How to adjust the rear ride height sensor on AHC equiped 100.

[1meancruiser]

Does anyone know how to adjust the rear ride height sensor on an AHC equipped Land Cruiser. I just added the 80 Series Springs and the car rides about an inch and a half higher than before in Low mode. I need it to be lower by 1.5", in order to get into subterranean parking.

 

[Actualeyes]

There is a whole thread on the topic of adjusting the ride height by "tricking" the sensors. If you haven't found it by searching (try Googling "AHC lift ih8mud") I'll find it for you.

But in your case I suspect there's an issue.

Unless you have already adjusted the sensors (so the computer thinks the car is lower than it really is) then the springs are the thing stopping the car from going to the Low setting perhaps.

Also, to stay in Low requires that you keep the speed less than 10MPH (or some low speed like that) because otherwise the car automatically goes into N suspension height setting.

I don't know of any solution that changes the computer so that N and H settings are higher than stock and L is stock - all the solutions rely on using the computer settings for L, N, H.

 

[codertimt]

Yep. Crawl underneath the back and the sensor isn't too hard to find. Adjusting is just loosening a bolt and sliding it down a bracket.

However I also believe the issue is that in low the springs are supporting 100% of the weight because your 100 isn't heavy enough to compress the 80 springs...

You can give it a try but the sensor should still be telling your truck to drop down to whatever level it was before the spring swap...but springs won't physically let that happen. Let us know what you discover...

 

[uHu]

With 80 springs, the low would be considerably higher than standard, except if you carry a lot of weight in the rear. Furthermore, the Neutral Pressure would be much too low and give a very weak damping from the actuators, much like driving without (or worn out) shock absorbers. 80 springs would fit in combination with a drawer system with lotsa junk in addition to a steel rear bumper etc.

 

[1meancruiser]

So sliding the bolt down lowers the car and moving it up raises it?

Also, just an FYI...in low mode, the LC sits at almost identical height as before I did the 80 spring swap. I happen to be running 275/70/18s and a front runner roof rack. With all this the LC sits .5" too high for me to clear a garage...!!!

 

[codertimt]

So sliding the bolt down lowers the car and moving it up raises it?

Also, just an FYI...in low mode, the LC sits at almost identical height as before I did the 80 spring swap. I happen to be running 275/70/18s and a front runner roof rack. With all this the LC sits .5" too high for me to clear a garage...!!!?de16

That's contrary to the info you posted originally(unless your saying in low its sitting where it used to sit in high)...so that's why you're getting the "too much spring" advice...

But yes I believe you slide it down.

 

[Actualeyes]

As codertimt said, this is different to what you first said.

Now lowering it another 0.5" might be achievable, but 1.5" which you originally suggested might well not be possible - you may be on the bump stops.

And watch the low points in that subterranean garage! if you accidently go too fast and it decides to go into N mode, you could jam yourself under something.

Finally, remember N and H are also lower by what ever you lower it... which means less load on the AHC and might need adustments to the torsion bars.

This is where you need the OBDII/techstream to check the pressures are in spec.

 

[1meancruiser]

That's contrary to the info you posted originally(unless your saying in low its sitting where it used to sit in high)...so that's why you're getting the "too much spring" advice...

But yes I believe you slide it down.

The point I'm trying to make is that before I was .5to 1 inch lower than the garage and now I'm half an inch higher. It is not noticeable to the eyes when you look at the Lc or at least it's wasn't to me. I don't want someone reading post to think that the Land Cruiser stays in normal mode and doesn't go any lower.

 

[1meancruiser]

As codertimt said, this is different to what you first said.

Now lowering it another 0.5" might be achievable, but 1.5" which you originally suggested might well not be possible - you may be on the bump stops.

And watch the low points in that subterranean garage! if you accidently go too fast and it decides to go into N mode, you could jam yourself under something.

Finally, remember N and H are also lower by what ever you lower it... which means less load on the AHC and might need adustments to the torsion bars.

This is where you need the OBDII/techstream to check the pressures are in spec.

Good point, but I think if I'm sitting on the bump stops in the rear then the torsion bars adjustment won't mean much. I got an obd II and the tech stream Software, my problem is finding a laptop which is running windows XP. I haven't been able to make the software work without it.

 

[1meancruiser]

Is this the rear height sensor, located just in front of the rear axle?

By the way, I checked and there is a solid inch and a half of clearance between the bump stops and the axle.

Whether or not I'm compressing the rear springs all the way in low mode is another question.

 

[codertimt]

Is this the rear height sensor, located just in front of the rear axle?

By the way, I checked and there is a solid inch and a half of clearance between the bump stops and the axle.

Whether or not I'm compressing the rear springs all the way in low mode is another question.

That is it.

Just for comparison my mostly stock weight LX with stock 140K mile springs(and 10mm spacer) also sits with about 1.5" of clearance to the bumpstops when in low. But I can pretty much sit on the tailgate and bottom it out...so it's mostly sitting on the springs with minimal pressure at that point...

