressures are at the low end of the OE factory ranges. No need for coil spacers if fitting 79s as we typically use spacers with softish OE AHC coils to get pressures even lower and help compensate for any additional weight/height.

 

[jonarnar]

Sounds like the KTRS 79's will be a good fit for me. Have placed an order, now I can work on a few other things I need to fix while the coils are traveling around half the globe..

Thanks for the information PADDO, greatly appreciated.

-- jon arnar