LC100 Heavy Duty springs Rear (V8, IFS, Hydraulic)

[feddomw]

Sorry for the delay, I finally got TS up and running. Long story that I won't bore you with.

I did three L-to-N cycles to get an average, and I measured center cap to fender. Full tank of gas (I have OEM sub-tank so 150L of gas), rearmost seats removed. So essentially the lightest load I can get. I have flushed AHC fluid, it was in great shape. 13 graduations from L to H if I recall from the flush. I do have an issue with a certain lack of comfort on certain roads/bumps, but I think that is more of a bushing issue (somewhere) than AHC issue.

Three issues I can see, based on what I have read here on 'Mud:

1 - Height control sensor values are off. What's the step here? Reset them?

2 - Pressures are high. Not crazy high, but deserve some attention. Front values (3 cycles) were 7.4-7.6. Rear pressures were 6.9-7.1
If I understand correctly, front pressures can be alleviated by adjustments to the torsion bar, rear pressures only by replacing springs or working with some sort of airbag (not my cup of tea, though I understand replacing rear springs is a nightmare due to lack of access to the topmount bolt).

3 - Measurements were strange to my untrained eye: rear was 52cm on both sides. Front Left was 48cm, front right was 49.5. That indicates "nose down" to me, but one would assume with some load it would level out. Why front left was lower than right? This relates to the height sensor specs in some way, correct?

What do I need to do and what steps in what order? I don't have access to jacks or a lift but can probably work with my local shop.

 

[PADDO]

Pm sent.

 

[Swisscheese]

Following this thread as i will domthe same process with my ahc. Feddomw, can you illustrate your steps like adjusting the tb with some pictures?

 

[uHu]

Finally got time to read this thread, and a bit of PM.

Feddo, coils for you would be the 515 mm ones, 48231-6B010 H=515.5 - $317.30.
That is the Oz spring for sub tank equipped HDJ100's. I presume the rear end of uzj and hdj is quite similar, so that would be ok. That is, afaik, the highest spring rate you can get from t0yota, which is designed for the ahc 100's.
If you have permanent extra weight, more than the sub tank (70 kg with fuel ?), you would need to find another solution.

I just fitted 500 mm spring on the left and 485 on the right, and that didn't lower the pressure much, compared to the two 6 yrs old 485 mm ones sitting there. Those have p#s:
48231-6A770 W(ACTIVE HEIGHT CONTROL); H=485, PURPLE PAINTED, RH
48231-6A780 W(ACTIVE HEIGHT CONTROL); H=500, BROWN PAINTED, LH
I still have the rear pressure in the middle of the range, even with the rear lowered about 10 mm. (I was hoping to get down to the lower end of the pressure range, as I always have a lot of junk at the back. The 100 is my toolbox on 4 wheels.) So for you, with the sub tank, 515 mm would not be too much.

To take out the rear coils is very easy. Just undo the bottom shocker bolt and slide it off, then lower the axle, in a controlled way, while keeping an eye on the lines for brakes, vent and abs; until you can pick the spring out.

On your measurements in the post above here, the negative value on the FL sensor correlates with the physical measurement of a lower FL fender. Adjust the torsion bars and youll be OK - i.e. tighten/lift the left TB until level L/R.
The front is supposed to be lower than the rear. There is a good way of checking the height in the FSM, although a bit more involved than hub centre to fender lip. And front/rear will not level out with more load/cargo, that's the whole point with the ahc.

There is really no need to have a lift to work on the ahc, if you don't mind lying on your back. A level floor, a good high-lift trolley jack and a few 6 ton (or 12t) jack stands is all you need.

BTW, does your steering angle sensor show 0 with the wheels straight?

Edit: The 515 mm spring, 48231-6B010 , is listed in parts lists for the ahc equipped hdj100r for arl (Oz), but it is also listed for the non-ahc version, so I think there must be a mistake somewhere.