So my guess for your situation is that before, the extra weight you have from any armor was cause the stock springs to actually sag even more in low and the 80 series spring are leaving it a little higher...so maybe you will be able to adjust it down some more.

Time for armchair quarterbacking is past...we need you to step up behind center and give us some real world results...

 

[1meancruiser]

That is it.

Just for comparison my mostly stock weight LX with stock 140K mile springs(and 10mm spacer) also sits with about 1.5" of clearance to the bumpstops when in low. But I can pretty much sit on the tailgate and bottom it out...so it's mostly sitting on the springs with minimal pressure at that point...

So my guess for your situation is that before, the extra weight you have from any armor was cause the stock springs to actually sag even more in low and the 80 series spring are leaving it a little higher...so maybe you will be able to adjust it down some more.

Time for armchair quarterbacking is past...we need you to step up behind center and give us some real world results...

Nicely said!

I'm Finishing up around the house and I'm going to try to get this done tonight. I will keep you posted.

 

[1meancruiser]

And the results are what most of you suggested. I played With the height sensor increasing and decreasing it. The lc did not go below a certain height, The same height as it was when I previously put it in low. Also, I noticed that the springs where completely compressed and look like they were wound up when in low. Again suggesting that the 100 doesn't have enough weight in the rear to Further compress the 80 series springs.

Lastly, I checked the height of the car in low and in normal mode. There's a 1 inch difference. I was trying to take a measurement from the rooftop to the ground and couldn't quite get exactly how many inches it was off by and Came out with about 1.5 inches. Before I put on The 80 series springs, the Land Cruiser was capable of dropping 2 inches from normal mode to low mode.

I may go back to the AHC Springs with 30 mm spacers or I'm considering cutting the 80 series springs by 1 inch And then reinstalling them, but I'm not crazy about that idea.

 

[Actualeyes]

Well I think your assessment makes it all pretty clear!

You can run a windows XP emulator that is with Windows 8 and the techstream does run under that... of buy a $50 XP clunker laptop off ebay - techstream software is pretty clunky anyway!

Finally, cutting seems like a bad idea to me. The springs are designed including the base of the spring to be a base (for instance).

With techstream you can come to a conclusion of what the load on the AHC is (e.g. are the pressures within spec or now). Then decide how much support you need - torsion bars in the front, coils optionally with air bags in the rear.

But the real issue is that damned roof rack - I have dispensed with roof racks because of the one day a month I need to go into the city and park in 2m or even 1.9m car parks! (and it is better for fuel economy anyway)

 

[uHu]

If you have a free standing garage, you could just jack the whole garage up 2 inches.

Have you checked the Neutral Pressure? With the AHC lifting only one inch more than the coils, there will be very little pressure for the TEMS (shock absobers) to work with. TechStream is cheap these days, and you can plug in and read and reset all codes and check height and pressure of the AHC.

 

[1meancruiser]

I'll probably pick up a cheap laptop and run the techstream software. Every attempt at running virtual XP on windows 8 has failed.

I'm pretty sure my best solution is a new set of AHC springs in the rear with 30mm spacers for the added weight of the sliders and roof rack.

My front runner roof rack really completed the LC, both in function and looks. I can't imagine the LC without it...

 

[1meancruiser]

I'll probably pick up a cheap laptop and run the techstream software. Every attempt at running virtual XP on windows 8 has failed.

I'm pretty sure my best solution is a new set of AHC springs in the rear with 30mm spacers for the added weight of the sliders and roof rack.

My front runner roof rack really completed the LC, both in function and looks. I can't imagine the LC without it...

I just ordered a new set of 100 series AHC springs from the local dealership. Does anyone know if I use it with 30 mm spacers, if I will have any problems? Or problems In low mode? I wouldn't think so but I thought I'd check...

 

[Actualeyes]

Does anyone know if I use it with 30 mm spacers, if I will have any problems? Or problems In low mode? I wouldn't think so but I thought I'd check...

Depends on how much load you're carrying... If you've got enough load to counteract the spacers no... If you haven't, it won't go into low...

I'd love to see some mathematics on this subject...

E.g. Effect of the various spring rates and spring lengths including with spacers. I've got a couple of old stock 100 series nonAHC to try in mine which is carrying extra 400kg unladen.

 

[PabloCruise]

I just ordered a new set of 100 series AHC springs from the local dealership. Does anyone know if I use it with 30 mm spacers, if I will have any problems? Or problems In low mode? I wouldn't think so but I thought I'd check...

Wondering if you ever got Tech Stream to work, and how your AHC pressures looked?

I understand your issue was getting the truck to drop enough in Low setting, but I wonder how you liked the ride in N mode with the 80 series rear springs? From what I can tell, the 80 rear coils are the same as 100 (non-AHC) rear coils...