 

[feddomw]

Very good input, thanks! I don't carry a lot of extra weight generally, and I have the third row seats removed and in storage. The sub tank easily adds 70 kg to the rearmost portion. 46L of gas and the tank with pump, lines, etc, can't be very light....
The local dealer mentioned he has 4 colors and thus 4 heights of coils for my VIN. If I recall, 515mm was an option, for sure the lowest option ws 485-ish.

I will be working on crosschecking the heights up front and lower pressure through TB's this week at a friends' shop with lift. I realise I could do it at home but I don't have a 30mm wrench or socket, and I think it will be easier/faster if I could just walk under and crank the TB's and check heights, than having to crawl under each time. I also don't have stands nor a good shop jack...

While I have the lift I will check out the rear coils as well, and I will most likely pull the propshafts to chase down if spiderjoints are shot and if so which ones....

 

[feddomw]

Finally got time to read this thread, and a bit of PM.

Feddo, coils for you would be the 515 mm ones, 48231-6B010 H=515.5 - $317.30.
That is the Oz spring for sub tank equipped HDJ100's. I presume the rear end of uzj and hdj is quite similar, so that would be ok. That is, afaik, the highest spring rate you can get from t0yota, which is designed for the ahc 100's. If you have permanent extra weight, more than the sub tank (70 kg with fuel ?), you would need to find another solution.

I just fitted 500 mm spring on the left and 485 on the right, and that didn't lower the pressure much, compared to the two 6 yrs old 485 mm ones sitting there. Those have p#s:
48231-6A770 W(ACTIVE HEIGHT CONTROL); H=485, PURPLE PAINTED, RH
48231-6A780 W(ACTIVE HEIGHT CONTROL); H=500, BROWN PAINTED, LH
I still have the rear pressure in the middle of the range, even with the rear lowered about 10 mm. (I was hoping to get down to the lower end, as I always have a lot of junk at the back. The 100 is my toolbox on 4 wheels.) So for you, with the sub tank, 515 mm would not be too much.

I finally got around to cleaning the underside as best I can and taking a closer look at my coils, I think I have found a single dollop of purple. That would indicate OEM 485mm. After 10 years and 255K km, my rear pressures are only slightly higher than normal, indicating that brand new 485's may help me out "enough" especially seeing how I don't carry a lot of weight.... I could go taller, but PADDO pointed out a few things to me, and going higher may not actually lower pressure.

I also spotted a LOT of cracked rubber bushings in all the various rods/bars/struts. I wonder how replacing all those will affect overall driving behavior, stance and AHC pressures. Almost all the bushings I looked at were cracked/torn on one side and the "center pin" was off-centered due to those tears.

 

[Julian Stead]

I finally got around to cleaning the underside as best I can and taking a closer look at my coils, I think I have found a single dollop of purple. That would indicate OEM 485mm. After 10 years and 255K km, my rear pressures are only slightly higher than normal, indicating that brand new 485's may help me out "enough" especially seeing how I don't carry a lot of weight.... I could go taller, but PADDO pointed out a few things to me, and going higher may not actually lower pressure.

I also spotted a LOT of cracked rubber bushings in all the various rods/bars/struts. I wonder how replacing all those will affect overall driving behavior, stance and AHC pressures. Almost all the bushings I looked at were cracked/torn on one side and the "center pin" was off-centered due to those tears.

I have changed all bushings/Arms front and rear, it didn't seem to affect pressures. I have changed the springs, adjusted T/bars and replaced spheres, which did improve the ride and pressures. If you are going to start changing bushings be prepared to change the lot as once you improve one part it amplifies the wear on others as it gets more focused, you just keep chasing the next rumble or vibration. That is why I made the decision to change all rubber. Just engine and trans mounts and steering rack left to do. The ride now is very good but it does cost a lot to get done in Europe due to the price of parts.

 

[uHu]

See the edit in post 24 above here. There's a confusion in the parts lists -- maybe someone with a better access to t0yota parts lists could look into this: Is the 500mm coil the longest/strongest OE spring you can get?
Anyhow, the brown painted, 48231-6A780 W(ACTIVE HEIGHT CONTROL); H=500, is for sure suitable for the ahc vehicle. That's the one I installed 2 months ago.